FXUS62 KTAE 070732
AFDTAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
232 AM EST MON DEC 7 2009
.SHORT TERM (TODAY-WEDNESDAY)...
OUTSIDE OF SOME MINOR TIMING DIFFERENCES...THIS MODEL PACKAGE IS IN
DECENT AGREEMENT OVER THE NEXT COUPLE OF DAYS. SOUTHWEST FLOW ALOFT
WITH A FEW WEAK IMPULSES WILL CONTINUE ACROSS THE SOUTHEAST AS A
STRONG SHORT WAVE TROUGH DIGS SOUTHEAST TOWARD THE FOUR CORNERS
REGION TODAY. THIS SHORT WAVE TROUGH WILL TRANSLATE EAST OVER THE
PLAINS TUESDAY...THEN NORTHEAST TOWARD THE GREAT LAKES WEDNESDAY. AT
THE SURFACE...MOISTURE AND TEMPERATURES WILL STEADILY RISE ACROSS
THE GULF COAST STATES AND THE REGION THROUGH THE PERIOD AS THE
WINDS VEER TOWARD THE SOUTH AHEAD OF AN APPROACHING COLD FRONT
COME THE MID-WEEK PERIOD.
TODAY THROUGH TUESDAY...A WEAK IMPULSE WITHIN THE SOUTHWEST FLOW
ALOFT COMBINED WITH A WEAK SURFACE REFLECTION AND DEVELOPING WARM
FRONT OVER THE NWRN GULF WILL LEAD TO INCREASING RAIN CHANCES OVER
EASTERN TX AND THE LOWER MS VALLEY THROUGH THE DAY TODAY. WINDS WILL
SHIFT TO SOUTHEAST THROUGH THE DAY TUESDAY AS THE WARM FRONT LIFTS
NORTHEAST ACROSS THE REGION...WHICH WILL ALLOW THE WARM SECTOR TO
EXPAND EASTWARD OVER THE GULF COAST STATES. DEW POINTS OVER OUR AREA
ARE FORECAST TO RISE INTO THE LOW TO MID 60S ACROSS THE SOUTHERN
HALF OF THE LOCAL AREA COME TUESDAY AFTERNOON. THIS MOISTURE
COMBINED WITH INCREASING LIFT WILL TRANSLATE INTO INCREASING RAIN
CHANCES TUESDAY...WITH A NW TO SE POP GRADIENT.
ON WEDNESDAY...LARGE SURFACE LOW OUT WEST WILL QUICKLY LIFT
NORTHEAST TOWARD THE GREAT LAKES DRAGGING A COLD FRONT ACROSS THE
DEEP SOUTH FROM WEST TO EAST. INCREASING LOW/DEEP LAYER WIND SHEAR
AND INSTABILITY MAY LEAD TO SOME STRONGER STORMS ACROSS PORTIONS OF
THE LOCAL AREA...ESPECIALLY OVER SOUTHEAST ALABAMA. THE NAM IS
INDICATING 50-60 KT 0-6KM BULK SHEAR AND SB CAPE INCREASING TO
AROUND 500-770 J/KG OVER SE ALABAMA.
.LONG TERM...(WEDNESDAY NIGHT-SUNDAY)...
THE MEDIUM RANGE GUIDANCE AGREES THAT THE RATHER AMPLIFIED H5/H2
TROUGH FROM NRN CANADA SEEN DURING THE MID WEEK PERIOD WILL MOVE EWD
AND TREND TOWARDS A BROADER/FLATTER PATTERN BY THE UPCOMING
WEEKEND...WITH LARGELY ZONAL FLOW ACROSS SRN HALF OF CONUS. AT SAME
TIME WE SEE EVIDENCE OF UPSTREAM RIDGING OVER WRN CONUS. STILL...SRN
STREAM REMAINS SUFFICIENTLY ACTIVE THRU MUCH OF EXTENDED TO CONTINUE
SENDING A SERIES OF SRN STREAM SHORTWAVES DOWNSTREAM TO GENERATE
SURFACE WAVES LIFTING STALLED FRONT(S) BACK NORTH AND PUSHING COLD
FRONTS INTO SE REGION IN A REPEAT OF RECENT EL NINO PATTERN.
AT LOWER LEVELS...AS ABOVE TROUGH MOVES EWD...ASSOCIATED COLD FRONT
MOVES ACROSS LOCAL REGION EXITING CWA LATE WED NIGHT. ALTHOUGH UPPER
SUPPORT REMAINS WELL NORTH OF THE FORECAST AREA...FRONT MAY BRING A
CHANCE OF TSTMS BEFORE STALLING ACROSS S/CNTRL GULF LATE WED NIGHT
INTO EARLY THURS. IN ITS WAKE...HIGH PRESSURE BUILDS OVER SE CONUS
BRIDGING THE FRONT WITH A RETURN TO LOW LEVEL NNE FLOW YIELDING A
MODESTLY DRIER AND COOLER AIRMASS. BUT...AS HIGH MOVES E OF
CWA...AHEAD OF NEXT UPSTREAM LOW...FLOW QUICKLY BECOMES ONSHORE
THURS/FRI. THIS LOW DEVELOPS IN THE LWR MS VALLEY TO MOVE RAPIDLY
ACROSS THE SOUTHEAST U.S. FRIDAY NIGHT REACHING THE MID-ATLC COAST
LATER ON SAT. INITIALLY THIS STRONGER LOW (WITH UPPER DYNAMICS
FURTHER S THAN PREVIOUS SYSTEM) WILL HELP LIFT STALLED GULF BOUNDARY
BACK NWD FOR INCREASING CLOUDS AND POSSIBLY LIGHT RAIN THURS AFTN
AND EVE (ESPECIALLY SRN THIRD OF CWA) FOLLOWED BY GOOD CHANCE OF
SHWRS/ISOLD TSTMS OVERSPREADING CWA FRI-SAT AHEAD OF COLD FRONT.
THIS FRONT WILL APPROACH CWA BY EARLY SAT AND EXIT RAPIDLY SEWD TO
N/CNTRL FL BY SAT EVE AND SHOW MORE UPPER SUPPORT THAN EARLIER
SYSTEM. IN ITS WAKE...EXPECT DRIER AND COOLER AIR ADVECTING SEWD
INTO THE LOCAL AREA LATE SAT NIGHT THRU SUNDAY.
WITH INITIAL COLD FRONT EXITING LOCAL REGION EXTENDED PERIOD
COMMENCES...LINGERING 20 PCT POPS WED NIGHT. IN WAKE OF THIS
FRONT/LOW...NIL POPS THURS INTO EARLY FRI MORN...THEN AHEAD AND
ALONG NEXT WX SYSTEM...HI SCT POPS FRI AFTN-FRI NIGHT
DECREASING TO SCT SAT THEN ISOLD-WDLY SCT SAT NIGHT AND NO POPS ON
SUN. AS FAR AS TEMPS...PERIOD BEGINS WITH MOISTURE/CLOUDS FROM
EXITING COLD FRONT KEEPING MIN TEMPS WED NIGHT 8-13 DEGREES ABOVE
CLIMO (CLIMO IS LOW 40S) WHILE MAX TEMPS ON THURS DROP TO LOW 60S OR
SLIGHTLY BELOW CLIMO (CLIMO IN MID 60S). THEN...WITH COOL DRY
AIRMASS BRIEFLY BUILDING IN...MIN TEMPS AROUND CLIMO THURS NIGHT
BEFORE INCHING UP TO AROUND 8 DEGREES ABOVE CLIMO BY SAT NIGHT AHEAD
OF NEXT WX SYSTEM. IN WAKE OF STRONGER FRONT...INLAND MIN TEMPS DROP
INTO UPPER 30S ON SUNDAY.
&&
.MARINE...WINDS AND SEAS WILL SHIFT TOWARD THE SOUTHEAST TONIGHT AND
TUESDAY...THEN SOUTHWEST THROUGH THE DAY WEDNESDAY AS ANOTHER FRONT
APPROACHES FROM THE WEST. ADVISORY LEVEL WINDS AND SEAS WILL BE
POSSIBLE TUESDAY NIGHT AND WEDNESDAY AS THE GRADIENT TIGHTENS ACROSS
THE GULF. IN ADDITION TO THE INCREASING WINDS AND SEAS...INCREASING
RAIN CHANCES WILL BE EXPECTED TUESDAY THROUGH WEDNESDAY. A COLD
FRONT WILL MOVE EAST OVER THE MARINE AREA SOMETIME AROUND WEDNESDAY
AND WEDNESDAY NIGHT WITH GUSTY NORTHWEST WINDS FOLLOWING ITS PASSAGE
THROUGH THE DAY THURSDAY.
&&
.AVIATION (THROUGH 06Z TUESDAY)...REST OF OVERNIGHT...SOME MID AND
HIGH CLOUDS WILL CONTINUE TO STREAM IN FROM THE SOUTHWEST. WITH
GRADUALLY VEERING FLOW...LOW LEVELS WILL CONTINUE TO MOISTEN WITH
CIGS/VSBYS REDUCED. MVFR CIGS POSSIBLE AT KPFN...OTHERWISE MVFR
CIGS/VSBY WITH BRIEF IFR LIKELY OTHER TERMINALS...AND WITH BRIEF
IFR/LIFR CONDITIONS AT VLD AND POSSIBLY AT TLH. LOW CLOUDS SHOULD
LIFT AND VISIBILITY SHOULD IMPROVE AFTER 9 AM EST WITH SUFFICIENT
HEATING. THIS WILL USHER IN VFR CONDITIONS WITH MAINLY HIGHER CLOUDS
FOR THE REST OF THE DAY. BY 06Z TUES...CLOUDS WILL BEGIN TO LOWER
AND MVFR CIGS/VSBYS WILL AGAIN BEGIN TO DEVELOP ESPECIALLY AT KVLD.
&&
.FIRE WEATHER...LOW LEVEL MOISTURE AND CLOUDINESS WILL INCREASE
TODAY AS THE NEXT SYSTEM TAKES SHAPE TO THE WEST. RAIN IS THEN
EXPECTED ON TUESDAY AND WEDNESDAY AHEAD OF A COLD FRONT. NO RED FLAG
CONDITIONS ARE ANTICIPATED THROUGH THE MIDDLE OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TALLAHASSEE 71 53 72 63 77 / 0 10 50 30 50
PANAMA CITY 67 55 70 63 75 / 10 10 50 40 50
DOTHAN 63 51 69 63 75 / 10 10 70 50 50
ALBANY 65 49 69 63 76 / 0 10 60 50 50
VALDOSTA 70 52 73 63 78 / 0 10 50 40 50
CROSS CITY 73 56 78 63 77 / 0 10 30 30 40
APALACHICOLA 67 56 69 63 74 / 0 10 40 30 50
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
GA...NONE.
FL...NONE.
GM...NONE.
&&
$$
GIBBS/BLOCK
