Area Forecast Discussion
Issued by NWS Wakefield, VA

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000
FXUS61 KAKQ 191745
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
145 PM EDT SUN APR 19 2015

.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE NEW ENGLAND COAST LATE TODAY. LOW
PRESSURE ORGANIZING OVER THE DEEP SOUTH WILL MOVE NORTHWARD
THIS AFTERNOON...AND WILL PUSH A WARM FRONT THROUGH THE LOCAL
AREA TONIGHT. A COLD FRONT THEN CROSSES THE AREA MONDAY NIGHT.
HIGH PRESSURE BUILDS BACK IN FROM THE SOUTHWEST ON TUESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SFC HI PRES CONTS TO MOVE E OF NEW ENG THROUGH THIS AFTN...AS LO
PRES DEVELOPS INVOF LWR/MID MS VLY. WNDS WILL BE GRADUALLY
BECOMING MORE E THROUGH REST OF THE DAY...GUSTY TO 20-25 MPH.
CLDS BEGINNING TO SPREAD INTO THE FA FM THE WSW...AND CIGS WILL
BE LWRG THROUGH LT AFTN/EARLY EVE. PATCHY -RA BEGINNING TO ARRIVE
INVOF FAR SSW LOCATIONS (IN SCNTRL VA/INTERIOR NE NC)...AND THAT
TREND WILL BE INCRSG (FM SW-NE). NUDGED CLD COVER AND POPS UP BY
ABT 10-20% OVR MUCH OF THE FA...W/ RA HOLDING OFF FM BAY TO THE
ERN SHORE UNTIL AFT 21Z/19. MOST HI TEMPS WILL BE REACHED BEFORE
RA ARRIVES...RANGING FM 65 TO 70F...U50S-L60S RIGHT ALG THE
IMMEDIATE CST.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
SIGNIFICANT INFLOW OF DEEP LAYERED MOISTURE INTO THE REGION TONIGHT
AS A WARM FRONT MAKES PROGRESS NE THROUGH THE FA. MAY BE PERIODS
OF MODERATE/HEAVY RAIN...AND WOULD NOT RULE OUT ISOLD (ELEVATED)
THUNDER. MAJORITY OF THE RAIN SHIFTS TO THE COAST BY 12Z
MONDAY...SO WILL SHOW LOWERING POPS FROM WEST TO EAST AFTER 06Z
TONIGHT. RAIN MAY BE ALL OVER IN OUR FAR WESTERN COUNTIES BY
DAYBREAK. TOTAL QPF AMOUNTS THRU TONIGHT WILL RANGE FROM
0.75"-1.50" WITH LOCALLY HIGHER AMOUNTS UP TO 2.00". DESPITE THE
POTENTIAL FOR BRIEF HEAVY RAIN...PCPN AMOUNTS WILL REMAIN BELOW
6-12HR FLASH FLOOD GUIDANCE SO A FLASH FLOOD WATCH IS NOT NECESSARY.
LOWS TONIGHT FROM THE MID 50S TO MID 60S.

THE AREA OF RAIN WILL SHIFT OFF THE COAST MON MORN...THEN CONCERN
SHIFTS TO A TROUGH ALOFT APPROACHING FROM THE WEST BY LATE MON
AFTN/EVE (LIKELY LEADING TO SCT SHWRS/TSTMS). SPC CURRENTLY HAS
THE AREA OUTLOOKED IN A SLIGHT RISK OF SVR TSTMS MON AFTN/EVE FOR
THE POTENTIAL OF ISOLD DAMAGING WIND GUSTS AND LARGE HAIL. THE
POTENTIAL FOR SVR WX IS CERTAINLY THERE GIVEN ML CAPE VALUES
EXPECTED TO BE IN THE 1000-1500 J/KG RANGE...STEEP LAPSE
RATES...AND A MODEST SHEAR PROFILE. WILL CONTINUE TO HIGHLIGHT
POSSIBLE STRONG/ISOLD SVR STORMS IN THE HWO FOR LATE MON AFTN/EVE.
OTW...VRB CLOUDS-PARTLY SUNNY MIDDAY/AFTN ON MON. HIGH TEMPS IN
THE 70S AT THE CST...80 TO 85 ELSEWHERE.

COLD FRONT CROSSES THE FA MON NIGHT WITH CHC POPS (HIGHEST NNE-
CNTRL)...THEN DRYING/COOLER WESTERLY FLOW TAKING OVR INTO TUE.
PARTLY/MOSTLY SUNNY TUE WITH HIGH TEMPS IN THE UPR 60S TO NR 70 AT
THE COAST...AND LOW/MID 70S ELSEWHERE.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
UPPER LOW REMAINS IN VIC OF THE GREAT LAKES THRU THE EXTENDED PERIOD
THANKS TO BLOCKY FLOW OVER THE HIGHER LATITUDES. FAST WLY/ZONAL FLOW
PROGGED OVER THE LOCAL AREA. SFC HIGH PRESSURE BUILDS OVER THE SE
STATES/SRN MID ATLANTIC TUES NIGHT-WEDS MORNING...SLIDING OFFSHORE
WEDS AFTERNOON. THE RESULT IS A MOSTLY SUNNY TO PARTLY CLOUDY SKY
WEDS WITH HIGHS RIGHT AROUND NORMAL...UPPER 60S TO 70 INLAND AND MID-
UPPER 60S COASTAL AREAS. POTENT SHORTWAVE ROUNDS THE BASE OF THE
STACKED UPPER LOW INTO THE OH VALLEY LATE WEDS-WEDS NIGHT.
ASSOCIATED FAST MOVING COLD FRONT REACHED THE CNTRL APPALACHIANS
WEDS NIGHT...CROSSING THE LOCAL AREA EARLY THURS. FRONT EXPECTED TO
STALL VIC NC THURS NIGHT DUE TO WLY FLOW ALOFT. QUESTION WILL BE HOW
MUCH MOISTURE RETURN THERE IS THURS AS ECMWF REMAINS DRY AND THE GFS
RATHER MOIST. DIFFERENCE IS LOW LEVEL SWLY FLOW IN GFS COMPARED TO
WLY FLOW IN THE ECMWF. TRENDED TOWARD DRIER ECMWF...DROPPING POPS TO
SILENT THURS-THURS NIGHT. HIGHS THURS REMAINING AROUND
NORMAL...GENERALLY IN THE MID-UPPER 60S. COOL CANADIAN HIGH PRESSURE
PROGGED TO BUILD INTO THE OH VALLEY THURS NIGHT-FRI...EXTENDING INTO
THE MID-ATLANTIC REGION. THE RESULT WILL BE DRY CONDITIONS...NWLY
WINDS AND BELOW NORMAL TEMPS FRI...GENERALLY IN THE LOW-MID 60S
INLAND TO UPPER 50S-LOW 60S COASTAL AREAS. MODELS PICKING UP ON A
SRN STREAM SYSTEM CROSSING THE SE STATES SAT. MENTIONED SLIGHT
CHANCE POPS SRN VA/NE NC...CLOSEST TO THE FRONTAL BOUNDARY AND BEST
MOISTURE RETURN.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
A BACKDOOR COLD FRONT HAS DROPPED SOUTH INTO THE CAROLINAS
RESULTING IN ENE WINDS OF 10 TO 15 KT BEHIND THE FRONT. WINDS NEAR
THE COAST WILL INCREASE TO 15-20KT THROUGH LATE AFTERNOON AND
EARLY EVENING. THE FRONT WILL LIFT BACK NORTH AS A WARM FRONT
LATER THIS EVENING AND TONIGHT AHEAD OF A COMPLEX LOW PRESSURE
SYSTEM OVER THE OHIO RIVER VALLEY. THIS WILL RESULT IN MVFR AND
IFR CONDITIONS SPREADING RAPIDLY NORTHEAST ACROSS THE ENTIRE AREA
LATER THIS AFTERNOON AND THROUGH THE EVENING/OVERNIGHT HOURS. IFR
CEILINGS AND OCCASIONAL HEAVY RAIN ARE EXPECTED THIS EVENING AND
ESPECIALLY OVERNIGHT AT ALL TAF SITES. EXPECT SEVERAL HOURS OF
IFR CONDITIONS TO PERSIST ACROSS THE REGION FROM AROUND 00-03Z
THROUGH AT LEAST 12-15Z. WIDESPREAD RAIN WHICH IS ALREADY MOVING
INTO SOUTH CENTRAL VA WILL SPREAD NORTHEAST AND WILL NOT DIMINISH
FROM SW- NE UNTIL 09Z TO 12Z MONDAY. ANOTHER IMPULSE TRACKS ACROSS
THE REGION MONDAY AFTERNOON/EVENING BRINGING A CHC OF SHRA/TSRA.
THERE IS A SLIGHT RISK OF SEVERE STORMS MONDAY AFTERNOON/EVENING
WITH THE MAIN THREAT BEING STRONG TO DAMAGING WIND GUSTS. HIGH
PRESSURE BUILDS ACROSS THE SOUTHEAST STATES TUESDAY AND WEDNESDAY
AS LOW PRESSURE LINGERS OVER THE GREAT LAKES. THIS WILL ALLOW DRY
CONDITIONS TO RETURN. A WEAK COLD FRONT DROPS ACROSS THE REGION
THURSDAY.

&&

.MARINE...
A BACKDOOR COLD FRONT PRESENTLY ENTERING THE NRN OCEAN ZONES WILL
DROP N-S ALONG THE COAST EARLY THIS MORNING. THIS WILL PRODUCE A
WIND SHIFT TO NE. SPEEDS ARE EXPECTED TO AVERAGE 10-
15KT...ALTHOUGH SPEEDS COULD BRIEFLY REACH 20KT IN THE IMMEDIATE
WAKE OF THE BOUNDARY THIS MORNING. OTHERWISE...LOW PRESSURE LIFTS
INTO THE ERN GREAT LAKES THIS AFTERNOON/EVENING...WITH SECONDARY
LOW PRESSURE DEVELOPING OVER THE MID ATLANTIC TONIGHT. THIS IS A
FAVORABLE PATTERN FOR A SHORT DURATION (~3-5 HR)OF STRONG SCA
CONDITIONS IN SE FLOW. AT THIS TIME IT APPEARS TO BE CENTERED
AROUND 09Z TONIGHT. WIND SPEEDS ARE EXPECTED TO INCREASE TO
15-20KT THIS AFTERNOON AND EVENING...BEFORE INCREASING TO 20-25KT
WITH GUSTS ~30KT LATER TONIGHT INTO EARLY MONDAY. SEAS BUILD TO
4-5FT TODAY...AND THEN 5-7FT TONIGHT...BEFORE BEGINNING TO
GRADUALLY SUBSIDE MONDAY AS THE FLOW BECOMES SOUTHERLY AND THE
PRESSURE GRADIENT RELAXES. INHERITED SCAS REMAIN SIMILAR. THE MAIN
CHANGES WERE TO ADD THE UPPER JAMES...AND EXTEND THE
BAY/SOUND/RIVERS SEGMENTS THROUGH 10AM MONDAY. ADDITIONALLY...THE
NRN OCEAN ZONES (N OF PARRAMORE ISLAND) WERE EXTENDED THROUGH
MONDAY NIGHT WHERE SEAS WILL REMAIN 4-5FT. A COLD FRONT APPROACHES
FROM THE W MONDAY AFTERNOON/EVENING...AND MOVES ACROSS THE COAST
LATE MONDAY NIGHT. THIS FRONT IS EXPECTED TO TRIGGER
SHOWERS/TSTMS...WHICH WILL HAVE THE POTENTIAL OF PRODUCING STRONG
WIND GUSTS. HIGH PRESSURE BUILDS ACROSS THE SOUTHEAST TUESDAY AND
WEDNESDAY AS LOW PRESSURE LINGERS OVER THE GREAT LAKES. A WEAK
COLD FRONT CROSSES THE REGION WEDNESDAY NIGHT INTO THURSDAY.

&&

.TIDES/COASTAL FLOODING...
A PERIOD OF ONSHORE FLOW TODAY FOLLOWED BY MODEST SE FLOW TONIGHT
WILL ALLOW TIDAL ANOMALIES TO BUILD TO ~1.0FT ABOVE NORMAL LATER
TONIGHT PRIMARILY IN THE MIDDLE BAY AND ALONG THE ATLANTIC COAST
OF THE MD ERN SHORE. SOUTHERLY FLOW MONDAY INTO MONDAY EVENING
WILL HELP MAINTAIN ~1.0FT ANOMALIES IN THE MIDDLE BAY THROUGH
MONDAY NIGHT. TIDAL ANOMALIES WILL BEGIN TO SUBSIDE TUESDAY AS
THE FLOW SHIFTS TO OFFSHORE. THE COMBINATION OF TIDAL ANOMALIES
AND HIGH ASTRO TIDES (NEW MOON PHASE) WILL PUSH MOST SITES OVER
HAT DURING HIGH TIDE SUNDAY NIGHT AND MONDAY. PORTIONS OF THE
MIDDLE BAY AND OCEAN CITY WILL APPROACH MINOR FLOODING
THRESHOLDS.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT MONDAY FOR ANZ630>638.
     SMALL CRAFT ADVISORY UNTIL 7 AM EDT TUESDAY FOR ANZ654-656-658.
     SMALL CRAFT ADVISORY UNTIL 1 PM EDT TUESDAY FOR ANZ650-652.

&&

$$
SYNOPSIS...ALB/JDM
NEAR TERM...ALB/JDM
SHORT TERM...ALB/JDM
LONG TERM...SAM
AVIATION...AJZ/JAO
MARINE...AJZ
TIDES/COASTAL FLOODING...



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