Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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. --
000 FXUS61 KLWX 290912 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 512 AM EDT WED JUL 29 2015 .SYNOPSIS... WEAK HIGH PRESSURE PERSISTS OVER THE AREA INTO TONIGHT. A COLD FRONT MOVES THROUGH THE REGION THURSDAY FROM THE WEST. HIGH PRESSURE THEN PERSISTS OVER THE AREA THROUGH THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... DENSE FOG ADVISORY UNTIL 9 AM FOR N-CNTRL VA AND N-CNTRL SHEN VLY PER AWOS AND TRAFFIC CAMS. AS OF 07Z...HIGH PRESSURE DOMINATES THE ERN HALF OF THE CONUS...H5 HIGH CENTERED OVER OK AND WEAK HIGH AT THE SFC...INCLUDING THE MID- ATLANTIC. DEEP COLD CORE LOW IS OVER LAKE WINNIPEG AND HEADING TOWARD HUDSON BAY. HIGH CLOUDS HAVE DISSIPATED AS THEY HAVE MOVED SOUTH INTO THE CWA. ANOTHER DAY OF HOT/HUMID CONDITIONS WITH LITTLE STEERING FLOW WITH AFTERNOON SLOW MOVING CONVECTIVE THUNDERSTORMS. SCATTERED COVERAGE IN HIGHER TERRAIN OF SWRN QUARTER OF THE CWA...ISOLATED ELSEWHERE. MAX TEMPS AROUND 90F ACROSS THE LOWER ELEVATIONS OF THE CWA. DEWPOINTS REMAIN IN THE LOW 70S FOR HEAT INDICES OF UPR 90S TO 100F IN URBAN CENTERS LIKE BALT AND WASH. TONIGHT...COLD FRONT (NOW STRUNG OUT FROM THE PARENT LOW OVER ONTARIO) CROSSES THE MID-ATLANTIC WITH PREFRONTAL THUNDERSTORM CHANCES REACHING THE CENTRAL APPALACHIANS AFTER MIDNIGHT. OTHERWISE INCREASING CLOUDS WITH MIN TEMPS LOW TO MID 70S. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... THURSDAY...COLD FRONT CROSSES THE CWA THROUGH THE DAY. POPS INCREASE AHEAD OF THE FRONT THROUGH THE DAY PER DIURNAL TRENDS. FRONT IS A BIT MORE PROGRESSIVE THAN PREVIOUS...COMES IN QUICKER WITH AFTERNOON LIKELY POPS FOR BALT-WASH METRO THUNDERSTORMS. MAX TEMPS LOW TO POSSIBLY MID 90S AHEAD OF THE FRONT. SHOULD IT PUSH THROUGH SOONER...TEMPS WOULD BE MODERATED. DEWPOINTS IN THE LOW 70S RESULT IN HEAT INDICES AROUND 100F. THURSDAY NIGHT...COLD FRONT CLEARS THE SERN ZONES THURSDAY EVENING WITH COOLER AIR TRAILING. MIN TEMPS 60S WEST OF I-95...LOW 70S EAST. && .LONG TERM /FRIDAY THROUGH TUESDAY/... FAIRLY TRANQUIL WEATHER PATTERN FOR LAST DAY OF JULY THROUGH THE FIRST FEW DAYS OF AUGUST...AS HIGH PRESSURE BUILDS IN FROM THE WEST BEHIND DEPARTING COLD FRONT. FRONT WILL HAVE MOVED THROUGH THE CWA BY 8 AM FRIDAY...THOUGH THERE COULD BE A FEW LINGERING SHOWERS OVER SOUTHERN MARYLAND. NOT MUCH OF A TEMPERATURE CHANGE WITH THIS FRONT...AS TEMPERATURES EXPECTED TO REMAIN IN THE U80S/L90S. BUT DEWPOINTS DROP AT LEAST TEN DEGREES...AND GENERALLY REMAIN AOB 65F THROUGH THE LONG TERM. SLOW WARMING TREND THROUGH TUESDAY...WITH TEMPS REMAINING A FEW DEGREES ABOVE NORMAL. PRECIP CHANCES THROUGH THE PERIOD ARE VERY LOW...WITH NO DECENT SOURCE OF LIFT AND QUALITY LOW-LEVEL MOISTURE SHUNTED OFF TO OUR SOUTHEAST. WHILE LOW...BEST CHANCES FOR PRECIP OCCUR MONDAY IN OUR SOUTHERN AND EASTERN ZONES AS MOISTURE RETURN SLOWLY COMMENCES. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... IFR VSBYS/POSSIBLE CIGS THROUGH SUNRISE UNDER WEAK FLOW AND CLEAR SKIES...PARTICULARLY WHERE IT RAINED LATE TUESDAY. VFR THEN PREVAILS INTO TONIGHT OUTSIDE OF LOW CHANCES FOR TSTMS...PARTICULARLY NEAR KCHO THIS AFTERNOON. WEAK COLD FRONT CROSSES TERMINALS THURSDAY WITH LIKELY THUNDERSTORMS IN THE AFTERNOON FOR DC METROS. VFR CONDITIONS EXPECTED FRIDAY THROUGH THE REMAINDER OF THE PERIOD UNDER HIGH PRESSURE. && .MARINE... SCA FOR SLY CHANNELING THIS EVENING SOUTH OF SANDY PT. OTHERWISE HIGH PRESSURE. WEAK COLD FRONT CROSSES WATERS THURSDAY AFTERNOON. WINDS EXPECTED TO BE SUB-SCA FRIDAY THROUGH THE REMAINDER OF THE PERIOD UNDER HIGH PRESSURE. LOW CHANCE FOR AFTERNOON THUNDERSTORMS OVER THE WATERS MONDAY AS LOW LEVEL MOISTURE SLOWLY INCREASES. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR VAZ026-027- 029-030-050>052-055-056-502. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 3 AM EDT THURSDAY FOR ANZ532>534-537-540-541-543. && $$ SYNOPSIS...BAJ/MSE NEAR TERM...BAJ SHORT TERM...BAJ LONG TERM...MSE AVIATION...BAJ/MSE MARINE...BAJ/MSE

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