National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KAKQ 100902
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
402 AM EST WED FEB 10 2010

.SYNOPSIS...
LOW PRESSURE WILL DEVELOP AND INTENSIFY OFF THE MID ATLANTIC COAST
TODAY. HIGH PRESSURE RETURNS TO THE REGION FOR THURSDAY AND
FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
COMPLICATED FCST THIS MORNING DEALING WITH LIGHT PRECIP (MAINLY -RA
BUT ALSO SOME -FZRA MIXING IN WITH TEMPS AT/NEAR FRZG MARK) MOVING
OVER OVER NORTH CENTRAL VA WITH INITIAL CONVERGENCE ZONE AND MID LVL
DRY SLOT BEHIND IT LEADING TO FOG FORMATION OVER THE FAR SOUTH. HAVE
ISSUED AN SPS FOR REDUCED VSBYS UNDER A MILE ERLY THIS AM BEFORE
WINDS SHIFT TO THE NW AND SCOUR OUT BOUNDARY LAYER.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/...
ATTENTION THEN TURNS TO CURRENT WINTER HEADLINES. LATEST RUC/NAM AND
LOCAL WRF ALL SHOW -SN TO DVLP OVER THE RGN OVER THE NEXT FEW HRS
(TWRDS DAYBREAK) W/E AS ARCTIC FRONT PUSHES THROUGH THE RGN. COULD
SEE A QUICK 1-2 INCHES AS IT MOVES QUICKLY OVER WNW THIRD 09-13Z AND
INTO NORTH CENTRAL VA 13Z-16Z. H70 FN CONVERGENCE VECTORS SHOW THIS
QUITE WELL AS BANDS MOVE OVER WRN VA ERLY THIS AM...BUT AGAIN THIS
AREA WILL MOVE QUICKLY AND NOT LEAD TO MORE THAN A FEW INCHES IN ONE
PLACE. HAVE WENT WITH ADVISORIES (1-3 INCHES) FOR NRN VA ZONES
(GENERALLY NORTH OF A FARMVILLE-PETERSBURG-EASTVILLE LINE). HAVE
ENDED ADVISORIES W/E AS THE AM/ERLY PM BEHIND BEST BANDS...BUT
-SN/FLY`S WILL CONTINUE BEHIND THEM (JUST WILL NOT AMOUNT TO MUCH
ADDITIONALLY). FURTHER SOUTH EXPECTING ACCUMS IN -SN/FLY`S TO HOLD
UNDER AN INCH THROUGH REMAINDER OF SYSTEM.

BEST H70 OMEGA AND PROLONGED H70 FN CONVERGENCE VECTORS WILL BE
SITUATED FURTHER TO THE NE OVER THE MD ERN SHORE...BUT MORE LIMITED
THAN PREV THINKING. HAVE LWRD SNOWFALL AMOUNTS WITH BEST FORCING TO
BE SITUATED NORTH OF THE CWA WHERE BEST PIVOT AXIS WILL EXIST.
STILL...DECENT DENDRITIC GROWTH WILL BE ALLOWED TO DVLP WITH 1-2
INCHES PER HOUR IN SNOW BANDS POSSIBLE LATER THIS AM INTO THE AFTN
HRS BEFORE SNOWFALL RATES TAPER OFF. HAVE GONE WITH 5-8 INCHES OF
SNOW TOTALS OVER THE WARNED AREA WITH THE HEAVIEST AMOUNTS LIKELY TO
OCCUR OVER NRN DORCHESTER COUNTY. ACCUMS MAY EVEN BE LESS THAN CRNT
THINKING (OR JUST AVERAGING TWRDS THE LWR END). SINCE WINDS WILL
BE GUSTING TO OVER 40 MPH AT TIMES...NEAR BLIZZARD CONDITIONS WILL
BE POSSIBLE IN HEAVIER BANDS. BULK OF DATA WOULD SUGGEST BLIZZARD
CRITERIA (SUST 35MPH AND 1/4 MI FOR 3 HRS) WILL BE DIFFICULT TO
MEET...BUT COULD EASILY SEE VSBYS UNDER A MILE AT TIMES. BOTTOM
LINE...DRIVING WILL BE HAZARDOUS IN SNOW SQUALLS/BANDS THAT DVLP.

FOR THE REMAINDER OF THE CWA...WINDS WILL BE MORE OF AN ISSUE TDY
INTO TNT. WINDS WILL INCREASE SIGNIFICANTLY AFTER DAYBREAK WITH SUST
WINDS OF 25-35 MPH AND GUSTS OF 40-50 MPH POSSIBLE. DUE TO ALREADY
SATURATED GROUNDS (WHERE SNOWCOVER DOES NOT EXIST)...THIS MAY LEAD
TO SMALL TREES/LARGER WEAKENED ROOT SYSTEMS TO POSSIBLY FALL
(POSSIBLY ONTO POWERLINES.

TEMPERATURES WILL CONTINUE TO FALL THIS AFTN/ERLY EVE THIS WILL
LIKELY LEAD TO ANY PONDING/WATER ON UNTREATED GROUND SURFACES TO
FREEZE (ESP OVER LOW LYING AREAS...CURBSIDES...AND ON BRIDGES AND
OVERPASSES).

LIGHT SNOW/FLY`S ENDING BY THIS EVE FOR MOST WITH SNOW TAPERING OFF
QUICKLY AFT 03Z...BUT SOME BAY EFFECT PLUMES MAY STILL BE POSSIBLE
AFTERWARDS (BUT AGAIN NOT AMOUNTING TO MUCH).

DRY NORTHWEST FLOW PREVAILS THROUGH THE END OF THE WEEK WITH BELOW
NORMAL TEMPERATURES.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
COLDER THAN NRML WX PTRN CONTS THROUGH THE XTNDD PD. NAO RMNG
NEG...W/ STRNG LO PRES CIRCULATING INVOF XTRM ERN CANADA/CANADIAN
MARITIMES...KPS ANOMALOUS/DP TROUGH LOCKED OVR THE ERN CONUS. LO
PRES STILL XPCTD TO STAY S OF THE RGN FRI INTO SAT. AFT THAT...XTNDD
GUID SUGGS THAT THERE WL BE A BRK IN THE SRN STMS TRACKING FM THE
LWR PLAINS TO THE E CST FM THE WKND THROUGH ERY NEXT NEXT WK.
RE-ENFORCEMENT OF COLD AIR SUGGD LT SUN INTO MON. OTRW...DRY/NW FLO
XPCTD ERY NEXT WK.

&&

.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
GENERALLY SEEING IFR CONDITIONS ACROSS THE REGION AS THE SURFACE
LOW HAS BEGUN TO DEEPEN OVER VIRGINIA BEACH. THE PARENT LOW IS
STILL WELL TO THE WEST NEAR THE WESTERN END OF LAKE ERIE. THE
PROCESS OF TRANSFERRING ENERGY TO THE COASTAL LOW WILL BEGIN LATER
THIS MORNING AS THE SURFACE COLD FRONT NOW IS WESTERN VA ARRIVES
ALONG THE COAST AND THE COLD AIR INTENSIFIES THE SFC LOW. IN THE
MEAN TIME...THE FLOW IS VERY WEAK AND WITH THE LOW LEVEL SATURATED
WILL SEE THE LOW CLOUDS AND VSBY UNTIL THE FRONT PASSES...RIC
AROUND 9Z...PHF 10Z AND THE REMAINING SITES BETWEEN 11Z AND 12Z.

AS THIS BOUNDARY PASSES...THE COMBINED WITH THE UPPER
SHORTWAVE...COULD SEE A BURST OF SNOW...MAINLY FOR RIC AND SBY.
ONCE THE LOW BEGINS TO STRENGTHEN OFF THE COAST...THE FLOW WILL
INCREASE FROM THE NORTHWEST WITH STRONG GUST DEVELOPING DURING THE
DAY TIME. THIS NW FLOW WILL HELP CLEAR OUT MOST OF VA AND NERN NC.
THE DELMARVA ON THE OTHER HAND WILL REMAIN IN THE WRAP AROUND
MOISTURE AND SHOULD CONTINUE TO SEE SNOW FALL WITH IFR CONDITIONS.
THE LOW PULLS FAR ENOUGH OFF THE COAST AFTER 00Z THAT THE SNOW
WILL TAPER OFF AT SBY AND CONDITIONS WILL IMPROVE.

&&

.MARINE...
-- Changed Discussion --
SURFACE LOW CONTINUES TO LIFT NE...JUST OFF THE SOUTHERN DELMARVA
COAST AND IS IT SLOWLY INTENSIFYING AT THIS TIME.  HOWEVER...WINDS
WITH THE SYSTEM ARE NOT THAT STRONG YET...WITH THE BAY STILL AROUND
10 KTS OR LESS AND THE COASTAL WINDS STRONGEST NEAR 44009.
HOWEVER...THE INTENSIFICATION OF THE SYSTEM IS ABOUT TO TAKE OFF AS
THE COLD AIR TO THE WEST CONTINUES TO PROGRESS OFF TO THE
EAST...HAVING REACHED A LINE FROM ROA TO HLX IN THE LAST HOUR.  ONCE
THIS COLD AIR HITS THE COAST LATER THIS MORNING...BETWEEN 12Z AND
15Z...THE LOW WILL BEGIN TO RAPIDLY INTENSIFY OFF THE NJ COAST.
ONCE THIS INTENSIFICATION BEGINS...WINDS WILL QUICKLY JUMP TO GALE
FORCE CONDITIONS THIS MORNING AND CONTINUE STRENGTHENING TO STORM
FORCE CONDITIONS IN THE OCEAN ZONES BY THIS AFTERNOON.  THE WINDS
WILL CONTINUE INTO THE OVERNIGHT HOURS AS THE LOW DROPS DOWN INTO
THE 970 MB RANGE BY EARLY EVENING.  BUT THE PROGRESSIVE NATURE OF
THE FLOW WILL PUSH THE CLOSE LOW ALOFT AND THE SURFACE CENTER AWAY
FROM THE COAST AFTER 3Z...WHICH WILL ALLOW THE WINDS TO GRADUALLY
WEAKEN DOWN TO GALES BY THURSDAY MORNING.  FOR NOW...HAVE HELD THE
STORM FORCE WINDS THROUGH 10Z THURS...BUT WILL PROBABLY NEED TO HAVE
GALES UP WELL INTO THE DAY ON THURSDAY...BEFORE HIGH PRESSURE FROM
THE WEST AND A RELAXING PRESSURE GRADIENT ALLOW THE WINDS TO
DECREASE.  SEAS WITH THIS SYSTEM DO LOOK TO BE AS HIGH AS THE LAST
ONE AS CONDITIONS AROUND 10 TO 12 FT LOOK REASONABLE DESPITE THE
STRONG WINDS AS THE FLOW WILL BE OFF SHORE AND THE SYSTEM HAS
DEVELOPED SO QUICKLY THAT THERE HAS BEEN LITTLE CHANCE TO GENERATE
MUCH SWELL.

THE AREA OF HIGH PRESSURE MOVES OVERHEAD ON THURSDAY EVENING INTO
FRIDAY SO WINDS WILL CONTINUE TO DECREASE BELOW SMALL CRAFT LEVELS
AND THE SEAS SHOULD FOLLOW SUIT AS WELL.
-- End Changed Discussion --

&&

.HYDROLOGY...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
-- Changed Discussion --
TIDES RUNNING ARND/A TOUCH BLO NRML ATTM. MAIN CONCERN IS W/
WNDSHFT TO NW (AND INCREASE) TDY...CONTG INTO THU. PSBL MINOR FLDG
ON THE ERN SHR OF THE CHES BAY...INVOF DORCHESTER CTY...(AND
THOUGH GUID CURRENTLY NOT REALLY SHOWING IT)...THE PTNTL BLOW OUT
TIDES ON THE CST/SRN BAY THIS AFTN THROUGH THU.
-- End Changed Discussion --

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
MD...WINTER STORM WARNING UNTIL 11 PM EST THIS EVENING FOR
     MDZ021>025.
     WIND ADVISORY FROM 10 AM THIS MORNING TO 6 AM EST THURSDAY FOR
     MDZ021>025.
NC...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR NCZ012>016-
     030>032.
     WIND ADVISORY FROM 10 AM THIS MORNING TO 6 AM EST THURSDAY FOR
     NCZ017-102.
VA...WIND ADVISORY UNTIL 9 PM EST THIS EVENING FOR VAZ048-049-
     060>076-079>084-087>097.
     WINTER STORM WARNING UNTIL 11 PM EST THIS EVENING FOR VAZ099.
     WIND ADVISORY FROM 10 AM THIS MORNING TO 6 AM EST THURSDAY FOR
     VAZ077-078-085-086-098>100.
     WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
     VAZ064-072-073-083-084-090.
     WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
     VAZ048-049-060>063-068>071-082.
     WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
     VAZ074>078-085-086-100.
MARINE...STORM WARNING FROM 10 AM THIS MORNING TO 6 AM EST THURSDAY FOR
     ANZ650-652-654.
     STORM WARNING UNTIL 6 AM EST THURSDAY FOR ANZ656-658.
     GALE WARNING UNTIL 6 PM EST THURSDAY FOR ANZ630>632.
     GALE WARNING UNTIL 4 PM EST THURSDAY FOR ANZ633.
-- End Changed Discussion --

&&

$$
SYNOPSIS...CCW
NEAR TERM...CCW
SHORT TERM...CCW
LONG TERM...ALB
AVIATION...ESS
MARINE...ESS
HYDROLOGY...CCW
TIDES/COASTAL FLOODING...ESS