000
FXUS62 KTAE 110821
AFDTAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
250 AM EDT SAT OCT 11 2008

.SYNOPSIS...
AT 2 AM EDT...FAIR SKIES DOMINATED THE FORECAST AREA. TEMPS RANGED
FROM MID 60S NORTH TO AROUND 70 COAST. 24 HR TEMP/DEW POINT
COMPARISON INDICATES THAT LOCAL AIRMASS SLIGHTLY WARMER AND WETTER
THAN SAME TIME YESTERDAY. WINDS WERE GENERALLY NE AROUND 5 MPH.

AT UPPER LEVELS...
AMPLIFIED CONUS PATTERN TO CONTINUE HIGHLIGHTED BY A POSITIVELY
TILTED TROF LOCATED ACROSS THE WRN CONUS AND A LARGE RIDGE BUILDING
OVER ERN CONUS. TWO UPPER LOWS OF NOTE. STRONG LOW OVER GREAT BASIN
TO DRIFT INTO CNTRL ROCKIES BY SUNDAY MORNING. CLOSER TO HOME...
STACKED LOW DRIFTING EWD JUST OFF THE SC/GA COAST. MID LEVEL
DRY AND STABLE AIR IS WRAPPING AROUND THIS LOW AND DOMINATING SE
REGION. AS THE DEEP TROUGH AMPLIFIES OVER WRN CONUS AND RIDGE
STRENGTHENS OVER THE ERN CONUS LATER TODAY...THE SC/GA LOW SEPARATES
FROM MAIN FLOW AND BECOMES EMBEDDED IN THE EASTERLIES. THIS WILL
FORCE IT TO RETROGRADE BENEATH RIDGE AND WWD ACROSS FL BEGINNING
TODAY WITH A MINOR INCREASE IN PVA...MAINLY ERN ZONES. MODELS SHOW
THAT LOW PROGGED TO SLOWLY FILL OVER THE NEXT 36 HRS...ENDING UP
OVER THE ERN GOMEX BY SUNDAY EVENING AND WRN GULF ON WEDNESDAY.

AT LOWER LEVELS...
LOW LEVELS HIGHLIGHTED TODAY BY AN AREA OF HIGH PRESSURE MOVING FROM
GREAT LAKES TO OVER NEW ENGLAND AND AN INVERTED TROF JUST OFF THE
SOUTH CAROLINA COAST (AND JUST E OF H5 LOW) WITH NORTHEASTERLY FLOW
DOMINATING THE SE REGION. AS UPPER RIDGE INTENSIFIES...SURFACE RIDGE
OVER N ENGLAND WILL DROP S ALONG ERN SEABOARD THRU MONDAY. THIS WILL
INDUCE THE TROUGH TO WEAKEN FURTHER AND SHIFT WSW UNDER RIDGE DURING
THAT TIME. LOCALLY...THE COMBINATION OF THE SURFACE RIDGE SLIDING
DOWN THE APPALACHIANS AND SWWD MOVING LOW WILL INCREASE LOW LEVEL
CONVERGENCE AND GENERATE TIGHTER NE GRADIENTS MOST PRONOUNCED ON
MONDAY. MOISTURE FIELD ALSO WRAPPING AROUND N SIDE OF LOW.

LEADING EDGE OF SHOWERS/RAIN WILL MOVE SWWD INTO THE ERN ZONES SAT
AFTERNOON THEN INCREASE IN COVERAGE ON SUN. THIS REFLECTED IN
TIME HEIGHT X-SECTIONS AND MODEL SOUNDINGS. I.E. GFS TAE 1.18 PWAT
AT 06Z SAT INCREASING TO 1.77 PWAT AT 00Z MON. ZFP WILL SHOW NE-SW
POP AND WIND GRADIENT. AS STACKED LOW DECOUPLES...DEEP MOISTURE WILL
BE LIMITED SO HEAVY RAIN NOT EXPECTED. MOSTLY CLOUDY SKIES WILL HELP
TO KEEP TEMPERATURES CLOSE TO SEASONAL NORMS. HIGH PRESSURE WILL
SHIFT S BY THE BEGINNING OF NEXT WEEK...WITH LIGHTER E FLOW AND
DRIER CONDITIONS.

.SHORT TERM (TODAY THROUGH MONDAY)...
THIS MORNING...00Z KTAE SOUNDING CONTINUES TO SHOW A MOIST LOW LEVEL
AROUND 890 MB WITH VERY DRY AIR NOTED ABOVE 815 MB. THE PRECIPITABLE
WATER CAME IN AT 1.07. SREF PROBABILITIES FOR REDUCTION IN
VISIBILITIES LESS THAN 3 MILES IS 30 TO 40 PERCENT WITH VALUES
AROUND 25 PERCENT FOR CIGS LESS THAN 1500 FT. LATEST SATELLITE PIX
SHOW FOG BEGINNING TO DEVELOP ALONG I-75 AND MOVING WWD. THINK WE
WILL SEE AREAS OF FOG AND/OR STRATUS DEVELOP FURTHER TOWARDS
SUNRISE...ESPECIALLY SE THIRD OF CWA. AND THIS REFLECTED IN GRIDS.

REST OF TODAY...AFTER ANY LOW CLOUDS BURN OFF...DRY SINKING AIR ON
WEST SIDE OF ABOVE LOW WILL ENCOURAGE SOME SUN. INLAND HIGHS IN LOW
80S. 0-30 PCT W-E POP GRADIENT WITH LIGHT RAIN. INCREASING BOUNDARY
LAYER WINDS AND CLOUD COVER SHOULD HELP PRECLUDE WIDESPREAD FOG FROM
FORMING TONIGHT AND KEEP INLAND LOWS IN MID 60S.

SUNDAY...20-50 PCT W-E POP GRADIENT...ISOLD TSTMS POSSIBLE
ESPECIALLY E HALF OF CWA. INLAND HIGHS IN FROM AROUND 80 N TO MID
80S S. E WINDS INCREASE TO MODERATE.

MONDAY...20 PCT POPS ACROSS CWA. INLAND HIGHS IN LOW 80S. LOCALLY
BREEZY EAST WINDS.

.LONG TERM (TUESDAY THROUGH SATURDAY)...AFTER SEVERAL RUNS SHOWING
GOOD AGREEMENT BETWEEN THE GFS AND 12 UTC ECMWF...THEIR LONG RANGE
SOLUTIONS ARE BEGINNING TO DIVERGE. BOTH MODELS SHOW AN UPPER RIDGE
HANGING ON OVER THE SE U.S ON TUESDAY. THE GFS THEN RETROGRADES THE
HIGH TO THE WESTERN GULF BY THURSDAY WITH A ZONAL PATTERN DEVELOPING
ACROSS MUCH OF THE CONUS WHICH STALLS A WEAK SURFACE FRONT WELL
NORTH OF THE LOCAL REGION. THE UPPER RIDGE THEN BUILDS DURING THE
REMAINDER OF THE PERIOD WITH AXIS THROUGH THE NATIONS MID SECTION
WHICH INDUCES WEAK TROUGHING ALONG THE EASTERN U.S.  THE ECMWF
SOLUTION SHOWS THE UPPER RIDGE LINGERING OVER THE SE CORNER OF THE
U.S WEDNESDAY. THE RIDGE THEN WEAKENS AND RETREATS TO THE EAST AS A
DEEPENING TROUGH SWINGS FROM THE PLAINS ON THURSDAY AND OFF THE SE
U.S COAST ON SATURDAY. AT THE SURFACE...THIS SENDS A COLD FRONT INTO
AND ACROSS OUR CWA LATE FRIDAY/EARLY SATURDAY WITH A MUCH DRIER
AIRMASS FILTERING IN ON SATURDAY. THE ECMWF SHOWS ONLY LIGHT QPF
AMOUNTS WITH THIS FRONT. EITHER SOLUTION...TUESDAY THROUGH THURSDAY
SHOULD BE DRY. THE ONLY DAYS IN QUESTION FOR POPS WILL BE FRIDAY AND
SATURDAY. DUE TO THE UNCERTAINTY...WILL LEAVE OUT ANY MENTION OF
POPS FOR NOW. TEMPS WILL CONTINUE TO BE ABOVE CLIMO WITH MAX
READINGS GENERALLY IN THE MID TO UPPER 80S AND MIN TEMPS IN THE
LOWER TO MID 60S.

&&

.AVIATION...THE FOG PRODUCT (11U-3.9U SATELLITE IMAGERY) AND
DOWNSTREAM METARS ARE SHOWING A BLANKET OF STRATUS RAPIDLY SPREADING
INTO THE REGION FROM THE EAST. BY DAYBREAK...MOST OR ALL OF OUR TAF
SITES SHOULD BE EXPERIENCING IFR/LIFR CIGS/VSBYS. LIKE YESTERDAY...
IT MAY TAKE UNTIL LATE MORNING OR EARLY AFTERNOON FOR CONDITIONS TO
IMPROVE TO VFR LEVELS. A FEW SHOWERS WILL DEVELOP IN THE AFTERNOON
OVER NE FLORIDA AND SE GEORGIA AND MOVE WEST. SOME OF THIS ACTIVITY
MAY REACH" onClick="return popup(this, 'notes')">REACH VLD IN THE EVENING. WENT WITH A PROB30 GROUP FOR SHOWERS
AT VLD FROM 00Z TO 06Z TO COVER THIS POSSIBILITY.

&&

.MARINE...GRADIENT WILL REMAIN WEAK THIS MORNING BEFORE SLOWLY
TIGHTENING DURING THE DAY AS TROUGH OF LOW PRESSURE/INVERTED TROUGH
SLIDES WEST AND HIGH PRESSURE BUILDS DOWN THE EAST SIDE OF
APPALACHIANS. EXERCISE CAUTION CONDITIONS POSSIBLE BY TONIGHT WITH
ADVISORY CONDITIONS BY LATE SUNDAY. THE TIGHT GRADIENT IS EXPECTED
TO KEEP WINDS NEAR ADVISORY LEVELS THROUGH EARLY NEXT
WEEK...ESPECIALLY OVER THE OFFSHORE LEGS.


&&

.FIRE WEATHER...AMPLE LOW LEVEL MOISTURE WILL KEEP AFTERNOON RH
VALUES ABOVE CRITICAL LEVELS THROUGH THE WEEKEND.

&&

.PRELIMINARY POINT TEMPS/POPS...
TALLAHASSEE  82  67  83  68 /  10  20  40  20
PANAMA CITY  82  69  84  70 /  05  10  20  20
DOTHAN       80  65  79  65 /  10  20  30  20
ALBANY       79  66  80  67 /  20  30  50  20
VALDOSTA     81  66  81  67 /  30  40  50  20
CROSS CITY   84  67  85  68 /  20  20  40  20

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
GA...NONE.
FL...NONE.
GM...NONE.
&&

$$

BLOCK/BARRY