Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
453 FXUS61 KLWX 251926 CCA AFDLWX AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 301 PM EDT MON APR 25 2016 .SYNOPSIS... HIGH PRESSURE WILL MOVE FURTHER OFFSHORE THROUGH TUESDAY. A COLD FRONT WILL CROSS THE AREA TUESDAY EVENING. WEAK HIGH PRESSURE BUILDS TUESDAY NIGHT THROUGH EARLY THURSDAY. ANOTHER COLD FRONT IS EXPECTED THURSDAY NIGHT. HIGH PRESSURE BUILDS FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... HIGH PRESSURE IS OFF THE EAST COAST WHILE LOW PRESSURE MOVES THROUGH THE UPPER MID-WEST THIS AFTERNOON. LIGHT SRLY FLOW AND MOSTLY SUNNY SKIES WILL ALLOW TEMPS TO MAX OUT IN THE U70S/L80S THIS AFTERNOON. A CU FIELD HAS FORMED ACROSS THE HIGHER TERRAIN. A FEW SHOWERS MAY FORM THIS AFTERNOON HOWEVER DRY AIR AND LOW DEWPTS WILL LIKELY KEEP THE COVERAGE ISOLATED. HIGH PRESSURE MOVES FURTHER OFF THE COAST TONIGHT AS LOW PRESSURE MOVES ACROSS THE GREAT LAKES. AN ASSOCIATED FRONTAL BOUNDARY WILL SLOWLY APPROACH THE MID-ATLANTIC REGION FROM THE NORTH. MOST SHOWERS ARE EXPECTED NORTH OF THE MD/PA BORDER OVERNIGHT HOWEVER DEPENDING ON THE STRENGTH OF THE SHOWERS AND THUNDERSTORMS THAT FORM TODAY ACROSS THE GREAT LAKES...THE MID-ATLANTIC MAY SEE MORE ACTIVITY MOVE INTO NRN MD. KEPT CHANCES LOW AT THIS TIME BUT WILL BE CLOSELY MONITORED. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AN ACTIVE PERIOD BEGINS TUESDAY AS THE FRONT MOVES SOUTHWARD ACROSS PA. THE MID-ATLANTIC WILL BE IN THE WARM SECTOR WITH BREEZY SW FLOW DURING THE DAY. TEMPS WILL CLIMB INTO THE 80S AND 70S IN THE MTNS BY AFTERNOON. SW FLOW WILL ALSO DRIVE DEWPTS UP ON TUESDAY SO IT WILL FEEL WARMER. AN UPPER LEVEL WIND MAX WILL DRIVE SOUTHWARD BY TUESDAY AFTERNOON AND 0-6KM BULK SHEAR WILL INCREASE TO 30-40KTS. THIS COUPLED WITH SBCAPE OF 1-2K K/JG WILL RESULT IN CONVECTIVE DEVELOPMENT. THE BEST FORCING SEEMS TO BE ACROSS PA WITH SOME ACTIVITY DROPPING INTO MD SO THE BEST CHANCE FOR STRONG TO SEVERE STORMS TUESDAY WILL LIKELY BE IN THE NRN HALF OF THE LWX CWA. DMG WINDS ARE THE MAIN THREAT IN STRONG THUNDERSTORM ACTIVITY. THE FRONT SINKS SOUTHWARD TUESDAY NIGHT AND NRLY WINDS WILL MOVE IN BEHIND. SHOWERS WILL DIMINISH OVERNIGHT HOWEVER THERE WILL STILL BE OVERRUNNING ALONG THE FRONT AND A FEW SHOWERS WILL BE POSSIBLE INTO WEDNESDAY MORNING. AS THE NEXT SYSTEM APPROACHES WEDNESDAY HIGH PRESSURE WILL LIKELY GET WEDGED ACROSS THE EASTERN HALF OF THE REGION RESULTING IN A COOL AND CLOUDY DAY. HIGH TEMPS WILL BE ABOUT 15 DEG COOLER ON WEDNESDAY THAN TUESDAY. THE WEDGE OF HIGH PRESSURE WILL LIKELY PERSIST WED NIGHT AS SHOWERS MOVE INTO THE REGION FROM THE WEST. && .LONG TERM /THURSDAY THROUGH MONDAY/... A WARM FRONT WILL MOVE NORTHWARD ACROSS THE MID ATLANTIC REGION THURSDAY...BRINGING AN INCREASED CHANCE OF SHOWERS AND A FEW THUNDERSTORMS. HIGH PRESSURE PERSISTENTLY TO THE NORTH OF THE FRONT WILL KEEP THE THUNDERSTORM THREAT MAINLY TO THE CENTRAL AND SOUTHERN SHENANDOAH VALLEY. AN AREA OF LOW PRESSURE WILL CONNECT TO THE WARM FRONT NEAR WESTERN VIRGINIA...ALLOWING FOR THE CHANCE OF RAIN SHOWERS TO LINGER THURSDAY NIGHT. SOME MID LEVEL ENERGY IS EXPECTED TO PUSH EAST ACROSS THE LOWER GREAT LAKES AND ALONG THE MASON-DIXON LINE FRIDAY. ADDITIONAL RAIN SHOWERS AND A THUNDERSTORM OR TWO CANNOT BE RULED OUT WITH THIS PASSING DISTURBANCE. WET CONDITIONS SHOULD BRIEFLY DRY OUT FRIDAY NIGHT AND SATURDAY AS HIGH PRESSURE BECOMES WEDGED ALONG THE EASTERN SLOPES OF THE APPALACHIAN MOUNTAINS. COOLER TEMPERATURES WILL DEVELOP. THE THREAT FOR SHOWERS AND A FEW THUNDERSTORMS WILL MOVE BACK INTO THE REGION SATRUDAY NIGHT AND SUNDAY AS THE NEXT MODEST MID LEVEL DISTURBANCE PIVOTS ACROSS THE OHIO AND TENNESSEE VALLEYS. AT THIS POINT...IT APPEARS THAT THE BEST CHANCE FOR RAIN WILL BE IN THE POTOMAC HIGHLANDS AND ACROSS THE VIRGINIA PIEDMONT. THE MAIN DISTURBANCE WILL SLOWLY MOVE ACROSS THE REGION LATER SUNDAY NIGHT INTO MONDAY. THE EUROPEAN MODEL TAKES THE SURFACE LOW WELL NORTH ACROSS NORTHERN PENNSYLVANIA BEFORE MOVING EAST...WHILE THE GFS MODEL KEEPS THE LOW ACROSS THE VIRGINIAS. THERE IS A LIKELIHOOD OF ENCOUNTERING SHOWERS AND PERHAPS A FEW THUNDERSTORMS. THE SEVERITY OF THE THUNDERSTORMS WILL DEPEND ON HOW FAR NORTH WILL THE SURFACE LOW TRACK. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... VFR CONDITIONS EXPECTED TODAY AND TONIGHT. LIGHT S WINDS BECOME SW TUESDAY WITH GUSTS UP TO 25 KTS TUE AFTERNOON. SHRA EXPECTED FROM NORTH TO SOUTH TUESDAY WITH THE POTENTIAL FOR TSRA. HIGHER GUSTS EXPECTED IN SHRA/TSRA TUESDAY. BEST CHANCE FOR TSRA WILL BE ACROSS THE NORTH...MRB/IAD/MTN/BWI. LOW CIGS/VSBYS EXPECTED IN ANY TS. A FRONT WILL CROSS THE REGION FROM N TO S TUESDAY AND WINDS WILL BECOME N BEHIND FRONT AND INTO WEDNESDAY. SUB-VFR CIGS POSSIBLE WED-WED NIGHT AS NE FLOW INCREASES AT THE SFC. IFR TO LIFR CONDITIONS POSSIBLE WITH SHOWERS AND PERHAPS A FEW THUNDERSTORMS THURSDAY INTO THURSDAY EVENING. THERE MAY BE A BRIEF PERIOD OF MVFR CONDITIONS THURSDAY OVERNIGHT. WINDS EAST 5 KNOTS THURSDAY. WINDS BECOMING NORTHEAST 5 KNOTS THURSDAY NIGHT. && .MARINE... S WINDS 5-10 KTS EXPECTED THIS AFTERNOON WITH SOME STRONGER GUSTS ACROSS DRUM PT TO SMITH ISLAND AND THE TANGIER SOUND. A SCA IS IN EFFECT FOR THIS AREA. WINDS WILL STRENGTHEN OVERNIGHT AND SCA CONDITIONS ARE EXPECTED SOUTH OF SANDY PT AND THE LOWER TIDAL POTOMAC. SHOWERS ARE EXPECTED TO CROSS THE WATERS FROM NORTH TO SOUTH TUESDAY. THERE IS A CHANCE OF THUNDERSTORMS AS WELL. ACTIVITY IS EXPECTED TO PRODUCE GUSTY WINDS ON THE WATERS AND SMW MAY BE WARRENTED. A SCA IS IN EFFECT FOR ALL THE WATERS TUESDAY. SHOWERS MOVE SOUTH TUES NIGHT AND GUSTY WINDS WILL DIMINISH INTO THE EVENING. WINDS BECOME NRLY LATE TUESDAY AND SCA ARE LIKELY. AT THIS TIME...CONFIDENCE IS LOW ON THE TIMING OF THE GUSTY WINDS DUE TO NRLY FLOW. NE WINDS EXPECTED WEDNESDAY AND LOOK BELOW SCA CONDITIONS. NO MARINE HAZARDS EXPECTED THURSDAY AND THURSDAY NIGHT. && .TIDES/COASTAL FLOODING... ANOMALIES WILL STAY ELEVATED TONIGHT THROUGH TUESDAY. THE NEXT HIGH TIDE WILL BE THE LOWER OF THE TWO SO NO FLOOD ISSUES CONCERNED THERE HOWEVER THE NEXT HIGH TIDE WILL NEED TO BE WATCHED MAINLY FROM ANNAPOLIS NORTH IF ANOMALIES STAY 1-1.5 FEET ABOVE NORMAL. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 9 PM EDT TUESDAY FOR ANZ530- 531-535-536-538-539. SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 9 PM EDT TUESDAY FOR ANZ532-533-537-540>542. SMALL CRAFT ADVISORY UNTIL 9 PM EDT TUESDAY FOR ANZ534-543. && $$ SYNOPSIS...LFR NEAR TERM...HAS SHORT TERM...HAS LONG TERM...KLW AVIATION...HAS MARINE...HAS TIDES/COASTAL FLOODING...HAS

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.