Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 240803 CCA AFDLWX AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 403 AM EDT FRI APR 24 2015 .SYNOPSIS... HIGH PRESSURE OVER INDIANA WILL BUILD ONTO THE EAST COAST TODAY. THIS WILL MOVE OFFSHORE SATURDAY. A LARGE AREA OF UPPER LEVEL LOW PRESSURE IS EXPECTED TO SET UP OVER NEW ENGLAND SUNDAY AND SPIN OVER THE NORTHEAST FOR THE FIRST PART OF THE NEW WEEK. AFTER A BREIF PERIOD OF HIGH PRESSURE A REINFORCING UPPER LEVEL LOW IS EXPECTED OVER THE NORTHEAST TO END NEXT WEEK. && .NEAR TERM /TODAY/... MAIN CONCERNS ARE FIRE WEATHER FOR THIS AFTERNOON (SEE SECTION BELOW) AND FROST/FREEZE AGAIN TONIGHT. AS OF 07Z...OCCLUDED UPR LOW APPARENT IN WATER VAPOR IMAGERY AS CENTERED OVER THE MAINE COAST. THIS LOW IS EXPECTED TO REMAIN CENTERED OVER MAINE THROUGH TONIGHT. BACK EDGE OF CLOUDS WITH THIS SYSTEM CONTINUES TO APPROACH THE CREST OF THE APPALACHIANS WITH SCT/BKN STRATUS/WAVE CLOUDS SLOWLY ERODING OVER THE NRN 3/4 OF THE CWA. NWLY FLOW 8 TO 15 MPH OVER THE AREA...COMBINED WITH MID CLOUDS ARE KEEPING TEMPERATURES ELEVATED SO FAR. TEMPERATURE GENERALLY IN THE 40S...UPR 30S UP ALONG THE MASON-DIXON. TEMPS WILL SLOWLY DROP REST OF THE NIGHT AS CLOUDS ERODE AND WINDS KEEP MIXING. TODAY...SUNNY SKIES WITH NWLY FLOW CONTINUING TO BE 15 GUST 20 MPH. SEE FIRE WX SECTION BELOW. MAX TEMPS MID TO UPR 50S NORTH...AROUND TO LOW 60S CENTRAL AND SOUTH IN THE DOWNSLOPING FLOW. && .SHORT TERM /TONIGHT THROUGH SATURDAY/... TONIGHT...PRESSURE GRADIENT SHIFTS EAST AS WRN SIDE OF MAINE LOW CONTRACTS EAST. OVERRUNNING HIGH CLOUDS OVERSPREAD THE AREA WITH POTENTIAL FOR ALTOSTRATUS AS WELL. DRY CONDITIONS PERSIST...ALLOWING TEMPERATURES TO DROP QUICKLY IN THE EVENING. FREEZE WATCH FOR ROUGHLY SAME AREA AS FRIDAY WARNING (THIS ONE INCLUDES ALL OF HARFORD). FROST WILL ALSO BE A CONCERN GIVEN THE EXPECTED DECOUPLED WINDS. CLOUDS THAT DO COME SHOULD NOT BE THICK...SO WENT A DEGREE OR SO COOLER THAN A MAV/MET/SREF BLEND. SATURDAY...LOW PRESSURE APPROACHING FROM THE MIDWEST WITH RETURN FLOW MOISTENING THE RATHER DRY CONDITIONS. WARM FRONT LIFTS INTO AREA WITH RAIN LIKELY BREAKING OUT FOR ALL BUT NERN MD THROUGH THE DAY. QPF GENERALLY QUARTER INCH OR LESS FOR THE DAYTIME. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... THIS IS CERTAINLY AN OUT-OF-THE-ORDINARY PTTN FOR THE END OF APR. AVG HIGH/LOW FOR END OF APR SHOULD BE A70/M40S...AND IT`S NOT LOOKING LK WE`LL BE SEE TOO MANY DAYS IN THE NEXT WK W/ HIGHS THAT WARM. ...AND THE REASON BEHIND THIS WL BE THE CONTINUED DOMINANCE OF THE UPR LVL LOW OVR THE NERN U.S. IT`S LOOKING LK SUNDAY WL BE A COOL CLDY DAY W/ PDS OF RAIN. THIS LOW WL SLOWLY MOVE OFFSHORE DURG THE 1ST PART OF THE WK...ALLOWING WK HIGH PRES INTO THE MID ALTC. SUNSHINE SHOULD ALLOW TEMPS TO APRCH NORMS. BUT ANYTHING RESEMBLING A "NRML" SPRING SHOULD BE SHORT-LIVED AS LATE NEXT WK IT APPEARS LOW PRES TRACKING NE OUT OF THE GULF STATES WL BE MERGING W/ ANOTHER UPR LVL LOW TRACKING NE OUT OF CANADA...SETTING UP ANOTHER VORTEX OVR NEW ENGLAND WHICH WL BE BRINGING COOL MOIST AIR INTO THE MID ATLC FOR NEXT FRI - THE 1ST DAY OF MAY LOOKING LK A CONTINUATION OF THE COOL SPRING WE`VE BEEN XPRCNG SO FAR. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/...
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VFR INTO SUNDAY AS HIGH PRESSURE BUILDS THROUGH TONIGHT AND LOW PRESSURE APPROACHES SUNDAY. NWLY FLOW GUSTS 20 TO 25 KT TODAY...EASING TONIGHT WITH FROST POSSIBLE EARLY SATURDAY. AIR MOISTENS SATURDAY WITH RAIN OVERSPREADING LATE MORNING THROUGH THE AFTERNOON. XTNSV CLD CVR XPCTD SAT NGT INTO SUN WL KEEP CONDS IN THE MVFR RANGE. CONDS SHOULD IMPRV ERLY IN THE NEW WK.
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&& .MARINE...
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SCA FOR ALL WATERS UNTIL 8PM AS NWLY FLOW IS 15 TO 20 KT WITH GUSTS UP TO 25 KT TODAY DUE TO LOW PRESSURE CENTERED OVER MAINE. SCA CONTINUES INTO SATURDAY MORNING FOR MAIN MD PARTS OF THE BAY DUE TO CONTINUED NWLY/NLY CHANNELING. LOW PRESSURE APPROACHES FROM THE MIDWEST SATURDAY WITH LIGHT FLOW SLOWLY BECOMING SLY. SCA LVL WINDS MAY BE PSBL SUN AND MON.
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&& .FIRE WEATHER... SUNNY SKIES WITH NWLY FLOW CONTINUING TO BE 15 GUST 20 MPH. RH DROPS INTO THE 20S WITH 10-HR FUEL MOISTURE LESS THAN 8 PERCENT. DAY SHIFT WILL NEED TO DO FIRE WEATHER COORDINATION. THINK AT LEAST A STATEMENT IS PRUDENT FOR TODAY. COULD MAKE A CASE FOR RED FLAG WARNING FOR CNTRL/W-CNTRL MD COUNTIES WHERE WIND IS EXPECTED TO BE A BIT HIGHER...CLOSER TO 20 MPH SUSTAINED CRITERION. OTW...VA AREAS LOOK TO HAVE SUB RED-FLAG WINDS OF 10 TO 15 MPH SUSTAINED. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...FREEZE WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING FOR MDZ003>006-503-505-507-508. FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR MDZ003>006-503- 505-507. VA...FREEZE WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING FOR VAZ025>031-505-507-508. FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR VAZ025>031-505- 507-508. FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR VAZ036>040-050- 051-501-502. WV...FREEZE WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING FOR WVZ051>053. FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR WVZ051>053. MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR ANZ531>534- 537-539>541-543. SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ536- 538-542. SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ530. SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR ANZ535. && $$ PRODUCTS...BAJ/WOODY!

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