Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 222311 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 711 PM EDT FRI MAY 22 2015 .SYNOPSIS... A COLD FRONT CROSSES THE AREA TONIGHT FOLLOWED BY HIGH PRESSURE BUILDING IN FOR SATURDAY. THE HIGH WILL SLIDE OFFSHORE AND REMAIN JUST OFF THE COAST THROUGH EARLY TO MID NEXT WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... LATEST SFC ANALYSIS REVEALS WEAK LO PRES OVER SE CANADA WITH ITS ATTENDANT COLD FRNT STRETCHING ACROSS THE THE PA/MD BORDER. THIS FRNT WILL DROP THRU THE AREA LATE THIS EVENG AND OVERNIGHT...WITHOUT ANY PCPN AND ONLY A FEW CLOUDS AS THE COLUMN REMAINS QUITE DRY (1000-500 MB RH LESS THAN 40%). SFC HI PRES WILL THEN QUICKLY BLD IN BEHIND THE FRNT LATE TNGT. TEMPS WILL BE A FEW DEGREES BLO NORMAL...WITH LOWS RANGING FM THE UPR 40S TO MID 50S. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... SHORT TERM PERIOD WILL BE CHARACTERIZED BY DRY WX WITH INCREASING TEMPS AND HUMIDITY THRU THE PERIOD. SFC HI PRES WILL CENTER DIRECTLY OVER THE MID ATLC BY MIDDAY SAT...THEN SLIDE OFFSHORE LATE IN THE DAY AS ONSHORE FLOW DEVELOPS. LIKE FRI...TEMPS WILL ONLY MAX OUT IN THE LO TO MID 70S UNDER A SUNNY SKY. WARMING TREND BEGINS SUN AND MON AS SLY FLOW DEVELOPS WITH THE HI OFFSHORE AND AN UPR-LEVEL RIDGE AMPLIFYING ACROSS THE ERN SEABOARD. EXPECT HI TEMPS SUN IN THE UPR 70S TO LWR 80S...AND THE MID TO UPR 80S MON. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... MEDIUM RANGE CONTINUES TO APPEAR TO BE DOMINATED WITH A STRONG UPPER LEVEL RIDGE CENTERED OVER THE SE/MID ATLC STATES THROUGH THE PERIOD. LATEST ECMWF/GFS REMAIN IN FAIRLY GOOD AGREEMENT...WITH THE GFS STILL A BIT MORE AGGRESSIVE AT BREAKING DOWN/WEAKENING THE RIDGE BY MID TO LATE WEEK (THOUGH NOT TO THE EXTENT IT HAD BEEN OVER THE PAST FEW DAYS). MODELS ALSO DIFFER SOMEWHAT WITH RESPECT TO 850 MB TEMPERATURES...THE ECMWF REMAINING WARMER BY ABOUT 2-3 C THAN THE GFS. OVERALL...THIS PATTERN WILL LEAD TO WARM /SUMMER- LIKE WX THROUGH THE ENTIRE PERIOD...WITH VERY MINIMAL CHANCES FOR RAIN...LIMITED TO ISOLATED/WIDELY SCATTERED MAINLY LATE AFTN OR EVENING TSTMS DEVELOPING TO OUR NORTH AND WEST DRIFTING INTO THE REGION. HAVE DROPPED POPS ALTOGETHER FOR MON NIGHT THROUGH MIDDAY WED...THEN WILL HAVE JUST 20% POP OVER JUST THE FAR NW PORTIONS OF THE CWA ON WED...AND GENLY A 20% POP IN THE LATE AFTN/EVENING OVER MUCH OF THE AREA THU/FRI (UP TO 30% FAR NW). INCREASING HUMIDITY AND HIGH TEMPS WARMING BACK TO THE UPPER 80S TO LOWER 90S THROUGH THE PERIOD...FAVORING ECMWF FOR HIGHS (GFS HIGHS ONLY IN MID 80S WELL INLAND APPEARS TOO COOL IN THIS PATTERN). CONDITIONS WILL GENLY BE ABOUT 5 DEGREES COOLER AT THE COAST. LOWS AVG IN THE MID 60S TO LWR 70S THROUGH THE PERIOD. && .AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
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WEAK COLD FRONT MOVING SEWD TOWARD THE REGION WILL CROSS ALL TERMINALS OVERNIGHT...REACHING KSBY FIRST AND KECG LAST. ANY GUSTINESS ASSOCIATED WITH FRONTAL PASSAGE SHOULD BE LIMITED TO KORF...AND HAVE INDICATED TEMPO GUSTS FOR A COUPLE OF HOURS LATE TONIGHT. CLOUD CEILINGS SHOULD BE IN THE 6KFT TO 9KFT RANGE...AND NO WORSE THAN BKN FOR A COUPLE HOURS AROUND FRONTAL PASSAGE. HIGH PRESSURE REMAINS IN VICINITY OF THE COAST SATURDAY NIGHT BEFORE MOVING OFFSHORE SUNDAY AND REMAINING ANCHORED OFF THE COAST THROUGH WEDNESDAY. THIS SHOULD PROVIDE VFR CONDITIONS MOST IF NOT ALL THE TIME DURING THAT PERIOD.
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&& .MARINE... WINDS DIMINISHING ACRS THE AREA THIS AFTN...CURRENT CONDS ARE BELOW SCA THRESHOLDS ALL ZONES. HOWEVER...ANOTHER COLD FRONT IS APPROACHING THE NRN MID ATLC REGION...AND WILL DROP SOUTH THROUGH THE WATERS LATER TONIGHT. NOT NEARLY AS STRONG AS WHAT OCCURRED LAST NIGHT AS THE PRESSURE GRADIENT IS WEAK...BUT SHOULD BE ENOUGH TO YIELD LOW END SCA CONDITIONS FOR THE BAY AFTER MIDNIGHT THROUGH 11-14Z/FRI MORNING. HAVE RAISED ANOTHER ROUND OF SCA HEADLINES FOR THE BAY...BEGINNING AT 05Z/FRI...AND LASTING THROUGH 11Z N OF NEW PT COMFORT...AND THROUGH 14Z SOUTH OF NEW PT COMFORT (05Z MAY BE A TAD EARLY FOR THESE LOWER BAY ZONES BUT DID NOT WANT TO GET TOO SPECIFIC ATTM). DID NOT RAISE ANY HEADLINES FOR OTHER ZONES AS IT LOOKS SOMEWHAT MARGINAL EVEN FOR THE BAY...ALTHOUGH A FEW GUSTS TO AROUND 20 KT MAY AFFECT THE RIVERS. SEAS ON THE COASTAL WATERS BUILD TO 4 FT IF THAT (AND THIS IS GOING WELL ABOVE WAVE WATCH WHICH KEEPS SEAS CAPPED AT 2-3 FT). PRESSURE GRADIENT SLACKENS QUICKLY SATURDAY AND EXPECT WINDS TO AGAIN DROP OFF QUICKLY BY LATE MORNING AS THE HIGH BUILDS OVERHEAD. WINDS SHIFT TO THE S/SE SAT NIGHT INTO SUN AS THE HIGH SHIFTS OFF THE COAST. WINDS SHOULD THEN FOLLOW A DIURNAL PATTERN...INCREASING A BIT MAINLY IN THE LATE AFTN/EVENING/EARLY AM HRS LATE SUN THROUGH MIDWEEK AS UPPER RIDGE DEVELOPS WITH SFC HIGH PRESSURE WELL OFF THE COAST. CONDITIONS WILL GENLY REMAIN SUB-SCA THOUGH SOUTHERLY FLOW MAY GUST TO NEAR 20 KT IN THE BAY DURING THIS LATE AFTN/EVENING/EARLY AM TIMEFRAME. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 1 AM TO 10 AM EDT SATURDAY FOR ANZ632-634. SMALL CRAFT ADVISORY FROM 1 AM TO 7 AM EDT SATURDAY FOR ANZ630- 631. && $$ SYNOPSIS...MAS NEAR TERM...MAS SHORT TERM...MAS LONG TERM...LKB AVIATION...AJZ/WRS MARINE...LKB

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