Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 270047 AAA AFDLWX AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 847 PM EDT WED AUG 26 2015 .SYNOPSIS... HIGH PRESSURE OVER THE MIDWEST TONIGHT WILL SHIFT EASTWARD TO THE MIDDLE ATLANTIC BY FRIDAY MORNING. IT WILL REMAIN OVER THE AREA THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH THURSDAY/...HIGH PRES WILL CONTINUE TO BUILD OVER THE REGION THROUGH THE END OF THE WEEK MAINTAINING FAIR WX CONDITIONS. GFS SHOWS SFC DEWPOINTS RISING OVERNIGHT AND GIVEN CLEAR SKIES AND LIGHT WINDS COULD LEAD TO SOME PATCHY FOG OVER THE SHENANDOAH VALLEY. ANOTHER STELLAR DAY AGAIN TOMORROW WITH HIGHS AROUND 80 AND LOW HUMIDITIES. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... HIGH PRESSURE WILL BUILD EASTWARD TOWARD OUR REGION ON THURSDAY NIGHT...AND HEIGHTS WILL RISE IN THE WAKE OF THE DEPARTING TROUGH...SO AFTERNOON CLOUDS SHOULD DISSIPATE AND THE CHANCE OF FOG WILL EXIST AGAIN AWAY FROM THE COAST AND THE METRO AREA. LOWS WILL LIKELY BE SIMILAR TO TONIGHT...WITH 50S AWAY FROM THE COAST AND THE METRO AND 60S IN BALTIMORE AND WASHINGTON. HIGH PRESSURE WILL BE IN PLACE FRIDAY WHILE WEAK TROUGHING ALOFT WILL MOVE ACROSS THE NORTHEASTERN US AGAIN. RETURN FLOW AROUND THE HIGH WILL BRING MOISTURE INTO SW VA. A CU FIELD WILL LIKELY DEVELOP OVER THE MTNS. CANT RULE OUT A SHOWER ACROSS THE VA HIGHLANDS IN THE AFTERNOON. FCST MAX TEMPS WILL RANGE FROM THE 70S IN THE MTNS AND LOW TO MID 80S ELSEWHERE. HIGH PRESSURE WILL STAY IN PLACE FRIDAY NIGHT. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... VERY LITTLE HAS CHANGED FROM PREVIOUS FORECASTS WITH REGARDS TO MAIN WEATHER FEATURES DURING THE LONG TERM...AS SFC HIGH PRESSURE GENERALLY REMAINS IN CONTROL AND SHIFTS IN ITS POSITIONING HELP TO INFLUENCE SUBTLE DAY-TO-DAY WEATHER CHANGES. OVER THE WEEKEND...CONTINUED MOISTURE ADVECTION AROUND SFC HIGH WILL HELP TO RAISE HUMIDITY SOMEWHAT...THOUGH EXPECTING DEWPOINTS TO REMAIN AOB 65 OVER ALL BUT SOUTHERN MARYLAND. HEAT WILL ALSO BE ON THE INCREASE...WITH DAYTIME TEMPS IN M/U80S...WHICH IS A FEW DEGREES ABOVE NORMAL. INCREASING HEAT AND HUMIDITY WILL ALSO AID IN INCREASING AFTERNOON SHOWER/THUNDERSTORM CHANCES. THINK MOST OF THE ACTIVITY SHOULD REMAIN OVER SOUTHWESTERN PORTIONS OF CWA FOR SATURDAY AND THEN SPREAD OVER MUCH OF THE AREA SUNDAY. CHANCES AT ANY ONE LOCATION ARE LOW...AS LIFT REMAINS RATHER LOCALIZED AND WEAK. EARLY NEXT WEEK...VERY LITTLE CHANGE IN SENSIBLE WEATHER AS WE MOVE INTO EARLY NEXT WEEK. NOT SEEING MUCH IN THE WAY OF APPROACHING BOUNDARY TO HELP REMOVE WARM AIRMASS...SO EXPECT CONTINUED AIRMASS MODIFICATION WITH A GRADUAL INCREASE IN TEMPERATURES EACH DAY. HUMIDITY SHOULD REMAIN MANAGEABLE WITH DEWPOINTS AOB 70. WHILE NON- ZERO...PRECIP CHANCES REMAIN RATHER LOW OVER THE ENTIRE AREA...WITH BEST CHANCES OVER THE HIGHER TERRAIN. && .AVIATION /01Z THURSDAY THROUGH MONDAY/... GENERALLY VFR THROUGH THE PERIOD. LIGHT NORTHWEST WINDS WILL CONTINUE THROUGH THE TAF PERIOD WITH SOME SCATTERED TO BROKEN MID-LEVEL CLOUDS BUT NO PRECIPITATION. THERE IS A POSSIBILITY OF PATCHY FOG TONIGHT AND AGAIN THURSDAY NIGHT...MOST LIKELY OCCURRING AT CHO WITH A LESSER RISK AT MRB. AN ISOLATED SHOWER OR THUNDERSTORM COULD BRIEFLY IMPACT CHO SATURDAY. THERE IS A LOW CHANCE OF LATE DAY THUNDERSTORMS AT ALL TERMINALS SUNDAY AND MONDAY. && .MARINE... HIGH PRESSURE WILL REMAIN TO THE WEST TONIGHT. HIGH PRESSURE BUILDING OVERHEAD BY FRIDAY MORNING AND PERISISTING THROUGH THE REST OF THE FORECAST PERIOD SHOULD KEEP WINDS BELOW SCA LEVELS. WINDS WILL TURN SOUTHERLY OVER THE WEEKEND. THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS SUNDAY AND MONDAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...RCM NEAR TERM...LFR SHORT TERM...HAS/RCM LONG TERM...HAS/MSE AVIATION...HAS/MSE/LFR MARINE...HAS/MSE/LFR

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