Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 011436 AAA AFDLWX AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1036 AM EDT WED JUL 1 2015 .SYNOPSIS... A COLD FRONT WILL APPROACH THE REGION FROM THE NORTHWEST TODAY. THE FRONT WILL STALL OUT IN CENTRAL VIRGINIA TONIGHT. THE FRONT WILL LINGER OVER THE REGION THROUGH THE WEEKEND...WITH SEVERAL WAVES OF LOW PRESSURE MOVING EAST ALONG IT. && .NEAR TERM /THROUGH TONIGHT/... WEAK COLD FRONT WILL CROSS THE REGION LATER TODAY. INSTABILITY OUT AHEAD OF THE FRONT WILL BE MARGINAL AT BEST WITH ISOLATED TO SCATTERED COVERAGE LATER THIS AFTERNOON INTO THE EARLY EVENING MAINLY TO THE SOUTH AND EAST OF THE DC/BALTIMORE METRO AREAS. SEVERE THREAT IS MINIMAL ATTM. AFTERNOON HIGH TEMPERATURES WILL LIKELY REACH THE MID TO UPPER 80S EAST OF THE BLUE RIDGE...LOWER 80S TO THE WEST. SHOWER AND THUNDERSTORM THREAT WILL DIMINISH AFTER SUNSET. OVERNIGHT LOWS WILL DIP BACK INTO THE 60S IN MOST LOCATIONS...EXCEPT LOWER 70S IN THE METROS. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... LOW PRESSURE WILL BE TRACKING ALONG THE FRONTAL ZONE...REACHING THE LOWER OHIO VALLEY ON THURSDAY. THIS WILL DRAW SOME MOISTURE INTO THE FRONT OVER OUR REGION. STILL SOME TIMING/PLACEMENT DIFFERENCES AMONGST MODELS...BUT EXPECT A S TO N PROGRESSION OF SHOWERS AND EMBEDDED THUNDER (AT LEAST SOME INSTBY MAY BE PRESENT...ESPECIALLY SOUTHERN TIER). QUESTIONABLE HOW MUCH IF ANY PRECIP REACHES THE M-D LINE DURING THE DAY ON THURSDAY. HEAVIEST ACTIVITY LIKELY STAYS OVER OHIO VALLEY DURING THE DAY. TEMPERATURES WILL BE LIMITED DOWN A FEW DEGREES BY THE CLOUDS AND PRECIP...UPPER 70S TO MID 80S. THURSDAY NIGHT THROUGH FRIDAY NIGHT...A GREAT DEAL OF UNCERTAINTY REMAINS...WITH DIFFERING SOLUTIONS ABOUT THE PATH AND TIMING OF LOW PRESSURE SYSTEMS RIDING EAST ALONG THE FRONT. SOME GUIDANCE LIKE THE GFS BRINGS A SIGNIFICANT WAVE OF LOW PRESSURE SLOWLY ACROSS THE REGION DURING THIS PERIOD...WHICH WOULD RESULT IN SHOWERS AND PERHAPS A FEW ISOLATED THUNDERSTORMS. THE EUROPEAN IN CONTRAST IS NOTABLY SLOWER...WITH THE MAIN WAVE OF LOW PRESSURE WAITING UNTIL FRIDAY NIGHT TO BEGIN AFFECTING THE AREA. THE CANADIAN GGEM IS EVEN SLOWER...HOLDING THE MOST SIGNIFICANT LOW BACK EVEN LONGER. WITH CONSIDERABLE UNCERTAINTY IN THE FORECAST...NO SIGNIFICANT CHANGES WERE MADE...SO KEPT CHANCE TO LOW- END LIKELY POPS AND TEMPS SOMEWHAT COOLER THAN NORMAL IN THE FORECAST. && .LONG TERM /SATURDAY THROUGH TUESDAY/... UNCERTAINTY REMAINS ABOUT THE WEEKEND INTO EARLY NEXT WEEK WITH THE AFOREMENTIONED SIGNIFICANT TIMING DISCREPANCIES REGARDING PASSING DISTURBANCES BETWEEN VARIOUS MODELS. THIS MAKES ANY ATTEMPT TO IRON OUT DETAILS VERY DIFFICULT. THE ONE CONSTANT IS THE APPARENTLY NEVER LEAVING QUASI-STATIONARY FRONT. INHERITED GENERALLY CHANCE POPS THRU THE PERIOD AND DID NOT MAKE MAJOR CHANGES. TEMPS START OUT BELOW NORMAL AND *MAY* RISE TO NEAR NORMAL IF THE FRONT CAN FINALLY NUDGE ITS WAY NORTH OF US EARLY NEXT WEEK. CONFIDENCE IS LOW. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... MOSTLY VFR EXPECTED TODAY INTO TONIGHT. A FEW ISOLATED/SCATTERED SHOWERS/STORMS POSSIBLE LATER THIS AFTERNOON AND EVENING MAINLY FROM KBWI AND KMTN TO KDCA AND KCHO. VFR TONIGHT...PERHAPS SOME PATCHY FOG IN SPOTS. NEXT CHANCE OF PRECIP WILL ARRIVE THURSDAY...WITH GREATEST POTENTIAL FOR IMPACTS AT CHO. FROM THURSDAY NIGHT ONWARD...MAIN CONCERN IS POSSIBLE IFR CIGS AND VIS FROM OCCASIONAL HEAVIER SHOWERS OR THUNDERSTORMS AS A FRONT REMAINS STALLED IN THE GENERAL AREA. WITH THE FRONT NEARBY...WINDS WILL BE HARD TO PREDICT WITH SIGNIFICANT CERTAINTY UNTIL THE PERIOD DRAWS CLOSER. && .MARINE... WINDS BELOW SCA EXPECTED MUCH OF TODAY. A FEW ISOLATED/SCATTERED SHOWERS AND THUNDERSTORMS COULD DEVELOP OVER A PORTION OF THE WATERS LATER THIS AFTERNOON AND EVENING. MAIN CONCERN IN THE EXTENDED FOR MARINE IS OCCASIONAL HEAVIER SHOWERS AND THUNDERSTORMS...WITH APPEARS POSSIBLE JUST ABOUT EVERY DAY FROM FRIDAY INTO EARLY NEXT WEEK. WINDS SHOULD GENERALLY BE SUB SCA BUT AS DISTURBANCES PASS THRU THE AREA...A PERIOD OF SCA WINDS IS NOT IMPOSSIBLE. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...KRW NEAR TERM...KRW SHORT TERM...ADS/RCM LONG TERM...RCM AVIATION...RCM/KRW MARINE...RCM/KRW

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