Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 210904 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 504 AM EDT TUE OCT 21 2014 .SYNOPSIS...
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LOW PRESSURE MOVES THROUGH THE REGION TODAY...AND PUSHES OFF THE COAST TONIGHT. THE LOW WILL INTENSIFY WHILE SLOWLY TRACKING NORTHEAST OFF THE MID ATLANTIC COAST THROUGH FRIDAY. COOL AND UNSETTLED CONDITIONS WILL PREVAIL ON WEDNESDAY...FOLLOWED BY DRIER CONDITIONS AND BREEZY NORTHWEST WINDS THURSDAY INTO FRIDAY.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATEST ANALYSIS SHOWING SFC LOW PRESSURE OVER LAKE ONTARIO WITH A TRAILING SFC COLD FRONT EXTENDING SW FROM THE LOW DOWN THROUGH THE OH VALLEY. WEAK/ELONGATED SHORTWAVE ALOFT IS PUSHING EAST ACRS THE CWA AND HAS ALLOWED FOR ENOUGH LIFT TO DEVELOP SOME VERY LIGHT SHOWERS/SPRINKLES OVER THE REGION (GENLY TOO DRY IN LOW LEVELS FOR ANYTHING MEASURABLE THUS FAR). MOISTURE WILL TEND TO DIMINISH FROM W TO E THROUGH 12Z AS DRY SLOT PUSHES BACK IN FROM THE SW BUT WILL MAINTAIN 20% POPS E OF I-95 THROUGH 12Z. AFTER 12Z...WILL TEND TO SALVAGE A PRETTY NICE DAY ACRS MOST OF THE LOCAL AREA AS SKIES BECOME PARTLY TO MOSTLY SUNNY AND WINDS SHIFT TO THE WEST. WITH TEMPERATURES STARTING OFF MUCH MILDER THAN YESTERDAY MORNING...SUN AND MIXING SHOULD ALLOW FOR FAIRLY RAPID WARMING THROUGH THE 60S AND INTO THE LOWER 70S BY EARLY AFTN. WITH A STRONG SHORTWAVE CURRENTLY SEEN ON WV SATELLITE OVER THE WESTERN GREAT LAKES PROGGED TO DIVE SE AROUND THE BASE OF THE AMPLIFYING UPPER LOW...EXPECT INCREASING CLOUDS FROM NW TO SE THIS AFTN. HIGH RES MODELS SHOWING A FAIRLY SIGNIFICANT AMOUNT OF SIMULATED REFLECTIVITY ACRS NW PORTIONS OF THE CWA AFTER 18Z...GRADUALLY ADVECTING THIS SE TO THE COAST PRIOR TO 00Z THIS EVENING. DUE TO DRY LOW LEVELS (DEW PTS IN 40S)...EXPECT THAT RADAR COVERAGE THIS AFTN WILL LOOK MORE IMPRESSIVE THAN REALITY AND THUS WILL KEEP POPS CAPPED IN CHANCE RANGE...AROUND 40% ACRS THE NORTH AFTER 20Z...TAPERED TO 20% OR LOWER ACRS THE SOUTH. QPF AMOUNTS WILL BE LIGHT...< .10". HIGHS TODAY WILL RANGE FROM THE MID TO UPPER 70S ACRS THE FAR SE (WHERE CLOUDS ARE SLOWER TO PUSH IN THIS AFTN)...TO THE UPPER 60S/AROUND 70 F OVER THE NW DUE TO EARLIER ONSET OF CLOUDS AN POTENTIAL SHOWERS. ALSO...DUE TO THE LOW DEW PTS...IF MEASURABLE RAINFALL DOES OCCUR...TEMPS LATE THIS AFTN WOULD POTENTIALLY DROP INTO THE LOWER 60S OR COOLER. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
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FLOW CONTINUES TO AMPLIFY THROUGH THE PERIOD AS A BLOCKING PATTERN DEVELOPS OVER ERN CANADA. THE UPPER LOW WILL PROGRESS SLOWLY EWD OVERNIGHT INTO WED...LOCATING OFF THE DELMARVA COAST LATE WED. WITH THE UPR LOW PIVOTING ACROSS THE LOCAL AREA TONIGHT...WILL SEE A BETTER CHANCE FOR SHOWERS DEVELOP ESPECIALLY NORTH/NE WHERE BEST UPWARD MOTION IS ANTICIPATED. LAPSE RATES ALOFT ARE FAIRLY IMPRESSIVE (H5 TO H7 LAPSE RATES OF 6.5 TO 7C) AND IF IT WERE SPRING WOULD ADD TSTMS TO THE FORECAST. LOW LEVELS ARE PROGGED TO BE FAIRLY STABLE HOWEVER SO FOR NOW HAVE KEPT TSTMS OUT OF FORECAST BUT CERTAINLY COULD HAVE SOME ELEVATED TSTMS AND WILL CONTINUE TO MONITOR TRENDS. HAVE BUMPED POPS UP TO LIKELY IN THESE AREAS...TAPERED TO LOWER CHANCES FARTHER S/W WHERE DEEP MOISTURE IS GENLY NOT PRESENT. LOWS TONIGHT IN THE UPPER 40S TO MID 50S. DEEP UPPER TROUGH/CLOSED LOW SLOWLY MOVES EAST AND OFFSHORE WED. AFTER A BRIEF INCREASE IN DEEP MOISTURE BETWEEN 09-15Z...FORECAST SOUNDINGS FAIRLY DRY ALOFT OVER INLAND SECTIONS AS THE TROUGH/SFC REFLECTION SWING FARTHER OFFSHORE...HOWEVER A FAIRLY SHARP MOSITURE GRADIENT PROGGED ALONG THE COAST. THE ERN SHORE IN PARTICULAR APPEARS TO BE SET FOR A CLOUDY/COOL DAY WITH SHOWERS LIKELY AT LEAST THROUGH THE MORNING HRS. WILL THEREFORE KEEP CHC POPS LIMITED TO AREAS MAINLY ALONG AND NE OF THE I-64 CORRIDOR WED...WITH EMPHASIS OF 60-70% POPS ON THE EASTERN SHORE. COULD END UP BEING DRY OVER FAR SW ZONES. QPF AMOUNTS WILL AVG 0.25-0.50" ON THE ERN SHORE...GENLY ONLY AROUND .10" OR LESS ELSEWHERE. FAVOR COOLER END OF GUIDANCE FOR HIGHS...MID 60S SW TO AROUND 60/LOWER 60S NE. OTHER FEATURE TO NOTE WILL BE THE INCREASING NW WINDS BY AFTN AS THE SFC LOW INTENSIFIES FAIRLY RAPIDLY OFF THE COAST. GUSTS TO 25-35 MPH WILL BE POSSIBLE BY LATER AFTN/EVENING. THE CLOSED LOW MOVES FARTHER NE WED NIGHT INTO THU...LOCATING OFF THE NEW ENGLAND COAST BY 00Z FRIDAY. ANY LEFTOVER SHOWER CHANCES BY THEN WILL BE LIMITED TO THE EASTERN SHORE (20%). DECREASING CLOUDS ARE ALSO EXPECTED ACROSS INTERIOR VA. LOWS WED NIGHT IN THE LOW 40S TO LOW 50S. COOL AGAIN THU ALTHOUGH WITH A BIT MORE SUN SHOULD SEE HIGHS INTO THE MID-UPPER 60S WELL INLAND WITH HIGHS ONLY IN THE LOWER 60S FARTHER NE. PRESSURE GRADIENT WILL REMAIN TIGHT IN BETWEEN SUB 1000 MB SFC LOW OFF LONG ISLAND AND 1020 MB SFC HIGH OVER THE OH/TN VALLEY. EXPECT BREEZY TO WINDY CONDITIONS WITH GUSTS TO 35 MPH ACRS THE ERN SHORE...AROUND 30 MPH ELSEWHERE.
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&& .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... LOW PRESSURE LIFTS TO THE NE THURSDAY NIGHT THROUGH SATURDAY AS UPPER RIDGING EXPANDS EASTWARD FROM THE CENTRAL US. A WEAK TROUGH CLIPS THE NRN MID-ATLANTIC SATURDAY NIGHT AND QUICKLY MOVES OFF THE COAST SUNDAY. MID/UPPER LEVEL RIDGING BUILDS OVER THE ERN US EARLY NEXT WEEK. OVERALL...DRY CONDITIONS SHOULD PREVAIL THROUGH THE MEDIUM RANGE PERIOD. HIGH TEMPERATURES SHOULD AVERAGE IN THE MID 60S TO AROUND 70 FRIDAY AND SATURDAY...AND TREND UPWARD INTO THE UPPER 60S TO LOW 70S SUNDAY...AND POTENTIALLY 70-75 BY MONDAY. LOWS SHOULD RANGE FROM THE LOW/MID 40S NW...TO THE LOW/MID 50S FOR SE COASTAL LOCATIONS. && .AVIATION /09Z TUESDAY THROUGH SATURDAY/... EXPECT MAINLY VFR CONDITIONS TODAY INTO THIS EVENG OVR THE TAF SITES...WITH PERIODS OF MID LVL CLOUDINESS...AS A WEAK COLD FRONT MOVES ACRS THE AREA. LATER TNGT THRU THU...LO PRES WILL INTENSIFY OFF THE NEW JERSEY AND NEW ENGLAND CSTS. THERE WILL BE A CHC FOR SHOWERS AND MVFR CIGS...ESPLY OVR NRN AND ERN PORTIONS LATE TNGT INTO WED NGT. MVFR CIGS MAY LINGER INTO EARLY THU AT SBY. THE LO PRES SYSTEM WILL MOVE FARTHER AWAY TO THE NE AND HI PRES BLDS IN FM THE NNW THU NGT INTO SUN. && .MARINE...
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BASED ON LATEST MODEL GUIDANCE...AND ASSOCIATED WIND SPEEDS FM THE NW STARTING WED AFTN DUE TO INTENSIFYING LO PRES OFF THE CST...HAVE HOISTED SCA`S FOR ALL WTRS STARTING WED AFTN AND WILL MAINTAIN THEM THRU AT LEAST THU AFTN FOR NOW. AT THIS TIME...HAVE GUSTS TO ARND 30 KT OVR THE CHES BAY ZNS AND CSTL ZNS FM EARLY WED EVENG THRU THU. WITH FLOW BEING OFFSHR FM THE NW...SEAS WOULD TEND TO STAY CAPPED AT 5-6 FT AND TIDAL FLOODING IS NOT EXPECTED. N/NW FLOW IS EXPECTED TO CONTINUE INTO NEXT WEEKEND WITH SPEEDS DIMINISHING TO 10-15 KT AND SEAS SUBSIDING.
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&& .AKQ WATCHES/WARNINGS/ADVISORIES...
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MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 1 PM WEDNESDAY TO 5 PM EDT THURSDAY FOR ANZ630>638-650-652-654-656-658.
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&& $$ SYNOPSIS...LKB NEAR TERM...LKB SHORT TERM...JDM/LKB LONG TERM...AJZ AVIATION...TMG MARINE...AJZ/TMG

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