Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 251408 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1008 AM EDT THU SEP 25 2014 .SYNOPSIS... COASTAL LOW PRESSURE WILL SLOWLY MOVE OUT TO SEA TO THE NORTHEAST THIS AFTERNOON AND TONIGHT. GREAT LAKES HIGH PRESSURE WILL SLOWLY BUILD INTO THE REGION FRIDAY...AND REMAIN THROUGH THE WEEKEND. LOW PRESSURE WILL APPROACH THE REGION DURING THE FIRST HALF OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LOW PRESSURE WAS HANGING OUT JUST OFF THE MID-ATLANTIC COAST. THE LOW WILL START TO TURN MORE NORTHEAST THROUGH THE DAY...BUT ITS EXIT WILL BE GRADUAL. THAT MEANS WE ARE LIKELY SOCKED IN WITH CLOUDS FOR THE DAY. AS FOR THE RAIN...HEAVIEST ECHOES HAVE SHIFTED TO THE NORTH. WILL LIKELY SEE THE WIDESPREAD RAIN BREAK UP OVER THE NEXT FEW HOURS...BUT WRAPPING AROUND THE LOW SOME AREAS OF RAIN WILL LINGER INTO THE AFTERNOON AND EVENING AND WITH PLENTY OF LOW LEVEL MOISTURE LINGERING THERE MAY BE POCKETS OF DRIZZLE AS WELL. REPOPULATED MAXIMA WITH LATEST ADJMAV/SREFS. RESULT IS A BELOW AVERAGE DAY AREA-WIDE WITH MOST PLACES IN THE 60S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... SEEING A SIZABLE SHIFT IN THE MODELS ON HOW SLOWLY THIS LOW WILL KICK OUT. MADE SIGNIFICANT SHIFTS IN THE FORECAST INTO FRIDAY KEEPING CLOUDS IN LONGER AND RAIN SHOWER CHANCES IN LONGER. EXPECT THE GREAT LAKES HIGH WILL MUSCLE IN AS THE DAY GOES ON FRIDAY...BUT UNTIL THEN SKIES WILL BE SLOW TO CLEAR AND SHOWER CHANCES WILL LINGER...ESP CLOSE TO THE CHES BAY. THIS IS BORNE OUT IN THE GFS NAM EURO AND WPC PROBABILISTIC QPF FIELDS...ALBEIT AT SLIGHTLY DIFFERENT SPEEDS OF MOVING IT OUT. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... HIGH PRESSURE REMAINS CENTERED OVER SRN ONTARIO FRIDAY NIGHT AND SATURDAY (WITH NORTH FLOW) BEFORE DRIFTING EAST TO NEW ENGLAND FOR SUNDAY (WITH AN ONSHORE FLOW) PER 00Z GFS/ECMWF. QUIET WEATHER IN THIS TIME WITH HIGH CLOUDS LINGERING FRIDAY INTO SATURDAY. WORTH NOTING THAT THE NLY FLOW SATURDAY IS ACTUALLY WARM AIR ADVECTION FROM CONTINENTAL AIR WRAPPING AROUND THE GREAT LAKES HIGH. BELIEVED MOS CONSENSUS OF LOW 80S FOR MAX TEMPS FOR BALT-WASH METRO WHICH SHOULD BE A COUPLE DEGREES HIGHER THAN KCHO WHICH IS FARTHER DOWNSTREAM OF THE WARM AIR ADVECTION. MAX/MINS ABOVE NORMAL THROUGH THIS WEEKEND AS THE CONTINENTAL AIR PERSISTS. CUTOFF LOW OVER THE DEEP SOUTH DRIFTS EAST/NORTHEAST MONDAY... STRUGGLING TO DISLODGE THE HIGH PRESSURE OVER THE NERN CONUS. POPS SLOWLY INCREASE MONDAY THROUGH TUESDAY BUT NOTHING ABOVE LOW CHANCES AS OF THIS TIME. THE 00Z GFS ALSO BRINGS A LOW FROM THE GREAT LAKES WHICH MAY PROVIDE A BOOST IN POPS SHOULD IT BE A FEATURE CARRIED ONTO FUTURE RUNS. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... LOW CIGS ARE LIKELY TO LINGER THROUGH THE DAY...MAINLY OF THE IFR VARIETY THIS MORNING THEN MVFR THIS AFTERNOON. PERIODS OF RAIN WILL ALSO BRING VIS RESTRICTIONS OCCASIONALLY TO IFR ALTHOUGH RAIN SHOULD DIMINISH BY AFTERNOON. IT/S UNCERTAIN WHETHER CIGS WILL DROP AGAIN /IFR OR BELOW/ OR NOT FOR THE OVERNIGHT AND WILL RE- EVALUATE FOR 18Z TAF CYCLE. HIGH PRESSURE/VFR PREVAILS FRIDAY NIGHT INTO MONDAY. LIGHT NLY FLOW FRIDAY NIGHT/SATURDAY BECOMES ONSHORE SUNDAY INTO MONDAY. WEAK LOW APPROACHES FROM THE SOUTHWEST INTO THE MIDDLE OF NEXT WEEK. && .MARINE... NORTHERLY WINDS ARE EFFICIENTLY FUNNELLING DOWN THE BAY WITH TPLM2 RECORDING G30KT LAST HOUR. WINDS OUTSIDE THE MAIN CHANNEL HAVE NOT BEEN THAT HIGH BUT STILL WITHIN SCA CRITERIA WITH FREQUENT GUSTS AOA 20 KT. SCA CONTINUES THROUGH THIS AFTERNOON ALL WATERS...LOSING THE UPPER/MIDDLE TIDAL POTOMAC THIS EVENING. HIGH PRESSURE LINGERS OVER THE NRN MID-ATLANTIC FRIDAY NIGHT THROUGH SATURDAY...THEN PERSISTS OVER NEW ENGLAND INTO MONDAY. LIGHT NLY FLOW FRIDAY NIGHT/SATURDAY BECOMES ONSHORE SUNDAY INTO MONDAY. WEAK LOW APPROACHES FROM THE SOUTHWEST INTO THE MIDDLE OF NEXT WEEK. && .TIDES/COASTAL FLOODING... NORTHERLY WINDS HAVE ALLOWED ANOMALIES TO DECREASE ON THE NORTHERN BAY/UPPER TIDAL POTOMAC...CLOSER TO 1/4 TO 1/2 FT ABOVE. STILL HAVE HIGHER ANOMALIES FURTHER SOUTH ON THE BAY BUT THESE TOO SHOULD LESSEN SOME THROUGH THE DAY. EITHER WAY...NO MINOR TIDAL FLOODING EXPECTED ATTM. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT FRIDAY FOR ANZ530>534-537- 539>541-543. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ535- 536-538-542. && $$ SYNOPSIS...BPP/CAS NEAR TERM...BPP SHORT TERM...CAS LONG TERM...BAJ AVIATION...BPP/CAS/BAJ MARINE...BPP/CAS/BAJ TIDES/COASTAL FLOODING...BPP

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