Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 240105 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 905 PM EDT THU APR 23 2015 .SYNOPSIS... UPPER LEVEL LOW PRESSURE WILL CONTINUE MOVING EAST FROM THE GREAT LAKES TOWARD NEW ENGLAND THROUGH THIS WEEKEND. MEANWHILE SURFACE LOW PRESSURE WILL TRACK FROM THE CENTRAL PLAINS...EMERGING OFF THE CAROLINA COAST SUNDAY. && .NEAR TERM /THROUGH FRIDAY/... AN UPPER-LEVEL TROUGH OVERHEAD LATE THIS EVENING WILL BEGIN TO LIFT OUT OVERNIGHT. HIGH PRESSURE WILL REMAIN TO OUR WEST OVER THE OHIO VALLEY AND A NORTHWEST FLOW WILL CONTINUE TO USHER IN CHILLY CONDITIONS FOR THIS TIME OF YEAR. IN FACT...A FREEZE WARNING IS IN EFFECT FOR THE FAR NORTHERN AND WESTERN SUBURBS OF WASHINGTON AND BALTIMORE AS WELL AS THE SHENANOAH VALLEY...EASTERN WEST VIRGINIA PANHANDLE AND NORTHERN MARYLAND. A FROST ADVISORY IS IN EFFECT FOR PORTIONS OF CENTRAL VIRGINIA INTO THE FOOTHILLS OF NORTHERN VIRGINIA. FURTHER NORTHEAST INTO THE WASHINGTON AND BALTIMORE METROPOLITAN AREAS...THE GRADIENT WIND MAY HOLD ON ENOUGH TO PREVENT WIDESPREAD FROST FROM DEVELOPING. THEREFORE...NO FROST HEADLINES HAVE BEEN ADDED FOR THESE AREAS. MIN TEMPS WILL RANGE FROM THE MIDDLE 20S IN THE ALLEGHENY HIGHLANDS...TO THE UPPER 20S AND LOWER 30S IN THE SHENANDOAH VALLEY AND NORTHERN MARYLAND...TO THE UPPER 30S IN DOWNTOWN WASHINGTON AND BALTIMORE. A BKN STRATOCU DECK HAS CAUSED MOSTLY CLOUDY CONDITIONS ACROSS NORTHERN AND CENTRAL PORTIONS OF THE CWA LATE THIS EVENING. THESE CLOUDS WILL DISSIPATE AFTER MIDNIGHT AS DRIER AIR MOVES IN FROM THE NORTHWEST...BEHIND THE DEPARTING UPPER-LEVEL TROUGH. FRI WILL BE MAINLY CLEAR AS THE UPPER-LEVEL TROUGH CONTINUES TO LIFT NORTHEAST AWAY FROM THE AREA. TEMPS WILL BE ON PAR W/ THURSDAYS CONDS AS WE START OFF COLDER BUT W/ LESS CLOUD COVER DURING THE DAY AND A DOWNSLOPING NORTHWEST FLOW...SHOULD BE ABLE TO MAKE UP FOR THE COLDER START. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... AREA WL BE AFFECTED BY A NARROW RIDGE OF HIPRES FRI NGT. FLOW ALOFT WL BE DISORGANIZED THROUGH AS DP H5 LOPRES WL BE EMERGING INTO THE GULF OF MAINE AND A SECOND STORM SYSTEM WL BE CROSSING THE PLAINS. MAY GET SOME HIGH CLDS LATE...OTRW WL BE IN A DCPLD ENVIRONMENT WITH LOW DEWPTS. TEMPS WL BE BELOW NORMAL ONCE AGAIN. FCST REFLECTS A BLEND. CLDS WL BE THICKENING AND LOWERING SAT AS WAA OVERSPREADS THE AREA. THERE SHUD BE ENUF UPGLIDE FOR PCPN...BUT THE ACTIVE SRN STREAM OF THE UPR JET SUGGESTS THAT PCPN WL STRUGGLE TO MAKE IT TOO FAR NORTH TOO QUICKLY. ASSOCIATED LOPRES WL BE NEAREST LATE SAT NGT...AND MADE THAT THE WETTEST PD. NE MD POPS STILL DONT RISE ABV CHC. ON THE OTHER HAND...CAT POPS FOR A PORTION OF THE PTMC HIGHLANDS. LKLY IN BTWN. SAT MIDDAY-AFTN WL BE THE PD WHEN PCPN OVERSPREADS AREA... AND HV OFFERED GRDLY INCRSG POPS. SUNDAY DOESNT LOOK PRETTY...BUT ITS DISORGANIZED. WL HV SFC LOPRES EMERGING OFF THE COAST WHILE THE UPR LOW RETROGRADES TO OUR NORTH AND STARTS TO FILL. THINK IT/LL BE FAIRLY CLOUDY BUT PCPN WL BE SPOTTY IF ANY. THIS WL KEEP TEMPS ON THE COOLER SIDE. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE WILL BUILD OVERHEAD FROM THE GREAT LAKES SUNDAY NIGHT THROUGH TUESDAY...BRINGING MAINLY DRY CONDITIONS ALONG WITH MORE BELOW NORMAL TEMPERATURES THANKS TO A NORTHERLY FLOW. LOW PRESSURE WILL PASS BY TO OUR SOUTH DURING THE MIDDLE PORTION OF NEXT WEEK...BRINGING THE NEXT CHANCE FOR RAIN. && .AVIATION /01Z FRIDAY THROUGH TUESDAY/... SOLID VFR CONDS THRU THE TAF PERIOD. NORTHWEST WINDS AROUND 5 TO 10 KNOTS ARE EXPECTED TONIGHT. ANOTHER INCREASE FOR WINDS IS EXPECTED FRIDAY WITH GUSTS AROUND 20 TO 30 KNOTS DURING THE LATE MORNING AND AFTERNOON HOURS. WINDS WILL DIMINISH TOWARD SUNSET FRIDAY EVENING. SATURDAY SHUD HV VFR FLGT CONDS FOR THE MRNG HRS...BUT CLDS WL THICKEN AND LOWER DURING THE DAY. MVFR-IFR LATE SAT INTO ELY SUN. LOWER CONFIDENCE WHAT FLGT CAT WE WL BE IN SUN AFTN...BUT SUSPECT RESTRICTIONS WL LINGER. VFR MON-TUE. && .MARINE... A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE MARYLAND CHESAPEAKE BAY AND LOWER TIDAL POTOMAC RIVER TONIGHT. NORTH TO NORTHWEST WINDS WILL CHANNEL DOWN THE WATERS WITH GUSTS AROUND 20 TO AS HIGH AS 30 KNOTS EXPECTED. THE STRONGEST WINDS WILL BE ACROSS THE MIDDLE PORTION OF THE MARYLAND CHESAPEAKE BAY OVERNIGHT. WINDS WILL INCREASE FOR ALL OF THE WATERS FRIDAY. AN SCA IS IN EFFECT OR ALL THE WATERS FROM MID-MORNING FRIDAY INTO FRIDAY EVENING. THE SMALL CRAFT ADVISORY MAY NEED TO BE EXTENDED INTO FRIDAY NIGHT FOR PORTIONS OF THE WATERS...BUT CONFIDENCE IS LOW AT THIS TIME. LGT/VRBL FLOW OVER THE WKND. && .FIRE WEATHER... DEAD FUEL MOISTURE IS LOW DUE TO THE RECENT DRY CONDITIONS OVER THE LAST COUPLE DAYS. MORE BREEZY AND DRY CONDITIONS ARE EXPECTED FRIDAY...AND THE RELATIVE HUMIDITY WILL DROP TO BETWEEN 20 AND 30 PERCENT IN THE AFTERNOON. THE COMBINATION OF BREEZY CONDITIONS...LOW RELATIVE HUMIDITY AND LOW FUEL MOISTURE MAY ENHANCE THE THREAT FOR THE SPREAD OF WILDFIRES LATER FRIDAY MORNING INTO EARLY FRIDAY EVENING. HOWEVER...LIVE FUEL MOISTURES MAY HAVE AN IMPACT DUE TO THE RECENT GREENUP. COORDINATION ABOUT FUEL MOISTURE WILL BE NECESSARY ON FRIDAY WITH FIRE CONTACTS TO SEE IF A STATEMENT IS NEEDED REGARDING THE POTENTIAL FOR AN ENHANCED THREAT FOR THE SPREAD OF WILDFIRES. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...FREEZE WARNING FROM 2 AM TO 9 AM EDT FRIDAY FOR MDZ003>006-503- 505-507. VA...FREEZE WARNING FROM 2 AM TO 9 AM EDT FRIDAY FOR VAZ025>031-505- 507-508. FROST ADVISORY FROM 2 AM TO 9 AM EDT FRIDAY FOR VAZ036>040-050- 051-501-502. WV...FREEZE WARNING FROM 2 AM TO 9 AM EDT FRIDAY FOR WVZ051>053. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT FRIDAY FOR ANZ530>534- 537>543. SMALL CRAFT ADVISORY FROM 10 AM TO 8 PM EDT FRIDAY FOR ANZ535- 536. && $$ SYNOPSIS...HTS NEAR TERM...BJL/GMS/HTS SHORT TERM...HTS LONG TERM...CEM AVIATION...BJL/GMS/HTS MARINE...BJL/GMS/HTS FIRE WEATHER...BJL

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