585
FXUS61 KAKQ 090938
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
438 AM EST TUE FEB 9 2010
SYNOPSIS
TWO LOW PRESSURE SYSTEMS WILL MOVE TOWARD THE MID ATLANTIC REGION
TODAY...THEN MERGE INTO ONE STRONG AREA OF LOW PRESSURE OFF THE
COAST TONIGHT AND WEDNESDAY. HIGH PRESSURE RETURNS TO THE REGION
THURSDAY.
NEAR TERM /UNTIL 6 PM THIS EVENING/
MODELS IN GNRL AGREEMENT WRT THE TRACK OF APPRCHG SYSTMS...BUT HAVE
DIFFERENCES IN SVRL FIELDS WHICH MAKES THIS A COMPLICATED FCST
ACROSS FA. LIKE THE SYSTM OF THIS PAST WKEND...THE WINTER WX PART
WILL COME IN TWO DIFFERENT WAVES...FIRST ONE TDY ACROSS NRN CNTYS.
A TRANSITION TO RAIN ACROSS THE S...THEN A CHANGE BACK TO SNOW
LATE TONITE AND WED. HEADLINES WERE BASED ON TOTAL SNOW AND ICE
ACCUM FOR ENTIRE EVENT. MOST IF NOT ALL THE SGNFCNT (WRNG CRITERIA)
ACCUM ARE XPCTD WED AS WRAP ARND MSTR COMBINES WITH COLDER AIR
DRAWN INTO THE RAPIDLY DEEPENING SYSTM OFF THE COAST. STAY TUNED.
ELECTED TO FOLLOW A SREF SOLN. UPSHOT WILL BE FOR PCPN TO OVRSPRD
FA SW-NE TDY. HAVE SLOWED DOWN ARRIVAL OF PCPN INTO TE I95 CORRIDOR
AND FRTHR E UNTIL THE AFTRN BASED ON LTST DATA. XPT SNOW/SLEET MIX
ERLY TO TRANSITION TO MAINLY LIQUID S OF A FVX-RIC-MVF LINE. SOUTH
OF THIS LINE IS WHERE PCPN SHUD TRANSITION TO LIQUID BY LATE AFTRN.
THUS WENT WITH A WNTR WX ADVSRY TO COVER THE MIXED PCPN UNTIL THEN.
SHUD SEE SOME MIXED PCPN EVEN AS FAR S AS THE NC/VA BRDR AT ONSET...
BUT THIS SHUD NOT LAST LONG ENUF...THUS WILL ISSUE AN SPS FOR THOSE
AREAS.
MSTR FROM CSTL LOW OVRSPRDS RGN FROM S AFTR 18Z. HIGHS IN THE M30S.
SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/
BOTH LOWS PROGGED TO PHASE INTO ONE MAIN LOW OFF DELMARVA COAST BY
12Z WED. THIS IS WHERE THE MSTR FCST GETS TRICKY AS WRAP ARND MSTR
WILL THEN BE FIGHTING A DRY SLOT MOVG IN FROM THE SW. MEANWHILE...
MIXED OR LIQUID PCPN BEGINS TO CHANGE BACK TO MOSTLY SNOW AS TMPS
FALL INTO THE U20S-L30S.
DEEPENING LOW PROGGED TO THROW BACK QPF BTWN 1/2 TO 3/4 INCH ACROSS
LWR MD ERN SHORE AND NRN NECK AREAS WED (HIGHEST ACROSS LWR MD ERN
SHORE). THIS IS WHERE AND WHEN THE SGNFCNT ACCUM WILL OCCUR. BASICALLY
FOLLOWED HPC'S GUID AS WELL AS COORD WITH OTHR OFFICES. AMTS BTWN 6-12
INCHS PSBL ACROSS LWR MD ERN SHORE (HIGHEST OVR DORCHESTER AND LOWEST
AT OXB). WENT WITH A 4-8 INCH BAND ACOSS NRN NECK....LWR AMTS TO THE
W. WNDS RPDLY INCRS INTO WNDY CAT AS P-GRDNT TIGHTENS. GUSTS UP TO
40 MPH XPCTD ALONG THE COAST WITH THE PTNTL FOR A WND ADVSRY. HIGHS
IN THE M-U30S.
THE STRONG CYCLONE DEPARTS TO THE NE WED NIGHT AND THUR WITH THE
POLAR HIGH SETTLING TO THE WEST LEAVING THE REGION IN DRY NW FLOW.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
COLDER THAN NRML WX PTRN CONTS THROUGH THE XTNDD PD. WK SFC HI PRES
WEAKENS OVER FRI. XTNDD GUID CONTS TO SUGG SRN STRM STM TRACKING
EWD NR THE GULF STATES LT IN THE WK...AND OFF THE GA/SC CST ON SAT.
WL RMN IN MONITOR MODE FOR ANY N TREND PROGRESSING THROUGH THE WK.
OTRW...HI PRES RETURNS BY LT IN THE WK AND FOR EARLY NEXT WK.
AVIATION /10Z TUESDAY THROUGH SATURDAY/
VFR CONDS WL CONTINUE THRU THIS AM AS HI PRES PUSHES OUT OF THE AREA.
LOW PRES OVER THE GRT LAKES WILL PHASE WITH DVLPG SYSTEM OFF THE VA
COAST LATE TDY/WED. EXPECT PCPN TO BEGIN EARLY THIS AFTN AS -SN TO
CHANGE OVER TO A -RA/PL MIX AT RIC BEFORE TO ALL RAIN BY LATE EVE
(COULD SEE A QUICKER/SLOWER TRANSITION). WILL EVENTUALLY SEE A
CHANGE BACK TO SN AFT 6Z WED. DELAYED PRECIP TILL THIS EVE OVER SBY
AND LOOKS TO START AS A RA/PL MIX BEFORE OVER TO ALL RAIN LATE EVE.
AGAIN A CHANGEOVER EXPECTED AFT 6Z AT SBY TO MORE PL TO SN. RAIN
WL BE PREDOMINANT P-TYPE AT THE REMAINDER OF TAF SITES THROUGH EARLY
WED. COULD SEE PERIODS OF MVFR/IFR CONDS WL BE PSBL IN RAIN (ESP
00-06Z WED). PCPN WL CHANGE BACK OVER TO ALL SN FOR ALL FROM W TO E
WED MRNG AS THE SYSTEM INTENSIFIES OFF THE VA/MD COAST.
STILL LOOKING AT STRONG NW WINDS TO DVLP ALONG THE COASTAL THIRD
(35-40 KTS+) ON WED AS SYSTEM INTENSIFIES OFF THE NJ/SRN NEW ENGL
COAST WED/THU. POSSIBLE LIFR WED PM IN SNOW (ESP NEAR/AT SBY).
WINDS WILL CONTINUE TO REMAIN STRONG INTO THU AS PRECIP CHCS ENDS
QUICKLY FROM SW TO NE. VFR RETURNING THROUGH THE END OF THE WEEK.
MARINE
RATHER BENIGN BEFORE THE STORM FOR THE FIRST HALF OF THE DAY. SEAS
WILL START TO RISE LATER THIS EVE AND DUE TO QUICK INCREASE IN SEAS
HAVE STARTED SCA HEADLINES FOR COASTAL WATERS LATE THIS AFTN (W/IN
12 HRS).
MAIN AREA OF LOW PRES WILL DROP SE THROUGH THE GRT LKS RGN AS A
SECONDARY LOW PRES SYSTEM DVLPS OFF THE VA CAPES TONIGHT.
ENERGY FROM LAND BASED LOW WILL BE TRANSFERRED TO SECONDARY LOW AND
ALLOW IT TO GREATLY INTENSIFY AS IT MOVES NORTHEAST OFF OF NJ/SRN
NEW ENGLD INTO WED. ENE WNDS AHEAD OF THE SYSTEM WILL INCREASE LATE
TNGT...THEN A SWING IN DIRECTION TO THE NW EXPECTED ON WED AND INTO
THU.
WINDS OUT OF THE NW INCREASE QUICKLY ON WED AND THEREFORE
STARTED GALES 10Z WED (AGAIN WITHIN 12 HRS OF ALL WATERS SEEING GALE
GUSTS). FELT SCA OVER THE BAY/CRT SND WILL BE TOO LIMITED FOR RAMP
UP HEADLINE. EXCELLENT MOMENTUM TRANSFER DVLPS TWRDS THE AFTN OVER
ALL THE WATERS WITH THE CHCS FOR STORM FORCE WIND GUSTS OVER THE
COASTAL WATERS (ESP NRN HALF) INTO EARLY THU. PROLONGED
STRONG/MODERATE NW WINDS CONTINUES THROUGH ERLY FRI.
HYDROLOGY
FLOOD WRNGS REMAIN IN EFFECT FOR SEVERAL LOCATIONS IN THE CHOWAN
RIVER BASIN. MINOR FLOODING IS OCCURRING AND EXPECTED TO CONT OVER
THE NEXT FEW DAYS. THE UPPER MEHERRIN AND NOTTOWAY RIVERS HAVE
CRESTED AND THE LOWER NOTTOWAY CONTINUES GRADUAL RISES. SEE FLSAKQ
FOR DETAILS.
TIDES/COASTAL FLOODING
MINOR TIDAL (POSSIBLE MODERATE-ERN SHORE) FLOODING MAY OCCUR
DURING HIGH TIDES WEDNESDAY AFTN/THU MORNING ALONG THE COASTAL
WATERS AND SRN BAY.
AKQ WATCHES/WARNINGS/ADVISORIES
MD...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 6 AM EST
THURSDAY FOR MDZ021>025.
NC...NONE.
VA...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 6 AM EST
WEDNESDAY FOR VAZ060>062-067>071-080>084-090.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 6 AM EST
THURSDAY FOR VAZ099.
WINTER STORM WARNING FROM 1 PM THIS AFTERNOON TO 6 PM EST
WEDNESDAY FOR VAZ048-049-063-064-072>078-085.
MARINE...STORM WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING
FOR ANZ650-652-654-656-658.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST
WEDNESDAY FOR ANZ650-652-654-656-658.
GALE WARNING FROM 4 AM TO 1 PM EST WEDNESDAY FOR ANZ650-652-
654-656-658.
GALE WARNING FROM 4 AM WEDNESDAY TO 7 PM EST THURSDAY FOR
ANZ630>632.
GALE WARNING FROM 4 AM WEDNESDAY TO 4 PM EST THURSDAY FOR
ANZ633.
SYNOPSIS...MPR
NEAR TERM...MPR
SHORT TERM...MPR
LONG TERM...ALB
AVIATION...CCW
MARINE...CCW
HYDROLOGY...
TIDES/COASTAL FLOODING...CCW
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