Area Forecast Discussion
Issued by NWS Sterling, VA

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178 FXUS61 KLWX 031857 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 257 PM EDT TUE MAY 3 2016 .SYNOPSIS...A SURFACE TROF WILL REMAIN ACROSS THE AREA THROUGH THURSDAY. A LARGE AREA OF UPPER LEVEL LOW PRESSURE IS EXPECTED TO IMPACT THE AREA THURSDAY AND FRIDAY BEFORE HIGH PRESSURE RETURNS FOR THE WEEKEND. && .NEAR TERM /THROUGH WEDNESDAY/...DIFFERENTIAL HEATING HAS ALLOWED A FEW SHOWERS AND T-STORMS TO DEVELOP OVER THE SRN SHENANDOAH VALLEY. A MODIFIED ACARS 1736Z SOUNDING FROM BWI YIELDS SKYNNY CAPE AROUND 350 J/KG. ANTICIPATING T-STORMS TO SHOW SOME WEAKENING AS THEY MOVE FARTHER EAST INTO THE DC METRO. OVERALL...THERE IS LITTLE FORCING TODAY FOR ORGANIZED CONVECTION OTHER THAN A WEAK SFC TROF OR CONVERGENCE LINE BETWEEN LOW PRES OFF SOUTHEAST VA AND DETROIT MI. AS INSTABILITY WANES TONIGHT AND ONLY WEAK FORCING IS AVAILABLE ANTICIPATE STRATIFORM LIGHT RAIN OR DRIZZLE TO BECOME THE MAIN PRECIP TYPE. SKIES MAY BRIGHTEN A LITTLE BIT LATE TOMORROW BUT OTHERWISE A LOT OF CLOUDS. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...A SHORTWAVE-TROUGH OVER THE WRN GREAT LKS WILL DIG INTO THE OH VALLEY WED AND FORM A DEEP CLOSED LOW ALOFT. LARGE SCALE LIFT INCREASES OVER THE AREA WED NIGHT WITH RAIN DEVELOPING NORTH OF THE H5 LOW TRACK. A SWATH OF 1 TO 2 INCHES OF RAIN APPEARS LIKELY ALONG AND WEST OF THE BLUE RIDGE MTNS WHERE MODELS SHOW A CONVERGENT UPSLOPE NORTHEAST LOW-LEVEL FLOW SETTING UP. THIS APPEARS A PROLONGED PERIOD OF MDT RAINS WHICH COULD RESULT IN SOME FLOODING ISSUES GIVEN INCREASINGLY SOGGY CONDITIONS AND VERY SLOW MOVEMENT OF PRECIP AREA. WE`LL NEED TO MONITOR RAINFALL TOTALS OVER THE NEXT DAY OR SO. && .LONG TERM /FRIDAY THROUGH TUESDAY/...AN UPPER LEVEL DISTURBANCE WILL MEANDER ABOUT THE NEW JERSEY COAST FRIDAY AND FRIDAY NIGHT. THE CHANCE FOR RAIN SHOWERS WILL EXIST THROUGHOUT THE PERIOD. TEMPERATURES WILL BE COOLER THAN NORMAL. AS THE DISTURBANCE WEAKENS AND SLIDES SLIGHTLY TO THE NORTH...A BRIEF RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE REGION SATURDAY. CONDITIONS WILL BE TEMPORARILY DRY BEFORE THE NEXT DISTURBANCE MOVES ACROSS THE GREAT LAKES...DRAGGING A COLD FRONT SOUTHWARD INTO OUR REGION. THE RAIN CHANCES RETURN SATURDAY NIGHT. TEMPERATURES WILL REMAIN COOLER THAN NORMAL. THE CHANCE OF RAIN SHOWERS LINGER SUNDAY AND IN THE WEST SUNDAY NIGHT WITH THE SURFACE FRONT AND AFFILIATED DISTURBANCE NEARBY. THE FRONT WILL TRY TO MOVE NORTHWARD AS A WARM FRONT MONDAY INTO TUESDAY. THIS WILL BRING BACK THREAT FOR SHOWERS OR A THUNDERSTORM. THE BIGGER THREAT WILL BE TUESDAY. TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/...MVFR CIGS EAST TAF SITES DETERIORATING TO IFR EVERYWHERE LATE TONIGHT IN LIGHT NORTHEAST FLOW AND DRIZZLE. A T-STORM IS POSSIBLE THIS AFTERNOON AND EARLY EVENING AT KDCA AND KCHO. MVFR TO IFR CONDITIONS WITH THE CHANCE OF RAIN SHOWERS FRIDAY INTO FRIDAY NIGHT. WINDS NORTHWEST AROUND 10 KNOTS FRIDAY. WINDS NORTHWEST 5 TO 10 KNOTS FRIDAY NIGHT. && .MARINE...WINDS 10 KT OR LESS THROUGH THU MORNING INCREASING SOMEWHAT THU AFTERNOON. SMALL CRAFT CONDITIONS LIKELY FRIDAY AS PRESSURE GRADIENT TIGHTENS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...LFR NEAR TERM...LFR SHORT TERM...LFR LONG TERM...KLW AVIATION...KLW MARINE...KLW

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