Area Forecast Discussion
Issued by NWS Wakefield, VA

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000
FXUS61 KAKQ 281826
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
126 PM EST WED JAN 28 2015

.SYNOPSIS...
HIGH PRESSURE SLOWLY BUILDS EAST INTO THE MID ATLANTIC REGION
THROUGH TONIGHT. THE HIGH SLIDES OFFSHORE THURSDAY...BEFORE A
COLD FRONT CROSSES THE AREA THURSDAY NIGHT. COLD HIGH PRESSURE
THEN RETURNS FOR LATE FRIDAY INTO SATURDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
LATEST WX ANALYSIS REVEALS STRONG COASTAL LOW (~989MB) LIFTING
INTO THE GULF OF MAINE/BAY OF FUNDY AREA TOWARDS ATLANTIC CANADA
AT SUNRISE THIS MORNING. TO THE WEST, ~1027MB SFC HIGH PRESSURE
CONTINUES TO DRIFT EAST OVER THE OHIO VALLEY, AND IS FORECAST
BUILD ACROSS THE LOCAL AREA TODAY INTO TONIGHT. DID NUDGE
TEMPERATURES UP SLIGHTLY EARLY THIS MORNING WITH WINDS KEEPING
TEMPS UP ABOVE GUIDANCE, BUT DO EXPECT WINDS TO DROP OFF BRIEFLY
JUST BEFORE DAWN...AND IN THE DRY AIRMASS IN PLACE, EXPECT
READINGS TO DROP OFF QUICKLY JUST BEFORE SUNRISE. THICKNESS TOOLS
MESH WELL WITH THE GOING FORECAST, WITH EXPECTED HIGHS TODAY IN
THE LOWER TO MIDDLE 40S ACROSS MUCH OF THE AREA, WITH SLIGHTLY
COOLER UPR 30S OVER THE EASTERN SHORE. CONDITIONS WL REMAIN A BIT
BREEZY THROUGH THE AFTN, WITH NORTHERLY WINDS AVGG 15-20 MPH
(GUSTS TO 25) ALONG THE COAST, 5-10 MPH INLAND. THIS WILL KEEP
WIND CHILLS IN THE 30S THROUGH THE DAY FOR MOST DESPITE A SUNNY TO
MOSTLY SUNNY SKY. HIGH PRESSURE MOVES OVERHEAD TONIGHT/ERY
THURSDAY. CLEAR SKIES AND LIGHT WINDS SHOULD YIELD GOOD RADIATING
CONDITIONS AND A COLDER NIGHT TNGT. EARLY MORNING LOWS THURSDAY
MORNING 15 TO 20 INLAND TO LOWER TO MID 20S ALONG THE COAST.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
HIGH PRESSURE PUSHES OFFSHORE THURSDAY MORNING, ALLOWING SOUTHERLY
FLOW TO RETURN AHEAD OF NORTHERN STREAM SHORT WAVE AND ASSOCIATED
COLD FRONT. NOT MUCH MOISTURE FOR THE SYSTEM TO WORK WITH AS IT
CROSSES THE OHIO VALLEY TOWARDS THE CENTRAL APPALACHIANS THU
AFTN/EVENING, OWING TO DOWNSLOPE FLOW ACROSS THE REGION. THUS, HAVE
KEPT A DRY FORECAST FOR MOST OF THE AREA ON THU...WITH ONLY A SLIGHT
CHC TO LOW CHC (20-30%) CHANCE FOR SOME PASSING RAIN SHOWERS, MAINLY
ALONG AND NORTH OF THE RICHMOND METRO AREA. ANY SHRAS LATE THU
AFTN/EVENING WOULD BE BRIEF, WITH QPF ON THE ORDER OF A FEW
HUNDREDTHS AT BEST. 00Z/28 DATA IS ALSO A BIT QUICKER TO DRY OUT
ANY PCPN OVER THE EASTERN SHORE, SO WILL GO WITH RN/SN LATE THU
NGT AND LOWER POPS AFTER MIDNIGHT. FOR HIGHS, PRE-FRONTAL SW FLOW
YIELDS A MODEST AND SHORT LIVED WARM UP ON THU, WITH HIGHS INTO
THE MID TO UPPER 40S (WARMEST I-85/US-1 CORRIDOR). ASSOCIATED SFC
COLD FRONT CROSSES THE AREA LATE THU NGT/FRIDAY MORNING, USHERING
IN A SHARPLY COLDER AND DRIER AIRMASS FOR FRIDAY INTO THE WEEKEND.
LOOK FOR BRISK WINDS OUT OF THE NW THROUGH THE DAY ON FRIDAY INTO
FRIDAY NIGHT TO YIELD WIND CHILLS IN THE 20S DURING THE DAY FRIDAY
AND INTO THE LOW TEENS FRIDAY NIGHT (SINGLE DIGITS TO NEAR ZERO ON
THE LOWER EASTERN SHORE).

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
NRN STREAM REMAINS ACTIVE DURING THE EXTENDED PERIOD WITH BELOW
NORMAL TEMPS PREVAILING. TROUGH EXITS THE COAST FRI NIGHT/SAT
MORNING...AS COLD CANADIAN HIGH PRESSURE CONTINUES TO BUILD OVER
THE MID-ATLANTIC DURING THE DAY SAT. THE RESULT WILL BE MOSTLY
SUNNY SKIES AND TEMPS IN THE LOW-MID 30S. H85 TEMPS PROGGED TO BE
AROUND -10C (-1 STD DEV). THEREAFTER...MODELS IN GOOD AGREEMENT
NOW WITH PUSHING THE SFC HIGH OFFSHORE SUN AS THE NEXT NRN STREAM
SHORTWAVE DIGS INTO THE SOUTHERN STATES. ASSOCIATED SFC LOW
PROGGED TO LIFT FROM THE LOWER MS VALLEY NEWD OVER THE CENTRAL
APPALACHIANS SUN...AND NORTH OF THE REGION SUN NIGHT. TRAILING
COLD FRONT PROGGED TO CROSS THE REGION SUN NIGHT. DEEP H85 TROUGH
EXPECTED TO ADVECT MOISTURE NWD FROM THE ERN GULF INTO THE REGION
IN ADVANCE OF THE FRONT. COMBINED WITH HEIGHT FALLS AND INCREASING
WINDS ALOFT...WIDESPREAD PRECIP IS EXPECTED TO OVERSPREAD MUCH OF
THE AREA LATE SUN INTO SUN NIGHT. RETURN FLOW WILL WARM TEMPS INTO
THE LOW-MID 40S (POSSIBLY WARMER) SUN...WITH THE COLDEST AIR
REMAINING OVER THE GREAT LAKES REGION. THE RESULT WILL BE
PREDOMINATELY RAIN...BUT A BRIEF RAIN/SNOW MIX IS POSSIBLE AT THE
ONSET AS WAA KICKS IN. HOWEVER...NO ACCUMULATION IS EXPECTED. ALL
RAIN LATE SUN-SUN NIGHT...WITH A POSSIBLE CHANGE OVER ACROSS THE
NRN ZONES LATE SAT NIGHT AS COLD AIR PUNCHES INTO THE REGION. WLY
PUSH BEHIND THE SHORTWAVE WILL RESULT IN DRYING CONDITIONS MON-
TUES AS COLD CANADIAN HIGH PRESSURE BUILDS IN FROM THE NW. BY
TUES...TEMPS FORECAST TO BE BACK INTO THE MID-UPPER 30S.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
SURFACE HIGH PRESSURE IS BUILDING IN FROM THE NW THIS AFTERNOON
UNDER A CLEAR SKY. A NW WIND IS AVERAGING 10-15KT...WITH GUSTS UP
TO 20KT CLOSER TO THE COAST. SURFACE HIGH PRESSURE SETTLES OVER
THE REGION TONIGHT RESULTING IN A CLEAR SKY AND CALM TO VERY LIGHT
WIND. HIGH PRESSURE MOVES OFFSHORE THURSDAY AS A COLD FRONT
APPROACHES FROM THE NW. THE WIND WILL BECOME SOUTHERLY ALONG WITH
AN INCREASE IN HIGH CLOUDS. THE COLD FRONT WILL CROSS THE AREA
THURSDAY NIGHT WITH ONLY A SLIGHT CHC OF -SHRA ALONG AND N OF A
RIC-SBY LINE...AND PERHAPS PCPN ENDING AS A MIX OF -RASN AT SBY.
A GUSTY NW WIND IS EXPECTED FRIDAY AS CANADIAN HIGH PRESSURE
BUILDS IN FROM THE NW. THAT AREA OF HIGH PRESSURE SLIDES ACROSS
THE REGION FRIDAY NIGHT AND SATURDAY...WITH A MORE MOIST FRONTAL
SYSTEM IMPACTING THE REGION SUNDAY INTO MONDAY.

&&

.MARINE...
UPDATE TO REMOVE THE RIVERS FROM THE SCA. OTHERWISE...THE
REMAINING FLAGS REMAIN AS IS.

PREVIOUS DISCUSSION...
COASTAL LOW LOCATED OFF THE MAINE AND NOVA SCOTIA COASTS WILL PUSH
OUT TO SEA TODAY AS HIGH PRESSURE BUILDS INTO THE REGION TODAY.
THERE IS STILL JUST ENOUGH OF A PRESSURE GRADIENT BTWN THESE
SYSTEMS TO KEEP BREEZY NW WINDS OVER THE WATERS TODAY THROUGH THIS
EVENING. SPEEDS WILL AVERAGE 15-25KT. GUSTS UP TO 30KT WILL
PERSIST ON THE BAY THROUGH THIS MORNING...AND ON THE COASTAL
WATERS ALL DAY. SEAS CURRENTLY RANGE FROM 5-8FT NORTH TO 7-10FT
SOUTH AND ARE EXPECTED TO SLOWLY SUBSIDE TODAY INTO TONIGHT...
DROPPING BELOW 5FT LATE TONIGHT. WAVES OF 3-5FT WILL ALSO SUBSIDE
TO 3-4FT THROUGH TODAY...DROPPING TO 2-3FT BY LATE THIS EVENING.
SCA FLAGS REMAIN IN EFFECT THROUGH THIS EVENING.

HIGH PRESSURE MOVES OVER THE WATERS TONIGHT...ALLOWING WINDS TO
DIMINISH AOB 15KT AS THE PRESSURE GRADIENT FINALLY RELAXES. THE
HIGH GETS SHUNTED OVER THE SE COAST THU AS A CLIPPER SYSTEM
APPROACHES THE MID ATLANTIC REGION. THE COLD FRONT ASSOCIATED WITH
THE CLIPPER IS EXPECTED TO CROSS THE WATERS LATE THU NIGHT. A
SUBSTANTIAL INCREASE IN WIND SPEEDS SHOULD BE ANTICIPATED
PRIMARILY DURING FRI/FRI NIGHT AS A COLD CANADIAN AIRMASS GETS
PULLED OVER THE WATERS BY THE DEPARTING LOW AND A CANADIAN HIGH
BUILDING INTO THE REGION. MODELS HAVE TRENDED COLDER WITH REGARD
TO THE AIRMASS TEMPERATURES THUS RESULTING IN STRONGER CAA
PROCESSES. SINCE MODELS TEND TO UNDERCUT WIND SPEEDS IN THESE
SITUATIONS...DECIDED TO GO ABOVE GUIDANCE WHICH PUTS THE WATERS
WITHIN POTENTIALLY SOLID GALE CONDITIONS (EXCEPT RIVERS/SOUND)
FRI/FRI NIGHT. NW WINDS WOULD AVERAGE 20-25KT WITH GUSTS OF
35-40KT. SEAS/WAVES ALSO EXPECTED TO BUILD QUICKLY ONCE THE WIND
SURGE BEGINS. SEAS COULD REACH 7-10FT...WAVES COULD REACH 4-6FT.
WILL NEED TO KEEP A CLOSE EYE ON MODEL TRENDS FOR POTENTIAL
HEADLINES IN THE POST-FRONTAL ENVIRONMENT. REGARDLESS OF STRENGTH...
CONDITIONS WILL BEGIN TO SUBSIDE/DIMINISH SAT NIGHT AS THE
CANADIAN HIGH SLIDES DIRECTLY OVER THE WATERS. A SOUTHERN STREAM
LOW PRESSURE SYSTEM IS ANTICIPATED TO TRACK INTO THE AREA FROM THE
SOUTHWEST LATE SUN INTO MON.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
     ANZ630>634.
     SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR ANZ650-652-
     654-656-658.

&&

$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...MAM
LONG TERM...SAM
AVIATION...AJZ
MARINE...BMD/AJZ



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