Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 191424 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1024 AM EDT TUE MAY 19 2015 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE AREA TODAY. BEHIND THE FRONT A COOLER AND DRIER AIR MASS WILL MOVE INTO THE REGION FOR THE MIDDLE OF THE WEEK. A WEAK SYSTEM MAY THEN BRING SOME RAIN BACK TO THE REGION THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SFC CDFNT APPROACHING FM THE OHVLY. IN ADDITION BACKDOOR FNT STILL APPEARS TO BE PRESENT IN THE PRES/THERMAL PTTN ACRS NE MD /DCA T/TD 78/69 VS PHL T/TD 65/60/. SYNOP FLOW TDA WL LARGELY BE FROM THE WEST...WHICH WL ADVECT A DRIER AMS EWD. THE MORE LMTD MSTR PROFILE WL MAKE CNVCTV INITIATION MORE PROBLEMATIC. SHEAR PROFILE MINIMAL...AND MEAN LYR CAPE ONLY 600-700 J/KG. ULTIMATELY THE MAXT WL DICTATE AMT IN STABILITY...BUT WITH LACK OF SHEAR AND WLY FLOW...DONT THINK TSRA WL BE A BIG DEAL TAFTN. BEST OPPORTUNITY WL COME ELY IN THE AFTN...BEFORE MSTR JUST BECOMES TOO LMTD. HV SCALED BACK LATE DAY CLOUD COVER AND ADJUSTED MAXT...SPCLY IN THE MTNS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... HIGH PRESSURE FROM THE PLAINS WILL BUILD EAST BEHIND THE COLD FRONT TONIGHT AND WEDNESDAY...WITH NORTHWESTERLY FLOW AT THE SURFACE BRINGING IN A SURGE OF COOLER...AND IN PARTICULAR...LESS HUMID AIR TO OUR REGION. LOWS TUESDAY NIGHT ARE EXPECTED TO BE 10-15 DEGREES COOLER THAN MONDAY NIGHT`S WERE AND HIGHS WEDNESDAY SHOULD BE SIMILARLY LOWER AS COMPARED TO TODAY`S EXPECTED HIGHS. COMBINED WITH THE LACK OF HUMIDITY...IT WILL FEEL VERY COMFORTABLE. SUNSHINE WILL DOMINATE WEDNESDAY AS WELL...THOUGH HIGH COULDS AHEAD OF ANOTHER DISTURBANCE APPROACHING FROM THE WEST MAY START MOVING IN TOWARDS DAY`S END. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... FOR THE PERIOD WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...THERE IS STILL NOT SUPERB AGREEMENT ABOUT HOW A NORTHERN STREAM SHORTWAVE TROUGH WILL INTERACT WITH SFC LOW PRESSURE MOVING THROUGH THE CAROLINAS. WITH THE 00Z GUIDANCE SUITE...THE GFS IS MORE OF AN OUTLIER WITH A DRIER SOLUTION. INCREASED POPS ACROSS THE SOUTHERN CWA WHERE THERE IS GREATER AGREEMENT ON THE POTENTIAL FOR SHOWERS. START/END OF PRECIP IS MOST IN QUESTION...ALTHOUGH THE PROBABILITY OF THUNDER IS LOW. THURSDAY WILL BE COOL AND CLOUDY REGARDLESS OF THE SOLUTION...WITH HIGH TEMPS ONLY IN THE UPPER 60S TO AROUND 70. UPPER LEVEL TROUGHING WILL ENVELOP THE EASTERN CONUS FOR THE END OF THE WEEK AS HIGH PRESSURE BUILDS INTO THE MS AND OH VALLEYS. TEMPS WILL REBOUND TO NEAR-NORMAL VALUES. THE HIGH WILL BEGIN TO MOVE OFFSHORE ON SUNDAY AND A WARM FRONT WILL LIFT NORTH THROUGH THE OH VALLEY. LOW CHANCE OF SHOWERS MAINLY IN NORTHERN AREAS ON SUNDAY WITH THIS FEATURE. BY MONDAY...UPPER LEVEL RIDGING WILL BUILD. WARMER AND MORE HUMID CONDITIONS WILL LIKELY RETURN WITH A CHANCE OF SHOWERS AND THUNDERSTORMS. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... THUNDERSTORMS MAY DEVELOP THIS AFTERNOON...BUT SHOULD BE RATHER HIT-OR-MISS. AT THE MOMENT...BEST ODDS APPEAR TO BE ELY-MID AFTERNOON SO HAVE INCLUDED VCTS DURING THIS PERIOD. WINDS SHOULD REMAIN MOSTLY BELOW 15 KNOTS...SHIFTING TO THE WEST AND NORTHWEST. NO AVIATION CONCERNS ON WEDNESDAY THOUGH WINDS WILL BE A BIT GUSTY FROM THE NORTHWEST. DEPENDING ON THE TRACK OF LOW PRESSURE TO OUR SOUTH...SUB-VFR CONDITIONS ARE POSSIBLE ON THURSDAY IN LOW CLOUDS AND SHOWERS. THE PROBABILITY IS SLIGHTLY HIGHER AT CHO. OTHERWISE NO WIDESPREAD AVIATION ISSUES ARE EXPECTED IN THE OUTLOOK PERIOD. && .MARINE... A FEW THUNDERSTORMS PSBL TAFTN..BUT DRY AIR INFILTRATING FROM THE WEST WL MAKE INITIATION INCREASINGLY DIFFICULT. BEHIND THE COLD FRONT...THE PRESSURE GRADIENT IS TIGHT ENOUGH SUCH THAT WINDS HAVE A GOOD SHOT AT GUSTING UP TO 20 KNOTS TUESDAY NIGHT AND WEDNESDAY. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THIS. LOW PRESSURE WILL PASS THROUGH THE CAROLINAS AND OFFSHORE FROM WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. DEPENDING ON ITS TRACK...WINDS MAY APPROACH SCA LEVELS OVER MAINLY SOUTHERN PARTS OF THE MD BAY/LOWER POTOMAC. SHOWERS ARE ALSO POSSIBLE. NORTHERLY CHANNELING MAY OCCUR ON FRIDAY...BUT CONFIDENCE IS LOW ON ABILITY TO REACH SCA LEVELS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 5 AM TO 5 PM EDT WEDNESDAY FOR ANZ530>543. && $$ SYNOPSIS...RCM NEAR TERM...HTS SHORT TERM...RCM LONG TERM...ADS AVIATION...HTS/RCM/ADS MARINE...HTS/RCM/ADS

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