420
FXUS61 KAKQ 271404
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
904 AM EST WED JAN 27 2021
SYNOPSIS
LOW PRESSURE TRACKS SOUTH OF THE LOCAL AREA LATE TODAY INTO THURSDAY
MORNING. HIGH PRESSURE BUILDS ACROSS THE REGION FOR THE END OF THE
WEEK. ANOTHER LOW PRESSURE SYSTEM WILL AFFECT THE REGION SUNDAY.
NEAR TERM /UNTIL 6 PM THIS EVENING/
AS OF 305 AM EST WEDNESDAY...
AS ANTICIPATED...WIDESPREAD LOW CLOUDS REMAIN STUBBORN OF THE FA ATTM.
AREAS OF FG ARE ALSO FOUND MAINLY OVER THE PIEDMONT W OF I 95. HAVE
AN SPS FOR THAT UNTIL 12Z/27. OTW...RUNNING THE FCST BASED LARGELY
ON PERSISTENCE. ON MODEL SOUNDINGS...CURRENT LOW LEVEL INVERSION
TO LIFT DURING TODAY BUT ATTM HARD TO SEE MUCH CLEARING GIVEN WINDS
LESS THAN 10 MPH AND THAT ITS LATE JAN. IN-SITU WEDGE WILL TO REMAIN
THROUGH THE DAY...W/ 20-30% POP (RAIN) S OF VA-NC BORDER.
REMAINING LARGELY MOSTLY CLOUDY W/ HIGHS FROM THE M-U40S N TO
THE L50S FAR S.
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/
AS OF 330 AM EST WEDNESDAY...
ONE AREA OF PCPN (MAINLY RAIN) SKIRTS BY ACROSS SRN VA ON S THROUGH
NC THIS EVENING WHILE AN UPPER LEVEL SYSTEM TRACKS INTO THE MOUNTAINS.
ITS THAT UPPER LEVEL TROUGH THAT WILL BE THE KEY TO ANY SNOW OCCURRING
OVER (MAINLY) THE FAR SRN PORTIONS OF THE FA TONIGHT. THE SYSTEM WILL
HAVE TO GENERATE COLD AIR THROUGH DYNAMICS (A RAIN-SNOW SCENARIO).
THE UPPER LEVEL SYSTEM EXITING THE MOUNTAINS THIS EVENING WILL BE
FEATURE THAT GENERATES BULK OF THE PCPN OVER THE FA TONIGHT AS SFC
LO PRES TRACKS TO COASTAL NC.
RAIN THIS EVENING (MAINLY OVER FAR SRN VA-NE NC) EXPECTED TO MIX
W/ AND CHANGE OVER TO A PERIOD OF WET SNOW (MAINLY) AFTER MIDNIGHT
AS DYNAMICS AND COOLING ALOFT TAKES PLACE. HIGHEST POTENTIAL FOR
SNOW ACCUMS 1" OR MORE ARE OVER FAR SRN/INTERIOR SE VA INTO NE
NC. WOULD NOT RULE OUT SLIGHTLY HIGHER TOTALS IF THERE ARE ANY
PERSISTENT BANDS OF MODERATE/HEAVY SNOW. ALSO...EXPECTING RAIN
TO BATTLE W/ SNOW NEAR THE COAST WHICH WOULD LIMIT ACCUMS. AFTER
COORD W/ RAH/MHX...WILL ISSUE A WINTER WEATHER ADVISORY FOR FAR
SRN TIER (INCLUDING SE LOCATIONS ALL THE WAY TO THE BAY/OCEAN)
IN VA AND ALL BUT THE NRN OUTER BANKS IN NC STARTING AT
MIDNIGHT. TIMING OF PCPN CHANGEOVER/TEMPERATURES AND INTENSITY
WILL BE KEY TO ANY EVENTUAL ACCUMS. LIGHT SNOW OR JUST FLURRIES
EXPECTED OVER MOST CENTRAL/NRN PORTIONS OF THE FA. NNW WINDS
WILL BEGIN TO INCREASE BY LATE TONIGHT. LOWS U20S N TO THE L30S
ALONG COASTAL SE VA-NE NC.
LO PRES EXITS QUICKLY THU MORNING W/ LINGERING PCPN AT THE COAST
ENDING. NNW WINDS WILL BE BREEZY/WINDY IN ITS WAKE AS CLEARING OCCURS.
GUSTS TO 35-45 MPH ARE EXPECTED...HIGHEST MOST LIKELY AT THE COAST
(WHERE A WIND ADVISORY WILL LIKELY BE ISSUED LATER TODAY). COLD THU
W/ HIGHS NOT TOO FAR FROM 40F...WIND CHILLS MAINLY IN THE 20S.
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/
AS OF 355 PM EST TUESDAY...
HIGH PRESSURE CENTERS OVER THE AREA FRIDAY THEN MOVES OFFSHORE
SATURDAY. TEMPS WILL REMAIN COOL FRIDAY WITH TEMPS IN THE UPPER
30S/LOWER 40S THEN ONLY SLIGHT WARMING INTO THE LOW-MID 40S
SATURDAY. THEN, THE MEDIUM RANGE MODELS HAVE ANOTHER AREA OF LOW
PRESSURE MOVING THROUGH THE GREAT LAKES THEN DEVELOPING ANOTHER LOW
OFF THE NE COAST BY MONDAY. THE ASSOCIATED COLD FRONT WILL MOVE
THROUGH THE REGION SUNDAY. SNOW TO RAIN POSS SUNDAY MORNING
BEFORE SOUTHERLY FLOW ALLOWS FOR RAIN AS TEMPS WARM INTO THE 40S
AND LOWER 50S. (12Z/26 ECMWF ENSEMBLES DO SHOW AN INCREASE IN
PROB SNOW ACCUMS 3" OR MORE OVER PORTIONS OF THE PIEDMONT, WITH
YET ANOTHER MILLER-B SET UP MODELED. GFS IS A BIT FASTER AND
MORE COMPACT. PRECIP CHANCES LOOK GOOD, SO HIGH END CHANCE TO
LIKELY POPS ARE IN ORDER, BUT PHASE WILL TAKE A BIT MORE TIME TO
ASCERTAIN. ECMWF SOLUTION WOULD PORTEND TO A SNOWIER SOLUTION IF
THE CURRENT IDEA IS MAINTAINED. DRYING OUT BEHIND THE SYSTEM,
BUT REMAINING COLD RELATIVE TO NORMAL AS MEAN EAST COAST TROUGH
LOOKS TO SET UP. STAY TUNED.
AVIATION /14Z WEDNESDAY THROUGH SUNDAY/
AS OF 615 AM EST WEDNESDAY...
WIDESPREAD LIFR/IFR CONDITIONS (MAINLY CIGS...THOUGH OCCASIONAL
VSBYS DOWN TO 1/2-1SM OR SO IN BR) TO CONTINUE UNTIL MID-LATE
MORNING (AND QUITE POSSIBLY ALL DAY...THOUGH LOW LEVEL INVERSION
IS EXPECTED TO LIFT RESULTING IN CIGS LIFTING INTO MVFR CAT).
MODELS SUGGEST AT LEAST PARTIAL CLEARING...BUT FOR NOW WILL GO
W/ PERSISTENCE GIVEN LOW LEVEL WEDGE/INVERSION AND RESIDUAL
MOISTURE. VRB WINDS BECOME MAINLY N AVGG ABOUT 10 KT. SUB-VFR
CONDITIONS EXPECTED TONIGHT...AS LOW PRES CROSSES THE FA (THEN
EXITS QUICKLY THU AFTERNOON). ADDITIONAL FLIGHT RESTRICTIONS
TONIGHT DUE TO LOW CIGS AND MIXED PCPN (RA/SN - BECOMING SN).
BECOMING VFR AND BREEZY/WINDY THU (GUSTS TO 25-35 KT AT THE
COAST)...POSS MVFR CIGS LINGER INVOF SE VA-NE NC. VFR CONDS TO
PREVAIL THU NIGHT- SAT NIGHT.
MARINE
AS OF 330 AM EST WEDNESDAY...
WEAK HIGH PRESSURE IS CENTERED JUST WEST OF THE WATERS EARLY THIS
MORNING, WITH W-NW WINDS BELOW 10 KT. SEAS ARE 2-3 FT, WITH WAVES OF
~1 FT ON THE BAY. A MODEST CAA SURGE ARRIVES FROM THE NW LATER THIS
MORNING, WHICH WILL ALLOW NW WINDS TO INCREASE TO 15-20 KT N/~15 KT
S. THIS SURGE WEAKENS AS IT MOVES SOUTHWARD THROUGH THE DAY TODAY.
HOWEVER, WIND PROBS ARE SHOWING A 3-6 HOUR WINDOW OF LOW-END SCAS ON
THE MIDDLE BAY (50-70% FOR SUSTAINED 18 KT WINDS NEAR TANGIER
ISLAND). WENT AHEAD AND ISSUED AN SCA FROM 12-21Z N OF WINDMILL PT
(630) TO ACCOUNT FOR THIS.
LOW PRESSURE IS STILL PROGGED TO DEEPEN AS IT TRACKS ACROSS THE
CAROLINAS TONIGHT BEFORE EXITING QUICKLY OUT TO SEA DURING THE
LATTER PART OF THU AM (AND THROUGH THE REMAINDER OF THE DAY ON THU).
THE LOW WILL RAPIDLY INTENSIFY SHORTLY AFTER IT MOVES OFF THE COAST.
N WINDS INCREASE TO ~20 KT BY 03-06Z THU ON THE BAY/OCEAN. THEN, BY
LATE WED NIGHT INTO THU MORNING, WINDS BECOME NNW AND WILL INCREASE
TO 25-35 KT (HIGHEST OVER THE SRN COASTAL WATERS) IN THE WAKE OF THE
STORM SYSTEM. THE STRONGEST WINDS WILL OCCUR FROM THU AM-THU EVENING
BEFORE DIMINISHING SLIGHTLY DURING THE FIRST PART OF THU NIGHT.
GUSTS 35-40 KT WILL BE COMMON FOR THE CHES BAY/CURRITUCK
SOUND/COASTAL WATERS AND AROUND 30 KT FOR THE UPPER RIVERS DURING
THIS TIME. HAVE UPGRADED ALL GALE WATCHES TO WARNINGS FOR THE
OCEAN/BAY/LOWER JAMES/CURRITUCK SOUND. HAVE STARTED THE GALE
WARNINGS FROM 00-03Z THU TO ACCOUNT FOR THE ONSET OF SCA
CONDITIONS. FOR NOW, WILL END GALE WARNINGS (AND THE SCA FOR THE
UPPER RIVERS) FROM 00-06Z FRI. A SECONDARY (FAIRLY STRONG) CAA SURGE
ARRIVES LATE THU NIGHT/FRIDAY MORNING WITH ROBUST (850 MB TEMPS ARE
PROGGED TO BOTTOM OUT BETWEEN -15 AND -17C N OF CAPE CHARLES). CAA
CONTINUES DURING THE DAY ON FRIDAY. THIS WILL RESULT IN AT LEAST THE
CONTINUATION OF SOLID/STRONG SCA CONDITIONS, WITH A GOOD CHC OF GALE
GUSTS NORTH OF CAPE CHARLES (MAINLY FROM 12-21Z FRI). WILL HOLD OFF
ON EXTENDING THE WARNINGS, GIVEN THAT IT WOULD BE MORE THAN 48 HOURS
OUT. ADDITIONALLY, CANNOT RULE OUT SOME LIGHT FREEZING SPRAY OVER
THE COASTAL WATERS N OF PARRAMORE ISLAND LATE THU NIGHT/FRI AM. NW
WINDS WILL SLOWLY DIMINISH FRI NIGHT-SAT AM. WINDS SHOULD FINALLY
FALL BELOW SCA THRESHOLDS BY LATE SAT AM. SEAS ARE EXPECTED TO TOP
OUT BETWEEN 7-10 FT WITH WAVES ON THE BAY 4-5 FT (PERHAPS 6 FT AT
THE MOUTH).
HYDROLOGY
FLOOD WARNING HAS BEEN POSTED FOR THE MEHERRIN RIVER AT
LAWRENCEVILLE. ADDITIONAL FLOOD WARNINGS MAY BE NEEDED LATER
THIS WEEK ALONG THE NOTTOWAY RIVER, AND WILL NEED TO MONITOR
STONY CREEK, AND SEBRELL.
AKQ WATCHES/WARNINGS/ADVISORIES
MD...WIND ADVISORY FROM 6 AM TO 6 PM EST THURSDAY FOR MDZ021>025.
NC...WIND ADVISORY FROM 6 AM TO 6 PM EST THURSDAY FOR NCZ017-102.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM EST
THURSDAY FOR NCZ012.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST
THURSDAY FOR NCZ013>017-030>032.
VA...WIND ADVISORY FROM 6 AM TO 6 PM EST THURSDAY FOR VAZ095-
098>100.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM EST
THURSDAY FOR VAZ065-079-087-088-092.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST
THURSDAY FOR VAZ093-095>098.
MARINE...GALE WARNING FROM 10 PM THIS EVENING TO 10 PM EST THURSDAY FOR
ANZ630>632-650-652-654.
GALE WARNING FROM 7 PM THIS EVENING TO 1 AM EST FRIDAY FOR
ANZ656-658.
SMALL CRAFT ADVISORY FROM 1 AM THURSDAY TO 1 AM EST FRIDAY FOR
ANZ635>637.
GALE WARNING FROM 10 PM THIS EVENING TO 1 AM EST FRIDAY FOR
ANZ634.
GALE WARNING FROM 10 PM THIS EVENING TO 7 PM EST THURSDAY FOR
ANZ633-638.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ630.
SYNOPSIS...MAM
NEAR TERM...ALB
SHORT TERM...ALB/MAM
LONG TERM...MAM
AVIATION...ALB
MARINE...ERI/TMG
HYDROLOGY...AKQ
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