FXUS61 KAKQ 302118
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
418 PM EST MON NOV 30 2009

.SYNOPSIS...
A COLD FRONT WILL DROP SOUTH INTO NORTH CAROLINA EARLY TONIGHT. HIGH
PRESSURE BUILDS BACK OVER THE AREA TUESDAY INTO EARLY WEDNESDAY.
LOW PRESSURE OVER THE CENTRAL GULF COAST REGION EARLY
WEDNESDAY...WILL STRENGTHEN AS IT TRACKS NORTHEAST AND MOVES UP ON
THE WEST SIDE OF THE APPALACHIANS WEDNESDAY NIGHT AND EARLY
THURSDAY...THEN INTO NORTHERN NEW ENGLAND BY LATE THURSDAY. THIS
PUSHES A COLD FRONT THROUGH THE AREA THURSDAY. HIGH PRESSURE WILL
BUILD INTO THE AREA FROM THE LOWER MISSISSIPPI VALLEY ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
PRECIPITATION HAS BEEN INCREASING ON RADAR DURING THE LAST SEVERAL
HOURS AS THE UPPER SYSTEM APPROACHES. MODELS HAVE A GOOD HANDLE ON
THIS EVENT. THE PRECIP WILL END IN WESTERN PARTS OF THE CWA BY
EARLY TONIGHT AND OVER THE SE PART BY AROUND MIDNIGHT. MOST QPF
WILL BE AROUND A QUARTER INCH BUT HIGHER AMOUNTS ARE POSSIBLE OVER
THE SOUTHEAST PART OF THE AREA WITH UP TO A HALF INCH THERE. SKIES
WILL CLEAR QUICKLY ONCE THE UPPER SYSTEM MOVES OFF THE COAST WILL
GOOD DOWNSLOPE WINDS DEVELOPING. THE QUESTION ON TEMPS TONIGHT IS
HOW FAST THE CLOUDS LEAVE AND HOW QUICKLY THE WINDS DIMINISH. WENT
JUST A LITTLE ABOVE MOS GUIDANCE FOR MINS.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
TUESDAY ALL MODELS AGREE WITH HIGH PRESSURE OVER THE AREA AND THEN
MOVES OFF THE MID ATLANTIC COAST BY TUESDAY NIGHT. WITH THE MAIN
UPPER DYNAMICS MOVING FARTHER WEST THIS MODEL RUNS THE TRACK OF
THE LOW CONTINUES TO SHIFT TO THE WEST. THE SRF AS WELL AS NAM AND
GFS ALL TRACK THE LOW UP TO THE WEST SIDE OF THE APPALACHIANS.
THIS SHOULD PUSH THE HEAVIEST PRECIP TO THE WEST OF THE AREA NOW.
HOWEVER THERE WILL BE SOME STRONG ISENTROPIC LIFT COMING UP LATE
WEDNESDAY INTO WEDNESDAY NIGHT. THIS SHOULD PRODUCE SOME MODERATE
TO HEAVY RAINFALL AS IT MOVES THROUGH.

THE NAM IS A LITTLE SLOWER THEN THE GFS ON PUSHING THE MOISTURE
AND FRONT OFF THE COAST. WENT WITH A COMPROMISE OF THE TWO FOR
NOW. ALSO NOTICED THE NAM BROUGHT MUCH HIGHER DEWPOINTS N INTO THE
AREA WEDNESDAY NIGHT AND EARLY THURSDAY. THIS BROUGHT CAPES UP
CLOSE TO 1000 LATE WEDNESDAY NIGHT. NOT SOLD ON THIS HIGH OF CAPE
BUT WITH THE VERY STRONG WIND SHEAR AT THAT TIME WILL HAVE TO
WATCH FOR ANY THUNDERSTORM DEVELOPMENT ESPECIALLY IF THE SLOWER
NAM IS CORRECT AND THE FRONT DOES NOT MOVE OFF UNTIL MIDDAY ON
THURSDAY. BY THURSDAY NIGHT ALL THE PRECIP IS OFF THE COAST AND
COLDER AIR IS ARRIVING.

TEMPERATURES WILL MODERATE QUICKLY ON TUESDAY AS THE CORE OF
TONIGHTS COLD PUSH MOVES BY EARLY IN THE DAY WITH PLENTY OF
AFTERNOON SUNSHINE AND DOWNSLOPE WINDS. MOS DOES A GOOD JOB
DEPICTING THIS. ALSO ON TUESDAY NIGHT WITH CLOUDS NOT COMING IN
UNTIL LATE AGAIN FOLLOWED A COLD MOS GUIDANCE. ON WEDNESDAY WITH
DEVELOPING SOUTH FLOW WARMING TEMPS BACK UP CLOSE TO 60 OR IN THE
60S. ALSO ON WEDNESDAY NIGHT WITH CONTINUED S FLOW KEEP TEMPS
STEADY OR SLOWLY RISING. THIS CORRESPONDS WELL WITH BOTH MET AND
MAV GUIDANCE. DID NOT GO AS WARM AS MET GUIDANCE. FINALLY ON THU
THE MAIN COLD PUSH AT 85H DOES NOT ARRIVE ON ANY MODEL UNTIL LATE
SO SOME RISE IN TEMPS IS LIKELY AND STARTING FROM FAIRLY MILD
CONDITIONS WILL PUS TEMPS WELL UP INTO THE 60S NOT GOING WITH THE
70S MET GUIDANCE IS ADVERTISING.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
MODELS CONTINUE TO SHOW GOOD AGREEMENT THROUGH SATURDAY...BUT
TIMING DIFFERENCES SHOWING UP TOWARD THE END OF THE FORECAST.
INITIALLY...ALL MODELS AGREE THAT THE SURFACE FRONT WILL BE OFF
THE COAST BY 00Z FRIDAY WITH SURFACE HIGH BUILDING IN AS COLD
ADVECTION PUSHES INTO THE REGION. THE NORTHWEST FLOW SHOULD ALLOW
FOR DRYING CONDITIONS. THIS CONTINUES INTO FRIDAY...BUT WITH THE
UPPER TROUGH STILL OVER THE WESTERN GREAT LAKES INTO THE MID
MISSISSIPPI VALLEY...WILL STILL SEE SW FLOW ALOFT. THIS WILL KEEP
LOTS OF HIGH CLOUDS AROUND FRIDAY.

THEN COMES THE INTERESTING PART OF THE FORECAST AS THE 00Z MODELS
HINTED THAT SHOULD THE UPPER TROUGH AMPLIFY A SHORTWAVE ROTATING
AROUND THE BASE OF THE UPPER TROUGH AS IT MOVED EAST...MORE
MOISTURE AND A STRONGER SURFACE LOW COULD PRODUCE SOME LIGHT
WINTRY PRECIP ACROSS THE MID ATLANTIC STATES. WELL THE 12Z RUNS
CONTINUED THAT TREND AS THE ECWMF/GFS AND CANADIAN OP RUNS ALL NOW
SHOW A BRIEF PERIOD OF TIME EARLY SATURDAY WHERE A SHORTWAVE COULD
PRODUCE SOME LIGHT SNOW...MAINLY I-95 AND AREAS TO THE WEST. FOR
NOW HAVE ADDED SOME LOW CHANCE POPS AS THE MODELS COULD JUST AS
QUICKLY SHIFT BACK TO A FLATTER WAVE SCENARIO WITH A WEAKER LESS
AMPLIFIED SHORTWAVE. BUT WILL HAVE TO WATCH THIS FEATURE AS IT
COULD BE THE FIRST WINTER EVENT OF THE SEASON.

ONCE THIS WAVE CLEARS AND THE UPPER TROUGH SLIDES ACROSS
SATURDAY...SHOULD SEE HIGH PRESSURE BUILD EAST WITH CLEARING
EXPECTED. THE GFS IS THEN FASTER IN PUSHING A FRONT INTO THE AREA
ON MONDAY...BUT THE ECMWF AND OTHER ARE SLOWER SO FOR NOW JUST
INTRODUCE SOME SLIGHT CHANCE POPS MONDAY INTO MONDAY NIGHT.

FOR TEMPERATURES GENERALLY RAN WITH HPC/MOS GUIDE VALUES...WHICH
SHOULD LEAD TO COLD WEATHER INTO SUNDAY BEFORE SW FLOW ALLOWS
READINGS TO MODERATE EARLY NEXT WEEK.

&&

.AVIATION /21Z MONDAY THROUGH SATURDAY/...
MID AND HI LVL CLDS OVERSPREADING THE AREA THIS AFTN WITH -RA
REACHING AS FAR E AS RIC...RA WILL SPREAD EAST AND AFFECT ALL
SITES BY 21Z. VIS WILL HOLD IN THE MVFR RANGE WHILE VFR CIGS
COULD LWR TO MVR. SW WNDS ALG THE COAST WILL GUST INTO THE 20 KT
RANGE BEFORE DIMINISHING OVERNIGHT. AS THE FRONT PUSHES THRU THE AREA
WINDS WILL BECOME NW AND RA WILL MOVE OFFSHORE OVERNIGHT WITH
MOSTLY CLR SKY FOR TUES. DEW POINTS DROP SHARPLY MON NIGHT WHICH
SHOULD PREVENT FOG FORMATION TUE MRNG.

HIGH PRESSURE OVER THE SOUTHEAST STATES WILL CONTINUE THE VFR 
CONDITIONS THROUGH WED. LOW PRESSURE FROM THE GULF COAST REGION WILL 
MOVE ON A NORTHEASTWARD TRACK TO THE WEST OF OUR AREA BUT WILL BRING 
PLENTY OF MOISTURE TO EASTERN VIRGINIA. LOOK FOR WIDESPREAD PCPN AND 
AREAS OF IFR WED NIGHT AND THU. A COLD FRONT WILL MOVE THROUGH LATE 
THU AND BRING IMPROVING CONDITIONS THU NIGHT...CONTINUING INTO FRI.

&&

.MARINE...
COLD FRONT EXTENDS FROM SE NJ SW THROUGH CENTRAL MD INTO NWRN NC.
THE NORTHERN PART OF THE FRONT HAS A STRONGER PUSH AND SHOULD MOVE
THROUGH THE DELMARVA MORE QUICKLY THAN AREAS TO THE SOUTH. EXPECT
THE FRONT TO CLEAR THE SOUTHERN ZONE AROUND 3Z. AHEAD OF THE FRONT
THE WINDS HAVE ACTUALLY WEAKENED THIS AFTERNOON TO AROUND 10 TO 15
KTS. BUT ONCE THE FRONT CLEARS...EXPECT TO SEE A SURGE MOVE OFF
THE SE WITH THE COLD ADVECTION. SO HAVE MAINTAINED SCA FOR THE
OVERNIGHT HOURS. AS HIGH PRESSURE MOVES IN ON TUESDAY
MORNING...SHOULD SEE CONDITIONS IMPROVE QUICKLY. THE WINDS SHOULD
RELAX AND THE SEAS SHOULD CALM SO WILL ALLOW THE SCA TO EXPIRE
AROUND 14Z. IT COULD LINGER A LITTLE LONGER AS A GUSTY TO SCA
CRITERIA MAY LINGER UNTIL AROUND 18Z. OTHERWISE...SFC HIGH SHOULD
ALLOW FOR LIGHT WINDS AND CALM SEAS INTO WEDNESDAY.

THE NEXT SYSTEM WILL LIFT UP WEST OF THE MOUNTAINS ON WEDNESDAY
INTO THURSDAY. THIS SYSTEM WILL PUSH A WARM FRONT ACROSS THE
REGION WEDNESDAY EVENING AND THEN A COLD FRONT ON THURSDAY. WINDS
AND SEAS WILL INCREASE WED AFTERNOON AND EVENING WITH THE SE FLOW.
WILL PROBABLY NEED SCA FOR THIS PERIOD. WHILE THE MODELS SHOW
STRONG 50 KT+ FLOW FROM 950 TO 850 MB ON WED NIGHT INTO
THURSDAY...WHEN THE REGION IS IN THE WARM SECTOR...DO NOT EXPECT
TO SEE THESE WINDS MIX DOWN IN THE WARM ADVECTION. BUT DO EXPECT
TO SEE WINDS TO 30 KTS IN THE GRADIENT.  

ON THURSDAY...COULD SEE SOME STRONGER CONVECTION DEVELOP ALONG THE
COLD FRONT WITH GUSTY WINDS. BEHIND THE FRONT... THE NW FLOW WILL
CONTINUE THE SCA WINDS INTO FRIDAY BEFORE HIGH PRESSURE ARRIVES TO
BRIEFLY CALM THE CONDITIONS OVER THE WATER.

&&

.CLIMATE...
TDA MARKS THE END OF NOV 2009. CERTAINLY BEEN A WET MONTH ACRS THE
FA...W/ MANY AREAS HVG PCPN DEPARTURES OF A CPL OF INCHES ABV NRML.

FOR RIC...
EVEN W/O RAINFALL TDA (THE 30TH)...NOV 2009 WILL END UP THE WETTEST ON
RCRD. OFFICIALLY...AS OF THE 29TH...RIC HAD MEASURED 9.20 INCHES
OF PCPN.

FOR ORF...
EVEN W/O RAINFALL TDA (THE 30TH)...NOV 2009 WILL END UP THE WETTEST ON
RCRD. OFFICIALLY...AS OF THE 29TH...ORF HAD MEASURED 8.78 INCHES OF
PCPN.

WRT TEMPS...
AFT AN UNSEASONABLY WRM DAY ON SUN (THE 29TH)...RIC AVG TEMPS MAY
END UP IN THE TOP 10 (FOR WRMST NOV)...TOPPING #9 (53.6 SET IN
1975) OR #10 (53.3 SET IN 1979).

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EST TUESDAY FOR ANZ630>633-650-
     652-654-656-658.

&&

$$
SYNOPSIS...JAB
NEAR TERM...JAB
SHORT TERM...JAB
LONG TERM...ESS
AVIATION...CY
MARINE...ESS
CLIMATE...