FXUS63 KGRB 201617
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1017 AM CST TUE JAN 20 2009
.UPDATE...A QUICK UPDATE TO REFLECT LATEST CLOUD AND TEMP
TRENDS. CLOUD MASS OVER NORTHERN WI IS SLOWLY PROGRESSING TO THE
EAST AND SHOULD MOVE INTO FAR NORTHEAST WISCONSIN LATER THIS
AFTERNOON. SCT TO OCCASIONAL FLURRIES WILL CONTINUE TO FALL OUT OF
THESE CLOUDS...ALTHOUGH DO EXPECT SOME EROSION OVER THE SOUTHERN
PERIPHERY AS THE SURFACE RIDGE AXIS SHIFTS EAST. BECAUSE OF THE
PROLONGED CLOUD COVER ACROSS THE NW...HAVE LOWERED TEMPS 2-3
DEGREES. REST OF THE FORECAST IS IN GOOD SHAPE.
ZONES ALREADY OUT.
MPC
&&
.PREV DISCUSSION...ISSUED AT 340 AM CST TUE JAN 20 2009...
SHORT TERM...TODAY THROUGH WEDNESDAY.
HIGHLY AMPLIFIED FLOW TO CONTINUE THROUGH MUCH OF THIS
PERIOD WITH STRONG WESTERN RIDGE AND TROF OVER THE EASTERN LAKES.
SOME WEAK DISTURBANCES TO CONTINUE TO SHIFT SOUTH THROUGH TROF
THIS AM. IN ADDITION NORTH TO NORTHEAST FLOW THIS MORNING BRINGING
CLOUDS AND LIGHT SNOW OFF THE LAKES OVER NORTH CENTRAL AND EASTERN
WISCONSIN. WILL CONTINUE THIS TREND THROUGH THE MORNING
HOURS...ENDING THIS AFTERNOON AS FLOW SHIFTS WEST. SURFACE TROF TO
SHIFT EAST THROUGH THE STATE LATE TONIGHT AND WED WITH WAA AHEAD OF
TROF. QUESTION IS HOW MUCH OF THIS WARMING WILL BE REALIZED AT THE
SURFACE AS LLVL INVERSION INCREASES.
NCEP MODELS ALSO ALL HINTING AT INCREASE IN LLVL MOISTURE AROUND
925MB LATE TONIGHT INTO WED. GIVEN CURRENT SAT TRENDS...VERY
PLAUSIBLE. THIS INCREASE IN CLOUDS AND THOUGHTS THAT MUCH OF
WARMING WILL BE REALIZED ALOFT...LEAD TO SIDING WITH COOLER
GUIDANCE...MORE TOWARDS SREF MEAN.
LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
FOR WEDNESDAY NIGHT...MODELS HINTING AT LOW LEVEL MOISTURE BEING
TRAPPED BELOW AN INVERSION. THIS IS ESPECIALLY TRUE WITH THE WRF
MODEL. SINCE THE SHORT TERM FORECASTER WENT WITH MORE CLOUDS ON 
WEDNESDAY...HAVE INCREASED CLOUDINESS FOR WEDNESDAY NIGHT AS WELL
SINCE THE CLOUDS WILL NOT DISSIPATE AFTER SUNSET. A TRANQUIL 
DAY IS EXPECTED ON THURSDAY AS THE NEXT ARCTIC COLD FRONT SLOWLY
PUSHES TOWARDS WISCONSIN.
FOR THURSDAY NIGHT...FRONT SAGS INTO THE AREA. DECENT LOW LEVEL
MOISTURE SPREADS SOUTH INTO NORTHERN WISCONSIN BEHIND THE FRONT.
ALL THE MODELS SHOW VERY LITTLE MOISTURE AROUND 700MB...SO ANY 
SNOW WILL BE CONFINED TO THE SNOWBELT REGION OF NORTHERN WISCONSIN
WHERE WIND TRAJECTORIES WILL BECOME FAVORABLE FOR SOME LAKE EFFECT
SNOW SHOWER ACTIVITY. SOME MID LEVEL MOISTURE WILL MOVE ACROSS
THE AREA FRIDAY...THEREFORE KEPT THE CHANCE OF SNOW SHOWERS 
ACROSS THE SNOWBELT REGION WITH A CHANCE OF FLURRIES OVER THE 
REMAINDER OF THE FORECAST AREA. STILL SOME DOUBT IF THERE WILL
BE ENOUGH MOISTURE IN THE SOUTHERN PORTION OF THE FORECAST AREA
FOR THE SEEDER FEEDER MECHANISM TO PRODUCE SNOW. LATER SHIFTS MAY 
NEED TO REASSESS THE FLURRIES OVER THE SOUTH FRIDAY.
MUCH COLDER AIR WILL WORK INTO THE REGION FRIDAY NIGHT WITH 
READINGS FALLING TO NEAR ZERO ALONG THE LAKE SHORE AND WELL BELOW
ZERO ACROSS CENTRAL AND NORTH CENTRAL WISCONSIN. BELOW NORMAL
TEMPERATURES WILL CONTINUE INTO EARLY NEXT WEEK.
AVIATION...LOW/MVFR/ CIGS EXPECTED FROM TIME TO TIME TODAY AS
LLVL MOISTURE CONTINUES TO CIRCULATE SOUTH OFF LAKES/THROUGH TROF.
EXPECT INCREASE IN LLVL MOISTURE THROUGH PERIOD WITH WIDESPREAD
MVFR CIGS LATE TUE INTO WED.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$