Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 250159 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 959 PM EDT THU JUL 24 2014 .SYNOPSIS...
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A COLD FRONT WILL CONTINUE TO PUSH INTO THE CAROLINAS TONIGHT. HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT THROUGH FRIDAY BEFORE MOVING OFF THE COAST DURING THE WEEKEND. A COLD FRONT WILL PASS THROUGH THE AREA EARLY NEXT WEEK.
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&& .NEAR TERM /THROUGH FRIDAY/...
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AS OF 01Z...RAIN HAS CLEARED THE THE CWA...DRY NRLY FLOW CONTINUES TO ADVECT INTO THE REGION BEHIND THE COLD FRONT AND DEWPTS HAVE DROPPED IN THE 50S FOR CNTRL MD...DC...TO PETERSBURG VA...WITH MID 60S SOUTH OF THERE. DEWPTS WILL CONTINUE TO DROP FROM NORTH TO SOUTH TONIGHT AS THE COLD FRONT MOVES THROUGH THE CAROLINAS. AN UPPER LEVEL TROUGH AXIS WILL CROSS THE REGION OVERNIGHT AND DRY AND COOLER CONDITIONS WILL ENSUE. FCST MIN TEMPS A BLEND OF MAV/MET/SREF AND RANGE FROM THE MID 50S WEST OF THE BLUE RIDGE AND NORTH OF BALTIMORE TO AROUND 60F IN INLAND AREAS SOUTH/EAST OF THERE...TO UPR 60S IN URBAN NEAR SHORE LOCALES. RECORD TYING MIN TEMP FORECAST FOR BALTIMORE (SEE CLIMATE SECTION BELOW). ONE FACTOR TO LIMIT TEMPS DECLINE IS CLOUDS WHICH ARE PROGRESSING EAST...BUT MAY NOT CLEAR OUT UNTIL THE TROUGH AXIS PUSHES THROUGH LATE TONIGHT. HIGH PRESSURE WILL CENTER OVER THE REGION FRIDAY AFTERNOON...WITH A LIGHT RETURN FLOW FOR FRIDAY NIGHT. FCST MAX TEMPS A BLEND OF MAV/MET/GMOS AND ARE IN THE LOW TO MID 80S. A CU FIELD SHOULD DEVELOP AS MOISTURE ALOFT PERSISTS. A FEW SHOWERS MAY BE POSSIBLE IN THE CENTRAL FOOTHILLS AS MOISTURE CREEPS INTO THE REGION FRI AFTERNOON. CONFIDENCE OF SHOWERS IS LOW AT THIS TIME.
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&& .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/... WESTERLY ZONAL FLOW ALOFT WILL CONTINUE INTO SATURDAY AS THE HIGH MOVES WELL OFF THE EAST COAST. A SHORTWAVE TROUGH MAY CROSS NORTH OF THE REGION SATURDAY AND SHOWERS AND THUNDERSTORMS MAY BE POSSIBLE NEAR THE MASON DIXON LINE. A LEE TROUGH IS EXPECTED TO FORM AND MAY INITIATE THUNDERSTORMS. MOISTURE BEGINS TO POOL INTO THE REGION WITH INCREASE PWATS AND THETA-E ADVECTION. FCST MAX TEMPS WILL BE IN THE UPPER 80S. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... A TROUGH TO THE EAST OF THE APPALACHIAN MOUNTAINS SATURDAY NIGHT AND PASSING UPPER LEVEL ENERGY MAY BE ENOUGH TO SPAWN A COUPLE OF SHOWERS AND THUNDERSTORMS. THERE IS A BETTER CHANCE FOR HEAVIER SHOWERS AND GUSTY THUNDERSTORMS SUNDAY AND SUNDAY NIGHT AS THE MAIN UPPER LEVEL FEATURE OVER THE GREAT LAKES BEGINS TO TREK ITS WAY EASTWARD...ALLOWING A SURFACE LOW PRESSURE TO DEVELOP ALONG THE ALREADY-ESTABLISHED TROUGH OF LOW PRESSURE ALONG THE SHENANDOAH VALLEY. THE MAIN THREAT FROM THE THUNDERSTORMS WILL BE DAMAGING WINDS AS LAPSE RATES APPEAR FAVORABLE AND MID LEVEL AND UPPER LEVELS MAY BE STRONGER THAN RECENT DAYS. AS THE MAIN UPPER LEVEL STORM MOVES INTO SOUTHEAST CANADA MONDAY INTO MONDAY NIGHT...ITS ASSOCIATED SURFACE COLD FRONT WILL PUSH TO THE EAST COAST BY TUESDAY MORNING. AHEAD OF THE FRONT...PERHAPS ONE FINAL ROUND OF SHOWERS AND THUNDERSTORMS COULD DEVELOP IN THE REGION MONDAY INTO MONDAY EVENING. TUESDAY AND WEDNESDAY WILL BE NOTICEABLY DRIER AND COOLER WITH HIGH PRESSURE BUILDING IN FROM THE WEST. A GRADUAL RETURN FLOW THURSDAY WILL BRING MOISTURE BACK INTO THE REGION. HIGH PRESSURE WILL BE OFFSHORE BY THIS TIME. SOME WEAK UPPER LEVEL ENERGY WILL SLIDE NORTHWARD AND COULD SPAWN A SHOWER OR THUNDERSTORM IN THE HIGHER TERRAIN. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/...
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HIGH PRESSURE WILL MOVE INTO THE REGION TONIGHT AND CENTER OVER THE AREA FRIDAY. NLY FLOW SHOULD KEEP FOG AT BAY...BUT AREAS THAT RECEIVED RAIN COULD GET FOG. WENT WITH MVFR VSBYS FOR KCHO AND SEE A REPORT OF IFR BR ALREADY...WILL HAVE MIDNIGHT SHIFT MONITOR THIS. VFR CONDITIONS EXPECTED FRIDAY. SOUTHERLY FLOW WILL BEGIN FRIDAY AFTERNOON AND CONTINUE INTO SATURDAY. SHOWERS AND THUNDERSTORMS POSSIBLE SATURDAY AFTERNOON. MVFR OR IFR CONDITIONS COULD DEVELOP WITH SHOWER AND THUNDERSTORM ACTIVITY SATURDAY NIGHT...MAINLY NEAR CHO AND MRB TERMINALS. SOUTHERLY WINDS AT 5 TO 10 KNOTS BUT GUSTING 15 TO 20 KNOTS CLOSE TO THE CHESAPEAKE BAY. IFR CONDITIONS MAY BE MORE LIKELY AT ANY OF THE TERMINALS SUNDAY INTO SUNDAY NIGHT WITH HEAVY SHOWERS AND GUSTY THUNDERSTORMS. SOUTH WINDS BECOMING SOUTHWEST AROUND 10 KNOTS AND GUSTING 15 TO 20 KNOTS NEAR THE BAY. VFR CONDITIONS ON MONDAY WITH HIGH PRESSURE BUILDING IN FROM THE WEST. WINDS BECOMING WEST AT 10 KNOTS WITH AN APPROACHING COLD FRONT.
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&& .MARINE...
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A COLD FRONT WILL CONTINUE TO MOVE THROUGH THE CAROLINAS TONIGHT. NLY CHANNELING IS INCREASING WITH AN EARLIER SCA FOR POOLES ISLAND TO DRUM PT BASED ON THE 18Z NAM FORECAST. THE SCA EXPANDS TO INCLUDE SRN MD WATERS BY 2AM AND CONTINUES UNTIL 8AM. HIGH PRESSURE MOVES OVER THE WATERS FRIDAY AND WINDS WILL SUBSIDE BEFORE BECOMING SOUTHERLY BY FRI AFTERNOON. SRLY WINDS WILL CONTINUE INTO SATURDAY. SMALL CRAFT ADVISORIES MAY BE NEEDED SATURDAY NIGHT THROUGH MONDAY WITH GUSTY SOUTHWEST TO WESTERLY WINDS AHEAD OF A COLD FRONT.
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&& .CLIMATE...
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59 DEGREES IS THE FORECAST FOR BWI TONIGHT. THE RECORD LOW FOR THE THREADED BALTIMORE CLIMATE RECORD IS 59...SET IN 2008... 1976...1973...AND 1876.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR ANZ531>533- 539>541. SMALL CRAFT ADVISORY FROM 2 AM TO 8 AM EDT FRIDAY FOR ANZ534- 537-542-543.
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&& $$ SYNOPSIS...BAJ/HAS NEAR TERM...BAJ/HAS SHORT TERM...HAS LONG TERM...KLW AVIATION...BAJ/HAS/KLW MARINE...BAJ/HAS/KLW CLIMATE...BAJ/CEB

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