Area Forecast Discussion
Issued by NWS Wakefield, VA

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000
FXUS61 KAKQ 100414
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
1114 PM EST TUE FEB 9 2016

.SYNOPSIS...
LOW PRESSURE LIFTS WELL OFF THE NORTHEAST COAST TONIGHT. AN UPPER
LEVEL TROUGH SWINGS THROUGH THE REGION LATER TONIGHT. HIGH PRESSURE
SLOWLY RETURNS WEDNESDAY THROUGH FRIDAY. LOW PRESSURE LIFTS ALONG
THE SOUTHEAST COAST FRIDAY AND FRIDAY NIGHT.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
STILL SEEING A COMBINATION OF LIGHT RAIN OR RAIN/SNOW SHOWERS
ACROSS THE NRN NECK AND MD/VA ERN SHORE. BEST SHORTWAVE ENERGY
PRESENT THIS EVENING IS STARTING TO PUSH INTO WRN PORTIONS OF NRN
VA AND IS EXPECTED TO TRACK ACROSS THE AFOREMENTIONED AREAS CLOSER
TO DAYBREAK. LIGHT SNOW ACCUMULATIONS OF LESS THAN ONE HALF INCH
STILL ANTICIPATED TO OCCUR ON ELEVATED AND GRASSY SFCS BETWEEN
400 TO 1000 AM.

PREVIOUS DISCUSSION...
ANOMALOUS MERIDIONAL FLOW PREVAILS OVER THE CONUS...HIGHLIGHTED
BY A DEEP TROUGH ENCOMPASSING MUCH OF THE ERN CONUS. AT THE
SFC...~991MB LOW PRESSURE HAS CENTERED WELL OFF THE MID-ATLANTIC
COAST WITH ANOTHER AREA OF LOW PRESSURE OVER THE ERN GREAT LAKES
REGION. A WEAK SFC TROUGH REMAINS OVER THE NERN LOCAL
AREA...PROVIDING BETTER LOW LEVEL CONVERGENCE FOR THE NRN NECK AND
MD ERN SHORE. NAM 285K THETA SURFACES HAVE HANDLED THE EARLIER
PRECIP WELL...SO CONTINUING WITH THAT TREND FAVORS THE
AFOREMENTIONED AREAS OF THE NRN NECK AND ERN SHORE...AS WELL AS SE
VA/NE NC THRU THE REST OF THE AFTERNOON. EXPECT A WINTRY MIX OF
RAIN/SNOW OVER THE NRN NECK AND MD ERN SHORE...BUT EXPECT ALL RAIN
SE VA/NE NC AS THE WARM LAYER IS DEEPER AND BETTER MIXED NEAR THE
COAST. NO SNOW ACCUMULATION IS EXPECTED FOR THE MD ERN SHORE THRU
6PM AS SFC TEMPS REMAIN IN THE LOW 40S WITH DEWPOINTS IN THE
MID/UPPER 30S.

FOR THE OVERNIGHT...EMBEDDED SHORTWAVE/VORT MAX REACHES NRN VA THIS
EVENING...DEVELOPING A WEAK WAVE OF LOW PRESSURE ALONG THE SFC
TROUGH OFF THE NEW JERSEY COAST. EXPECT PRECIP TO LINGER OVER THE
NRN NECK/ERN SHORE THRU THE EVENING HOURS. LOW LEVEL CRITICAL
THICKNESSES BEGIN TO DROP OFF SHARPLY THIS EVENING AS A COLDER/DRIER
AIR MASS SURGES INTO THE REGION. EXPECT A WINTRY MIX TO TRANSITION
TO SNOW SHOWERS THIS EVENING FOR THE NRN NECK/MD ERN SHORE...BUT SFC
TEMPS FORECAST TO HOVER IN THE MID 30S. DEWPOINTS WILL FALL INTO THE
UPPER 20S RESULTING IN WET BULBS IN THE LOW 30S. DO NOT EXPECT THE
BEST DYNAMICS TO ARRIVE UNTIL LATE TONIGHT...BUT NOT BEFORE THE BEST
MOISTURE PUSHES OFFSHORE. MINOR SNOWFALL ACCUMULATIONS ARE POSSIBLE
ON ELEVATED AND GRASSY SURFACES...WITH AMOUNTS GENERALLY AOB HALF AN
INCH...MAINLY OVER THE MD ERN SHORE. WILL HOLD ON TO CHANCE POPS FOR
SNOW SHOWERS THRU LATE TONIGHT FOR THE MD ERN SHORE AS THE VORT MAX
PUSHES THRU. SKY REMAINS GENERALLY PARTLY CLOUDY TO MOSTLY CLOUDY
WITH WLY WINDS 10-15 MPH...PREVENTING A SHARP DROP OFF IN TEMPS.
LOWS IN THE MID/UPPER 20S.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
ANOMALOUS/DEEP UPPER TROUGH PREVAILS ACROSS THE ERN CONUS WEDS AS A
STRONG RIDGE PERSISTS ALONG THE WEST COAST. SFC LOW PRESSURE LIFTS
OFF THE NEW ENGLAND COAST THRU THE DAY WEDS AS HIGH PRESSURE BUILDS
OVER THE GULF OF MEXICO. WILL MAINTAIN SLIGHT CHANCE FOR SNOW
SHOWERS EARLY WEDS MORNING AS THE POTENT VORT MAX PUSHES OFF THE
DELMARVA. OTHERWISE...DRY CONDITIONS PREVAIL WEDS AS A COLD/DRY AIR
MASS ADVECTS INTO THE REGION. STEEP LAPSE RATES STILL PRESENT DUE TO
THE COLD POOL ALOFT SO EXPECT PARTLY CLOUDY TO MOSTLY CLOUDY
CONDITIONS. HAVE STAYED ON THE COLD SIDE OF GUIDANCE...WITH HIGHS
GENERALLY IN THE LOW/MID 40S. WLY WIND 10-15 MPH.

TROUGH AXIS ALIGNS ALONG THE MID-ATLANTIC COAST WEDS NIGHT AS
ADDITIONAL SHORTWAVE ENERGY DIVES DOWN THE BACK SIDE OF THE UPPER
TROUGH. EXPECT MOSTLY DRY CONDITIONS AS PWATS WILL BE AOB 0.10
INCHES...BUT AS COLDER AIR SPILLS IN...COULD SEE A FEW BAY ENHANCED
SNOW SHOWERS ACROSS MAINLY THE VA ERN SHORE SO WILL MAINTAIN 20-30
POPS THERE. COLD WEDS NIGHT WITH LOWS IN THE UPPER TEENS PIEDMONT
TO MID 20S ALONG THE COAST. DRY/COLD THURS AS THE TROUGH AXIS
PUSHES OFFSHORE...USHERING IN AN EVEN COLDER AND DRIER ARCTIC AIR
MASS. HIGHS GENERALLY IN THE LOW/MID 30S...OR -1 TO -1.5 STD DEV.
SKY AVERAGES SUNNY TO MOSTLY SUNNY.

HIGH PRESSURE SETTLES OVER THE REGION THURS NIGHT AND FRI AS
ADDITIONAL ENERGY DIGS OVER THE MIDWEST INTO THE GULF STATES.
ASSOCIATED AREA OF LOW PRESSURE PROGGED TO DEVELOP OFF THE SOUTHEAST
COAST FRI...WITH A SLIGHT CHANCE FOR RAIN/SNOW ACROSS THE SOUTHEAST
LATE FRIDAY. SLIGHTLY WARMER...BUT STILL COLD WITH HIGHS IN THE
MID/UPPER 30S (-1 STD DEV).

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
STRONG COLD FRONT CROSSES THE REGION THROUGH THE DAY ON SATURDAY.
BEHIND THE FRONT...ARCTIC AIRMASS IS USHERED INTO THE MID-ATLANTIC.
STRONG UPPER LEVEL DYNAMICS MAY BE ENOUGH TO FORM A FEW SNOW SHOWER
SAT MORNING. WRAP AROUND MOISTURE FROM WEAK AREA OF LOW PRESSURE
DEVELOPING OFF THE COAST OF THE CAROLINAS MAY BRING A SLIGHT CHANCE
FOR -SN/-RASN ACROSS NE NC.

STRONG COLD AIR ADVECTION CONTINUES THROUGH THE DAY ON SAT WITH
925MB TEMPS DROPPING 10C THROUGH THE DAY. THICKNESSES AND
TEMPERATURES ALOFT CONTINUE DROPPING THROUGH THE WEEKEND AS UPPER
TROUGH SWINGS ACROSS THE AREA AND SURFACE HIGH PRESSURE BUILDS
WEST...CENTERING OVER THE GREAT LAKES REGION. EXPECT HIGH TEMPS IN
THE MID/UPR 30S. COLDEST AIRMASS OF THE SEASON SETTLES IN SAT NIGHT
WITH LOWS DROPPING INTO THE SINGLE DIGITS AND LOW TEEN SUN
MORNING(LOWS OVER 20F BELOW NORMAL). EXPECT HIGHS IN MID/UPR 20S ON
SUN WITH TEMPERATURES FALLING BACK INTO THE TEENS SUN NIGHT.

ACTIVE WEATHER PATTERNS CONTINUES FOR THE BEGINNING OF THE WORK
WEEK. WITH THE SURFACE HIGH PRESSURE MOVING OFF THE COAST...ANOTHER
POTENT UPPER TROUGH SWINGS ACROSS THE DEEP SOUTH. THIS WILL HELP
FORM AN AREA OF LOW PRESSURE ACROSS THE SE U.S. THAT WILL MOVE NE
LATE MONDAY INTO TUE. UNCERTAINTY EXISTS WITH THIS FEATURE DUE TO
SLIGHT MODEL DIFFERENCES IN TIMING OF LOW DEVELOPMENT AND TRACK OF
LOW. THE MODELS DO SUGGEST A MULTI-PRECIPITATION TYPE EVENT WITH AN
ONSET OF WINTER PRECIP TRANSITIONING TO A MIX ON TUES. PRECIP
PROGGED TO MOVE NE OFF THE COAST BY TUE NIGHT

&&

.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
UPR LVL LOW SLOWLY MOVES EAST ACROSS THE RGN THRU THIS FCST PRD.
CIGS GNRLY VFR 5K-8K FT XPCT FOR SCT-BKN MVFR CNDTNS (2-3K FT)
INVOF SBY. RADAR TRENDS HAVE SHOWN A DECREASE IN ECHO COVERAGE
SINCE SUNSET LARGELY DUE TO THE DIURNAL NATURE OF THE PCPN DRNG
THE DAYLIGHT HRS. HIGH RES MODELS SHOW SOME RN/SN SHWR ACTIVITY
SCT ABOUT THE NRN NECK/ERN SHORE AS WELL AS SERN CSTL AREAS THIS
EVE BUT LTL IN THE WAY OF PCPN BEING RPTD AT ANY OB SITES. THIS
DATA ALSO SHOWS A CONTINUED DECREASE IN COVERAGE NXT SVRL HRS
WITH ONLY A LOW CHC OF ANY PCPN MOVG OVR A TAF SITE. THUS...KEPT
ALL FCST DRY THRU THE NITE. ANTHR WEAK IMPULSE OF ENERGY PROGGED
TO SWING ACROSS THE LWR MD ERN SHORE ARND 12Z. THIS MAY PRODUCE A
SNOW SHWR AT SBY BUT CONFIDENCE NOT HIGH ENUF TO INCLUDE IN FCST.

W DOWNSLOPING WINDS BTWN 10-15 KTS WITH G20 KTS ACROSS ERN SHORE
AREAS WED. THIS KEEPS LWR LVLS DRY WITH ONLY SCT-BKN CLDNS XPCTD.

OUTLOOK...VFR CONDITIONS PREVAIL WED NGT THRU FRI...AS HI PRES
BLDS INTO THE MID ATLC REGION.

&&

.MARINE...
7-9FT SEAS IN THE ATLANTIC CONTINUE THROUGH THIS EVENING BEFORE
DROPPING TO 5-7FT OVERNIGHT.

MODERATELY STRONG PRESSURE GRADIENT AND CONTINUAL SHOTS OF COLD AIR
ALOFT WILL HELP STRENGTHEN WESTERLY FLOW OVER THE WATERS TONIGHT
THROUGH THURS NIGHT. THE RESULT WILL BE PROLONGED SCA CONDITIONS
ACROSS THE CHES BAY AND NC/VA/MD COASTAL WATERS. EXPECT WIND GUSTS
TO AVG 25-30KT WED MORNING THROUGH THUR NIGHT OVER THE COASTAL WATER
AND 20-25KT OVER THE BAY. EXPECT SEAS 3FT NEARSHORE UP TO 5/6FT 20NM
OFF THE COAST WITH THE OFFSHORE FLOW. WEAK AREA OF HIGH PRESSURE
SETTLES OVER THE MID-ATLANTIC BY FRI ALLOWING FOR A BRIEF PERIOD OF
NON-SCA CONDITIONS.

STRONG ARCTIC FRONT PROGGED TO CROSS THE WATERS SAT NIGHT. GALE
CONDITIONS WILL BE POSSIBLE SAT NIGHT THROUGH SUN NIGHT AS STRONG
CAA ADVECTION TAKES PLACE AND SURFACE PRESSURE GRADIENT TIGHTENS
BETWEEN DEPARTING LOW TO THE NE AND BUILDING HIGH FROM THE WEST. A
PERIOD OF FREEZING SPRAY WILL ALSO EXIST AS TEMPERATURES WILL
QUICKLY DROP INTO THE 20S AND TEENS SUN MORNING WITH WINDS GUSTING
OVER 30KT. WINDS DIMINISH QUICKLY SUN NIGHT AS SURFACE HIGH CENTERS
OVER THE WATERS.

&&

.HYDROLOGY...
RIVER FLOOD WARNING REMAINS IN EFFECT FOR THE NOTTOWAY AT SEBRELL.
THE WARNING FOR FRANKLIN WAS CANCELLED. SEE FLSAKQ FOR DETAILS.

&&

.TIDES/COASTAL FLOODING...
ISSUED ANOTHER ROUND OF COASTAL FLOOD ADVISORIES AND WARNINGS FOR
THE NEXT HIGH TIDE CYCLE TONIGHT GIVEN THE ELEVATED WATER LEVELS
DUE TO THE HIGH ANOMALIES. WARNINGS HAVE BEEN POSTED FOR THE CHES
BAY SIDE OF THE LWR MD ERN SHORE...CHES BAY SIDE OF THE VA ERN
SHORE AND NRN NECK. ADVISORIES HAVE BEEN POSTED FARTHER SOUTH
ACROSS THE MIDDLE AND LWR CHES BAY EXCEPT THE MOUTH OF THE BAY.

THIS ALL DUE TO ELEVATED WATER LEVELS ACRS THE BAY AS THE RECENT
HIGH SEAS HAS PREVENTED WATER FROM EXITING THE BAY AND TIDAL RIVERS.
IN MOST AREAS THE SURGE WAS 2 FT OR GREATER.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...COASTAL FLOOD WARNING UNTIL 4 AM EST WEDNESDAY FOR MDZ021>023.
NC...NONE.
VA...COASTAL FLOOD ADVISORY UNTIL 2 AM EST WEDNESDAY FOR VAZ084-086-
     090-093-095>097-523>525.
     COASTAL FLOOD WARNING UNTIL 1 AM EST WEDNESDAY FOR VAZ099-100.
     COASTAL FLOOD WARNING UNTIL 5 AM EST WEDNESDAY FOR VAZ075>078-
     085.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR ANZ630>634-
     650-652-654-656-658.

&&

$$
SYNOPSIS...LKB/SAM
NEAR TERM...BMD/SAM
SHORT TERM...LKB/SAM/JAO
LONG TERM...DAP
AVIATION...MAS/MPR
MARINE...DAP
HYDROLOGY...AKQ
TIDES/COASTAL FLOODING...AKQ


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