Area Forecast Discussion
Issued by NWS Wakefield, VA

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000
FXUS61 KAKQ 022009
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
409 PM EDT TUE JUN 2 2015

.SYNOPSIS...
LOW PRESSURE AND ASSOCIATED COLD FRONT WILL SLOWLY DROP SOUTH ACROSS
THE REGION TODAY...THEN STALL ACROSS THE CAROLINA COAST TONIGHT AND
WEDNESDAY. A SERIES OF WEAK LOWS WILL TRACK EAST ALONG THIS BOUNDARY
THROUGH THURSDAY. THE BOUNDARY LINGERS ALONG THE COAST INTO FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THUNDERSTORMS THIS AFTN HAVE TRAINED ACROSS PRIMARILY SE VA AND NE
NC...BRINGING TORRENTIAL DOWNPOURS TO THE LOCAL AREA IN A SHORT
PERIOD OF TIME. RAINFALL AMOUNTS OF 1.00 TO 2.00 INCHES IN
10-20 MINUTES HAVE BEEN OBSERVED. A FLASH FLOOD WARNING WAS ISSUED
FOR VIRGINIA BEACH WHEN ONE HOUR RADAR PRECIP ESTIMATES REACHED
3.00 INCHES. REPORTS FROM THE 911 DISPATCH CENTER CONSIST OF
NUMEROUS FLOODED ROADS AND ROAD CLOSURES. ELSEWHERE THROUGHOUT THE
TIDEWATER...PENINSULA/MIDDLE PENINSULA AREAS...AND NORTHEAST NC...
URBAN AND SMALL STREAM FLOOD ADVISORIES HAVE BEEN ISSUED TO
ACCOUNT FOR THE COPIOUS AMOUNTS OF RAINFALL RECEIVED IN SHORT
PERIODS OF TIME.

WATER VAPOR AND INFRARED SATELLITE IMAGERY BLOSSOMED BTWN 1230 AND
200 PM TODAY...WITH RAPID CLOUD TOP COOLING OBSERVED. THIS IS NOT
ONLY A GOOD INDICATOR OF STRONG UPDRAFT POTENTIAL (AND SUBSEQUENT
DOWNDRAFT WIND GUSTS) BUT ALSO THE POTENTIAL FOR HAIL.
THUNDERSTORM WIND GUSTS THIS AFTN AVERAGED 30 TO 35 MPH...WITH THE
HIGHEST GUST OF 43 MPH MEASURED AT SUFFOLK AIRPORT (KSFQ). OVERALL
RADAR AND LIGHTNING TRENDS INDICATE THAT WEAKENING IS STARTING TO
TAKE PLACE OVER FAR SE VA/NE NC...WITH ONE LAST BATCH OF STRONGER
STORMS CURRENTLY LOCATED OVER THE PENINSULA AND MIDDLE PENINSULA
AREAS. JUST NORTH OF HERE...EXPECT THE STORMS TO RUN INTO A MORE
STABLE AIRMASS WITH N-NE WINDS. ADDITIONAL COOLING FROM THE MARINE
LAYER WILL ACT TO FURTHER STABILIZE THE AIRMASS ACROSS THE FAR NRN
COUNTIES OF THE CWA. A SECONDARY AREA OF THUNDERSTORMS OVER THE NC
COASTAL PLAIN AND SW VA HAS FIRED UP INVOF AN UPPER TROUGH
SPINNING OVER THE TN VALLEY. VISIBLE SATELLITE IMAGERY SHOWS THAT
SOME CLEARING HAS OCCURRED BTWN THE I-85 AND I-81 TRAVEL CORRIDORS
OVER THE PAST 1-2 HOURS...HOWEVER THIS TIMING MAY BE TOO LATE TO
SUPPORT INCOMING CONVECTION GOING INTO THIS EVENING AND THE
OVERNIGHT HOURS. FOR THE ERN PIEDMONT...THE KEY PLAYER WILL BE THE
SFC COLD FRONT AS IT SLOWLY SAGS SOUTH TWD THE VA/NC BORDER THIS
EVENING AND FLATTENS AS HIGH PRESSURE BUILDS OVER THE ST LAWRENCE
RIVER VALLEY. EVEN IF THUNDERSTORMS DIE OFF OVER THE COASTAL PLAIN
THIS EVENING... THERE SHOULD STILL BE PLENTY OF ATLANTIC AND GULF
COAST MOISTURE BEING PULLED INTO THE MID ATLANTIC REGION BY THE
UPPER LEVEL TN VALLEY LOW OVERNIGHT. SHORT- RANGE MODELS SHOW
VARIOUS BULLSEYES OF ISENTROPIC LIFT PASSING OVER THE REGION
TONIGHT. HRRR MODEL PRECIP SHOWS A SECONDARY PUSH OF PRECIP
OVERNIGHT AND SINCE IT HANDLED THE CONVECTIVE COVERAGE WELL DURING
THIS AFTN...WILL CARRY 70-80 PERCENT POP THROUGH TONIGHT. TEMPS
WILL BE COOL TO THE NORTH AND WARM TO THE SOUTH BUT STILL
GENERALLY IN THE 60S. MORE DAMP FEELING THAN MUGGY TONIGHT.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
HIGH PRESSURE SLIDES DOWN INTO NEW ENGLAND WED AND OFF THE NEW
ENGLAND COAST ON THU. THIS WILL CAUSE THE SFC COLD FRONT TO SLOWLY
PUSH SWD AND STALL ALONG THE CAROLINA COAST...AS THE UPPER LEVEL
LOW OVER THE TN VALLEY DIGS SE INTO THE CAROLINAS DURING THIS
TIME. SPOKES OF SHORTWAVE MOISTURE/ENERGY WILL RIDE ALONG THE
STALLED BOUNDARY AND KEEP UNSETTLED CONDITIONS ACROSS THE AREA WED
THROUGH THU NIGHT. EXPECT PERIODS OF SHOWERS AND THUNDERSTORMS
EACH DAY/NIGHT. HEAVY RAINFALL CONTINUES TO BE THE MAIN IMPACT
WITH ANY THUNDERSTORMS AS STEERING FLOW REMAINS LIGHT AND PWATS
HOVER BTWN 1.50-1.75 INCHES. FOR FRIDAY...THE UPPER LOW FINALLY
BEGINS TO EXIT THE CAROLINA COAST AND PRECIPITATION WILL HAVE LESS
OF A GRIP ON THE REGION. REALLY ONLY EXPECTING AFTN THUNDERSTORMS
CLOSER TO THE COAST ON FRI. TEMPS WILL BE MUCH COOLER WED WITH
HIGHS IN THE UPPER 60S TO LOWER 70S NW TO MID- UPPER 70S SE. LOWS
WED/THU NIGHTS IN THE 60S (UPPER 50S FAR NW COUNTIES WED NIGHT).
HIGHS IN THE 70S ON THU. HIGHS ON FRI IN THE LOWER 80S.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LONG TERM PERIOD WILL FEATURE SOMEWHAT UNSETTLED CONDITIONS
ALTHOUGH THE MAIN UPPER TROUGH AXIS SHOULD BE MOVING OFFSHORE AND
WEAKENING SO CHANCES FOR PRECIP WILL TEND TO BE LOWER THAN WHAT
OCCURS IN THE NEAR/SHORT PERIOD. LATEST GFS/ECMWF FEATURE FAIRLY
LIGHT N/NW FLOW ALOFT SAT INTO SUN AS THE MID ATLC BECOMES
SITUATED IN BETWEEN AN UPPER RIDGE CENTERED OVER TEXAS AND A WEAK
UPPER LOW OVER FLORIDA. TEMPS. A MORE SIGNIFICANT UPPER TROUGH
DEVELOPS OVER LAKE SUPERIOR LATE SUN AND SLOWLY TRACKS EAST
THROUGH CANADA THROUGH NEXT TUE. GFS IS MORE AGGRESSIVE THAN THE
ECMWF AT SFC HIGH PRESSURE BUILDING SOUTH INTO THE DELMARVA ON
SUN. WILL MAINTAIN CHC POPS MOST AREAS SAT/SUN AS THE GFS IS A BIT
OF A CHANGE FROM CONTINUITY AND THINK IT IS LIKELY TOO STRONG
GIVEN THE PATTERN AND TIME OF YR. DID DROP POPS TO 20% ACRS NE
ZONES. SKIES AVG MOSTLY CLOUDY SAT...AND PARTLY TO MOSTLY CLOUDY
SUN...WITH HIGHS GENLY IN THE UPPER 70S TO LOWER 80S. FLOW
GRADUALLY SHIFTS MORE TO THE SSE AND EVENTUALLY THE SSW MON AHEAD
OF THE APPROACHING UPPER TROUGH AND SFC COLD FRONT. TEMPS SHOULD
WARM A BIT...INTO THE MID-UPPER 80S WELL INLAND AND UPPER 70S TO
MID 80S CLOSER TO THE COAST. WILL HAVE HIGHER POPS MON
AFTN/EVENING WITH THE FRONT...THEN GO ONLY 20% OR LESS TUE AS
DRIER AIR MOVES IN FROM THE WEST. LOWS GENLY IN THE 60S THROUGH
THE PERIOD.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
SCT TO NUMEROUS TSTMS OVR SE VA/INTERIOR NE NC ATTM..CONTG INTO
THE EARLY EVE HRS. CDFNT WILL CONT TO SETTLE S ACRS THE RGN INTO
TNGT...BECOMING STNRY OVR NC FOR WED. LIFR/IFR VSBYS IN TSTMS THIS
AFTN/EVE. WIDESPREAD IFR CONDS (MNLY DUE TO CIGS) XPCD FOR MUCH
OF THE AREA TNGT THROUGH WED ALG W/ INTERMITTENT RA CHCS.

ONSHORE NE FLOW TUE NIGHT THROUGH THU AND MOIST AIRMASS SHOULD
LEAD TO UNSETTLED/MOSTLY CLOUDY CONDITIONS AND PERIODIC MVFR TO
MARGINAL IFR CIGS/VSBYS. SHOWERS AND PSBLY ISOLD TSTMS (MNLY INVOF
NE NC) CAN BE EXPECTED WED THEN CHANCE FOR SHOWERS AND POSSIBLY
THUNDERSTORMS THURSDAY THROUGH SUNDAY.

&&

.MARINE...
HAVE ALREADY RAISED SCA HEADLINES FOR COASTAL WATERS N OF
PARRAMORE ISLAND...BOUNDARY HAS DROPPED SOUTH THROUGH THIS REGION
AND SEAS HAVE RAPIDLY RISEN TO 5 FT AT BUOY 44009. LATEST SUITE OF
HIGH RES MODELS SEEMS TO HAVE A FAIRLY DECENT HANDLE ON CURRENT
CONDITIONS...AND HAVE DECIDED TO RAISE SCA HEADLINES IN THE BAY
LATER THIS EVENING FOR 15-20 KT NE WINDS EVEN THOUGH IT WILL BE
SOMEWHAT MARGINAL.

SIMILAR WINDS OVERNIGHT/WED (WITH SOME INCREASE POSSIBLE OVER THE
NRN AREAS) AS SFC HIGH PRESSURE REMAINS TO THE NORTH AND SFC LOW
PRESSURE STALLS SOMEWHERE NEAR THE VA/NC BORDER. EXACT LOCATION
OF BOUNDARY WILL DETERMINE THE SOUTHWARD EXTENT OF WHERE HEADLINES
WILL BE NEEDED...IN GENERAL SOUTHERN 1/2 OF THE AREA IS WHERE MOST
UNCERTAINTY WILL EXIST...SEAS SHOULD BE AT LEAST 5-7 FT OVER THE
NRN WATERS ON WED DUE TO ONSHORE FLOW...BUT LOOK TO REMAIN 3-4 FT
ACRS THE SOUTH. PRESSURE GRADIENT RELAXES FOR THU AND FRI...
ALLOWING FOR IMPROVED MARINE CONDITIONS.

PER THE ONSHORE FLOW ALSO RAISED RIP RISK TO MODERATE FOR THE MD
ZONES FOR THE REST OF TODAY.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EDT WEDNESDAY FOR ANZ632-634.
     SMALL CRAFT ADVISORY UNTIL 7 PM EDT WEDNESDAY FOR ANZ630-631.
     SMALL CRAFT ADVISORY UNTIL 1 AM EDT THURSDAY FOR ANZ650-652.

&&

$$
SYNOPSIS...BMD
NEAR TERM...BMD
SHORT TERM...BMD
LONG TERM...LKB
AVIATION...ALB/JDM
MARINE...LKB



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