[top]
000
FXUS63 KMPX 052306
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
606 PM CDT TUE MAY 5 2009
.UPDATE...FOR 00Z AVIATION DISCUSSION BELOW
&&
.DISCUSSION.../ISSUED 412 PM CDT TUE MAY 5 2009/
H5 LOW HAS BEEN WORKING ACROSS NRN MN TODAY AND ELONGATED
SHORTWAVE CAN BEEN SEEN ON WATER VAPOR SOUTH OF THE LOW PUSHING
ACROSS CWA. AT THE SURFACE COLD FRONT AND WIND SHIFT IS SITTING
FROM NEW ULM...THROUGH THE WEST SIDE OF THE TWIN CITIES...TO THE
MILLE LACS LAKE REGION. HAVE SEEN ML CAPES GET INTO THE 500 TO
1000 J/KG RANGE OUT AHEAD OF THE FRONT AND AS A RESULT SCATTERED
THUNDERSTORMS HAVE DEVELOPED. WITH DEWPOINTS IN THE LOW 50S AND
0-6 KM SHEAR IN THE 25 TO 45 KT RANGE...ARE SEEING JUST ENOUGH
INSTABILITY AND SHEAR TO SQUEEZE OUT SOME MARGINAL HAIL WITH A FEW
STORMS. EXPECT STORMS TO CONTINUE TO DEVELOP ALONG AND EAST OF THE
FRONT THE REST OF THE AFTERNOON...WITH ACTIVITY CALMING DOWN AFTER
SUNSET.
UPPER WAVE IS FORECAST TO SHEAR OUT OVERNIGHT AND WITH THE LOSS OF
THE UPPER FORCING...FRONT IS FORECAST TO DO THE SAME ACROSS ERN
CWA OVERNIGHT. ALSO...ECMWF CONTINUES TO GENERATE SOME CONVECTION
OVER IOWA OVERNIGHT IN AN AREA OF ENHANCED H85 MOISTURE TRANSPORT.
NAM AND GFS HAVE CONTINUED THEIR TREND OF NOT DEVELOPING MUCH ON
THE SOUTHERN END OF THE FRONT TONIGHT. ARE SEEING A COUPLE OF
CELLS POP UP IN IOWA NOW...BUT GIVEN TREND OF MODELS FOR LESS
QPF...HAVE LOWERED POPS SOME ACROSS S CENTRAL MN AND WI FOR THE
OVERNIGHT HOURS. BY THE AFTERNOON...FRONT IS PROGGED TO ACROSS
FAR ERN MN. BOTH NAM AND GFS ONCE AGAIN GENERATE MLCAPES NEAR 1000
J/KG BY THE AFTERNOON FROM THE TWIN CITIES EAST AND EXPECT A
REPEAT PERFORMANCE TOMORROW AFTERNOON OUT AHEAD OF THE FRONT WITH
SCATTERED AFTERNOON THUNDERSTORMS. ONCE AGAIN...BETTER MOISTURE
WILL BE BOTTLED UP IN THE SOUTHERN PLAINS...SO NOT ANTICIPATING
MUCH MORE THAN A COUPLE OF STRONG STRONG STORMS...WITH MARGINAL
SEVERE HAIL POSSIBLE.
FRONT WILL GET SHUNTED EAST OF THE AREA WEDNESDAY NIGHT AS
SHORTWAVE CURRENTLY JUST NORTH OF MONTANA SWEEPS ACROSS NRN MN.
STRONG PACIFIC JET AND ACTIVE NORTHWEST FLOW WILL HELP KEEP
SCATTERED SHOWERS AROUND THE AREA FROM THURSDAY THROUGH
SATURDAY...AS A SERIES OF WEAK SHORTWAVES WILL BRING CHANCES FOR
SHOWERS THURSDAY INTO SATURDAY. HAVE REMOVED ANY MENTION OF
THUNDER FROM THURSDAY AFTERNOON ON AS COOLER AIR MOVES INTO THE
AREA AND INSTABILITIES BECOME MINIMAL. BOTH ECMWF AND GFS SLIP
HIGH PRESSURE INTO THE AREA SATURDAY NIGHT AND SHOULD SEE A BRIEF
BREAK IN RAIN CHANCES SATURDAY NIGHT AND SUNDAY. WILL BE
TRANSITIONING INTO A MORE ZONAL FLOW AT THE BEGINNING OF NEXT
WEEK AND RAIN CHANCES LOOK TO INCREASE AGAIN AS MORE PRONOUNCED
TROUGHINESS BUILDS INTO THE WEST.
TEMPERATURES WILL REMAIN MILD THROUGH THURSDAY...BUT ALL MODELS
START CAA THURSDAY AFTERNOON...SO HAVE DROPPED TEMPERATURES SOME
FROM FRIDAY INTO THE WEEKEND...AS WE GO BACK TO NEAR OR SLIGHTLY
BELOW SEASONAL NORMS FOR TEMPERATURES THIS WEEKEND WITH HIGHS IN
THE 50S AND 60S.
&&
.AVIATION.../00Z TAF ISSUANCE/
ISOLATED THUNDERSTORMS WILL BE POSSIBLE THROUGH 03Z AT THE WI TAF
SITES /KRNH AND KEAU/. OTHERWISE...CLOUDS SHOULD SCATTER OUT
SOMEWHAT THIS EVENING...LEAVING ONLY A FEW MID/HIGH CLOUDS OVERNIGHT. MAY
SEE SOME LIGHT FOG FORMATION AT KEAU OVERNIGHT...OTHERWISE VFR
CONDITIONS ARE EXPECTED. WESTERLY WINDS WILL BACK TO MORE TRUE
SOUTHERLY THIS EVENING...AND THEN VEER TO SOUTHWESTERLY IN
DIRECTION FOR WEDNESDAY. SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED AGAIN ON WEDNESDAY...ESPECIALLY AFTER 18Z...AS ANOTHER
SHORTWAVE AND SURFACE FRONT MOVE ACROSS MN/WI. WINDS WILL SHIFT TO
WESTERLY AND BECOME GUSTY /TO AROUND 20 KTS/ DURING THE AFTERNOON
AS THE TROUGH MOVES THROUGH. FORECAST INSTABILITY PARAMETERS PIN
POINT EAST CENTRAL MN AND WEST CENTRAL WI AS HAVING THE HIGHEST POTENTIAL
FOR SCATTERED THUNDERSTORM DEVELOPMENT DURING THE AFTERNOON.
COVERAGE WILL BE SIMILAR TO TODAY...SO HAVE MERELY INCLUDED VCSH
IN THE TAFS AT THIS POINT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LS/MPG
000
FXUS63 KMPX 052112
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
412 PM CDT TUE MAY 5 2009
.DISCUSSION...
H5 LOW HAS BEEN WORKING ACROSS NRN MN TODAY AND ELONGATED SHORTWAVE
CAN BEEN SEEN ON WATER VAPOR SOUTH OF THE LOW PUSHING ACROSS CWA. AT
THE SURFACE COLD FRONT AND WIND SHIFT IS SITTING FROM NEW
ULM...THROUGH THE WEST SIDE OF THE TWIN CITIES...TO THE MILLE LACS
LAKE REGION. HAVE SEEN ML CAPES GET INTO THE 500 TO 1000 J/KG RANGE
OUT AHEAD OF THE FRONT AND AS A RESULT SCATTERED THUNDERSTORMS HAVE
DEVELOPED. WITH DEWPOINTS IN THE LOW 50S AND 0-6 KM SHEAR IN THE
25 TO 45 KT RANGE...ARE SEEING JUST ENOUGH INSTABILITY AND SHEAR
TO SQUEEZE OUT SOME MARGINAL HAIL WITH A FEW STORMS. EXPECT
STORMS TO CONTINUE TO DEVELOP ALONG AND EAST OF THE FRONT THE REST
OF THE AFTERNOON...WITH ACTIVITY CALMING DOWN AFTER SUNSET.
UPPER WAVE IS FORECAST TO SHEAR OUT OVERNIGHT AND WITH THE LOSS OF
THE UPPER FORCING...FRONT IS FORECAST TO DO THE SAME ACROSS ERN
CWA OVERNIGHT. ALSO...ECMWF CONTINUES TO GENERATE SOME CONVECTION
OVER IOWA OVERNIGHT IN AN AREA OF ENHANCED H85 MOISTURE TRANSPORT.
NAM AND GFS HAVE CONTINUED THEIR TREND OF NOT DEVELOPING MUCH ON
THE SOUTHERN END OF THE FRONT TONIGHT. ARE SEEING A COUPLE OF
CELLS POP UP IN IOWA NOW...BUT GIVEN TREND OF MODELS FOR LESS
QPF...HAVE LOWERED POPS SOME ACROSS S CENTRAL MN AND WI FOR THE
OVERNIGHT HOURS. BY THE AFTERNOON...FRONT IS PROGGED TO ACROSS
FAR ERN MN. BOTH NAM AND GFS ONCE AGAIN GENERATE MLCAPES NEAR 1000
J/KG BY THE AFTERNOON FROM THE TWIN CITIES EAST AND EXPECT A
REPEAT PERFORMANCE TOMORROW AFTERNOON OUT AHEAD OF THE FRONT WITH
SCATTERED AFTERNOON THUNDERSTORMS. ONCE AGAIN...BETTER MOISTURE
WILL BE BOTTLED UP IN THE SOUTHERN PLAINS...SO NOT ANTICIPATING
MUCH MORE THAN A COUPLE OF STRONG STRONG STORMS...WITH MARGINAL
SEVERE HAIL POSSIBLE.
FRONT WILL GET SHUNTED EAST OF THE AREA WEDNESDAY NIGHT AS
SHORTWAVE CURRENTLY JUST NORTH OF MONTANA SWEEPS ACROSS NRN MN.
STRONG PACIFIC JET AND ACTIVE NORTHWEST FLOW WILL HELP KEEP
SCATTERED SHOWERS AROUND THE AREA FROM THURSDAY THROUGH
SATURDAY...AS A SERIES OF WEAK SHORTWAVES WILL BRING CHANCES FOR
SHOWERS THURSDAY INTO SATURDAY. HAVE REMOVED ANY MENTION OF
THUNDER FROM THURSDAY AFTERNOON ON AS COOLER AIR MOVES INTO THE
AREA AND INSTABILITIES BECOME MINIMAL. BOTH ECMWF AND GFS SLIP
HIGH PRESSURE INTO THE AREA SATURDAY NIGHT AND SHOULD SEE A BRIEF
BREAK IN RAIN CHANCES SATURDAY NIGHT AND SUNDAY. WILL BE
TRANSITIONING INTO A MORE ZONAL FLOW AT THE BEGINNING OF NEXT
WEEK AND RAIN CHANCES LOOK TO INCREASE AGAIN AS MORE PRONOUNCED
TROUGHINESS BUILDS INTO THE WEST.
TEMPERATURES WILL REMAIN MILD THROUGH THURSDAY...BUT ALL MODELS
START CAA THURSDAY AFTERNOON...SO HAVE DROPPED TEMPERATURES SOME
FROM FRIDAY INTO THE WEEKEND...AS WE GO BACK TO NEAR OR SLIGHTLY
BELOW SEASONAL NORMS FOR TEMPERATURES THIS WEEKEND WITH HIGHS IN
THE 50S AND 60S.
&&
.AVIATION.../18Z TAF ISSUANCE/
SURFACE BOUNDARY EXTENDING THROUGH CENTRAL MN...WITH SHOWERS AND
ISOLATED THUNDERSTORMS DEVELOPING AHEAD OF THIS LINE. GENERALLY
VFR CEILINGS IN THIS AREA BUT SOME BRIEF MVFR CIGS AND 4-5SM IN
THE SHOWERS. ISOLATED THUNDER AND SHOWERS TO AFFECT MAINLY
KRNH...KMSP AND KEAU UNTIL AROUND 00Z...BUT ENDING VCNTY KMSP AT
21Z. OTHERWISE EXPECT VFR CONDITIONS WITH MAINLY A FEW MID AND
HIGH LEVEL CLOUDS BEHIND THE WAVE. GUSTY WSW WINDS OVER WEST
CENTRAL AND SOUTHWEST MN DECREASING BY EVENING. SOME CHANCE OF
MVFR VSBYS IN BR IN WEAKER PRESSURE GRADIENT OVER SOUTH CENTRAL MN
OR WEST CENTRAL WI. THIS WOULD DEPEND ON EXTENT OF HIGH LEVEL
CLOUDS LATE TONIGHT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/JPR
[top]
000
FXUS63 KDLH 052110
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
410 PM CDT TUE MAY 5 2009
.DISCUSSION...STORMS THE CONCERN IN THE IMMEDIATE SHORT TERM.
STORMS HAVE BEEN NEAR SEVERE...PINE COUNTY FINALLY REPORTED HAIL
TO THE SIZE OF QUARTERS IN THE VICINITY OF CLOVERDALE. THE SEVERE
THREAT APPEARS TO BE LIMITED TO NW WI WHERE SUFFICIENT BOUNDARY
LAYER WARMING HAS OCCURRED. LAPS SFC DATA INDICATE A THETAE RIDGE
AXIS THE FOCUSING POINT FOR NEAR SEVERE TO SEVERE STORMS. SFC
BASED CAPE FROM 200 TO 500 J/KG AND NO CINH.
UPPER LEVEL LOW CROSSING THE FA THIS AFTERNOON WILL LIFT INTO
ONTARIO BY 06Z WEDNESDAY. SHOWERS WILL LINGER ACROSS THE EASTERN
HALF OF THE FA INTO THE OVERNIGHT. BRIEF BREAK IN THE ACTION UNTIL
LATE WEDNESDAY MORNING/EARLY AFTERNOON WHEN NEXT UPPER LEVEL LOW
MOVING THROUGH SOUTHERN CANADA SENDS AN UPPER LEVEL WAVE THROUGH
THE AREA. MORE SHOWERS AND THUNDERSTORMS EXPECTED TO DEVELOP. THIS
WAVE WILL PUSH A COLD FRONT THROUGH THE FA WEDNESDAY NIGHT WITH
SHOWERS AND A FEW THUNDERSTORMS ALONG AND AHEAD OF THE FRONT.
YET ANOTHER...STRONGER COLD FRONT IS FORECAST TO MOVE THROUGH THE
AREA ACCOMPANIED BY POTENT VORT MAX. MORE SHOWERS AND
THUNDERSTORMS ARE EXPECTED IN THE AFTERNOON. UNSTABLE AIRMASS
PROGGED THROUGH FRIDAY WITH POPS WARRANTED THROUGH THIS TIME.
.EXTENDED...FRIDAY NIGHT THROUGH TUESDAY.
AS AN UPPER LEVEL LOW DEPARTS...SOME LINGERING SHOWERS ARE POSSIBLE
ACROSS THE FA FRIDAY NIGHT. SATURDAY AND SUNDAY ARE SETTING UP TO BE
RAIN FREE AS HIGH PRESSURE ARRIVES. BY NEXT MONDAY...MODELS DIVERGE
IN HANDLING OF THE NEXT SYSTEM MOVING OUT OF THE ROCKIES INTO THE
PLAINS. HAVE SOME POPS IN PLACE...BUT CONFIDENCE REMAINS LOW.
&&
.AVIATION...SCATTERED SHOWERS AND THUNDERSTORMS WILL IMPACT
KHIB/KDLH/KHYR THROUGH 06/00Z. CIGS IN VICINITY OF SHOWERS AND
STORMS WILL BE IN THE MVFR. VFR CONDITIONS WILL DEVELOP BETWEEN
04Z-06Z.
&&
POINT TEMPS/POPS...
DLH 43 67 42 65 / 50 50 20 30
INL 42 68 42 57 / 30 40 30 40
BRD 44 70 45 64 / 20 30 20 20
HYR 48 72 44 66 / 50 60 30 30
ASX 45 70 42 66 / 50 50 50 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
$$
GRANING/GSF
000
FXUS63 KMPX 051806
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
106 PM CDT TUE MAY 5 2009
.UPDATE...
ADDED 18Z TAF DISCUSSION BELOW.
&&
.PREV DISCUSSION.../ISSUED 250 AM CDT TUE MAY 5 2009/
WELL DEFINED VORT IN SC NODAK MOVING ENE AND CARRYING A SHORTWAVE
TROF EXTENDING INTO E NEB WITH RATHER NICE TIGHT 700 MB OMEGA FIELD
AHEAD OF SHORTWAVE. MOISTURE SOMEWHAT LIMITED...BUT PWATS HAVE BEEN
INCREASING TO AROUND .75 INCH WITH IN SOUTHERLY FLOW AHEAD OF THIS
WAVE. SWATH OF SHWRS WITH SOME EMBEDDED THUNDERSTORMS WILL CARRY
EASTWARD ACROSS FORECAST AREA REMAINDER OF TONIGHT AND THIS MORNING.
SWLY FLOW IN WAKE OF TROF WILL BRING SOME CLEARING ACROSS SW AREAS
DURING DAY WITH WEDGE OF 850 MB AIR AROUND 10C WHICH SHOULD BRING
TEMPS AT LEAST INTO THE LOWER 70S S OF MN RIVER ALONG WITH DRIER
AIRMASS. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS SHOULD DEVELOP
AGAIN THIS AFTERNOON IN E CWA WHERE INSTABILITY INCREASES AHEAD OF
WEAK SURFACE TROUGH.
UPSTREAM TROF NOW COMING ACROSS PACIFIC NW. FAST ZONAL FLOW WILL
BRING ANOTHER CHANCE OF CONVECTION TO AREA BY WEDNESDAY MORNING.
ASSOCIATED SURFACE TROF WILL MOVE ACROSS WESTERN CWA IN THE MORNING
AND ACROSS EASTERN AREAS DURING THE AFTERNOON. SBCAPE INCREASES TO
AROUND 1000 J/KG SE MN INTO WI DURING THE AFTERNOON.
ACTIVE PATTERN CONTINUES AS A VIGOROUS UPPER TROF DROPS OUT OF THE
CANADIAN PRAIRIES THEN ACROSS N MN ON THURSDAY WITH A REINFORCING
UPPER TROF AND ANOTHER COLD FRONT FOR THE WEEKEND. THIS WILL BRING A
PERIOD OF SEVERAL DAYS OF TEMPERATURES BELOW NORMAL.
&&
.AVIATION.../18Z TAF ISSUANCE/
SURFACE BOUNDARY EXTENDING THROUGH CENTRAL MN...WITH SHOWERS AND
ISOLATED THUNDERSTORMS DEVELOPING AHEAD OF THIS LINE. GENERALLY
VFR CEILINGS IN THIS AREA BUT SOME BRIEF MVFR CIGS AND 4-5SM IN
THE SHOWERS. ISOLATED THUNDER AND SHOWERS TO AFFECT MAINLY
KRNH...KMSP AND KEAU UNTIL AROUND 00Z...BUT ENDING VCNTY KMSP AT
21Z. OTHERWISE EXPECT VFR CONDITIONS WITH MAINLY A FEW MID AND
HIGH LEVEL CLOUDS BEHIND THE WAVE. GUSTY WSW WINDS OVER WEST
CENTRAL AND SOUTHWEST MN DECREASING BY EVENING. SOME CHANCE OF
MVFR VSBYS IN BR IN WEAKER PRESSURE GRADIENT OVER SOUTH CENTRAL MN
OR WEST CENTRAL WI. THIS WOULD DEPEND ON EXTENT OF HIGH LEVEL
CLOUDS LATE TONIGHT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BAP/JPR
000
FXUS63 KDLH 051504
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1004 AM CDT TUE MAY 5 2009
.UPDATE...
NO SIGNIFICANT CHANGES TO FCST. ADJUSTED MORNING POPS TO BETTER
REPRESENT CURRENT RADAR/RAIN TRENDS. STILL EXPECTING TSTM
DEVELOPMENT OVER MUCH OF CWA THIS AFTRN...INTO THE EVENING...AHEAD
OF CUT OFF LOW SEE ON WV MOVING QUICKLY ROTATING EWD OUT OF ERN
NO DAK AND INTO NW MN. NAM BUFR SOUNDINGS...STILL FROM 06Z
RUN...SHOW LAPSE RATES STEEPEN AS A STRONGER OF 400-600 J/KG OF CAPE
PUSHES E OVER FA AHEAD OF SFC REFLECTION LOW/TROUGH. KEPT LIKELY
POPS FOR MOST AREAS THIS AFTRN...WITH ISOLD TSTM. ATTM...STORMS
THAT DEVELOP THIS AFTN/EVENING ARE NOT EXPECTED TO BECOME
SVR. HOWEVER...WITH FZING LVLS AROUND 5.5 KFT IN NE MN...PEA/DIME
SIZE HAIL MAY BE POSSIBLE IN THE STRONGER STORMS.
&&
.PREV DISCUSSION... /ISSUED 350 AM CDT TUE MAY 5 2009/
DISCUSSION...MID LVL LOW OVER CTRL NDAK PER LATEST WV APPEARS
REASONABLY HANDLED BY MDLS AT THIS TIME. AS HT FALLS SWEEP OVER
CWA...RESPONDING LLJ HAS SWUNG INTO ACTION FROM SWRN MN INTO PINE
COUNTY. INITIALLY DRY AIR HAS TO BE MOISTENED SO PRECIP WILL BE SLOW
IN ARRIVING THIS MORNING. AS MID LVL TROF MOVES OVERHEAD
ATMOSPHERE SHOULD GRADUALLY DESTABILIZE WITH INCREASING LAPSE
RATES. RESTRICTED THUNDER TO SWRN CWA THRU MORNING AS MUCAPE AND
CPTP...CLOUD PHYSICS THUNDER PARAMETER FROM SPC SREF... SUGGEST
VERY LOW CHANCES. AFTER 18Z...CPTP AREAL COVERAGE INCREASES OVER
CWA EXCEPT NE WHERE AIR MAY REMAIN STABLE AND POPS ARE LESS. INSPECTION
OF 70/85H COND PRESS DEFICITS INDICATES MUCH DEEPER LAYER OF
SATURATION ARRIVES FROM 21Z INTO EVENING.BEST COLLOCATION OF 0-6KM
SHEAR/SBCAPE IS ACROSS LOWER ST CROIX VALLEY THIS AFTERNOON/EVENING.
SHOULD BE A RELATIVELY QUICK DECREASE IN CONVECTION AFTER 3Z AS
INSTABILITY LESSENS AND MID LVL FEATURE MOVES EAST OF AREA. SECOND
MID LVL SYSTEM ARRIVES BY LATE WEDNESDAY WITH A HIGHER AMOUNT OF
LOW LEVEL INSTABILITY AVAILABLE. SREF PICKS UP ON THIS AND GREATLY
INCREASES POPS AFTER 18Z OVER CTRL/ERN 2/3 OF CWA IN REGION OF LOW/MID
LVL THETAE AXIS.
WEDNESDAY NIGHT THROUGH SUNDAY...
DIFFICULT TIMING ISSUES REMAIN IN THE MEDIUM/LONG RANGE FORECAST
PERIOD DUE TO A FAST ZONAL FLOW PATTERN DEVELOPING MUCH OF THE LOWER
48...BUT THE GENERAL CONSENSUS IS THAT A SERIES OF UPPER LEVEL
DISTURBANCES WILL PASS THROUGH THE NORTHLAND THROUGH EARLY
SATURDAY...WITH HIGH PRESSURE RETURNING SUNDAY. WHILE POPS ARE IN
MANY PERIODS IN THE MEDIUM/LONG TERM...NO TIME FRAME WILL BE A
COMPLETE WASH OUT.
ON WEDNESDAY NIGHT...A NEGATIVELY TILTED 500 MB TROUGH AHEAD OF THE
ASSOCIATED MID LEVEL LOW PRESSURE WILL PUSH THROUGH THE FORECAST
AREA WEDNESDAY NIGHT INTO THURSDAY MORNING. GFS MODEL THE FASTEST
WITH UPPER LEVEL FORCING. INSTABILITY LINGERS IN NORTHWEST
WISCONSIN...THOUGH BEST INSTABILITY WILL BE SHOVED EAST OF THE
FORECAST AREA AS SUGGESTED BY CAPE AND CLOUD TOP PHYSICS PARAMETER
OFF THE SREF MODEL. RAISED POPS SLIGHTLY WITH ADDITIONAL CONFIDENCE
IN NORTHWEST WISCONSIN...AND ADDED AN ISOLATED THUNDER MENTION TO
THE FAR SOUTHEASTERN COUNTIES OF NW WISC.
MODELS THEN BRING THE CORE OF THE UPPER LOW AND ASSOCIATED SURFACE COLD
FRONT THROUGH THE ARROWHEAD ON THURSDAY AFTERNOON INTO EARLY FRIDAY
MORNING...TIMING DEPENDING ON YOUR MODEL OF CHOICE...WITH THE GFS
THE FASTEST WITH SOME SUPPORT FROM THE CANADIAN MODEL AND ENSEMBLE
MEANS...THOUGH SIGNIFICANT SPREAD EXISTS IN THE ENSEMBLE MEMBERS.
THE NAM/ECMWF KEEP THE UPPER LOW IN SOUTHERN CANADA LONGER. HAVE
SIDED WITH A BLEND OF SLOWER NAM/ECMWF AND FASTER GFS WITH TIMING FOR
POPS/QPF/FRONTAL PASSAGE FOR NOW...AND FUTURE SHIFTS WILL FINE TUNE
THIS TIMING.
A LULL IN THE ACTIVE PATTERN APPEARS LIKELY ON FRIDAY MORNING...AS
WEAK UPPER LEVEL RIDGING BUILDS IN...THOUGH IT WILL BE SHORT LIVED
AS THE RIDGE WILL BREAK DOWN QUICKLY. ANOTHER DISTURBANCE MOVES
THROUGH THE REGION ON FRIDAY NIGHT/SATURDAY...BEFORE UPPER LEVEL
RIDGING RETURNS. SIGNIFICANT MODELS DIFFERENCES STILL EXIST...SO DID
NOT MAKE LARGE SCALE CHANGES...AND KEPT ON THE ONGOING DRY FORECAST
FOR SUNDAY.
AVIATION...RAIN SHOWERS WILL PASS THROUGH THE SOUTHERN TERMINALS THROUGH
THE MORNING HOURS...AFFECTING KBRD AND KHYR. MVFR VISBYS ARE
POSSIBLE FOR A SHORT TIME...WITH CEILINGS REMAINING VFR...ALTHOUGH
SCATTERED 1000-2500 FOOT CLOUDS WILL BE FOUND IN THE SHOWERS.
MODELS WEAKEN THE FIRST ROUND OF SHOWERS THROUGH THE MORNING...SO
GENERALLY INCLUDED VCSH MENTION. INSTABILITY INCREASES DURING THE
AFTERNOON AS AN UPPER LEVEL LOW PRESSURE SYSTEM MOVES THROUGH THE
NORTHLAND. SCATTERED SHOWERS/TSTRMS ARE POSSIBLE...ESPECIALLY IN
THE 20-24Z TIME FRAME IN MINNESOTA TERMINALS...SLIGHTLY LATER AT
KHYR...WHERE INSTABILITY LINGERS AFTER 0Z. INCLUDED CB MENTION FOR
NOW IN ALL TERMINALS...WITH OCCASIONAL MVFR CONDITIONS.
&&
POINT TEMPS/POPS...
DLH 61 43 64 39 / 60 30 50 30
INL 62 42 65 40 / 60 30 40 30
BRD 67 44 70 43 / 50 10 20 20
HYR 66 48 69 41 / 60 40 60 30
ASX 66 45 68 42 / 60 50 50 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
$$
GRANING/GSF
000
FXUS63 KMPX 051145
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
645 AM CDT TUE MAY 5 2009
.DISCUSSION...
WELL DEFINED VORT IN SC NODAK MOVING ENE AND CARRYING A SHORTWAVE
TROF EXTENDING INTO E NEB WITH RATHER NICE TIGHT 700 MB OMEGA FIELD
AHEAD OF SHORTWAVE. MOISTURE SOMEWHAT LIMITED...BUT PWATS HAVE BEEN
INCREASING TO AROUND .75 INCH WITH IN SOUTHERLY FLOW AHEAD OF THIS
WAVE. SWATH OF SHWRS WITH SOME EMBEDDED THUNDERSTORMS WILL CARRY
EASTWARD ACROSS FORECAST AREA REMAINDER OF TONIGHT AND THIS MORNING.
SWLY FLOW IN WAKE OF TROF WILL BRING SOME CLEARING ACROSS SW AREAS
DURING DAY WITH WEDGE OF 850 MB AIR AROUND 10C WHICH SHOULD BRING
TEMPS AT LEAST INTO THE LOWER 70S S OF MN RIVER ALONG WITH DRIER
AIRMASS. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS SHOULD DEVELOP
AGAIN THIS AFTERNOON IN E CWA WHERE INSTABILITY INCREASES AHEAD OF
WEAK SURFACE TROUGH.
UPSTREAM TROF NOW COMING ACROSS PACIFIC NW. FAST ZONAL FLOW WILL
BRING ANOTHER CHANCE OF CONVECTION TO AREA BY WEDNESDAY MORNING.
ASSOCIATED SURFACE TROF WILL MOVE ACROSS WESTERN CWA IN THE MORNING
AND ACROSS EASTERN AREAS DURING THE AFTERNOON. SBCAPE INCREASES TO
AROUND 1000 J/KG SE MN INTO WI DURING THE AFTERNOON.
ACTIVE PATTERN CONTINUES AS A VIGOROUS UPPER TROF DROPS OUT OF THE
CANADIAN PRAIRIES THEN ACROSS N MN ON THURSDAY WITH A REINFORCING
UPPER TROF AND ANOTHER COLD FRONT FOR THE WEEKEND. THIS WILL BRING A
PERIOD OF SEVERAL DAYS OF TEMPERATURES BELOW NORMAL.
&&
.AVIATION.../12Z TAF ISSUANCE/
SWATH OF SHOWERS CENTERED FROM KRZN TO KRST AT 12Z PROGRESSING
EAST THROUGH THE REMAINDER OF THE MORNING AND WEAKENING AS IT
DOES. THIS WILL BRING LIGHT RAIN TO EAU CLAIRE WITH A SMALL CHANCE
FOR MVFR CIGS. GIVEN LARGE TEMP/TD SPREADS STILL OBSERVED NEAR THE
AIRPORT AM NOT TOO EXCITED ABOUT THOSE CHANCES. STRONG UPPER LOW TO
MOVE EAST FROM ERN ND INTO NRN MN THIS AFTN. ROTATING AROUND IT
WILL BE SPOKES OF FOCUS FOR SHOWERS AND ISOLD THUNDER...WITH THE
BEST CHANCES ACROSS THE NRN HALF OF MN. LOW LEVEL WIND CONVERGENCE
AXIS /PSEUDO-FRONT/ TO BE POISED FROM NORTH CTRL MN TOWARDS STC BY
MID-AFTN AND WILL LIKELY BE THE AREA WITH THE HIGHEST COVERAGE.
HAVE INCLUDED A TEMPO AT STC FOR REDEVELOPING SHOWERS. THUNDER
POSSIBLE THERE...WITH SMALLER CHANCES FOR OCCURRENCE AT MSP AND WI
SITES. WINDS TO VEER THROUGH EARLY AFTN TO A MORE SSW DIRECTION.
AT AXN AND RWF...MORE OF A SW WIND IS LIKELY WITH MSP COMING CLOSE
TO 220 DEGREES. SHOWER POSSIBILITY SHOULD FADE BY 01Z OR SO AND
ALLOW FOR A TRANQUIL EVE. WEDS WILL SEE ANOTHER LOW TRACK ACROSS
SRN MN BRINGING RETURNING SHOWER CHANCES THERE FOR THE MORNING AND
BY AFTN TO WRN WI.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BAP/MTF
000
FXUS63 KDLH 050850
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
350 AM CDT TUE MAY 5 2009
.DISCUSSION...MID LVL LOW OVER CTRL NDAK PER LATEST WV APPEARS
REASONABLY HANDLED BY MDLS AT THIS TIME. AS HT FALLS SWEEP OVER
CWA...RESPONDING LLJ HAS SWUNG INTO ACTION FROM SWRN MN INTO PINE
COUNTY. INITIALLY DRY AIR HAS TO BE MOISTENED SO PRECIP WILL BE SLOW
IN ARRIVING THIS MORNING. AS MID LVL TROF MOVES OVERHEAD
ATMOSPHERE SHOULD GRADUALLY DESTABILIZE WITH INCREASING LAPSE
RATES. RESTRICTED THUNDER TO SWRN CWA THRU MORNING AS MUCAPE AND
CPTP...CLOUD PHYSICS THUNDER PARAMETER FROM SPC SREF... SUGGEST
VERY LOW CHANCES. AFTER 18Z...CPTP AREAL COVERAGE INCREASES OVER
CWA EXCEPT NE WHERE AIR MAY REMAIN STABLE AND POPS ARE LESS. INSPECTION
OF 70/85H COND PRESS DEFICITS INDICATES MUCH DEEPER LAYER OF
SATURATION ARRIVES FROM 21Z INTO EVENING.BEST COLLOCATION OF 0-6KM
SHEAR/SBCAPE IS ACROSS LOWER ST CROIX VALLEY THIS AFTERNOON/EVENING.
SHOULD BE A RELATIVELY QUICK DECREASE IN CONVECTION AFTER 3Z AS
INSTABILITY LESSENS AND MID LVL FEATURE MOVES EAST OF AREA. SECOND
MID LVL SYSTEM ARRIVES BY LATE WEDNESDAY WITH A HIGHER AMOUNT OF
LOW LEVEL INSTABILITY AVAILABLE. SREF PICKS UP ON THIS AND GREATLY
INCREASES POPS AFTER 18Z OVER CTRL/ERN 2/3 OF CWA IN REGION OF LOW/MID
LVL THETAE AXIS.
.WEDNESDAY NIGHT THROUGH SUNDAY...
DIFFICULT TIMING ISSUES REMAIN IN THE MEDIUM/LONG RANGE FORECAST
PERIOD DUE TO A FAST ZONAL FLOW PATTERN DEVELOPING MUCH OF THE LOWER
48...BUT THE GENERAL CONSENSUS IS THAT A SERIES OF UPPER LEVEL
DISTURBANCES WILL PASS THROUGH THE NORTHLAND THROUGH EARLY
SATURDAY...WITH HIGH PRESSURE RETURNING SUNDAY. WHILE POPS ARE IN
MANY PERIODS IN THE MEDIUM/LONG TERM...NO TIME FRAME WILL BE A
COMPLETE WASH OUT.
ON WEDNESDAY NIGHT...A NEGATIVELY TILTED 500 MB TROUGH AHEAD OF THE
ASSOCIATED MID LEVEL LOW PRESSURE WILL PUSH THROUGH THE FORECAST
AREA WEDNESDAY NIGHT INTO THURSDAY MORNING. GFS MODEL THE FASTEST
WITH UPPER LEVEL FORCING. INSTABILITY LINGERS IN NORTHWEST
WISCONSIN...THOUGH BEST INSTABILITY WILL BE SHOVED EAST OF THE
FORECAST AREA AS SUGGESTED BY CAPE AND CLOUD TOP PHYSICS PARAMETER
OFF THE SREF MODEL. RAISED POPS SLIGHTLY WITH ADDITIONAL CONFIDENCE
IN NORTHWEST WISCONSIN...AND ADDED AN ISOLATED THUNDER MENTION TO
THE FAR SOUTHEASTERN COUNTIES OF NW WISC.
MODELS THEN BRING THE CORE OF THE UPPER LOW AND ASSOCIATED SURFACE COLD
FRONT THROUGH THE ARROWHEAD ON THURSDAY AFTERNOON INTO EARLY FRIDAY
MORNING...TIMING DEPENDING ON YOUR MODEL OF CHOICE...WITH THE GFS
THE FASTEST WITH SOME SUPPORT FROM THE CANADIAN MODEL AND ENSEMBLE
MEANS...THOUGH SIGNIFICANT SPREAD EXISTS IN THE ENSEMBLE MEMBERS.
THE NAM/ECMWF KEEP THE UPPER LOW IN SOUTHERN CANADA LONGER. HAVE
SIDED WITH A BLEND OF SLOWER NAM/ECMWF AND FASTER GFS WITH TIMING FOR
POPS/QPF/FRONTAL PASSAGE FOR NOW...AND FUTURE SHIFTS WILL FINE TUNE
THIS TIMING.
A LULL IN THE ACTIVE PATTERN APPEARS LIKELY ON FRIDAY MORNING...AS
WEAK UPPER LEVEL RIDGING BUILDS IN...THOUGH IT WILL BE SHORT LIVED
AS THE RIDGE WILL BREAK DOWN QUICKLY. ANOTHER DISTURBANCE MOVES
THROUGH THE REGION ON FRIDAY NIGHT/SATURDAY...BEFORE UPPER LEVEL
RIDGING RETURNS. SIGNIFICANT MODELS DIFFERENCES STILL EXIST...SO DID
NOT MAKE LARGE SCALE CHANGES...AND KEPT ON THE ONGOING DRY FORECAST
FOR SUNDAY.
&&
.AVIATION...RAIN SHOWERS WILL PASS THROUGH THE SOUTHERN TERMINALS THROUGH
THE MORNING HOURS...AFFECTING KBRD AND KHYR. MVFR VISBYS ARE
POSSIBLE FOR A SHORT TIME...WITH CEILINGS REMAINING VFR...ALTHOUGH
SCATTERED 1000-2500 FOOT CLOUDS WILL BE FOUND IN THE SHOWERS.
MODELS WEAKEN THE FIRST ROUND OF SHOWERS THROUGH THE MORNING...SO
GENERALLY INCLUDED VCSH MENTION. INSTABILITY INCREASES DURING THE
AFTERNOON AS AN UPPER LEVEL LOW PRESSURE SYSTEM MOVES THROUGH THE
NORTHLAND. SCATTERED SHOWERS/TSTRMS ARE POSSIBLE...ESPECIALLY IN
THE 20-24Z TIME FRAME IN MINNESOTA TERMINALS...SLIGHTLY LATER AT
KHYR...WHERE INSTABILITY LINGERS AFTER 0Z. INCLUDED CB MENTION FOR
NOW IN ALL TERMINALS...WITH OCCASIONAL MVFR CONDITIONS.
&&
POINT TEMPS/POPS...
DLH 60 43 64 39 / 60 30 50 30
INL 63 42 65 40 / 60 30 40 30
BRD 67 43 70 43 / 60 10 20 20
HYR 65 48 69 41 / 60 40 60 30
ASX 63 45 68 42 / 60 40 50 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
$$
CANNON/DONOFRIO
000
FXUS63 KMPX 050750
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
250 AM CDT TUE MAY 5 2009
.DISCUSSION...
WELL DEFINED VORT IN SC NODAK MOVING ENE AND CARRYING A SHORTWAVE
TROF EXTENDING INTO E NEB WITH RATHER NICE TIGHT 700 MB OMEGA FIELD
AHEAD OF SHORTWAVE. MOISTURE SOMEWHAT LIMITED...BUT PWATS HAVE BEEN
INCREASING TO AROUND .75 INCH WITH IN SOUTHERLY FLOW AHEAD OF THIS
WAVE. SWATH OF SHWRS WITH SOME EMBEDDED THUNDERSTORMS WILL CARRY
EASTWARD ACROSS FORECAST AREA REMAINDER OF TONIGHT AND THIS MORNING.
SWLY FLOW IN WAKE OF TROF WILL BRING SOME CLEARING ACROSS SW AREAS
DURING DAY WITH WEDGE OF 850 MB AIR AROUND 10C WHICH SHOULD BRING
TEMPS AT LEAST INTO THE LOWER 70S S OF MN RIVER ALONG WITH DRIER
AIRMASS. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS SHOULD DEVELOP
AGAIN THIS AFTERNOON IN E CWA WHERE INSTABILITY INCREASES AHEAD OF
WEAK SURFACE TROUGH.
UPSTREAM TROF NOW COMING ACROSS PACIFIC NW. FAST ZONAL FLOW WILL
BRING ANOTHER CHANCE OF CONVECTION TO AREA BY WEDNESDAY MORNING.
ASSOCIATED SURFACE TROF WILL MOVE ACROSS WESTERN CWA IN THE MORNING
AND ACROSS EASTERN AREAS DURING THE AFTERNOON. SBCAPE INCREASES TO
AROUND 1000 J/KG SE MN INTO WI DURING THE AFTERNOON.
ACTIVE PATTERN CONTINUES AS A VIGOROUS UPPER TROF DROPS OUT OF THE
CANADIAN PRAIRIES THEN ACROSS N MN ON THURSDAY WITH A REINFORCING
UPPER TROF AND ANOTHER COLD FRONT FOR THE WEEKEND. THIS WILL BRING A
PERIOD OF SEVERAL DAYS OF TEMPERATURES BELOW NORMAL.
&&
.AVIATION.../06Z TAF ISSUANCE/
A BROKEN LINE OF SHOWERS AND EMBEDDED THUNDERSTORMS CONTINUED TO
MOVE FROM CENTRAL SOUTH DAKOTA...AND INTO FAR SOUTHWEST MINNESOTA
AS OF 1130 PM. ALTHOUGH THIS LINE WILL BE MOVING INTO MUCH MORE
STABLE AIR AND DRIER CONDITIONS...INCREASING LOW LEVEL FLOW AND
MOISTURE ADVECTION SHOULD AT LEAST CONTINUE SOME OF THE ORGANIZED
CONVECTION AS IT MOVES ACROSS SOUTHERN AND PORTIONS OF CENTRAL
MINNESOTA DURING THE NEXT 6 HRS. OVERALL...MOST OF THE CEILINGS
WILL BE ABOVE 3500`...WITH A SMALL WINDOW OF 1-2SM AND HEAVY
SHOWER/STORM ACTIVITY. HOWEVER...HAVE KEPT MORE OF A 5SM IN
SHOWERS WITH CB`S AND NO TSRA AT THIS TIME. BEST POTENTIAL IN THE
NEXT 6 HRS WILL BE AT RWF. BETWEEN 12-18Z...AREAS AROUND
STC/MSP/RHN AND EAU WILL BEGIN TO SEE LOWER CEILINGS AS LCL`S
LOWER AND MOISTURE LEVELS BELOW 900H INCREASE SIGNIFICANTLY. LATER
SHIFTS WILL NEED TO UPDATE AS THE TSRA PROGRESS FURTHER EASTWARD
AND TIMING WILL BE EASIER TO ESTIMATE.
...JLT...
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BAP/JLT
000
FXUS63 KMPX 050425
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1125 PM CDT MON MAY 4 2009
.DISCUSSION...
MILD WEATHER WILL CONTINUE THIS WEEK...BUT SIGNS OF CHANGE TO A
MORE ACTIVE WEATHER PATTERN OUR JUST OFF TO OUR WEST THIS
AFTERNOON. STRONG SHORTWAVE IS EVIDENT ON WATER VAPOR CROSSING
FROM MONTANA INTO NODAK. THIS WAVE IS PROGGED TO TRACK INTO NRN MN
OVERNIGHT. AT THE SURFACE...COLD/OCCULLUDED FRONT IS PUSHING
ACROSS THE DAKOTAS...WITH A WEAK WARM FRONT MOVING NORTH ACROSS
SODAK. HAVE SEEN SOME LIMITED INSTABILITY WORK INTO THE WARM
SECTOR THIS AFTERNOON...BUT WITH GULF ESSENTIALLY BLOCKED BY A
STATIONARY FRONT DRAPED ACROSS THE TEXAS GULF COAST...MOISTURE
RETURN HAS BEEN WEAK. THIN LINE OF SHOWERS STRETCHING FROM NE
NEBRASKA INTO SOUTH CENTRAL NODAK IN AREA OF PVA AND WEAK
ISENTROPIC ASCENT WILL WORK INTO THE WRN CWA EARLY THIS EVENING
AND SLOWLY MARCH EAST DURING THE MORNING HOURS. CURRENT FORECAST
HANDLED TIMING OF RAIN WELL...ONLY CHANGE MADE WAS TO SLOW
EASTWARD PROGRESSION SOME...AS ANTECEDENT DRY AIRMASS WILL LIKELY
SLOW THE ONSET OF RAINFALL. GFS AND NAM WANT TO BRING THE MODIFIED
WARM SECTOR INTO SOUTHERN MN OVERNIGHT...BUT WITH STEEPER MID
LEVEL LAPSE RATES STAYING OFF TO THE WEST...INSTABILITY WILL BE
MINIMAL HERE...SO NOT ANTICIPATING MUCH IF ANY OF A SEVERE THREAT.
FOR TUESDAY...FRONT IS PROGGED TO STALL OUT ACROSS CENTER OF CWA.
DEWPOINTS ARE PROGGED TO SNEAK INTO THE LOW 50S AND BOTH NAM AND
GFS GENERATE MLCAPES BETWEEN 500 AND 1000 J/KG FROM THE TWIN
CITIES EAST. LOCAL WRF GENERATES SOME SCATTERED CONVECTION ALONG
THE FRONT FROM THE TWIN CITIES EAST IN THE AFTERNOON. BEST
MOISTURE WILL STILL BE BOTTLED UP IN THE SOUTHERN PLAINS...SO
SEVERE THREAT WILL AGAIN BE MINIMAL...BUT MAY END UP WITH MORE
WIDESPREAD THUNDERSTORM ACTIVITY THAN WILL BE SEEN HERE OVERNIGHT.
AT THE SAME TIME...ANOTHER H7 TROUGH IS FORECAST TO DEVELOP ACROSS
NEBRASKA DURING THE AFTERNOON. ALL GUIDANCE GENERATES AN AREA OF
CONVECTION NEAR THE NEBRASKA/SODAK/IOWA BORDERS TUESDAY AFTERNOON
AHEAD OF DEVELOPING SHORT WAVE IN LEFT EXIT REGION OF STRONG POLAR
JET. THIS ENERGY IS FORECAST TO LIFT NE ALONG THE FRONT TUESDAY
NIGHT...BRING AN ELEVATED THREAT OF THUNDERSTORMS FROM SOUTH
CENTRAL MN INTO WI DURING THE EVENING.
FRONT WILL FINALLY BEGIN PUSHING EAST DURING THE DAY WEDNESDAY...WHICH
SHOULD HELP PUSH BETTER RAIN CHANCES EAST OF THE AREA. THE ONLY
MODEL GOING AGAINST THIS TREND IS THE ECMWF...WHICH IS A LITTLE
SLOWER WITH THIS SECOND WAVE...HOLDING THE FRONT AND RAINFALL BACK
ACROSS ERN PARTS OF CWA THROUGH WEDNESDAY AFTERNOON. GIVEN TIMING
ISSUES...HAVE HELD POPS IN AT LEAST THE CHANCE CATEGORY ACROSS THE
EAST UNTIL THURSDAY MORNING. ONLY PERIOD WITH SOME CONFIDENCE FOR
BEING DRY IS FRIDAY NIGHT INTO SUNDAY AS HIGH PRESSURE SLIPS INTO
THE AREA AND WEAK RIDGING BUILDS IN ALOFT. FROM SUNDAY NIGHT ON
INTO NEXT WEEK...SW FLOW SETS UP ALOFT AND AREA AGAIN RETURNS INTO
A MORE ACTIVE AND WET PATTERN.
TEMPERATURES THROUGH ALL OF THIS WEEK LOOK MILD. HAVE SEEN LOW TO
MID 70S DEVELOP THIS AFTERNOON...WHICH SHOULD BE THE CASE UNTIL
FRIDAY...WHEN COOLER AIR STARTS FILTERING IN BEHIND THE
FRONT...KNOCKING HIGHS BACK DOWN INTO THE 60S. FOR TONIGHT...MORE
MILD EVENING IS IN STORE WITH LOWS STAYING IN THE 40S AND 50S
THANKS TO INCREASED CLOUD COVER AND RAIN...ALONG WITH WAA SEEN
TODAY.
&&
.AVIATION.../06Z TAF ISSUANCE/
A BROKEN LINE OF SHOWERS AND EMBEDDED THUNDERSTORMS CONTINUED TO
MOVE FROM CENTRAL SOUTH DAKOTA...AND INTO FAR SOUTHWEST MINNESOTA
AS OF 1130 PM. ALTHOUGH THIS LINE WILL BE MOVING INTO MUCH MORE
STABLE AIR AND DRIER CONDITIONS...INCREASING LOW LEVEL FLOW AND
MOISTURE ADVECTION SHOULD AT LEAST CONTINUE SOME OF THE ORGANIZED
CONVECTION AS IT MOVES ACROSS SOUTHERN AND PORTIONS OF CENTRAL
MINNESOTA DURING THE NEXT 6 HRS. OVERALL...MOST OF THE CEILINGS
WILL BE ABOVE 3500`...WITH A SMALL WINDOW OF 1-2SM AND HEAVY
SHOWER/STORM ACTIVITY. HOWEVER...HAVE KEPT MORE OF A 5SM IN
SHOWERS WITH CB`S AND NO TSRA AT THIS TIME. BEST POTENTIAL IN THE
NEXT 6 HRS WILL BE AT RWF. BETWEEN 12-18Z...AREAS AROUND
STC/MSP/RHN AND EAU WILL BEGIN TO SEE LOWER CEILINGS AS LCL`S
LOWER AND MOISTURE LEVELS BELOW 900H INCREASE SIGNIFICANTLY. LATER
SHIFTS WILL NEED TO UPDATE AS THE TSRA PROGRESS FURTHER EASTWARD
AND TIMING WILL BE EASIER TO ESTIMATE.
...JLT...
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BAP/JLT
000
FXUS63 KDLH 050219
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
919 PM CDT MON MAY 4 2009
.UPDATE...SHOWERS AND A FEW THUNDERSTORMS CONTINUED TO LIFT INTO
WESTERN MINNESOTA AS OF 9 PM. PREVIOUS ZONES/GRIDS HAD A GREAT
HANDLE ON THE TIMING OF THIS AREA OF PRECIPITATION AND HAVE MADE
VERY FEW CHANGES TO THE EVENING ZONES/GRIDS. NEW NAM SUPPORTS
GOING FORECAST VERY WELL WITH THE BEST CHANCE OF OVERNIGHT SHOWERS
AND THUNDERSTORMS IN THE SOUTHWEST 1/3 OF THE CWA.
&&
.PREV DISCUSSION... /ISSUED 258 PM CDT MON MAY 4 2009/
DISCUSSION...MAIN FORECAST CHALLENGE IS POPS IN THE SHORT TERM.
AFTERNOON SURFACE ANALYSIS DEPICTS LOW PRESSURE NOW STRENGTHENING
ACROSS THE NORTHERN HIGH PLAINS. SURFACE OBSERVATIONS INDICATING
THE LEADING EDGE OF RETURN MOISTURE STRETCHED FROM CENTRAL NORTH
DAKOTA...THROUGH EASTERN SOUTH DAKOTA PER HIGHER DEWPOINTS...AND
ALSO SEEN CLEARLY AS CLOUD LINE ON VISIBLE SATELLITE. JUST CIRRUS
OVER THE NORTHLAND THIS AFTERNOON WITH LOW LEVEL WARM AIR
ADVECTION RESULTING IN MID TO UPPER 60S FOR MOST LOCATIONS...THE
EXCEPTION IS NEAR THE LAKE WHERE THE LAKE BREEZE HAS PUSHED
THROUGH...AS SEEN ON THE KDLH WSR-88D.
AXIS OF MOISTURE/INSTABILITY WILL ADVECT EAST TONIGHT WITH THE AID
OF DEVELOPING 35+ KT LOW LEVEL JET...AND AHEAD OF APPROACHING POTENT
NORTHERN STREAM SHORT WAVE...CURRENTLY SEEN ON WATER VAPOR IMAGERY
OVER THE WESTERN DAKOTAS/MONTANA BORDER. MODELS GENERALLY AGREE NOW
IN TRACK OF THE UPPER LOW THROUGH NORTHERN MINNESOTA TUESDAY
AFTERNOON...HOWEVER NAM IS A BIT FARTHER WEST...AND THEREFORE SLOWER
WITH EASTWARD PROGRESSION OF PRECIP. SHOULD SEE ORGANIZED AREA OF
SHOWERS/ISOLD CONVECTION ALONG THE INSTABILITY AXIS LATE TONIGHT
THROUGH TOMORROW GIVEN STRONG DYNAMICS AND LOW LEVEL FORCING. ALSO
SHOULD SEE SOME INSTABILITY SHOWERS DEVELOP UNDERNEATH LOW CENTER
DURING PEAKING HEATING TUESDAY. INSTABILITY GENERALLY REMAINS WEAK
EXCEPT FOR THE SOUTH/SOUTHEAST ZONES TUESDAY AFTERNOON WHERE 500+
J/KG SBCAPE AND MOISTURE AXIS SET UP. TUESDAY NIGHT...PRECIP SHOULD
MOVE OFF TO THE EAST/NORTHEAST AS THE UPPER LOW PUSHES INTO
ONTARIO...BRINGING A TEMPORARY LULL IN THE ACTIVE PATTERN.
SECONDARY SHORT WAVE IN THE FAST ZONAL FLOW PATTERN WILL TRAVERSE
ACROSS SOUTHERN MN/WI AS IT BECOMES MORE NEGATIVELY TILTED ON
WEDNESDAY...WHILE YET ANOTHER VORT MAX PUSHES INTO NORTHWEST
MINNESOTA. SHOULD SEE STRONG BOUNDARY LIFT INTO THE SOUTHEAST FA
WEDNESDAY...ALONG WITH SUFFICIENT MOISTURE/INSTABILITY/LIFT TO
TRIGGER CONVECTION...AND HAVE RAISED POPS THERE A BIT ACCORDINGLY.
AS NORTHWEST SHORT WAVE TROUGH DEEPENS INTO LOW OVER THE WESTERN
GREAT LAKES WEDNESDAY NIGHT AND THURSDAY...RAIN SHOWERS WILL
ACCOMPANY A SIGNIFICANT LOW LEVEL COLD FRONT...WITH H85 TEMPS
FALLING BELOW ZERO CELSIUS ACROSS THE NORTHERN ZONES BY 00Z FRIDAY.
EXTENDED...THURSDAY NIGHT THROUGH MONDAY.
A COLD FRONT WILL DEPART THE FA THURSDAY NIGHT. SOME SHOWERS MAY
OCCUR ALONG AND BEHIND THE FRONT. HIGH PRESSURE SETTLES IN
OVERNIGHT. ON FRIDAY...A STRENGTHENING SFC LOW IS PROGGED TO MOVE
THROUGH SOUTHERN MN/WI. THE FA WILL BE ON THE NORTHERN FRINGE OF
THIS SYSTEM WITH A QUESTION OF HOW FA NORTH THE RAIN WILL GET.
MODELS ARE POINTING TO MAINLY THE SOUTHERN HALF OF THE AREA GETTING
WET AND POPS REFLECT THIS PLACEMENT. SOME SHOWERS MAY STILL AFFECT
THE SOUTHERN FA FRIDAY NIGHT AS THE SYSTEM SLOWLY DEPARTS.
SATURDAY AND SUNDAY ARE SETTING UP TO BE RAIN FREE AS HIGH PRESSURE
OVER LAKE SUPERIOR KEEPS DRY AIR FLOWING INTO THE FA. BY NEXT
MONDAY...MODELS DIVERGE IN HANDLING OF THE NEXT SYSTEM MOVING OUT OF
THE ROCKIES INTO THE PLAINS. HAVE SOME POPS IN PLACE...BUT
CONFIDENCE IS EXTREMELY LOW.
AVIATION...EVEN THOUGH VFR CONDITIONS ARE EXPECTED THROUGH 18Z
TUESDAY...SOME SHOWERS ARE EXPECTED TO BE IN THE VICINITY OF KBRD BY
12Z TUESDAY. THE SHOWERS WILL GRADUALLY SPREAD NORTH AND EASTWARD
WITH TIME AND ARE LIKELY TO BE IN THE VICINITY OF ALL TAF SITES
THROUGH 18Z.
&&
POINT TEMPS/POPS...
DLH 40 60 41 64 / 30 60 30 30
INL 39 61 42 66 / 40 60 30 30
BRD 48 67 44 69 / 60 60 20 20
HYR 42 65 46 69 / 40 60 40 40
ASX 41 63 44 68 / 10 60 40 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
$$
DAP/BETTWY
000
FXUS63 KMPX 042331
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
631 PM CDT MON MAY 4 2009
.UPDATE...
ADDED AVIATION DISCUSSION FOR 00Z TAFS BELOW...
&&
.DISCUSSION...
MILD WEATHER WILL CONTINUE THIS WEEK...BUT SIGNS OF CHANGE TO A
MORE ACTIVE WEATHER PATTERN OUR JUST OFF TO OUR WEST THIS
AFTERNOON. STRONG SHORTWAVE IS EVIDENT ON WATER VAPOR CROSSING
FROM MONTANA INTO NODAK. THIS WAVE IS PROGGED TO TRACK INTO NRN MN
OVERNIGHT. AT THE SURFACE...COLD/OCCULLUDED FRONT IS PUSHING
ACROSS THE DAKOTAS...WITH A WEAK WARM FRONT MOVING NORTH ACROSS
SODAK. HAVE SEEN SOME LIMITED INSTABILITY WORK INTO THE WARM
SECTOR THIS AFTERNOON...BUT WITH GULF ESSENTIALLY BLOCKED BY A
STATIONARY FRONT DRAPED ACROSS THE TEXAS GULF COAST...MOISTURE
RETURN HAS BEEN WEAK. THIN LINE OF SHOWERS STRETCHING FROM NE
NEBRASKA INTO SOUTH CENTRAL NODAK IN AREA OF PVA AND WEAK
ISENTROPIC ASCENT WILL WORK INTO THE WRN CWA EARLY THIS EVENING
AND SLOWLY MARCH EAST DURING THE MORNING HOURS. CURRENT FORECAST
HANDLED TIMING OF RAIN WELL...ONLY CHANGE MADE WAS TO SLOW
EASTWARD PROGRESSION SOME...AS ANTECEDENT DRY AIRMASS WILL LIKELY
SLOW THE ONSET OF RAINFALL. GFS AND NAM WANT TO BRING THE MODIFIED
WARM SECTOR INTO SOUTHERN MN OVERNIGHT...BUT WITH STEEPER MID
LEVEL LAPSE RATES STAYING OFF TO THE WEST...INSTABILITY WILL BE
MINIMAL HERE...SO NOT ANTICIPATING MUCH IF ANY OF A SEVERE THREAT.
FOR TUESDAY...FRONT IS PROGGED TO STALL OUT ACROSS CENTER OF CWA.
DEWPOINTS ARE PROGGED TO SNEAK INTO THE LOW 50S AND BOTH NAM AND
GFS GENERATE MLCAPES BETWEEN 500 AND 1000 J/KG FROM THE TWIN
CITIES EAST. LOCAL WRF GENERATES SOME SCATTERED CONVECTION ALONG
THE FRONT FROM THE TWIN CITIES EAST IN THE AFTERNOON. BEST
MOISTURE WILL STILL BE BOTTLED UP IN THE SOUTHERN PLAINS...SO
SEVERE THREAT WILL AGAIN BE MINIMAL...BUT MAY END UP WITH MORE
WIDESPREAD THUNDERSTORM ACTIVITY THAN WILL BE SEEN HERE OVERNIGHT.
AT THE SAME TIME...ANOTHER H7 TROUGH IS FORECAST TO DEVELOP ACROSS
NEBRASKA DURING THE AFTERNOON. ALL GUIDANCE GENERATES AN AREA OF
CONVECTION NEAR THE NEBRASKA/SODAK/IOWA BORDERS TUESDAY AFTERNOON
AHEAD OF DEVELOPING SHORT WAVE IN LEFT EXIT REGION OF STRONG POLAR
JET. THIS ENERGY IS FORECAST TO LIFT NE ALONG THE FRONT TUESDAY
NIGHT...BRING AN ELEVATED THREAT OF THUNDERSTORMS FROM SOUTH
CENTRAL MN INTO WI DURING THE EVENING.
FRONT WILL FINALLY BEGIN PUSHING EAST DURING THE DAY WEDNESDAY...WHICH
SHOULD HELP PUSH BETTER RAIN CHANCES EAST OF THE AREA. THE ONLY
MODEL GOING AGAINST THIS TREND IS THE ECMWF...WHICH IS A LITTLE
SLOWER WITH THIS SECOND WAVE...HOLDING THE FRONT AND RAINFALL BACK
ACROSS ERN PARTS OF CWA THROUGH WEDNESDAY AFTERNOON. GIVEN TIMING
ISSUES...HAVE HELD POPS IN AT LEAST THE CHANCE CATEGORY ACROSS THE
EAST UNTIL THURSDAY MORNING. ONLY PERIOD WITH SOME CONFIDENCE FOR
BEING DRY IS FRIDAY NIGHT INTO SUNDAY AS HIGH PRESSURE SLIPS INTO
THE AREA AND WEAK RIDGING BUILDS IN ALOFT. FROM SUNDAY NIGHT ON
INTO NEXT WEEK...SW FLOW SETS UP ALOFT AND AREA AGAIN RETURNS INTO
A MORE ACTIVE AND WET PATTERN.
TEMPERATURES THROUGH ALL OF THIS WEEK LOOK MILD. HAVE SEEN LOW TO
MID 70S DEVELOP THIS AFTERNOON...WHICH SHOULD BE THE CASE UNTIL
FRIDAY...WHEN COOLER AIR STARTS FILTERING IN BEHIND THE
FRONT...KNOCKING HIGHS BACK DOWN INTO THE 60S. FOR TONIGHT...MORE
MILD EVENING IS IN STORE WITH LOWS STAYING IN THE 40S AND 50S
THANKS TO INCREASED CLOUD COVER AND RAIN...ALONG WITH WAA SEEN
TODAY.
&&
.AVIATION.../00Z TAF ISSUANCE/
A FAIRLY ACTIVE PERIOD LIES AHEAD THIS ISSUANCE WITH AN UPPER
LEVEL TROUGH MOVING EASTWARD ACROSS THE CENTRAL DAKOTAS WITH A
SURFACE TROUGH MOVING AHEAD OF IT ACROSS THE EASTERN DAKOTAS. MID
AND HIGH CLOUDS CONTINUE TO INCREASE ACROSS THE TAF SITES WITH
SOUTHERLY WINDS IN PLACE. WIND SPEEDS AND DIRECTIONS ARE A BIT
ERRATIC AT 23Z BUT SHOULD BECOME MORE UNIFORM FROM THE SOUTH OR SOUTH-
SOUTHEAST OVER THE NEXT FEW HOURS. CEILINGS WILL LOWER FROM WEST
TO EAST STARTING MID EVENING AS THE TROUGH APPROACHES AS DOES A
BAND OF SHOWERS AND ISOLATED THUNDERSTORMS. ACTIVITY SHOULD ARRIVE
AT KRWF AND KAXN AROUND 05-06Z. THE PRECIP WILL MOVE EASTWARD
REACHING THE TWIN CITIES AROUND 09-10Z AND CONTINUE EAST UNTIL
REACHING KEAU BY MID MORNING. BEST CHANCE FOR THUNDER WILL BE AT
KRWF WHERE BETTER INSTABILITY WILL HANG ON /HAVE INCLUDED TEMPO
TSRA THERE/ BUT THUNDER CANNOT BE RULED OUT ANYWHERE SO WILL CARRY
A CB AT THE REMAINING SITES. MVFR CIGS AND VIS WILL BE POSSIBLE
WITH THE PRECIPITATION WITH A NARROW WINDOW OF MVFR CIGS
CONTINUING INTO MID MORNING/MIDDAY BEHIND THE MAIN AREA SHOWERS/THUNDER.
THE SFC TROUGH WILL STALL OUT ACROSS EASTERN MN DURING THE MORNING
LEAVING SCATTERED SHOWER CHANCES AHEAD OF IT AND REMAIN IN PLACE
INTO TUESDAY NIGHT. INSTABILITY WILL BUILD AHEAD OF THE TROUGH AS
SKIES SCATTER DURING THE EARLY AFTERNOON AND EXPECT BETTER
COVERAGE OF SHOWERS/THUNDER TO REDEVELOP. EXPECT SCATTERED
ACTIVITY FROM KRNH TO KEAU BY MID AFTERNOON... BUT SOME
SHOWERS/STORMS MAY DEVELOP OVER OR JUST EAST OF THE TWIN CITIES
AROUND 20Z OR SO AND WILL INCLUDE CB AT KMSP AT THAT TIME WITH
PROB30 SHRA CB AT KRNH AND KEAU FOR NOW DUE TO SCATTERED COVERAGE
WITH SOMEWHAT LIMITED MOISTURE. WINDS EAST OF KMSP WILL BE FROM
THE SOUTH AHEAD OF THE TROUGH. SITES WEST OF THE TROUGH
/KAXN/KRWF/KSTC WILL SEE BREEZY SOUTH-SOUTHWEST WINDS BECOMING
WESTERLY DURING THE AFTERNOON AS DRIER AIR MOVES IN WITH GUSTS TO
AROUND 25 KTS. ..MDB..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/MDB
000
FXUS63 KMPX 042059
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
359 PM CDT MON MAY 4 2009
.DISCUSSION...
MILD WEATHER WILL CONTINUE THIS WEEK...BUT SIGNS OF CHANGE TO A
MORE ACTIVE WEATHER PATTERN OUR JUST OFF TO OUR WEST THIS
AFTERNOON. STRONG SHORTWAVE IS EVIDENT ON WATER VAPOR CROSSING
FROM MONTANA INTO NODAK. THIS WAVE IS PROGGED TO TRACK INTO NRN MN
OVERNIGHT. AT THE SURFACE...COLD/OCCULLUDED FRONT IS PUSHING
ACROSS THE DAKOTAS...WITH A WEAK WARM FRONT MOVING NORTH ACROSS
SODAK. HAVE SEEN SOME LIMITED INSTABILITY WORK INTO THE WARM
SECTOR THIS AFTERNOON...BUT WITH GULF ESSENTIALLY BLOCKED BY A
STATIONARY FRONT DRAPED ACROSS THE TEXAS GULF COAST...MOISTURE
RETURN HAS BEEN WEAK. THIN LINE OF SHOWERS STRETCHING FROM NE
NEBRASKA INTO SOUTH CENTRAL NODAK IN AREA OF PVA AND WEAK
ISENTROPIC ASCENT WILL WORK INTO THE WRN CWA EARLY THIS EVENING
AND SLOWLY MARCH EAST DURING THE MORNING HOURS. CURRENT FORECAST
HANDLED TIMING OF RAIN WELL...ONLY CHANGE MADE WAS TO SLOW
EASTWARD PROGRESSION SOME...AS ANTECEDENT DRY AIRMASS WILL LIKELY
SLOW THE ONSET OF RAINFALL. GFS AND NAM WANT TO BRING THE MODIFIED
WARM SECTOR INTO SOUTHERN MN OVERNIGHT...BUT WITH STEEPER MID
LEVEL LAPSE RATES STAYING OFF TO THE WEST...INSTABILITY WILL BE
MINIMAL HERE...SO NOT ANTICIPATING MUCH IF ANY OF A SEVERE THREAT.
FOR TUESDAY...FRONT IS PROGGED TO STALL OUT ACROSS CENTER OF CWA.
DEWPOINTS ARE PROGGED TO SNEAK INTO THE LOW 50S AND BOTH NAM AND
GFS GENERATE MLCAPES BETWEEN 500 AND 1000 J/KG FROM THE TWIN
CITIES EAST. LOCAL WRF GENERATES SOME SCATTERED CONVECTION ALONG
THE FRONT FROM THE TWIN CITIES EAST IN THE AFTERNOON. BEST
MOISTURE WILL STILL BE BOTTLED UP IN THE SOUTHERN PLAINS...SO
SEVERE THREAT WILL AGAIN BE MINIMAL...BUT MAY END UP WITH MORE
WIDESPREAD THUNDERSTORM ACTIVITY THAN WILL BE SEEN HERE OVERNIGHT.
AT THE SAME TIME...ANOTHER H7 TROUGH IS FORECAST TO DEVELOP ACROSS
NEBRASKA DURING THE AFTERNOON. ALL GUIDANCE GENERATES AN AREA OF
CONVECTION NEAR THE NEBRASKA/SODAK/IOWA BORDERS TUESDAY AFTERNOON
AHEAD OF DEVELOPING SHORT WAVE IN LEFT EXIT REGION OF STRONG POLAR
JET. THIS ENERGY IS FORECAST TO LIFT NE ALONG THE FRONT TUESDAY
NIGHT...BRING AN ELEVATED THREAT OF THUNDERSTORMS FROM SOUTH
CENTRAL MN INTO WI DURING THE EVENING.
FRONT WILL FINALLY BEGIN PUSHING EAST DURING THE DAY WEDNESDAY...WHICH
SHOULD HELP PUSH BETTER RAIN CHANCES EAST OF THE AREA. THE ONLY
MODEL GOING AGAINST THIS TREND IS THE ECMWF...WHICH IS A LITTLE
SLOWER WITH THIS SECOND WAVE...HOLDING THE FRONT AND RAINFALL BACK
ACROSS ERN PARTS OF CWA THROUGH WEDNESDAY AFTERNOON. GIVEN TIMING
ISSUES...HAVE HELD POPS IN AT LEAST THE CHANCE CATEGORY ACROSS THE
EAST UNTIL THURSDAY MORNING. ONLY PERIOD WITH SOME CONFIDENCE FOR
BEING DRY IS FRIDAY NIGHT INTO SUNDAY AS HIGH PRESSURE SLIPS INTO
THE AREA AND WEAK RIDGING BUILDS IN ALOFT. FROM SUNDAY NIGHT ON
INTO NEXT WEEK...SW FLOW SETS UP ALOFT AND AREA AGAIN RETURNS INTO
A MORE ACTIVE AND WET PATTERN.
TEMPERATURES THROUGH ALL OF THIS WEEK LOOK MILD. HAVE SEEN LOW TO
MID 70S DEVELOP THIS AFTERNOON...WHICH SHOULD BE THE CASE UNTIL
FRIDAY...WHEN COOLER AIR STARTS FILTERING IN BEHIND THE
FRONT...KNOCKING HIGHS BACK DOWN INTO THE 60S. FOR TONIGHT...MORE
MILD EVENING IS IN STORE WITH LOWS STAYING IN THE 40S AND 50S
THANKS TO INCREASED CLOUD COVER AND RAIN...ALONG WITH WAA SEEN
TODAY.
&&
.AVIATION.../18Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED THRU ABOUT 06Z AHEAD OF AN ADVANCING LOW
PRESSURE TROUGH IN THE DAKOTAS. SCT MID LEVEL CLOUDS AND BKN HIGH
LEVEL CLOUDS WILL COMMON AHEAD OF THE TROUGH. EXPECT SHOWERS TO
MOVE INTO FAR WESTERN MN PRIOR TO MIDNIGHT WITH CIGS OF 040-060
DEVELOPING. VSBYS POSSIBLY DOWN TO MVFR IN SHOWERS BUT MAINLY 5SM.
THUNDER CHANCES SLIM...WITH THE BEST CHANCE VCNTY KRWF. WILL
INCLUDE CB CLOUDS GROUPS IN ALL TAFS AT THIS POINT BUT HOLD OFF ON
THE THUNDER. BEST INSTABILITY ADVECTION TAKING AIM AT EASTERN SD
INTO SW AND SOUTH CENTRAL MN...GENERALLY SW OF TAF SITES. EXPECT
THE SHOWERS TO MOVE ACROSS THE REST OF THE FORECAST AREA LATE
TONIGHT AND TUESDAY MORNING. THERE MAY BE A PERIOD OF MVFR CIGS
DEVELOPING JUST BEHIND THE SHOWERS. SFC TROF FORECAST TO PUNCH INTO
SW MN LATE TUESDAY MORNING WITH DRYING AND CLEARING OUT OF THE
LOWER CLOUDS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/JPR
000
FXUS63 KDLH 041958
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
258 PM CDT MON MAY 4 2009
.DISCUSSION...MAIN FORECAST CHALLENGE IS POPS IN THE SHORT TERM.
AFTERNOON SURFACE ANALYSIS DEPICTS LOW PRESSURE NOW STRENGTHENING
ACROSS THE NORTHERN HIGH PLAINS. SURFACE OBSERVATIONS INDICATING
THE LEADING EDGE OF RETURN MOISTURE STRETCHED FROM CENTRAL NORTH
DAKOTA...THROUGH EASTERN SOUTH DAKOTA PER HIGHER DEWPOINTS...AND
ALSO SEEN CLEARLY AS CLOUD LINE ON VISIBLE SATELLITE. JUST CIRRUS
OVER THE NORTHLAND THIS AFTERNOON WITH LOW LEVEL WARM AIR
ADVECTION RESULTING IN MID TO UPPER 60S FOR MOST LOCATIONS...THE
EXCEPTION IS NEAR THE LAKE WHERE THE LAKE BREEZE HAS PUSHED
THROUGH...AS SEEN ON THE KDLH WSR-88D.
AXIS OF MOISTURE/INSTABILITY WILL ADVECT EAST TONIGHT WITH THE AID
OF DEVELOPING 35+ KT LOW LEVEL JET...AND AHEAD OF APPROACHING POTENT
NORTHERN STREAM SHORT WAVE...CURRENTLY SEEN ON WATER VAPOR IMAGERY
OVER THE WESTERN DAKOTAS/MONTANA BORDER. MODELS GENERALLY AGREE NOW
IN TRACK OF THE UPPER LOW THROUGH NORTHERN MINNESOTA TUESDAY
AFTERNOON...HOWEVER NAM IS A BIT FARTHER WEST...AND THEREFORE SLOWER
WITH EASTWARD PROGRESSION OF PRECIP. SHOULD SEE ORGANIZED AREA OF
SHOWERS/ISOLD CONVECTION ALONG THE INSTABILITY AXIS LATE TONIGHT
THROUGH TOMORROW GIVEN STRONG DYNAMICS AND LOW LEVEL FORCING. ALSO
SHOULD SEE SOME INSTABILITY SHOWERS DEVELOP UNDERNEATH LOW CENTER
DURING PEAKING HEATING TUESDAY. INSTABILITY GENERALLY REMAINS WEAK
EXCEPT FOR THE SOUTH/SOUTHEAST ZONES TUESDAY AFTERNOON WHERE 500+
J/KG SBCAPE AND MOISTURE AXIS SET UP. TUESDAY NIGHT...PRECIP SHOULD
MOVE OFF TO THE EAST/NORTHEAST AS THE UPPER LOW PUSHES INTO
ONTARIO...BRINGING A TEMPORARY LULL IN THE ACTIVE PATTERN.
SECONDARY SHORT WAVE IN THE FAST ZONAL FLOW PATTERN WILL TRAVERSE
ACROSS SOUTHERN MN/WI AS IT BECOMES MORE NEGATIVELY TILTED ON
WEDNESDAY...WHILE YET ANOTHER VORT MAX PUSHES INTO NORTHWEST
MINNESOTA. SHOULD SEE STRONG BOUNDARY LIFT INTO THE SOUTHEAST FA
WEDNESDAY...ALONG WITH SUFFICIENT MOISTURE/INSTABILITY/LIFT TO
TRIGGER CONVECTION...AND HAVE RAISED POPS THERE A BIT ACCORDINGLY.
AS NORTHWEST SHORT WAVE TROUGH DEEPENS INTO LOW OVER THE WESTERN
GREAT LAKES WEDNESDAY NIGHT AND THURSDAY...RAIN SHOWERS WILL
ACCOMPANY A SIGNIFICANT LOW LEVEL COLD FRONT...WITH H85 TEMPS
FALLING BELOW ZERO CELSIUS ACROSS THE NORTHERN ZONES BY 00Z FRIDAY.
.EXTENDED...THURSDAY NIGHT THROUGH MONDAY.
A COLD FRONT WILL DEPART THE FA THURSDAY NIGHT. SOME SHOWERS MAY
OCCUR ALONG AND BEHIND THE FRONT. HIGH PRESSURE SETTLES IN
OVERNIGHT. ON FRIDAY...A STRENGTHENING SFC LOW IS PROGGED TO MOVE
THROUGH SOUTHERN MN/WI. THE FA WILL BE ON THE NORTHERN FRINGE OF
THIS SYSTEM WITH A QUESTION OF HOW FA NORTH THE RAIN WILL GET.
MODELS ARE POINTING TO MAINLY THE SOUTHERN HALF OF THE AREA GETTING
WET AND POPS REFLECT THIS PLACEMENT. SOME SHOWERS MAY STILL AFFECT
THE SOUTHERN FA FRIDAY NIGHT AS THE SYSTEM SLOWLY DEPARTS.
SATURDAY AND SUNDAY ARE SETTING UP TO BE RAIN FREE AS HIGH PRESSURE
OVER LAKE SUPERIOR KEEPS DRY AIR FLOWING INTO THE FA. BY NEXT
MONDAY...MODELS DIVERGE IN HANDLING OF THE NEXT SYSTEM MOVING OUT OF
THE ROCKIES INTO THE PLAINS. HAVE SOME POPS IN PLACE...BUT
CONFIDENCE IS EXTREMELY LOW.
&&
.AVIATION...EVEN THOUGH VFR CONDITIONS ARE EXPECTED THROUGH 18Z
TUESDAY...SOME SHOWERS ARE EXPECTED TO BE IN THE VICINITY OF KBRD BY
12Z TUESDAY. THE SHOWERS WILL GRADUALLY SPREAD NORTH AND EASTWARD
WITH TIME AND ARE LIKELY TO BE IN THE VICINITY OF ALL TAF SITES
THROUGH 18Z.
&&
POINT TEMPS/POPS...
DLH 40 60 41 64 / 30 60 30 30
INL 39 61 42 66 / 40 60 30 30
BRD 48 67 44 69 / 60 60 20 20
HYR 42 65 46 69 / 40 60 40 40
ASX 41 63 44 68 / 10 60 40 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
$$
HENRY/GSF
000
FXUS63 KMPX 041808
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
108 PM CDT MON MAY 4 2009
.UPDATE...
ADDED 18Z TAF DISCUSSION BELOW.
&&
.DISCUSSION...
MULTIPLE SYSTEMS TO HAVE SOME IMPACT ON THE FORECAST AREA THROUGH
THIS WEEK...WITH MOST COVERAGE OF RAIN CHANCES TONIGHT AND THEN
TUES NIGHT...WITH THE LATTER STILL FOCUSED MORE IN SRN MN.
TEMPERATURES LOOK TO BE NEAR OR SLIGHTLY ABOVE NORMAL THROUGH THU.
SATELLITE ANALYSIS SHOWS POTENT WAVE OVER THE MT/WY BORDER WITH
LEAD IMPULSE WAVE SHEARING OUT ACROSS THE SD/NE BORDER. LATTER
WAVE IS EXPECTED TO RIDE NORTHEAST ACROSS WESTERN MN
TODAY...KEEPING SOME SCT TO BKN MID TO HIGH CLOUDS. WHILE SOME
SHOWERS HAVE BEEN OBSERVED IN ERN NE...COLUMN IS VERY DRY WITH 00Z
MPX RAOB PWAT AT 60 PERCENT OF NORMAL. MOISTURE RETURN SHOULD BE
SLOW PARTICULARLY IN THE LOW-LEVELS THROUGH TODAY. MIX DOWN
YESTERDAY WAS TO A DEPTH OF ABOUT 750 MB. TODAY IS EXPECTED TO BE
SLIGHTLY UNDER THIS...BUT WITH A WARMER COLUMN THE HIGH TEMPS
SHOULD BE 3 TO 5 DEGREES WARMER. FAR WRN MN WILL BE ALMOST THE
SAME GIVEN SLIGHTLY MORE CLOUDS.
MID-LEVEL VORTEX ACROSS THE MT/WY BORDER TO DEEPEN FURTHER
TONIGHT AS IT MOVES INTO NRN MN. THIS WILL BE IN RESPONSE TO A
LEFT EXIT REGION OF A STRONG JET ENTERING THE WEST COAST THIS
MORNING. THICKNESS DIFLUENCE AHEAD OF THE WAVE INCREASES ACROSS
WRN AND CTRL MN AS THE NIGHT GOES ON. RESPONSIVE STRENGTHENING TO
THE LOW LEVEL JET WILL OCCUR THIS EVE ACROSS THE CTRL TO NRN
PLAINS. THE 300K THETA SFC CAPTURES BOTH ISENTROPIC OMEGA IN THE
MID-LEVELS ALONG WITH STRONG MOISTURE CONVERGENCE FROM THE CTRL
DAKOTAS MOVING INTO MN LATE THIS EVE AND OVERNIGHT. ELEVATED
CONVECTIVE INDICES IMPROVE AS WELL...HOWEVER LACK OF MOISTURE AND
STEEP LAPSE RATES SHOULD KEEP CONVECTION IN CHECK AND MAINLY
CONFINE THE GREATEST COVERAGE TO WESTERN THIRD OF FORECAST AREA.
SOME SMALL HAIL IS POSSIBLE WITH STORMS IN THAT AREA. HAVE BROKEN
OUT A HIGHER TEMPORAL RESOLUTION TO FORECAST WITH PASSING OF
SHOWERS. SHOWERS TO BE LINGERING FROM ERN MN INTO WRN WI EARLY
TUES MORNING.
LOW LEVEL TROUGH ASSOCIATED WITH THE SYSTEM WILL SLOW IN ERN
MN/WRN WI AND SRN MN DURING THE DAY TUES. MOISTURE RETURN AHEAD
WILL CONTINUE UNDER THE MID-LEVEL DRY AIR ADVECTION AND COOL
POCKET...ALLOWING FOR THE POTENTIAL FOR TUES AFTN INSTABILITY AND
THUNDERSTORMS. COVERAGE OF ANY REDEVELOPMENT WOULD BE SCATTERED
AND HAVE KEPT POP TRENDS. ANOTHER WAVE TO RIDE EAST FROM THE CTRL
PLAINS ON TUES NIGHT INTO EARLY WEDS. THIS WOULD BRING POTENTIALLY
BETTER COVERAGE OF RAIN TO SRN MN DURING THAT TIME WITH
OVERRUNNING AND CONVERGENCE ALONG THE ELEVATED BOUNDARY. HAVE
INCREASED POPS BUT NOTE TIMING DIFFERENCES IN THE MODELS AND THUS
HAVE ONLY TRENDED SLOWLY UP. TIMING ISSUES ALSO LEAD TO POPS
BEING HELD ON THE IN THE SOUTHERN AND EASTERN AREAS ON WED.
WHILE TROUGH SHUNTS EAST...THU INTO THE EARLY WEEKEND REMAIN
TRICKY WITH AN ACTIVE WNW FLOW. HAVE BASICALLY KEPT POPS AS IS
JUST WITH SLIGHT REORIENTATION`S. THE DEVELOPING TREND MAY BECOME
FOR INCREASING POPS ON FRI AS 00Z ECMWF BRINGS A FAIRLY POTENT
WAVE THROUGH IN THAT TIME AND HINTS OF THIS IN OTHER DETERMINISTIC
MODELS AND 00Z GFS ENSEMBLE. TEMPS REMAIN AROUND EARLY MAY NORMALS
THROUGH FRI WITH COOLER AIR TO ADVECT IN TO START THE WEEKEND.
CONTINUED UNSETTLED WEATHER /ACTIVE IT SEEMS/ HAS SHOWN UP IN THE
MAY 10TH-11TH TIME FRAME FOR A FEW DAYS NOW SO LIKELY NO BREAK IN
THE SHOWER/T-STORMS CHANCES.
&&
.AVIATION.../18Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED THRU ABOUT 06Z AHEAD OF AN ADVANCING LOW
PRESSURE TROUGH IN THE DAKOTAS. SCT MID LEVEL CLOUDS AND BKN HIGH
LEVEL CLOUDS WILL COMMON AHEAD OF THE TROUGH. EXPECT SHOWERS TO
MOVE INTO FAR WESTERN MN PRIOR TO MIDNIGHT WITH CIGS OF 040-060
DEVELOPING. VSBYS POSSIBLY DOWN TO MVFR IN SHOWERS BUT MAINLY 5SM.
THUNDER CHANCES SLIM...WITH THE BEST CHANCE VCNTY KRWF. WILL
INLCUDE CB CLOUDS GROUPS IN ALL TAFS AT THIS POINT BUT HOLD OFF ON
THE THUNDER. BEST INSTABILITY ADVECTION TAKING AIM AT EASTERN SD
INTO SW AND SOUTH CENTRAL MN...GENERALLY SW OF TAF SITES. EXPECT
THE SHOWERS TO MOVE ACROSS THE REST OF THE FORECAST AREA LATE
TONIGHT AND TUESDAY MORNING. THERE MAY BE A PERIOD OF MVFR CIGS
DEVELOPING JUST BEHIND THE SHOWERS. SFC TROF FORECAST TO PUNCH INTO
SW MN LATE TUESDAY MORNING WITH DRYING AND CLEARING OUT OF THE
LOWER CLOUDS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MTF/JPR
000
FXUS63 KMPX 041035
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
535 AM CDT MON MAY 4 2009
.AVIATION... /12Z TAF ISSUANCE/
HIGH PRESSURE OVER THE REGION THIS MORNING WILL MOVE EAST TODAY AS
A TROF OF LOW PRESSURE ENTERS WESTERN MN AFT 05/06Z. LIGHT WINDS
EARLY IN THE TAF PERIOD WILL BECOME SE BY LATE IN THE MORNING AND
INCREASE TO 10 TO 15 KNOTS BY AFTERNOON. SOME GUSTS TO 20 KNOTS
FOR KAXN AND KRWF AS PRESSURE GRADIENT TIGHTENS. SCT-BKN CI OVER
THE AREA THIS MORNING WILL GIVE WAY TO INCREASING AC/AS THIS
AFTERNOON AND EVENING. A BAND OF SHOWERS AND ISOLATED
THUNDERSTORMS TO PRECEDE THE TROF TONIGHT AND EARLY TUESDAY. BASED
ON TIMING FROM THE 04/00Z 4KM WRF-NMM...USED A 3 HOUR TEMPO GROUP
FOR SHOWERS AND INDICATED CB TO DENOTE THE THREAT OF THUNDER.
EXPECT CEILINGS TO LOWER INTO THE 035-045 FOOT RANGE WITH 3-5 MILE
VISIBILITY AS THE SHOWERS MOVE THROUGH.
&&
.DISCUSSION... /ISSUED 357 AM CDT MON MAY 4 2009/
MULTIPLE SYSTEMS TO HAVE SOME IMPACT ON THE FORECAST AREA THROUGH
THIS WEEK...WITH MOST COVERAGE OF RAIN CHANCES TONIGHT AND THEN
TUES NIGHT...WITH THE LATTER STILL FOCUSED MORE IN SRN MN.
TEMPERATURES LOOK TO BE NEAR OR SLIGHTLY ABOVE NORMAL THROUGH THU.
SATELLITE ANALYSIS SHOWS POTENT WAVE OVER THE MT/WY BORDER WITH
LEAD IMPULSE WAVE SHEARING OUT ACROSS THE SD/NE BORDER. LATTER
WAVE IS EXPECTED TO RIDE NORTHEAST ACROSS WESTERN MN
TODAY...KEEPING SOME SCT TO BKN MID TO HIGH CLOUDS. WHILE SOME
SHOWERS HAVE BEEN OBSERVED IN ERN NE...COLUMN IS VERY DRY WITH 00Z
MPX RAOB PWAT AT 60 PERCENT OF NORMAL. MOISTURE RETURN SHOULD BE
SLOW PARTICULARLY IN THE LOW-LEVELS THROUGH TODAY. MIX DOWN
YESTERDAY WAS TO A DEPTH OF ABOUT 750 MB. TODAY IS EXPECTED TO BE
SLIGHTLY UNDER THIS...BUT WITH A WARMER COLUMN THE HIGH TEMPS
SHOULD BE 3 TO 5 DEGREES WARMER. FAR WRN MN WILL BE ALMOST THE
SAME GIVEN SLIGHTLY MORE CLOUDS.
MID-LEVEL VORTEX ACROSS THE MT/WY BORDER TO DEEPEN FURTHER
TONIGHT AS IT MOVES INTO NRN MN. THIS WILL BE IN RESPONSE TO A
LEFT EXIT REGION OF A STRONG JET ENTERING THE WEST COAST THIS
MORNING. THICKNESS DIFLUENCE AHEAD OF THE WAVE INCREASES ACROSS
WRN AND CTRL MN AS THE NIGHT GOES ON. RESPONSIVE STRENGTHENING TO
THE LOW LEVEL JET WILL OCCUR THIS EVE ACROSS THE CTRL TO NRN
PLAINS. THE 300K THETA SFC CAPTURES BOTH ISENTROPIC OMEGA IN THE
MID-LEVELS ALONG WITH STRONG MOISTURE CONVERGENCE FROM THE CTRL
DAKOTAS MOVING INTO MN LATE THIS EVE AND OVERNIGHT. ELEVATED
CONVECTIVE INDICES IMPROVE AS WELL...HOWEVER LACK OF MOISTURE AND
STEEP LAPSE RATES SHOULD KEEP CONVECTION IN CHECK AND MAINLY
CONFINE THE GREATEST COVERAGE TO WESTERN THIRD OF FORECAST AREA.
SOME SMALL HAIL IS POSSIBLE WITH STORMS IN THAT AREA. HAVE BROKEN
OUT A HIGHER TEMPORAL RESOLUTION TO FORECAST WITH PASSING OF
SHOWERS. SHOWERS TO BE LINGERING FROM ERN MN INTO WRN WI EARLY
TUES MORNING.
LOW LEVEL TROUGH ASSOCIATED WITH THE SYSTEM WILL SLOW IN ERN
MN/WRN WI AND SRN MN DURING THE DAY TUES. MOISTURE RETURN AHEAD
WILL CONTINUE UNDER THE MID-LEVEL DRY AIR ADVECTION AND COOL
POCKET...ALLOWING FOR THE POTENTIAL FOR TUES AFTN INSTABILITY AND
THUNDERSTORMS. COVERAGE OF ANY REDEVELOPMENT WOULD BE SCATTERED
AND HAVE KEPT POP TRENDS. ANOTHER WAVE TO RIDE EAST FROM THE CTRL
PLAINS ON TUES NIGHT INTO EARLY WEDS. THIS WOULD BRING POTENTIALLY
BETTER COVERAGE OF RAIN TO SRN MN DURING THAT TIME WITH
OVERRUNNING AND CONVERGENCE ALONG THE ELEVATED BOUNDARY. HAVE
INCREASED POPS BUT NOTE TIMING DIFFERENCES IN THE MODELS AND THUS
HAVE ONLY TRENDED SLOWLY UP. TIMING ISSUES ALSO LEAD TO POPS
BEING HELD ON THE IN THE SOUTHERN AND EASTERN AREAS ON WED.
WHILE TROUGH SHUNTS EAST...THU INTO THE EARLY WEEKEND REMAIN
TRICKY WITH AN ACTIVE WNW FLOW. HAVE BASICALLY KEPT POPS AS IS
JUST WITH SLIGHT REORIENTATION`S. THE DEVELOPING TREND MAY BECOME
FOR INCREASING POPS ON FRI AS 00Z ECMWF BRINGS A FAIRLY POTENT
WAVE THROUGH IN THAT TIME AND HINTS OF THIS IN OTHER DETERMINISTIC
MODELS AND 00Z GFS ENSEMBLE. TEMPS REMAIN AROUND EARLY MAY NORMALS
THROUGH FRI WITH COOLER AIR TO ADVECT IN TO START THE WEEKEND.
CONTINUED UNSETTLED WEATHER /ACTIVE IT SEEMS/ HAS SHOWN UP IN THE
MAY 10TH-11TH TIME FRAME FOR A FEW DAYS NOW SO LIKELY NO BREAK IN
THE SHOWER/T-STORMS CHANCES.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/MTF
000
FXUS63 KMPX 040857
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
357 AM CDT MON MAY 4 2009
.DISCUSSION...
MULTIPLE SYSTEMS TO HAVE SOME IMPACT ON THE FORECAST AREA THROUGH
THIS WEEK...WITH MOST COVERAGE OF RAIN CHANCES TONIGHT AND THEN
TUES NIGHT...WITH THE LATTER STILL FOCUSED MORE IN SRN MN.
TEMPERATURES LOOK TO BE NEAR OR SLIGHTLY ABOVE NORMAL THROUGH THU.
SATELLITE ANALYSIS SHOWS POTENT WAVE OVER THE MT/WY BORDER WITH
LEAD IMPULSE WAVE SHEARING OUT ACROSS THE SD/NE BORDER. LATTER
WAVE IS EXPECTED TO RIDE NORTHEAST ACROSS WESTERN MN
TODAY...KEEPING SOME SCT TO BKN MID TO HIGH CLOUDS. WHILE SOME
SHOWERS HAVE BEEN OBSERVED IN ERN NE...COLUMN IS VERY DRY WITH 00Z
MPX RAOB PWAT AT 60 PERCENT OF NORMAL. MOISTURE RETURN SHOULD BE
SLOW PARTICULARLY IN THE LOW-LEVELS THROUGH TODAY. MIX DOWN
YESTERDAY WAS TO A DEPTH OF ABOUT 750 MB. TODAY IS EXPECTED TO BE
SLIGHTLY UNDER THIS...BUT WITH A WARMER COLUMN THE HIGH TEMPS
SHOULD BE 3 TO 5 DEGREES WARMER. FAR WRN MN WILL BE ALMOST THE
SAME GIVEN SLIGHTLY MORE CLOUDS.
MID-LEVEL VORTEX ACROSS THE MT/WY BORDER TO DEEPEN FURTHER
TONIGHT AS IT MOVES INTO NRN MN. THIS WILL BE IN RESPONSE TO A
LEFT EXIT REGION OF A STRONG JET ENTERING THE WEST COAST THIS
MORNING. THICKNESS DIFLUENCE AHEAD OF THE WAVE INCREASES ACROSS
WRN AND CTRL MN AS THE NIGHT GOES ON. RESPONSIVE STRENGTHENING TO
THE LOW LEVEL JET WILL OCCUR THIS EVE ACROSS THE CTRL TO NRN
PLAINS. THE 300K THETA SFC CAPTURES BOTH ISENTROPIC OMEGA IN THE
MID-LEVELS ALONG WITH STRONG MOISTURE CONVERGENCE FROM THE CTRL
DAKOTAS MOVING INTO MN LATE THIS EVE AND OVERNIGHT. ELEVATED
CONVECTIVE INDICES IMPROVE AS WELL...HOWEVER LACK OF MOISTURE AND
STEEP LAPSE RATES SHOULD KEEP CONVECTION IN CHECK AND MAINLY
CONFINE THE GREATEST COVERAGE TO WESTERN THIRD OF FORECAST AREA.
SOME SMALL HAIL IS POSSIBLE WITH STORMS IN THAT AREA. HAVE BROKEN
OUT A HIGHER TEMPORAL RESOLUTION TO FORECAST WITH PASSING OF
SHOWERS. SHOWERS TO BE LINGERING FROM ERN MN INTO WRN WI EARLY
TUES MORNING.
LOW LEVEL TROUGH ASSOCIATED WITH THE SYSTEM WILL SLOW IN ERN
MN/WRN WI AND SRN MN DURING THE DAY TUES. MOISTURE RETURN AHEAD
WILL CONTINUE UNDER THE MID-LEVEL DRY AIR ADVECTION AND COOL
POCKET...ALLOWING FOR THE POTENTIAL FOR TUES AFTN INSTABILITY AND
THUNDERSTORMS. COVERAGE OF ANY REDEVELOPMENT WOULD BE SCATTERED
AND HAVE KEPT POP TRENDS. ANOTHER WAVE TO RIDE EAST FROM THE CTRL
PLAINS ON TUES NIGHT INTO EARLY WEDS. THIS WOULD BRING POTENTIALLY
BETTER COVERAGE OF RAIN TO SRN MN DURING THAT TIME WITH
OVERRUNNING AND CONVERGENCE ALONG THE ELEVATED BOUNDARY. HAVE
INCREASED POPS BUT NOTE TIMING DIFFERENCES IN THE MODELS AND THUS
HAVE ONLY TRENDED SLOWLY UP. TIMING ISSUES ALSO LEAD TO POPS
BEING HELD ON THE IN THE SOUTHERN AND EASTERN AREAS ON WED.
WHILE TROUGH SHUNTS EAST...THU INTO THE EARLY WEEKEND REMAIN
TRICKY WITH AN ACTIVE WNW FLOW. HAVE BASICALLY KEPT POPS AS IS
JUST WITH SLIGHT REORIENTATION`S. THE DEVELOPING TREND MAY BECOME
FOR INCREASING POPS ON FRI AS 00Z ECMWF BRINGS A FAIRLY POTENT
WAVE THROUGH IN THAT TIME AND HINTS OF THIS IN OTHER DETERMINISTIC
MODELS AND 00Z GFS ENSEMBLE. TEMPS REMAIN AROUND EARLY MAY NORMALS
THROUGH FRI WITH COOLER AIR TO ADVECT IN TO START THE WEEKEND.
CONTINUED UNSETTLED WEATHER /ACTIVE IT SEEMS/ HAS SHOWN UP IN THE
MAY 10TH-11TH TIME FRAME FOR A FEW DAYS NOW SO LIKELY NO BREAK IN
THE SHOWER/T-STORMS CHANCES.
&&
.AVIATION.../06Z TAF ISSUANCE/
SFC HI PRES MVG ACRS AREA OVRNITE PROVIDING WK WNDS. SFC HI MVS
ACRS GRT LKS ON MON AS TROF MVS INTO DKTS RESULTING IN INCRSG PRES
GRADIENT. WITH MIXING AND INCRSG GRADIENT...W TAF SITES (AXN/RWF) WL
SEE GUSTS NR 20 KTS AFT 20Z. VEIL OF HIGH CLDS MVG ACRS SW MN ATTM
WL CONTINUE TO LIFT NE TNGHT/MON MRNG. UPR TROF MVS ACRS CNTL DKTS
BY 00Z TUE AND INTO W MN BY 06Z. RATHER MARKED INCRS IN MID LVL
INSTAB WITH ARPCH OF TROF. MAY SEE SHWRS/TSTMS REACH W MN TAF SITES
ARND 06Z.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MTF/BAP
000
FXUS63 KDLH 040853
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
353 AM CDT MON MAY 4 2009
.DISCUSSION...MID LVL/SFC SFC RIDGE AXIS LOCATED OVER CWA EARLY
THIS MORNING. CLEAR SKIES/LIGHT WIND/DRY AIR HAS ALLOWED TEMPS TO
FALL INTO MID 20S OVER ARROWHEAD AND INTERIOR WISCONSIN ZONES.
WARMEST READINGS...LOW 40S.. ARE LOCATED ALONG LAKESHORE WHERE
MESOSCALE INFLUENCE OF LAND BREEZE IS NOT ALLOWING AS MUCH
RADIATIONAL COOLING.
TODAY...FCST/GRIDS IN GOOD SHAPE WITH VERY LITTLE CHANGE MADE.
ABUNDANT SUNSHINE EXPECTED WITH DRY AIR COLUMN OVERHEAD. WARMING
TREND CONTINUES WITH 85H TEMPS A FEW DEGREES HIGHER TODAY.
EXCEPTION ALONG LAKE WHERE ONSHORE WIND IN RESPONSE TO FALLING
PRESSURES INLAND WILL KEEP IT NOTICEABLY COOLER...UPPER 40S/LOW 50S.
TONIGHT...LATEST EC/SREF/CMC/NAM/GFS ARE SLOWER WITH
PRECIPITATION ARRIVAL BEFORE 6Z. TWEAKED ZONES/GRIDS ACCORDINGLY
OTHERWISE MAIN FORCING/QPF MOVES IN AFTER 6Z. CONVECTIVE
PARAMETERS...MUCAPE/SHEAR ...NOT VERY SUPPORTIVE OF MUCH
DEVELOPMENT HOWEVER GIVEN MAGNITUDE OF LLJ AND DEVELOPMENT OF
SFC/85H THETAE AXIS.
TUESDAY...INITIAL AREA OF SYNOPTIC SCALE OMEGA WILL PUSH ACROSS CWA
WITH AREA OF RAIN/ISO TSTORMS DURING MORNING HRS. WILL PROBABLY
SEE A LULL BEFORE REDEVELOPMENT OCCURS IN THE AFTERNOON. AS MID
LVL TROF MOVES OVERHEAD EXPECT LAPSE RATES WILL STEEPEN. DESPITE
EXTENSIVE CLOUD CANOPY...SHOULD BE ENOUGH BDRY LAYER WARMING TO
GENERATE INCREASING INSTABILITY. AFTERNOON CONVECTION MAY INCREASE
OVER NWRN WISC IN AREA OF HIGHER 0-6KM SHEAR/MUCAPE.
.TUESDAY NIGHT THROUGH SATURDAY...
INSTABILITY WILL LINGER IN NORTHWEST WISCONSIN ON TUESDAY NIGHT
ALONG THE NOSE OF THE THETA-E RIDGE...AND AHEAD OF A SECONDARY SHORT
WAVE ON THE BACK SIDE OF A DEPARTING LOW PRESSURE SYSTEM. SHOWERS
AND ISOLATED THUNDERSTORMS ARE POSSIBLE BEFORE THE SYSTEM
DEPARTS...AND HAVE RAISED POPS TUESDAY NIGHT.
EXTENDED GETS MORE UNCERTAIN LATER IN THE PERIOD...AS A FAST PACIFIC
FLOW DEVELOPS. THE MAIN UPPER LEVEL PATTERN WILL BE CHARACTERIZED BY
A STRONG UPPER LEVEL (300-200 MB) JET CRUISING THROUGH THE CENTER OF
THE COUNTRY. SHORT WAVES WILL MOVE THROUGH THE FORECAST AREA THROUGH
SATURDAY WITH DIFFICULT TIMING...AND HPC SHOWS LOWER CONFIDENCE IN
THE LONG RANGE PERIOD WITH EQUAL CHANCES OF ANY PARTICULAR MODEL
PANNING OUT. MOISTURE IS NOT ABUNDANT WITH ANY OF THESE LONGER RANGE
SYSTEMS.
THERE ARE SOME SIGNIFICANT DISCREPANCIES BETWEEN THE
EUROPEAN AND THE GFS ON FRIDAY...WITH THE GFS SHIFTING WINDS AT THE
HEAD OF THE LAKE TO EASTERLY AND TRYING TO SNEAK A BACK DOOR COLD
FRONT IN...WHILE THE EUROPEAN KEEPS NORTHWEST FLOW UNTIL
SATURDAY...AND THEN BRINGS THE FRONT THROUGH IN NORTHWEST FLOW.
&&
.AVIATION...VFR FLYING WILL PREVAIL THROUGH THE 6Z TIME FRAME. CIRRUS
WILL RETURN AFTER 0Z. A LOW PRESSURE SYSTEM WILL BRING IN SOME
LOWER CLOUDS DURING THE 6Z - 12Z PERIOD ON TUESDAY. CURRENT TAFS
HAVE A VCSH MENTION AT KBRD AND KHYR BEFORE 6Z...BUT LATEST MODEL
RUNS LOOK TO KEEP ALL TERMINALS DRY THROUGH 6Z. PREVAILING WINDS
WILL GENERALLY BE OUT OF THE SOUTHEAST...WITH MORE OF AN EASTERLY
COMPONENT AT KDLH.
&&
POINT TEMPS/POPS...
DLH 61 45 59 44 / 0 50 50 30
INL 68 45 63 43 / 0 50 40 20
BRD 69 49 67 47 / 10 70 30 20
HYR 70 49 65 47 / 0 50 50 40
ASX 66 43 63 47 / 0 30 60 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
$$
CANNON/DONOFRIO
000
FXUS63 KMPX 040332 AAA
AFDMPX
AREA FORECAST DISCUSSION...UPDATED FOR 06Z TAF
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1030 PM CDT SUN MAY 3 2009
.DISCUSSION...ISSUED 346 PM CDT
QUIET WEATHER ON TAP THROUGH MONDAY AFTERNOON AS WEAK RIDGING AT THE
SURFACE AND ALOFT DRIFTS ACROSS THE UPPER MISSISSIPPI VALLEY. THIS
WILL ALLOW FOR ONE MORE COOL EVENING...AS SKIES CLEAR OUT AND WINDS
GO NEARLY CALM. GUIDANCE HAS BEEN PERFORMING WELL THE LAST COUPLE OF
NIGHTS...SO STAYED CLOSE TO MAV/MET NUMBERS FOR TONIGHT...WHICH WILL
ALLOW FOR 40S SOUTHWEST AND 30S FOR THE NORTHEAST CWA. CLOUDS WILL
BE ON THE INCREASE...ALONG WITH SOUTHEAST WINDS TOMORROW. WITH DRY
AIRMASS IN PLACE...RAIN WILL BE DELAYED IN GETTING HERE AS
MOISTURE STRUGGLES TO RETURN TO THE LOW LEVELS...BUT FELT GOING
FORECAST WAS GOOD ON TIMING OF THINGS MONDAY NIGHT WITH RAINS
AHEAD OF WARM FRONT NOT COMING INTO CWA UNTIL AFTER 00Z TUESDAY.
BEST LIS FROM BOTH GFS AND NAM ARE FORECAST TO BE A LITTLE BELOW
ZERO MONDAY NIGHT/TUESDAY MORNING...SO SHOULD SEE A FEW THUNDERSTORMS
WITH THE WAA/WARM FRONT...THOUGH WITH MINIMAL MOISTURE RETURN THIS
FAR NORTH...SHOULD NOT SEE ANY SEVERE WEATHER.
FROM MONDAY NIGHT INTO WEDNESDAY...ACTIVE PATTERN IS ADVERTISED BY
MODELS AS 120KT PACIFIC JET NOSES INTO NRN PLAINS...KEEPING CWA IN
FAVORED LEFT EXIT REGION OF UPPER JET FOR A PROLONGED PERIOD OF
TIME. AT THE SAME TIME...NORTH/SOUTH ORIENTED FRONT BECOMES STALLED
OUT NEAR THE AREA...AND WITH FAVORABLE UPPER DYNAMICS...ALL MODELS
ARE EXCITING CLUSTERS OF STORMS ACROSS THE CENTRAL CONUS TUESDAY
INTO WEDNESDAY NIGHT. THERE ARE MULTIPLE DISAGREEMENTS BETWEEN
MODELS THIS WEEK...AS EACH STRUGGLES WITH HANDLING OF SUBTLE
FEATURES THAT WILL BE IMPACTING THE WEATHER. MOST PRONOUNCED WAVE IS
ON THE ECMWF AND NAM TUESDAY NIGHT INTO WEDNESDAY AFTERNOON. GFS HAS
THE FEATURE AS WELL...BUT IT IS WEAKER AND FURTHER SOUTH. GIVEN
AGREEMENT BETWEEN NAM AND ECMWF ON THE WAVE...BUMPED POPS UP TO THE
50S FOR SE PORTION OF CWA.
FOR THE REST OF THE PERIOD...WILL SEE RAIN CHANCES DECREASE...WITH
MORE DRY THAN WET PERIODS FOR THE END OF THE WEEK INTO THE WEEKEND
AS PAC JET FINALLY SHIFTS EAST...ALLOWING HIGH PRESSURE TO BUILD
INTO THE AREA. FOR THE END OF THE WEEKEND INTO THE BEGINNING OF NEXT
WEEK...BOTH GFS AND ECMWF ARE GENERATING AN IMPRESSIVE SURFACE LOW
ACROSS THE CENTRAL PLAINS AND BRINGING IT UP THIS DIRECTION...THOUGH
ECMWF IS ABOUT 24 HOURS SLOWER WITH TIMING. IF TRENDS SEEN IN 12Z
RUNS OF ECMWF AND GFS CONTINUE...THIS STORM SYSTEM WILL NEED TO BE
MONITORED CLOSELY IN THE DAYS TO COME.
TEMPERATURES THROUGH THIS WEEK WILL BE VERY SEASONABLE...AS EVEN
MINIMAL SUNSHINE SHOULD ALLOW HIGHS TO GET NEAR 70 THROUGH THURSDAY.
FOR FRIDAY INTO THE WEEKEND...HIGH PRESSURE COMING INTO THE AREA
FROM CANADA WILL HELP BUMP HIGHS BACK DOWN INTO THE LOWER 60S.
&&
.AVIATION.../06Z TAF ISSUANCE/
SFC HI PRES MVG ACRS AREA OVRNITE PROVIDING WK WNDS. SFC HI MVS
ACRS GRT LKS ON MON AS TROF MVS INTO DKTS RESULTING IN INCRSG PRES
GRADIENT. WITH MIXING AND INCRSG GRADIENT...W TAF SITES (AXN/RWF) WL
SEE GUSTS NR 20 KTS AFT 20Z. VEIL OF HIGH CLDS MVG ACRS SW MN ATTM
WL CONTINUE TO LIFT NE TNGHT/MON MRNG. UPR TROF MVS ACRS CNTL DKTS
BY 00Z TUE AND INTO W MN BY 06Z. RATHER MARKED INCRS IN MID LVL
INSTAB WITH ARPCH OF TROF. MAY SEE SHWRS/TSTMS REACH W MN TAF SITES
ARND 06Z.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/BAP
000
FXUS63 KDLH 040246 AAA
AFDDLH
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
946 PM CDT SUN MAY 3 2009
.UPDATE...
MINOR ADJUSTMENT TO CONTINUE DOWNWARD TREND OF TEMPERATURES
OVERNIGHT ANOTHER 3-5 F OVER NRN HALF OF FA WHERE TEMPERATURES IN
THE LAST HR FELL ON THE ORDER OF 10-15 F DUE OT THE STRONG
RADIATIONAL COOLING AND DRY AIR MASS IN PLACE. ADJUSTED DEW
PTS/RH FIELDS DOWNWARD AS WELL TO BETTER REPRESENT CURRENT
READINGS IN THE UPR TEENS TO MID 20S...ABOUT 5 F LOWER THAN
GUIDANCE ATTM.
&&
.PREV DISCUSSION... /ISSUED 333 PM CDT SUN MAY 3 2009/
DISCUSSION...MAIN FORECAST CHALLENGE IS POPS EARLY THIS WEEK.
AFTERNOON SURFACE ANALYSIS DEPICTS ANOTHER WEAK TROUGH CURRENTLY
PUSHING INTO NORTHWEST WISCONSIN. NORTHLAND REMAINS UNDER
INFLUENCE OF BROAD CANADIAN UPPER TROUGH. A WEAK VORT MAX MOVING
SOUTHEAST THROUGH THE FLOW ALOFT...ALONG WITH STRONG SURFACE
HEATING AND MIXING...HAS RESULTED IN SUBSTANTIAL CUMULUS FIELD
ACROSS THE NORTHWEST WISCONSIN ZONES. CU FIELD/GUSTY WINDS SHOULD
DIMINISH QUICKLY WITH LOSS OF HEATING AND EXIT OF SHORT WAVE THIS
EVENING. HIGH PRESSURE SETTLING INTO THE REGION TONIGHT WITH A
CLEAR AND DRY AIRMASS IN PLACE...WILL RESULT IN STRONG RADIATIONAL
COOLING. WENT A BIT COOLER THAN GUIDANCE ACCORDINGLY FOR OVERNIGHT
LOWS TONIGHT.
RETURN FLOW SETS IN MONDAY WITH STRONG LOW LEVEL WARM AIR ADVECTION
AND RIDGE OVERHEAD. H85 TEMPS CLIMB TO 5C TO 8C ACROSS THE FA BY 00Z
TUESDAY. WITH MOSTLY SUNNY CONDITIONS...TEMPERATURES WILL BE A FEW
DEGREES OR MORE WARMER THAN TODAY. THE EXCEPTION HOWEVER WILL BE
NEAR LAKE SUPERIOR...WHERE THE NE LAKE BREEZE IS LIKELY TO PUSH
ONSHORE MONDAY WITH SSE SFC WINDS ELSEWHERE. AXIS OF MOISTURE RETURN
EVIDENT IN LOW LEVEL THETA-E FIELD...DEVELOPS ACROSS THE HIGH
PLAINS MONDAY AND PUSHES EASTWARD MONDAY EVENING/NIGHT IN RESPONSE
TO APPROACHING AND STRENGTHENING NEGATIVELY TILTED SHORT
WAVE...CURRENTLY OVER THE PACIFIC NORTHWESTERN STATES PER WATER
VAPOR IMAGERY.
AS THIS LOW PUSHES NORTHEAST INTO ONTARIO MONDAY NIGHT...LIFT ALONG
LEADING EDGE OF THETA-E RIDGE...ALONG WITH FORCING FROM 40+ KT LOW
LEVEL JET WILL RESULT IN SOME ORGANIZED SHOWERS/TSTMS MONDAY NIGHT
INTO TUESDAY. SOME TIMING DIFFERENCES IN THE MODELS STILL...WITH THE
NAM STILL THE SLOWEST WITH EASTWARD PROGRESSION OF QPF.
TUESDAY...SHOWER/ISO TSTMS ALONG AXIS OF WEAK INSTABILITY WILL PUSH
EAST ACROSS THE FA...AS DRY SLOT PUSHES IN FROM THE WEST. FOR
TUESDAY NIGHT INTO WEDNESDAY...SOME MAJOR DIFFERENCES EXIST IN THE
MODELS REGARDING SECONDARY SHORT WAVE TO THE SOUTH...AND THE
NORTHERN EXTEND OF ASSOCIATED PRECIP. WILL LEAVE JUST CHANCE POPS
ATTM AS MOST OF THE FORCING LOOKS TO REMAIN SOUTH OF THE FA.
EXTENDED...WEDNESDAY NIGHT THROUGH THE FOLLOWING WEEKEND...
A PACIFIC FLOW WILL CARRY WEAK PROGRESSIVE RIDGES AND TROUGHS
ALOFT THROUGH THE AREA DURING THE PERIOD. WITH A FAIRLY COLD
COLUMN ALOFT AND A HIGH SUN ANGLE...SCATTERED MOSTLY AFTERNOON AND
EARLY EVENING SHOWERS INTERSPERSED BY SUNNY PERIODS WILL CONTINUE
THROUGH THE PERIOD. WITH NO ACTUAL MOISTURE SOURCE...PRIND SHOWERS
WILL BE WEAK. THE EUROPEAN TRIES TO DEEPEN A TROUGH ENOUGH TO
BRING POLAR AIR AND WET SNOW INTO OUR AREA EARLY THE COMING
WEEKEND...BUT THE OTHER MODELS DO NOT SUPPORT THIS.
AVIATION...VFR CONDS THROUGH THE TAF PD. SCT CUMULUS WILL CLEAR
LATE THIS AFTERNOON...AND GUSTY WINDS WILL BECOME LIGHT TO CALM BY
SUNSET. WINDS BECOME SERLY ON MON ON THE BACK SIDE OF HIGH PRES.
&&
POINT TEMPS/POPS...
DLH 30 61 42 59 / 0 10 40 40
INL 24 68 44 63 / 0 10 50 40
BRD 34 69 48 67 / 0 10 50 30
HYR 28 70 45 65 / 0 0 30 40
ASX 28 66 42 63 / 0 0 20 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
$$
GRANING/HENRY
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