Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 270056 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 856 PM EDT FRI SEP 26 2014 .SYNOPSIS... HIGH PRESSURE OVER ONTARIO WILL CONTINUE TO BUILD INTO THE REGION TONIGHT...AND REMAIN THROUGH LATE SUNDAY. A LOW PRESSURE SYSTEM WILL FORM OVER THE SOUTHEAST GULF COAST STATES SUNDAY NIGHT...AND MOVE TO THE NORTHEAST TOWARDS THE CAROLINAS MONDAY AND TUESDAY. HIGH PRESSURE WILL THEN ONCE AGAIN BUILD INTO THE REGION FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH SATURDAY/... HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE GREAT LAKES TONIGHT. A DRY NORTHERLY FLOW WILL BRING MAINLY CLEAR SKIES ALONG WITH SEASONABLY COOL CONDITIONS. PATCHY FOG IN THE RIVER VALLEYS AND RURAL AREAS CANNOT BE RULED OUT...BUT IT IS TOO DRY FOR FOG WIDESPREAD FOG TO DEVELOP. MIN TEMPS WILL RANGE FROM THE LOWER 40S IN SOME OF THE COLDER VALLEYS IN THE POTOMAC HIGHLANDS TO THE UPPER 50S/NEAR 60 IN DOWNTOWN WASHINGTON AND BALTIMORE. ON SATURDAY...THE HIGH MOVES FROM THE GREAT LAKES TO BECOME ALMOST CENTERED OVER THE MASON-DIXON LINE. ANY PATCHY FOG FROM TONIGHT WILL BURN OFF QUICKLY WITH MAX SUNSHINE. WITH H85 TEMPS AROUND 15C IN FULL SUN ON A NE WIND...WILL HAVE MAX TEMPS SATURDAY REACHING THE LOWER 80S IN THE WARMER SPOTS WHICH IS ABOUT 5-10 DEG F OVER NORMAL VALUES. THERE WILL BE STILL A N/NE COMPONENT TO THE WIND WHICH WILL KEEP TEMPS BELOW THE MID 80S...WHICH IS WHAT I WOULD EXPECT WITH FULL SUN...H85 TEMPS 15C...AND A WESTERLY WIND. WINDS SHOULD BE LIGHT NE...BUT MAY GUST 10-15 KTS DURING MAX SOLAR HEATING IN THE AFTERNOON. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/... A CLEAR AND CALM SAT NIGHT...WITH ONCE AGAIN PATCHY FOG DEVELOPING IN THE NORTHERN AND CENTRAL VA PIEDMONT. TEMPS WILL BE A FEW DEG WARMER THAN TONIGHT. SUNDAY WILL START OFF SUNNY...BUT WILL SEE HIGH CLOUDS INCREASING FROM THE SW IN RESPONSE TO THE GULF COAST LOW. TEMPS SHOULD BE A FEW DEGREES WARMER ON SUNDAY...WHICH WILL BE A SOLID 10 DEG F HIGHER THAN NORMAL. WINDS WILL ONCE AGAIN BE LIGHT...BUT MORE VARIABLE IN DIRECTION THAN ON SATURDAY. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... SUNDAY NIGHT THE 12Z ECMWF BRINGS A CHC OF OVERRUNNING RAIN TO THE SW PORTION OF THE CWA IN ADVANCE OF THE LOW. THE 12Z GFS HOLDS OFF THE CHC OF RAIN UNTIL MONDAY. SO THERE IS SOME DIFFERENCES IN THE TIMING AND EVEN THE PLACEMENT OF THE POTL RAINFALL ON SUNDAY NIGHT. CLOUDS WILL DEFINITELY BE ON THE INCREASE ON SUN NIGHT NO MATTER WHAT MODEL SOLN/SOLNS YOU CHOOSE. THE GREATEST CHC OF PCPN FOR THE SUN NIGHT THROUGH MONDAY TIMEFRAME WILL BE THE SOUTHERN HALF OF OUR CWA. THE LOW EXITS OFF CAPE HATTERAS TUESDAY...AND ONCE AGAIN HIGH PRESSURE BUILDS BACK INTO THE REGION FROM THE GREAT LAKES THROUGH THE REMAINDER OF THE WEEK. BOTH MAX AND MIN TEMPS WILL BE ABOVE NORMAL DURING THIS ENTIRE LONG TERM PERIOD. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... PATCHY MVFR VSBYS IN THE VA PIEDMONT AND SHEN VALLEY TONIGHT. OTHERWISE VFR THROUGH SUNDAY. POTL MVFR CIGS/VSBYS AT KCHO SUN NIGHT AND MONDAY...ELSEWHERE VFR. WINDS WILL BE LIGHT THROUGHOUT THE ENTIRE PERIOD. && .MARINE... FAIR MARINE WEATHER WITH NO HEADLINES. NEXT CHC FOR SCA WINDS WILL MONDAY NIGHT INTO TUE AS THE LOW PULLS OFF HATTERAS. && .TIDES/COASTAL FLOODING... A NORTH-NORTHEAST FLOW HAS CAUSED TIDAL ANOMALIES TO BE AROUND ONE HALF TO THREE QUARTERS OF A FOOT ABOVE NORMAL. THE NORTH-NORTHEAST FLOW WILL CONTINUE TO CAUSE ELEVATED WATER LEVELS LATE TONIGHT INTO SATURDAY MORNING...BUT MINOR FLOODING IS NOT EXPECTED SINCE THE HIGH TIDE WILL BE THE LOWER OF THE TWO ASTRONOMICAL NORMS. THE FLOW MAY TURN MORE TOWARD THE EAST SATURDAY AFTERNOON INTO SATURDAY EVENING...THIS MAY CAUSE WATER LEVELS TO INCREASE A BIT. THE HIGH TIDE WILL ALSO BE THE HIGHER OF THE TWO ASTRONOMICAL NORMS. MINOR TIDAL FLOODING WILL BE POSSIBLE FOR SENSITIVE AREAS NEAR HIGH TIDE. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...LEE NEAR TERM...BJL/LEE SHORT TERM...LEE LONG TERM...LEE AVIATION...BJL/LEE MARINE...BJL/LEE TIDES/COASTAL FLOODING...BJL

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