Area Forecast Discussion
Issued by NWS Wakefield, VA

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000
FXUS61 KAKQ 280759
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
359 AM EDT THU MAY 28 2015

.SYNOPSIS...
HIGH PRESSURE REMAINS ANCHORED WELL OFF THE MID ATLANTIC COAST
TODAY...WITH A TROUGH OF LOW PRESSURE NEARLY STATIONARY EAST OF
THE MOUNTAINS. HIGH PRESSURE WILL BUILD OVER THE NORTHEAST STATES
FRIDAY...THEN SLIDE OFF THE COAST SATURDAY. A SLOW MOVING COLD
FRONT WILL ENTER THE LOCAL AREA FROM THE NORTHWEST ON SUNDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
CURRENT ANALYSIS INDICATING SFC HIGH PRESSURE WELL OFF THE MID
ATLC/NE COAST...RIDGING SW TO OFF THE NC COAST. SFC COLD FRONT IS
SITUATED FROM WRN NY STATE SW INTO THE OHIO VALLEY. FLOW ALOFT IS
FROM THE WSW. WV SATELLITE SHOWING DECENT SHORTWAVE PUSHING ACRS
THE GREAT LAKES...AND THIS IS PROGGED TO SHIFT EAST INTO NY STATE
BY THIS AFTN. FLOW ALOFT BECOMES VERY LIGHT ACRS THE MID ATLC REGION
THIS AFTN AS THE SFC COLD FRONT DISSIPATES OFF TO OUR NORTH AND
WEAK UPPER RIDGING DEVELOPS IN THE WAKE OF THE SHORTWAVE. NUMERICAL
GUIDANCE/MAV/MET POPS ARE QUITE LOW TODAY...SUGGESTING LITTLE IF
ANY CHC FOR AFTN CONVECTION. WHILE THIS IS PROBABLY UNDERDONE...THERE
WILL BE LITTLE TRIGGER FOR WIDESPREAD PRECIP TODAY OTHER THAN
DEVELOPING LOCAL BOUNDARIES AND ML CAPES ON THE ORDER OF 1000 TO
2000 J/KG THIS AFTN. SHEAR IS ABOUT AS WEAK AS IT GETS...10-15 KT
OR LESS OF 0-6 KM EFFECTIVE SHEAR. WILL MAINTAIN ABOUT A 30% CHC
FOR AFTN/EARLY EVENING TSTMS OVER MOST OF THE AREA....A LITTLE
HIGHER (TO AROUND 40%) IN THE FAR NW AS DEVELOPMENT IS MORE
LIKELY OVER THE MTNS DUE TO SE LOW LEVEL FLOW. ALSO WILL HAVE A
ZONE OF POPS TO ~40% FOR INTERIOR SE VA/NE NC DUE TO POTENTIAL FOR
SEABREEZE ENHANCEMENT. AT THE IMMEDIATE COAST POPS WILL TEND TO BE
A BIT LOWER/GENLY AROUND 20% WHERE FLOW TURNING ONSHORE FROM THE
SE THIS AFTN WILL TEND TO STABILIZE CONDITIONS. WEAK SHEAR WILL
MAKE ORGANIZED STRONG STORMS UNLIKELY TODAY...MAIN CONCERN WILL BE
LOCALLY HEAVY RAIN IN SLOW MOVING STORMS DUE TO WEAK FLOW AND
PWATS OVER 1.50". HIGHS TODAY MAINLY FROM 85-90 F...EXCEPT UPPER
70S TO LOWER 80S AT THE COAST. LOW CHC POPS LINGER THIS
EVENING...MAINLY WELL INLAND...OTHERWISE PARTLY CLOUDY WITH LOWS
MAINLY FROM 65-70 F.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
WK SFC HI PRES SLIDES E ACRS NEW ENG FRI. MDLS SHOW A SLGT DROP
IN DEWPTS ACRS FAR NNE COUNTIES FOR THE DAY...WHILE RMNG UP ELSW.
HI PRES JUST OFFSHORE BEGINS TO SLGTLY BUILD WWD DURING THE
DAY...SO FOCUS OF HIGHER POPS (30-40%) NW 1/2 OF FA WITH ONLY 10-20%
POPS ELSW. BY SAT...CDFNT FM THE NW APPROACHES...THOUGH RMNS FAR
ENOUGH AWAY FOR SIGNIFICANT IMPACT ON THE WX HERE. WILL KEEP
CONDS WARM W/ VRB CLDS/PCLDY AND MAINLY JUST ABOUT A 20% POP INLAND...10%
AT THE CST. HI TEMPS FRI A TAD COOLER MAINLY IN THE MID TO UPPER
80S INLAND...70S AT THE CST. LO TEMPS M60S- ARND 70F. SAT A LITTLE
WARMER WITH HIGHS UPPER 80S/NEAR 90 F INLAND TO THE 70S TO LWR 80S
AT THE COAST.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE MEDIUM RANGE PERIOD REMAINS CHARACTERIZED BY MID/UPPER LEVEL
RIDGING OVER THE ERN CONUS WITH A TROUGH LINGERING OVER THE
INTERMOUTAIN WEST. SURFACE HIGH PRESSURE BUILDS ACROSS ERN CANADA
SATURDAY NIGHT AND SUNDAY PUSHING A COLD FRONT INTO THE NRN MID
ATLANTIC. 12Z GFS/ECMWF DIVERGE SUNDAY NIGHT/MONDAY WITH THE GFS
BRINGING THE SURFACE COLD FRONT THROUGH THE LOCAL AREA SUNDAY
NIGHT AND THE ECMWF WAITING UNTIL MONDAY. HIGH PRESSURE SETTLES IN
VICINITY OF THE NEW ENGLAND COAST TUESDAY AND WEDNESDAY...AND
MOVES OFFSHORE THURSDAY. THE BEST FOCUS FOR CONVECTION APPEARS TO
BE SUNDAY AFTERNOON/EVENING AHEAD OF THE COLD FRONT WITH 40-50%
POPS FORECAST ACROSS THE NRN HALF OF THE AREA. THE WIND PROFILE
WILL REMAIN WEAKLY SHEARED SO ANY THUNDERSTORMS SHOULD BE RATHER
UNORGANIZED. POPS MONDAY AFTERNOON AND EVENING ARE FORECAST TO BE
30-40% MONDAY AFTERNOON/EVENING...AND THEN TREND DOWNWARD TO
20-30% BY TUESDAY AND SUB-15% THROUGH MIDWEEK AS SURFACE HIGH
PRESSURE PREVAILS. HIGH TEMPERATURES SUNDAY ARE FORECAST TO RANGE
FROM THE MID TO UPPER 80S...WITH UPPER 70S TO LOW 80S BEHIND THE
FRONT TUESDAY THROUGH THURSDAY. LOWS SHOULD AVERAGE THROUGH THE
60S.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE REMAINS CENTERED WELL OFFSHORE THIS MORNING WITH A
SFC TROUGH JUST EAST OF THE MOUNTAINS. THE RESULT IS S-SW FLOW
WITH SPEEDS GENERALLY 5-10 KT. FEW GUSTS UP TO 20 KT LOWER ERN
SHORE. EARLIER PRECIP ACROSS SE VA HAS ENDED WITH ONLY FEW-SCT MID
CLOUDS BETWEEN 2500 AND 4000 FT AGL. OTHERWISE...BKN HIGH CLOUDS
AOA 25K FT AGL REMAIN OVER THE REGION. HAVE REMOVED ANY MENTION OF
FOG AT THE TAF SITES AS MIXING/CLOUD COVER/WARM TEMPS WILL INHIBIT
FOG. TAF SITES ALSO MISSED OUT ON LAST EVENINGS PRECIP. MODELS
INDICATE POSSIBLE MVFR CIGS AGAIN BY 10-12Z CNTRL AND ERN VA...BUT
THINK MOISTURE FIELDS ARE RATHER BULLISH. HAVE MAINTAINED SCT
1500-2500 FT AGL AT TAF SITES KRIC/KPHF/KECG.

FOR TODAY...A COLD FRONT WILL APPROACH FROM THE NW BEFORE WASHING
OUT LATE TODAY. SFC WINDS BECOME SELY THIS AFTERNOON...AVERAGING
10 KT. SCATTERED AFTERNOON AND EARLY EVENING SHOWERS AND
THUNDERSTORMS ARE EXPECTED AGAIN TODAY. BEST COVERAGE EXPECTED TO
BE ACROSS THE SE COUNTIES AND W COUNTIES. SCT-BKN CU DEVELOP THIS
AFTERNOON WITH DECKS GENERALLY BETWEEN 3-5K FT AGL.

UPPER/SFC HIGH PRESSURE REMAINS OVER THE REGION INTO THE WEEKEND.
DRY CONDITIONS ARE EXPECTED TO PREVAIL...BUT THERE IS A CHANCE FOR
DIURNALLY DRIVEN SHOWERS/THUNDERSTORMS ACROSS THE PIEDMONT FRI-
SAT. BETTER CHANCES FOR MEASURABLE PRECIP EXPECTED SUN-MON AS A
COLD FRONT REACHES...AND THEN STALLS OVER THE REGION.

&&

.MARINE...
HIGH PRESSURE REMAINS CENTERED WELL OFF THE MID-ATLANTIC COAST EARLY
THIS MORNING WITH A WEAK SFC TROUGH JUST WEST OF THE WATER. THE
RESULT IS A SW WIND OF 10-15 KT. WAVES HAVE SUBSIDED TO GENERALLY 1
TO 2 FT WITH SEAS RUNNING 2 TO 4 FT (HIGHEST IN THE NRN COASTAL
WATERS). HIGH PRESSURE PUSHES FARTHER OFFSHORE TODAY AS A WEAK COLD
FRONT DROPS INTO THE REGION...WASHING OUT WEST OF THE WATERS THIS
AFTERNOON. FLOW BECOMES SELY THIS AFTERNOON...AVERAGING 10-15 KT.
SELY FLOW AOB 10 KT PERSISTS FRI. GRADIENT STRENGTHENS FRI NIGHT-SAT
AS A COLD FRONT APPROACHES FROM THE WEST. SPEEDS REMAIN SUB-SCA.
SEAS BUILD TO 3-4 FT FRI NIGHT-SAT THANKS TO PERSISTENT AND
INCREASING SE FLOW. COLD FRONT REACHES...AND THEN STALLS OVER THE
REGION SUN INTO EARLY NEXT WEEK.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...LKB
NEAR TERM...LKB
SHORT TERM...ALB/LKB
LONG TERM...AJZ
AVIATION...SAM
MARINE...SAM


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