Area Forecast Discussion
Issued by NWS Wakefield, VA

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FXUS61 KAKQ 231500
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
1100 AM EDT WED APR 23 2014

.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION EARLY THIS MORNING. COOL
CANADIAN HIGH PRESSURE BUILDS BACK OVER THE REGION TONIGHT AND
THURSDAY. A SERIES OF WEAK FRONTS WILL CROSS THE AREA FRIDAY INTO
THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
BASE OF THE UPPER TROUGH HAS LOCATED OVER THE LOCAL AREA PER
LATEST WATER VAPOR IMAGERY. AT THE SFC...COLD FRONT HAS PUSHED
WELL OFFSHORE AS MODIFYING CANADIAN HIGH PRESSURE HAS CENTERED
OVER THE GREAT LAKES REGION. THE RESULT WILL BE A DRY...BREEZY AND
COOL DAY OVER THE LOCAL AREA.

FOR TODAY...SFC LOW WILL PUSH OFF THE NEW ENGLAND COAST TODAY AS
HIGH PRESSURE BUILDS SOUTH AND EAST. PRESSURE GRADIENT WILL REMAIN
RATHER STRONG OVER THE REGION...RESULTING IN SUSTAINED NW WINDS OF
15 TO 20 MPH WITH GUSTS UP TO 30 MPH. STRONGER WINDS NEAR THE BAY
AND OVER THE ERN SHORE WITH SPEEDS 20 TO 25 MPH AND GUSTS TO 35
MPH. COMBINATION OF BREEZY CONDITIONS AND LOW RH WILL RESULT IN A
CRITICAL FIRE WEATHER DAY. PLEASE REFER TO THE FIRE WEATHER
SECTION BELOW FOR MORE INFORMATION. REMNANT MID-LEVEL MOISTURE AND
GOOD MIXING/STEEP LOW LEVEL LAPSE RATES WILL RESULT IN SOME
AFTERNOON CU...ESPECIALLY OVER THE NRN LOCAL AREA AND ERN SHORE
WHERE DOWNSLOPE FLOW WILL HAVE LESS OF AN IMPACT. NW FLOW...CAA
WILL RESULT IN TEMPS WARMING INTO THE MID-UPPER 60S...EVEN ALONG
THE COASTAL WATERS THANKS TO NW WINDS. THE EXCEPTION WILL BE THE
ERN SHORE WHERE TEMPS ONLY EXPECTED TO WARM INTO THE LOW 60S.

HIGH PRESSURE BUILDS INTO THE REGION TONIGHT. EXPECT CHILLY EARLY
MORNING LOWS THU MORNING IN THE MID-UPPER 30S ALONG/W OF I-95 TO
THE UPPER 30S TO LOWER 40S ELSEWHERE UNDER CLEAR SKIES. DO NOT
EXPECT ANY FREEZE ISSUES AND PROBABLY TOO DRY FOR MUCH MORE THAN
SOME PATCHY FROST IN SHELTERED LOCALES.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
DRY AGAIN ONCE AGAIN THU AS HIGH PRESSURE SLIDES OVER THE
NORTHEAST/MID-ATLANTIC REGION, BEFORE SLIDING OFF THE ATLANTIC
SEABOARD ERY FRIDAY. HIGHS THURS GENERALLY IN THE UPPER 60S (A
LITTLE COOLER NEAR THE COAST). ONCE AGAIN, MIN RH VALUES FALL INTO
THE 20S THU AFTN BUT WINDS WILL BE LIGHTER. NEXT FAST MOVING WAVE
OF MOISTURE MOVES IN FROM THE PLAINS ON FRI. GFS REMAINS FASTER
WITH BRINGING SYSTEM THROUGH, WITH THE NAM/ECMWF A BIT SHARPER
WITH THE UPPER WAVE...AND HENCE A BIT SLOWER. PUSHED BACK ONSET OF
POP JUST SLIGHTLY AND CONTINUED TO SPLIT THE DIFFERENCE BETWEEN
THESE STILL DIVERGENT SOLUTIONS. GIVEN THIS, EXPECT A SCENARIO
NOT UNLIKE THAT OF EARLIER YESTERDAY (TUESDAY); RATHER MEAGER
INSTABILITY WITH MODEST DEEP LAYER SHEAR/LAPSE RATES THAT RESULT
IN SOME WEAK DISORGANIZED CONVECTION LATE IN THE DAY FRIDAY. WILL
KEEP CHC POPS ALL ZONES FOR SCT SHRAS AND PERHAPS A THUNDERSTORM
PUSHING THROUGH AT SOME POINT IN THE AFTN/EVENING. WARMER SSW
FLOW SHOULD PUSH HIGHS WELL INTO THE 70S TO NEAR 8O.

CLEARING BEHIND THE FRONT FRIDAY NIGHT, WITH POPS QUICKLY ENDING
WEST TO EAST. LOWS GENERALLY IN THE 50S TO NEAR 60 ALONG AREA
COASTLINES.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
PROGRESSIVE FLOW WILL BEGIN TO EVOLVE INTO A HIGHLY AMPLIFIED/BLOCKY
PATTERN OVER THE CONUS DURING THE EXTENDED...LIKELY RESULTING IN A
COOL/WET PERIOD BY EARLY NEXT WEEK.

MEDIUM RANGE GUIDANCE TENDS TO STRUGGLE WITH BLOCKY FLOW...AND THIS
IS NO EXCEPTION. TRENDED TOWARD ENSEMBLE AND WPC GUIDANCE TO SMOOTH
OUT DIFFERENCES IN THE MODELS. OVERALL...UPPER PATTERN WILL BE
CHARACTERIZED BY AN ANOMALOUS UPPER TROUGH OVER THE WRN CONUS...HIGH
PRESSURE RIDGING FROM THE GULF STATES INTO THE NORTHWEST TERRITORIES
AND ANOTHER UPPER TROUGH OVER SE CANADA AND NEW ENGLAND. WHILE
MEANINGFUL DIFFERENCES EXIST IN THE MODELS...A SECOND (DRY) COLD
FRONT IS PROGGED TO CROSS THE LOCAL AREA ON SAT. THIS FRONT WILL
BRING COOLER/DRIER AIR TO THE REGION ON SUN. A STATIONARY BOUNDARY
WILL THEN SET UP OVER THE MID-ATLANTIC REGION (DEPENDING ON THE
MODEL IT COULD BE FROM THE CAROLINAS NWD TO THE MASON DIXON LINE).
THIS BOUNDARY WILL BE THE FOCUS OF PRECIP EARLY NEXT WEEK.
MEANWHILE...A BROAD AREA OF LOW PRESSURE OVER THE PLAINS WILL
PROGRESS EWD SUN-TUES...TAPPING INTO GULF MOISTURE. WILL MAINTAIN
SLIGHT CHANCE POPS SUN NIGHT-TUES BASED ON UNCERTAINTY...BUT
INCREASE TO LOW-END CHANCE POPS TUES NIGHT AS THE UPPER/SFC LOW GETS
CLOSER.

HAVE TRENDED TO THE COOLER SIDE OF GUIDANCE WITH HIGHS GENERALLY IN
THE MID-UPPER 60S SUN-TUES. OVERNIGHT LOWS GENERALLY IN THE UPPER
40S-LOW 50S.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
A SFC COLD FRONT IS DRAPED ACROSS THE AREA FROM THE SRN NJ COAST
INTO THE NC PIEDMONT REGION EARLY THIS MORNING. WINDS QUICKLY TURN
TO THE NW BEHIND THE FRONT AND BECOME GUSTY DUE TO A DECENT SURGE
OF COLD AIR FLOWING IN FROM THE NW. WIND SPEEDS SHOULD AVERAGE
ABOUT 34015G25KT DURING THIS INITIAL PUSH OF COLDER AIR. AS THE
FRONT EXITS THE COAST SHORTLY AFTER SUNRISE THIS MORNING...THE
PRESSURE GRADIENT WILL TIGHTEN UP NEAR THE IMMEDIATE COAST WHERE
WNW-NW WINDS SHOULD AVERAGE CLOSE TO 20G30KT FROM MID MORNING
THROUGH LATE AFTN/EARLY EVENING BEFORE TAPERING OFF DURING THE
EVENING AND OVERNIGHT HOURS. NW WIND SPEEDS BRIEFLY INCREASE THU
MORNING AND THEN DROP OFF THROUGH THE AFTN AS HIGH PRESSURE SLIDES
ACROSS THE AREA AND BECOMES LOCATED OFF THE SOUTHEAST COAST BY THU
EVENING. THE NEXT COLD FRONT APPROACHES THE REGION THU NIGHT...
CAUSING NW WINDS TO BACK AROUND TO THE S-SE. THE FRONT IS EXPECTED
TO CROSS THE MID ATLANTIC REGION FRI AFTN/EVENING...BRINGING
SHOWERS AND A SLIGHT CHANCE FOR THUNDERSTORMS TO AREA TAF SITES.
BEHIND THIS FRONT...WINDS WILL GENERALLY BE NLY AROUND 15 KT OR
LESS THROUGH THE REST OF THE WEEKEND.

&&

.MARINE...
A SFC COLD FRONT IS JUST STARTING TO TRACK ACROSS THE WATERS FROM
NW TO SE EARLY THIS MORNING. THE FRONT IS EXPECTED TO CLEAR THE
COAST BY SUNRISE. JUST BEHIND THE FRONT...STRONG SCA WINDS WILL
OCCUR DUE TO A DECENT SURGE OF COLD AIR FLOWING IN FROM THE NW. AS
A RESULT...NW WINDS WILL AVERAGE 20-25 KT WITH GUSTS TO AROUND
30 KT EARLY THIS MORNING AND CONTINUING THROUGH MOST OF TODAY
BEFORE TAPERING OFF TONIGHT. THE NW WIND DIRECTION WILL GENERALLY
PREVENT SEAS FROM BUILDING ANY HIGHER THAN 5-6 FT...WITH 3-4 FT
WAVES ON THE BAY (LOCALLY UP TO 5 FT SRN BAY AROUND SUNRISE WITH
THE INITIAL PUSH OF COLD AIR) AND 2-3 FT NEAR THE MOUTH OF THE
RIVERS. A SECONDARY...ALBEIT WEAKER...COLD AIR SURGE IS EXPECTED
TO OCCUR TONIGHT. THIS WILL KEEP NW WINDS ON THE BAY/OCEAN TO STAY
AROUND 20-25 KT OVERNIGHT...WITH GUSTS UP TO 30 KT NRN COASTAL
WATERS. SCA FLAGS ARE CURRENTLY IN EFFECT FOR AREA WATERS. PLEASE
REFER TO WWW.WEATHER.GOV/WAKEFIELD OR MWWAKQ FOR FURTHER DETAILS.

CONDITIONS GRADUALLY IMPROVE ON THU AS HIGH PRESSURE BUILDS OVER
THE WATERS. NW WIND SPEEDS AND SEAS ARE ANTICIPATED TO FALL BELOW
SCA THRESHOLDS BY THU AFTN (AOB 15 KT CHES BAY/AOB 25 KT AND SEAS
BELOW 5 FT)...HOWEVER OVERALL CONDITIONS WILL STILL BE SOMEWHAT
BREEZY DURING THE DAY BEFORE FINALLY DIMINISHING BY EARLY THU
EVENING. HIGH PRESSURE SLIDES OFF THE SOUTHEAST COAST THU NIGHT AS
ANOTHER COLD FRONT APPROACHES THE WATERS. THIS WILL CAUSE NW WINDS
TO BACK AROUND TO THE S-SE. THE FRONT IS EXPECTED TO CROSS THE
WATERS FRI EVENING...BRINGING SHOWERS AND A SLIGHT CHANCE FOR
THUNDERSTORMS TO THE AREA. BEHIND THIS FRONT...WINDS WILL
GENERALLY BE NLY AROUND 15 KT OR LESS THROUGH THE REST OF THE
WEEKEND AND WAVES/SEAS WILL AVERAGE 1-2 FT/2-3 FT RESPECTIVELY.

&&

.FIRE WEATHER...
DRY AND BREEZY CONDITIONS TODAY...AND IN COORDINATION WITH STATE
FIRE OFFICIALS/NEIGHBORING FORECAST OFFICES...A RED FLAG WARNING HAS
BEEN ISSUED FOR THIS AFTERNOON/EVENING FOR PORTIONS OF CENTRAL AND
EASTERN VA (MAINLY ALONG AND NORTH OF RIC METRO AREA) AS WELL AS
THE LOWER MD EASTER SHORE. WINDS ARE EXPECTED TO BE THE STRONGEST
THIS AFTN (20-25 MPH WITH GUSTS TO 35-40 MPH) ALONG AND NORTH OF A
LINE FROM FVX-PTB-LFI...AND THIS IS ESSENTIALLY THE WARNING AREA.
FARTHER SOUTH...WINDS WILL NOT BE AS STRONG (10-20 MPH WITH GUSTS
TO 30 MPH)...SO HAVE OPTED TO ISSUE AN SPS FOR INCREASED FIRE
DANGER OVER THESE AREAS TO HIGHLIGHT DRYING FUELS.

DRY CONDITIONS (MIN RH VALUES 20-25%) WILL OCCUR AGAIN ON
THURSDAY. HOWEVER...WINDS ARE NOT EXPECTED TO BE AS STRONG. THIS
WILL LIKELY PRECLUDE THE NEED FOR ANY FIRE WX WATCHES/WARNINGS
OVER OUR AREA...EXCEPT FOR THE LOWER MD EASTERN SHORE WHERE WINDS
MAY REMAIN ELEVATED. HOWEVER, ANYONE PLANNING/INVOLVED IN OUTDOOR
BURNING ACTIVITIES SHOULD CONTINUE TO EXERCISE CAUTION. WILL
THEREFORE MENTION CONTINUED DRY CONDITIONS FOR TOMORROW IN THE
HWO/FWF.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR MDZ021>025.
NC...INCREASED FIRE DANGER UNTIL 8 PM EDT THIS EVENING FOR
     NCZ012>017-030>032.
VA...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR VAZ048-049-
     061>064-068>078-081>086-089>091-094-099-100.
     INCREASED FIRE DANGER UNTIL 8 PM EDT THIS EVENING FOR VAZ060-
     065>067-079-080-087-088-092-093-095>098.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THURSDAY FOR ANZ650-652-
     654-656-658.
     SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR ANZ633-
     635>637.
     SMALL CRAFT ADVISORY UNTIL 10 AM EDT THURSDAY FOR ANZ630>632-
     634.
     SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ638.

&&

$$
SYNOPSIS...MAM/SAM
NEAR TERM...MAM/SAM
SHORT TERM...LKB/MAM
LONG TERM...SAM
AVIATION...BMD
MARINE...BMD
FIRE WEATHER...






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