FXUS61 KAKQ 262237
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
537 PM EST THU NOV 26 2009

.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION TONIGHT...AS AN UPPER LEVEL
LOW PRESSURE SYSTEM MOVES ACROSS THE MID ATLANTIC STATES ON
FRIDAY. HIGH PRESSURE WILL THEN BUILD INTO THE AREA FRIDAY NIGHT
AND SATURDAY...THEN MOVES OFF THE SOUTHEAST COAST ON SUNDAY. A
COLD FRONT APPROACHES FROM THE WEST ON MONDAY...THEN MOVES OFF THE
COAST MONDAY NIGHT. HIGH PRESSURE REBUILDS INTO THE AREA ON TUESDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
LATEST STLT IR/WV LOOPS SHOW MID/UPR LOW SPINNING ACROSS LK HURON
AND ERN LWR MI. RESIDUAL LLVL AIRMASS (MOISTURE) OVER MID ATLC
REGION HAS BEEN TOUGH TO DISLODGE THUS FAR GIVEN THE LACK OF
MIXING...BOTH HORIZONTALLY (LIGHT NE FLOW) AND VERTICALLY (LOW
LATE NOV SUN ANGLE). 

UPR TROUGH TO BECOME MORE NEGATIVELY TILTED OVERNIGHT AS IT PIVOTS
INTO THE ERN SEABOARD. WILL CONTINUE WITH THE CHC OF SHOWERS...
BEGINNING THIS EVENING...AS THE UPR TROUGH DROPS INTO THE MID ATLC
REGION. QG FORCING IS FAIRLY IMPRESSIVE...AT LEAST COMPARED TO
WHAT HAD BEEN EXPECTED A DAY OR SO AGO...AS IT APPEARS FROM ALL
THE SHORT TERM MODELS THE MID LVL VORT WILL DROP A BIT FARTHER S
THAN PREVIOUS EXPECTATIONS. THIS IN TURN WILL BOOST THE DPVA
FORCING ACROSS THE FCST AREA...WHILE ALSO STEEPEN MID LEVEL LAPSE
RATES (7-8C BTWN 700-500 MB)...WHICH WILL LEAD TO SCATTERED
SHOWERS...ESPECIALLY FROM LATE THIS EVENING THROUGH EARLY FRI.

AS FOR PCPN TYPE...PARTIAL THICKNESS SUPPORT RAIN THROUGH THE
MAJORITY OF THIS EVENT. HOWEVER...BY EARLY FRI AM...AS 1000-850 MB
THICKNESSES DROP TO NEAR 1305/1310 M OVER WRN AREAS...AND WITH
THE CAA (STEEPENING LAPSE RATES) ALOFT AND THUS CONVECTIVE NATURE
OF THE PCPN...CANNOT RULE OUT A CHANCE THAT THE SHOWERS WILL END
AS A PERIOD OF WET SNOW OR MIXED RAIN/SNOW W OF I-95. CERTAINLY
NOT EXPECTING A BIG DEAL OTHER THAN PERHAPS THE FIRST FEW
SNOWFLAKES OF THE SEASON.

THIS SYSTEM WILL ALSO INVIGORATE LLVL MIXING (FOR A CHANGE)
TONIGHT... WHICH WILL PUT AN END TO THE FOG/LLVL STRATUS THAT
IS STILL PLAGUING PTNS OF THE AREA CURRENTLY. LOWS MID-UPR 30S
W/NW PTNS TO LWR 40S E/SE.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
ONCE THE COLD FRONT EXITS THE COAST EARLY FRIDAY MORNING...THE
COLD AIR WILL HELP TIGHTEN THE THERMAL GRADIENT WHICH WILL HELP
INVIGORATE THE AREA OF LOW PRESSURE THAT IS LIFTING NE ALONG THE
COAST. THIS LOW WILL INTENSIFY OFF THE NEW ENGLAND COAST. THIS
WILL HELP THE NW FLOW TO STRENGTHEN. THIS WILL LEAD TO A CLEARING
PATTERN WITH THE DOWNSLOPE FLOW AND ALSO ALLOW FOR GOOD MIXING IN
THE COLD ADVECTION. WILL KEEP MINIMAL (20-30%) CHANCES OVER THE
LWR ERN SHORE ON FRI (HIGHEST OVER LWR MD ERN SHORE)...GIVEN THE
CLOSER PROXIMITY TO THE UPR LOW AND LESS DOWNSLOPE DRYING EFFECTS
TYPICALLY SEEN IN THIS REGION WITH NW/WNW FLOW.

EXPECT TO SEE GUSTY CONDITIONS ON FRIDAY...WHILE LOCAL 1000-850
MB LLVL THICKNESS SCHEME SUPPORTS MAX TEMPS ONLY AROUND 50 TO THE
LWR 50S WITH FULL SUN. BECAUSE OF MORE CLOUDS/HIGHER PCPN
CHANCES...HAVE CAPPED HIGHS ONLY IN THE UPR 40S OVER LWR MD ERN
SHORE...50 TO 54 ELSEWHERE.

THE STRONG LOW AND UPPER TROUGH SLIDE OFF THE COAST FRIDAY
NIGHT...WHICH ALLOW THE FLOW TO WEAKEN...BUT IT WILL STILL BE COLD
WITH SOME LOCATIONS GOING BELOW FREEZING OVER CENTRAL VA. AS
RIDGING BUILD EAST ALOFT...WILL SEE A WARM ADVECTION PATTERN
DEVELOP SO TEMPERATURES WILL BEGIN TO MODERATE AND WITH VERY DRY
AIR AROUND...EXPECT SUNNY CONDITIONS WITH LIGHT WINDS.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
FRONTAL BOUNDARY DRAPED ACROSS THE GRT LKS INTO THE SRN PLAINS WILL 
SLOWLY TREK TWRD THE RGN ON MON AS A LOW PRES SYSTEM RIDES ALONG IT.
HIGH CLOUDS WILL INCREASE SUN NIGHT BEFORE FRONTAL SYSTEM AND ASSCD 
LOW PRES SYSTEM MOVES OVER THE RGN MON AFTN/EVE. LOOK FOR SHRA 
ACTIVITY TO CONTINUE INTO ERLY TUE BEFORE HIGH PRES STARTS TO BUILD 
BACK INTO THE RGN. STRONG UPR LVL SYSTEM DVLPS OVER THE SRN CALIF ON 
SAT AND DIGS FURTHER OVER NRN MEXICO/SRN TX INTO MON. SYSTEM PUSHES 
INTO THE GULF COAST TUE/WED AND QUICKLY MOVES TWRDS THE RGN ON THU 
AS SRN STREAM FLOW STARTS TO FLATTEN. GFS ONCE AGAIN TRIES TO DVLP A 
COASTAL SYSTEM...BUT OTHER GUIDANCE HINTING AT MORE OF A SUPRESSED
AND WEAKER SYSTEM FURTHER SOUTH (WHICH WOULD BE MORE SUPPORTIVE
OF A FLATTER FLOW). FOR NOW WILL GO WITH BULK OF GUIDANCE.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
SKIES ARE MOSTLY VFR THIS AFTN EXCEPT ON THE EASTERN SHORE AS
FOG/STRATUS BURNED OFF LATE THIS AM. WNDS ARE GENLY LGT AND VRBL
BUT WILL GRADUALLY TREND NE-N-NW THRU THE LATE EVENING AND
OVERNIGHT AS COASTAL LOW MOVES NORTH AND FRONT APPROACHES FROM THE
WEST. ANOTHER LOW MOVG THRU GRT LAKES AREA WILL DROP SE AND GET
ABSORBED INTO LARGER FLOW OF THE COASTAL LOW. COMBINED WITH THE
FRONT...CLOUDS WILL INCREASE ACROSS THE REGION TONIGHT AND BRING A
CHC OF -RA INTO THE AREA INTO EARLY FRI.  

BIGGER OPERATIONAL CONCERN GOING FORWARD LOOKS TO BE WITH GUSTY WNDS 
LATE TONIGHT AND FRIDAY AS A COLD FNT CROSSES THE REGION AFTER
MIDNIGHT INTO ERY FRI AM. WNDS BEHIND THE FNT BECOME W/NW WHICH
WL USHER IN DRIER AIR. TIGHTENING PRESSURE GRADIENT BETWEEN COASTL LOW
AND APPROACHING SFC RIDGE TO THE SOUTH WL ALLOW FOR BREEZY TO
WINDY CONDITIONS FRI AFTN...WITH GUSTS TO 20-30KT POSSIBLE DURING
THIS PERIOD. OTW...LOOK FOR MAINLY VFR CONDS BY LATE AM/ERLY PM FRI
AND THROUGH THE WEEKEND. NEXT CHC OF PCPN LOOKS TO BE LATE MON
INTO TUE.

&&

.MARINE...
CONTINUE WITH TIMING OF SCA TONIGHT OVER ALL WATERS AS FRONTAL 
BOUNDARY PUSHES TWRDS THE RGN. LOOK FOR WINDS TO INCREASE TONIGHT AS 
FRONT PUSHES OVER THE RGN (AFTER MIDNIGHT). COULD SEE SOME GUSTS TO 
NEAR GALE OVER THE BAY AS FRONT MOVES OVERHEAD...BUT THINK THIS WILL 
BE FOR ONLY A FEW HRS UNTIL MORE SUSTAINED GUSTS OCCUR LATER ON FRI.
AS WINDS SHIFT TO THE WNW...LOOK FOR GALE GUSTS TO START TO OCCUR 
OVER THE BAY FRI AFTN AND CONTINUE INTO SAT AM BEFORE GRADIENT 
RELAXES. 

HAVE HOISTED GALES OVER THE COASTAL ZONES AND CRT SND FRI AM THRU 
ERLY SAT. ALTHOUGH GUSTS MAY BE BELOW GALES FOR A TIME FRI AM ALONG 
THE COAST/CRT SND...WINDS SHOULD INCREASE W/IN 4 HRS AFTER INITIAL 
PASSAGE OF FRONT.

GRADIENT RELAXES VERY SLOWLY SATURDAY...AND SCA FOR SEAS WL LIKELY 
BE NEEDED OVER THE COASTAL WATERS INTO LTR SAT AT LEAST. CONDITIONS 
LOOK TO BECOME A BIT MORE BENIGN FOR SUNDAY INTO MONDAY AS FLOW 
LOOKS TO TURN SSW AS HIGH PRESSURE OVER THE SOUTHEAST CONUS BUILDS 
SOUTH OF THE REGION. ANOTHER FRONT APPROACHES FROM THE WEST BY LTR
MONDAY/TUESDAY.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO NOON EST 
     FRIDAY FOR ANZ630>632.
     GALE WARNING FROM NOON FRIDAY TO 5 AM EST SATURDAY FOR 
     ANZ630>632.
     SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST 
     FRIDAY FOR ANZ633-650-652-654-656-658.
     GALE WARNING FROM 6 AM FRIDAY TO 5 AM EST SATURDAY FOR ANZ633-
     650-652-654-656-658.

&&

$$
SYNOPSIS...BKH
NEAR TERM...BKH
SHORT TERM...BKH
LONG TERM...CCW
AVIATION...JEF
MARINE...CCW