Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 030202 AAA AFDLWX AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1002 PM EDT THU JUL 2 2015 .SYNOPSIS... A STATIONARY FRONT WILL REMAIN OVER CENTRAL VIRGINIA AND SOUTHERN MARYLAND THROUGH THE WEEKEND. SEVERAL WAVES OF LOW PRESSURE WILL MOVE EAST ALONG THE FRONT AS AN ACTIVE PATTERN CONTINUES. HIGH PRESSURE WILL RETURN FOR THE FIRST HALF OF NEXT WEEK. && .NEAR TERM /THROUGH FRIDAY/... A WEAK BOUNDARY REMAINS NEARLY STATIONARY OVER CENTRAL VIRGINIA THIS EVENING. THERE IS A SMALL DEWPOINT GRADIENT ALONG THE BOUNDARY...LOWER TO MIDDLE 60S NORTH OF THE BOUNDARY AND UPPER 60S/LOWER 70S SOUTH OF THE BOUNDARY. THIS BOUNDARY WILL REMAIN NEARLY STATIONARY OVER CENTRAL VIRGINIA TONIGHT. AN UPPER-LEVEL DISTURBANCE AND SURFACE LOW PRESSURE ALONG THE BOUNDARY WILL CONTINUE TO MOVE OFF TO THE EAST THIS EVENING. SUBSIDENCE BEHIND THIS WILL ALLOW FOR MOST AREAS TO TURN OUT DRY ALONG WITH BREAKS IN THE CLOUD COVER. ANOTHER WAVE OF LOW PRESSURE AND ITS ASSOCIATED UPPER-LEVEL DISTURBANCE WILL TRACK THROUGH THE MIDWEST TONIGHT AND INTO THE OHIO VALLEY BY DAYBREAK. AS THIS SYSTEM DRAWS CLOSER...MORE HIGH AND MID-LEVEL CLOUDS WILL OVERSPREAD THE AREA AND OVERRUNNING WILL ALSO INCREASE AS THE LOW-LEVEL FLOW BACKS TO THE SOUTHEAST...ALLOWING FOR WARM AND MOIST AIR TO OVERRUN THE SURFACE COOLER AIR IN PLACE. THIS WILL CAUSE PRECIPITATION TO DEVELOP ACROSS CENTRAL VIRGINIA WELL AFTER MIDNIGHT WHERE OVERRUNNING WILL BE DEEPEST. ELSEWHERE...CONDITIONS SHOULD REMAIN DRY WITH INCREASING CLOUDS AND AREAS OF FOG. FOG MAY BE LOCALLY DENSE DUE TO BREAKS IN THE CLOUD COVER THIS EVENING AND SATURATED SOILS FROM RECENT RAINFALL. THE WAVE OF LOW PRESSURE WILL TRACK EAST ALONG THE STALLED FRONT ON FRIDAY...IN ADDITION TO POTENTIAL MID-LEVEL DISTURBANCES ROTATING OUT OF A DEEPENING TROUGH OVER THE OHIO VALLEY. EXPECT SHOWERS TO INCREASE IN COVERAGE FROM SW TO NE FROM MORNING INTO THE AFTERNOON. A LITTLE QUESTIONABLE HOW FAR NORTH THE ACTIVITY GETS AND WHETHER IT WILL BE IN ONE SLUG OR THE OFF/ON VARIETY. THEREFORE HAVE A GRADIENT OF POPS FROM 40 TO 80 NE TO W AND SW...BUT THESE MAY NEED TO BE RAISED. WE WILL LIKELY BE ON THE STABLE SIDE OF THE BOUNDARY...SO THUNDER SHOULD BE RATHER LIMITED...ESPECIALLY WITH NORTHWARD EXTENT. THINK THAT THE RAIN WILL FALL AT A SLOW ENOUGH RATE TO LIMIT A FLOOD THREAT...BUT WITH A MOIST ATMOSPHERE AND WET SOILS...THIS WILL NEED TO BE MONITORED. WENT ON COOL SIDE OF GUIDANCE FOR HIGHS WITH CLOUDS/PRECIP...WITH MOST LOCATIONS IN THE 70S. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... FRONTAL BOUNDARY WILL REMAIN JUST SOUTH OF THE REGION WITH WAVES OF LOW PRESSURE RIDING NORTHWARD ALONG THE BOUNDARY. SHOWERS WILL REMAIN IN THE FORECAST FRIDAY NIGHT AND INTO THE 4TH OF JULY HOLIDAY. WINDS WILL LIKELY REMAIN OUT OF THE EAST OR NORTHEAST WHICH WILL KEEP THE ATMOSPHERE COOLER AND MORE STABLE. HAVE REMOVED MENTION OF THUNDERSTORMS FROM THE FORECAST ATTM. HIGH TEMPERATURES WILL LIKELY ONLY REACH THE MIDDLE TO UPPER 70S DURING SATURDAY WITH LOWS IN THE 60S. && .LONG TERM /SUNDAY THROUGH THURSDAY/... FRONTAL BOUNDARY SOUTH OF THE AREA DRIFTS FARTHER SOUTH SUNDAY AND MONDAY AS UPR RIDGE BUILDS EAST OVER THE MIDWEST. ANY ISOLATED TO POSSIBLY SCATTERED THUNDERSTORMS BOTH DAY LOOK TO BE DIURNALLY DRIVEN. BY TUESDAY FRONT RETURNS TO AREA AND A COASTAL LOW DEVELOPS OFF DELMARVA IN RESPONSE TO UPPER LEVEL TROUGH. INCREASING CHANCE OF CONVECTIVE DEVELOPMENT ESPECIALLY OVER EASTERN MD AND VA TIDEWATER. NEXT COLD FRONT APPROACHES REGION FROM THE MIDWEST WEDNESDAY AND SLOWS WITH MORE ACTIVE WEATHER INTO LATE NEXT WEEK. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... MAINLY DRY CONDITIONS THIS EVENING. SHOWERS MAY OVERSPREAD KCHO TOWARD DAYBREAK. SHOWERS WILL OVERSPREAD MOST OF THE TERMINALS FRIDAY...BUT COVERAGE ACROSS KBWI AND KMTN IS STILL A BIT UNCERTAIN AT THIS TIME. THERE IS A LIMITED CHANCE OF THUNDER DURING THE AFTERNOON AND EVENING HOURS. IN ADDITION...FOG AND/OR LOW CIGS MAY DEVELOP TONIGHT INTO FRIDAY MORNING. GENERALLY HAVE MVFR/IFR CONDITIONS INDICATED. WINDS WILL REMAIN LIGHT TONIGHT...TURNING TOWARD THE SOUTHEAST FRIDAY AFTERNOON. OVERCAST CONDITIONS ALONG WITH A CHANCE FOR SHOWERS WILL PERSIST SATURDAY AND PERHAPS INTO SUNDAY. CONDITIONS WILL LIKELY IMPROVE LATER SUNDAY AND INTO EARLY NEXT WEEK. && .MARINE... FRONT STALLED SOUTH OF THE AREA THROUGH FRIDAY. SUB-SCA CONDITIONS LIKELY. HOWEVER BY LATE FRIDAY AFTERNOON...LOW PRESSURE WILL TRACK ALONG THE FRONT AND MAY INCREASE EASTERLY WINDS OVER THE SOUTHERN PARTS OF THE WATERS. PERIODS OF SHOWERS WILL CROSS THE WATERS...MAINLY FRIDAY AFTERNOON AND EVENING. THEIR MAIN IMPACT WILL BE TO REDUCE VSBY...BUT EMBEDDED THUNDERSTORMS COULD ALSO BRING GUSTIER WINDS. EXPECT THESE TO BE ISOLATED AND CONFINED TOWARD THE SOUTHERN PARTS OF THE WATERS. WINDS ARE EXPECTED TO REMAIN BELOW SCA LEVELS SATURDAY INTO MONDAY. OCCASIONAL SHOWERS COULD IMPACT THE WATERS DURING THIS TIME BUT THE THREAT FOR THUNDERSTORMS IS LOW. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...KRW NEAR TERM...BJL/ADS SHORT TERM...KRW LONG TERM...CEM AVIATION...BJL/ADS/KRW MARINE...BAJ/BJL/ADS/KRW

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