796
FXUS61 KAKQ 252100
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
400 PM EST WED NOV 25 2009
SYNOPSIS
WEAK HIGH PRESSURE REMAINS OVER THE REGION TONIGHT INTO THURSDAY.
A STRONG COLD FRONT WILL MOVE THROUGH THURSDAY NIGHT...PROVIDING
A CHANCE FOR SHOWERS. AN UPPER LEVEL LOW PRESSURE SYSTEM MOVES
ACROSS THE MID ATLANTIC STATES ON FRIDAY...THEN HIGH PRESSURE
BUILDS IN FROM THE WEST OVER THE WEEKEND.
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/
CLDNS RMNS STUBBORN OVR MUCH OF THE FA ATTM...HWVR...VSBL SATL
LOOP/SFC OBS SHOWS DRYING BEGINNING TO SPRD INTO FAR WRN SXNS OF
FA. MNWHL...LGT RA MVG THROUGH XTRM ERN NC ASSOCIATED W/ - OUT AHD
OF SFC LO PRES DVLPMNT E OF GA/NRN FL CST. LAST BIT OF SPOTTY LGT
-RA/DZ INVOF ERN SHR NEXT CPL OF HRS...OTRW WL GO W/ PRTL CLRG
THIS EVE INTO OVRNGT HRS FOR MOST AREAS (FM W-E). W/ GRND
SATURATED...AND WNDS GENLY LGT/VRBL...GOOD PTNTL FOR FG
DVLPMNT...AND WL HV AREAS OF FG INCLDD AFT MDNGT. LO TEMPS MNLY IN
THE 40S.
SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/
LRGLY INBTWN SYSTEMS ON THU...SFC LO PRES TRACK E OF THE CST...AND
STRNG M/ULVL SYSTEM CRASHING ESE THROUGH THE LAKES/OH VLY. AFT
ERY FG...XPCTG PSNY AND RATHER MILD CONDS. M/ULVL SYSTEM CRSS THE
MTNS LT IN THE DAY...AND CONTS E THROUGH FRI. MNWHL...XPCTG STRNG
CDFNT TO MV ACRS THE FA BY MID MRNG FRI. WL INCLD CHC SHRAS...MNLY
OVR MD/VA CTYS THU NGT (CHCS MAY LINGER ERY FRI ON THE ERN
SHR)...THEN MOD LLVL CAA FOR FRI...BUT W/ DRYING. LEANING CLSR TO
GFS WRT MVMNT OF M/ULVL SYS THROUGH THE RGN AND INTO NEW ENG (BY
SAT MRNG). LLVL CAA SHUTS OFF BY ERY SAT. SFC HI PRES BUILDS ACRS
THE SE CONUS ON SAT...LEADING TO RETURN OF SW LLVL FLO (AND A
START TO MODERATING TEMPS).
HI TEMPS THU FM THE U50S TO M60S...THEN MNLY IN THE L/M50S
FRI...AND M/U50S SAT. LO TEMPS MNLY IN THE L/M40S THU NGT...THEN
FM THE U20S TO M/U30S FRI NGT.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
ONCE AGAIN...HAVE INCORPORATED THE LATEST HPC GUIDANCE FOR THE
EXTENDED PERIOD...WHICH IS LARGELY BASED ON THE ECMWF. THE ECMWF
CONTINUES TO SHOW MORE FVRBL RUN-TO-RUN CONSISTENCY WITH
TIMING/LOCATION OF SYNOPTIC FEATURES EARLY-MID WEEK...MOST NOTABLY
WITH THE NEXT COLD FRONT MON NIGHT AND TUE...AND THE POTENTIAL FOR
YET ANOTHER DUAL-LOW SCENARIO TAKING SHAPE BY MID-WEEK AS A
DEEPENING LOW DROPS INTO THE NRN MS VLY...WHILE LOW PRES FORMS ALONG
THE EXITING LLVL FRONT/BAROCLINIC BOUNDARY (WRN PERIPHERY OF GULF
STREAM) JUST OFF THE SE-MID ATLC COAST.
CONTINUED FAIR CONDITIONS WITH MODERATING TEMPS ON TAP FOR SUN TO
WRAP UP THE HOLIDAY WEEKEND. HIGHS THROUGH THE 60S (LOW-MID 60S N...
MID/UPR 60S S)...CONSISTENT WITH THE LLVL THICKNESS. ECMWF STILL
SLOWER WITH THE FROPA EARLY NEXT WEEK...THOUGH RECENT GFS RUNS HAVE
TRENDED TOWARD THE ECMWF (WHICH IS AGAIN A GOOD SIGN FOR THE ECMWF'S
CREDIBILITY WITH THIS EVOLVING PATTERN). DEPENDING ON HOW QUICKLY WE
SEE INCREASING CLOUDS/RAIN CHCS MOVING IN FROM THE W...TEMPS CAN GET
QUITE MILD ONCE AGAIN BASED ON THE PROJECTED LLVL THICKNESS
STRUCTURE. FOR NOW...HAVE FCSTD UPR 50S OVER FAR NW PTNS TO MID/UPR
60S FAR SE.
SHOWERS WITH THE FROPA MOST LIKELY MON NIGHT AND TUE...AND AS SUCH
HAVE RAISED POPS TO 40-50% (STILL TOO EARLY TO GO HIGHER BASED ON
THE HIGH PROBABILITY OF TIMING ERRORS 5-6 DAYS AWAY). ANOTHER SWATH
OF SYNOPTIC "STRATIFORM" RAIN/DRIZZLE LOOKS LIKE A GOOD POSSIBILITY
BY WED-THU...AS ANOTHER LOW FORMS OFF THE SE CST ALONG THE LLVL
BAROCLINIC ZONE AND TRACKS NE.
AVIATION /21Z WEDNESDAY THROUGH MONDAY/
NNE FLOW REGIME CONTINUES ACRS THE TERMINALS THIS MORNING...WITH
AREAS OF VERY LGT RAIN/DRIZZLE NOW NOTED MAINLY INVOF KRIC...WITH
DZ/BR PERSISTING ACROSS SE TERMINALS. IFR CONDS SHOULD PERSIST
THROUGH MUCH OF THIS MORNING...EVEN AS ORGANIZED SHRAS DIMINISH.
SOME IMPROVEMENT EXPECTED LT THIS MORNING INTO THE AFTN...AS CIGS
CLIMB FROM S TO N...AND RECOVERING TO MVFR/LOW END VFR (WITH LLVL
CLD CVR SCATTERING OUT A BIT BY LATER IN THE DAY. BY
TONIGHT...VSBYS LOOK TO FALL QUICKLY AGAIN AFTER SUNSET WITH SOME
AREAS OF FOG ONCE AGAIN LIKELY AS WNDS DROP OFF.
A COLD FNT CROSSES THE REGION THROUGH THU NIGHT. WNDS BEHIND THE
FNT BECOME W/NW WHICH WL USHER IN DRIER AIR. TIGHTENING PRESSURE
DIFFERENTIAL BETWEEN LOW TO THE NE AND APPROACHING SFC RIDGE TO
THE SOUTH WILL ALLOW FOR BREEZY TO WINDY CONDITIONS FRIDAY
AFTN...WITH GUSTS TO 20-30KT POSSIBLE DURING THIS PERIOD.
OTW...LOOK FOR MAINLY VFR CONDITIONS FRIDAY AND THROUGH THE
WEEKEND.
MARINE
SCAS...MAINLY FOR LINGERING ENE SWELL...REMAIN IN PLACE THROUGH
THURSDAY MORNING. WEAK LOW PRES ALONG THE DELMARVA THIS AFTN WILL
TRACK WELL OFFSHORE TONIGHT INTO EARLY THU. PROXIMITY TO THIS LOW
HAS ALLOWED NE WINDS TO SHIFT TO SW/WSW EARLIER TODAY...AND THIS
WILL CONTINUE INTO TONIGHT BEFORE TURNING BACK TO THE NE
THANKSGIVING MORNING AS ANOTHER AREA OF LOW PRESSURE DEVELOPS
ALONG THE SE COAST (PUSHING WELL NE OF THE MARINE AREA BY LATE
THURSDAY NIGHT).
BY THIS TIME THURSDAY NIGHT...THE UPPER TROUGH CURRENTLY OVER THE
DAKOTAS IS FORECAST TO DEEPEN/AMPLIFY...AND TAKE ON AN NEGATIVE TILT
BY 12Z FRIDAY. AS PREV SHIFT NOTED...CONCERN CONTINUES TO EXIST THAT
THE TRACK OF THIS LOW WL NEED TO BE MONITORED CLOSELY. IF THE LOW
DOES END UP CLOSER TO THE COAST...A GREATER IMPACT WOULD BE NOTED
ACROSS COASTAL ZONES. HAVE MAINTAINED THE LIGHTER WINDS AND SEAS IN
THE 3 TO 4 FT RANGE SET BY PREVIOUS SHIFT...BUT WILL HAVE TO
CONTINUE MONITORING...AS THIS COULD BE UNDERDONE IF THE LOW IS
CLOSER TO THE COAST.
EITHER WAY...A STRONG COLD FRONT LOOKS CROSSES THE REGION EARLY IN
THE DAY FRIDAY...W/ ALL MODELS SHOWING A QUICKLY DEVELOPING CYCLONE
DEVELOPING OFF THE NEW ENGLAND COAST FRIDAY. GIVEN WHAT SHOULD BE AN
INCREASINGLY STRONG PRES GRADIENT AND CAA OVER STILL RELATIVELY WARM
COASTAL WATERS...THIS SHOULD EASILY YIELD STRONG SCA WNDS FRIDAY...
WITH LOW-END GALES APPEARING MORE LIKELY FROM FRI AFTN THROUGH EARLY
SAT MORNING. NAM MODEL IS MOST AGGRESSIVE WITH THE MOMENTUM XFER AND
925-850 MB WIND SPEEDS (40-45 KTS PER THE NAM...WHILE CLOSER TO
30-35 KTS PER THE GFS). AT THIS POINT...SINCE WE ARE STILL DEALING
WITH A FIRST PERIOD EVENT THAT WILL ULTIMATELY RAMP-DOWN TO SUB-SCA
CONDITIONS BEFORE THIS NEXT EVENT BEGINS...PER COORD WILL HOLD OFF
ON ANY GALE WATCHES/WARNINGS UNTIL THE CURRENT HEADLINES EXPIRE.
AKQ WATCHES/WARNINGS/ADVISORIES
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ650-652-
654-656-658.
SYNOPSIS...ALB/ESS
NEAR TERM...ALB
SHORT TERM...ALB
LONG TERM...BKH
AVIATION...MAM
MARINE...BKH
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page