Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 250741 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 341 AM EDT SAT OCT 25 2014 .SYNOPSIS...
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HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY. A REINFORCING COLD FRONT WILL PASS THROUGH THE REGION LATE TONIGHT INTO SUNDAY BEFORE HIGH PRESSURE RETURNS FOR MONDAY. THE HIGH WILL MOVE OFF THE COAST TUESDAY AND ANOTHER COLD FRONT WILL PASS THROUGH THE AREA WEDNESDAY.
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&& .NEAR TERM /THROUGH TONIGHT/...
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AN UPPER LEVEL VORT MAX RIBBON HELPING MIX-DOWN THE GUSTY WINDS ATTM AND WILL CONTINUE HOVERING OVER THE AREA INTO THE POST-DAWN HRS THIS MRNG. OCCASIONAL GUSTS IN THE 20-25KT RANGE...W/ OVERALL SFC WINDS AT A STEADY 10-15KT CLIP OUT OF THE NW. THE EXITING AND SLOW-MOVING UPPER LEVEL SYSTEM FROM A COUPLE OF DAYS AGO STILL HANGING AROUND NEW ENGLAND...E OF THE HUDSON RVR/ERN NY. THE VORT MAX MERELY SWINGING AROUND THE BACKSIDE OF THE UPPER LOW...BEING PULLED ALONG BY THE SYSTEM...NOT EXPECTED TO MAKE MUCH EWD PROGRESS IN THE COMING HRS. FOR THIS REASON...WINDS WILL STAY FAIRLY BREEZY OVERNIGHT WHICH IS NOT ALL THAT COMMON - THEN PICK BACK UP EVEN FURTHER AFTER DAWN. TRAPPED LOW LEVEL MOISTURE ALSO MIXING-DOWN W/ SOME OF THE GUSTS...WHICH IS KEEPING DEWPOINTS RELATIVELY HIGHER THAN W/ A NW FLOW REGIME. EVEN THOUGH SKIES ARE GENERALLY CLEAR ATTM...DEWPOINTS ARE REMAINING RELATIVELY HIGH AND THIS IS KEEPING TEMPS ON THE WARMER SIDE. IF NOT FOR THE MOISTURE...TEMPS WOULD LIKELY BE DROPPING WELL INTO THE 40S AND 30S IN SHELTERED VLYS...BUT MOST SITES ARE BARELY AOB 55F CURRENTLY. NOT QUITE AS GUSTY TODAY AS ON THU BUT TEMPS WILL END UP IN ABOUT AROUND THE SAME LEVELS - M60S...U60S OVER THE SRN TIER COUNTIES. PLENTY OF SUN TODAY...A FEW PASSING UPPER DECKS AS A PRECIP-LESS SHORTWAVE DIGS WELL TO OUR SOUTH...OVER THE SRN APLCNS. THIS FEATURE WILL KEEP ITS INFLUENCES AWAY FROM THE MID-ATLC BUT WILL HELP TO USHER-IN THE MORE CALMING EFFECT OF AN UPPER MIDWEST HIGH. AFTER THE SFC FLOW DISSIPATES POST-SUNSET TONIGHT...DEWPOINTS WILL SLOWLY REBOUND AGAIN INTO THE 40S...FOR ANOTHER REL MILD TEMP RANGE FOR OUR OVERNIGHT LOWS. APPLIED A BIAS-CORRECTED MET/MEX FOR TODAY`S HIGH/LOW TEMP GRIDS. ALSO MODIFIED WINDS IN THE NEAR/SHORT TERMS W/ NEWER HI-RES WRK GUIDANCE.
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&& .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
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THE NOSE OF A POTENT UPPER LEVEL JET WILL MAKE A QUICK ENTRANCE ON SAT...SLAMMING UP AGAINST THE EXITING UPPER LEVEL JET FROM THE OFFSHORE LOW. THIS FAST UPPER NW FLOW WILL START TO BRING IN THE CLOUD COVER TO THE MTNS ON SAT...BUT LEAVE THE REMAINDER OF THE AREA FAIRLY DRY AND CLEAR UNTIL LATER IN THE EVE. BEING ON THE RIGHT-EXIT DOWNWARD MOTION SIDE OF THE UPPER JET WILL KEEP THE AREA DRY HEADING INTO THE WEEKEND. WEAK BUT STEADY DOWNSLOPING FLOW MAY HELP BRING TEMPS UP A FEW MORE DEG...PEAKING IN THE M-U60S - POSSIBLY JUST ABOVE 70F FOR SAT AFTN. HIGH PRESSURE WILL BUILD OVERHEAD SUNDAY NIGHT...CAUSING WINDS TO DIMINISH. LIGHT WINDS...MAINLY CLEAR SKIES AND DRY CONDITIONS WILL PROVIDE A GOOD SETUP FOR RADIATIONAL COOLING. THEREFORE...MIN TEMPS SUNDAY NIGHT WILL BE CHILLY...ESPECIALLY IN SHELTERED VALLEYS AND RURAL AREAS. MIN TEMPS WILL RANGE FROM THE MID 30S IN PORTIONS OF THE SHENANDOAH VALLEY...EASTERN WEST VIRGINIA...NORTHERN MARYLAND AND THE NORTHERN AND WESTERN SUBURBS OF WASHINGTON/BALTIMORE...TO THE MID 40S IN DOWNTOWN WASHINGTON AND BALTIMORE. FROST IS POSSIBLE ACROSS MANY LOCATIONS LATE SUNDAY NIGHT AND EARLY MONDAY MORNING...ESPECIALLY NORTH AND WEST OF INTERSTATE 95. HIGH PRESSURE OVER THE REGION MONDAY MORNING WILL SHIFT TO THE COAST BY LATE IN THE DAY. A RETURN SOUTHERLY FLOW WILL DEVELOP...ALLOWING FOR MILDER CONDITIONS MONDAY AFTERNOON ALONG WITH PLENTY OF SUNSHINE. MAX TEMPS WILL RANGE FROM THE MID 60S ACROSS NORTHEASTERN MARYLAND TO THE MIDDLE 70S IN PORTIONS OF CENTRAL VIRGINIA. A SOUTHERLY FLOW WILL CONTINUE AROUND THE HIGH MONDAY NIGHT...ALLOWING FOR MILDER CONDITIONS COMPARED TO SUNDAY NIGHT. MIN TEMPS WILL RANGE FROM THE MID AND UPPER 40S ACROSS SHELTERED VALLEYS AND RURAL AREAS TO THE MIDDLE 50S IN DOWNTOWN WASHINGTON AND BALTIMORE.
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&& .LONG TERM /TUESDAY THROUGH FRIDAY/...
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A COLD FRONT WILL APPROACH FROM THE WEST TUESDAY...BUT IT WILL REMAIN TO OUR WEST AND A SOUTHWEST FLOW AHEAD OF THIS SYSTEM WILL USHER IN UNUSUALLY WARM CONDITIONS FOR THIS TIME OF YEAR. MAX TEMPS WILL APPROACH 80 DEGREES ACROSS MANY LOCATIONS. THE COLD FRONT WILL MOVE INTO WESTERN PORTIONS OF OUR CWA TUESDAY NIGHT. CLOUDS WILL INCREASE AHEAD OF THIS SYSTEM AND THERE MAY EVEN BE A FEW SHOWERS LATE ACROSS THE POTOMAC HIGHLANDS...BUT PRECIPITATION AMOUNTS WILL BE LIGHT. THE COLD FRONT WILL MOVE THROUGH THE AREA WEDNESDAY INTO WEDNESDAY NIGHT...BRINGING THE CHANCE FOR SHOWERS. PRECIPITATION AMOUNTS WILL BE LIGHT SINCE LITTLE MOISTURE WILL BE ASSOCIATED WITH THE FRONT. HIGH PRESSURE WILL BUILD OVERHEAD FOR LATE IN THE WEEK...BRINGING A RETURN OF MORE SEASONABLE CONDITIONS.
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&& .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
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ANOTHER BREEZY AFTN TODAY BUT A TIER LOWER IN TERMS OF PEAK GUSTS...WHERE 15-20KT WILL BE FAIRLY COMMON FROM AFTER SUNRISE. SEVERAL MORE HEADING INTO THE DAYTIME HRS...OF THE STEADY BREEZE TODAY. WINDS WILL THEN QUICKLY DROP OFF TOWARD SUNSET. HIGH PRESSURE CONTINUE STRENGTHENING OVER THE AREA INTO SAT. VFR CONDITIONS ARE EXPECTED MOST OF THE TIME SUNDAY NIGHT THROUGH WEDNESDAY. A SOUTHERLY FLOW WILL INCREASE AHEAD OF A COLD FRONT MONDAY AND TUESDAY. WINDS WILL SHIFT TO THE NORTHWEST BEHIND THE FRONT FOR WEDNESDAY.
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&& .MARINE...
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A WEAK UPPER LOW WILL MEANDER JUST OFF THE COAST INTO THE LATE NIGHT HRS TONIGHT BUT TAKE IT`S BREEZY INFLUENCE. SCA CONTINUED FOR ALL THE WATER THIS AFTN. MAY NEED TO FURTHER EXPAND THE SCA FOR THE LOWEST BAY ZONES BUT WILL MONITOR UPCOMING SCA POTENTIAL. HIGH PRESSURE OVER THE WATERS SUNDAY NIGHT WILL MOVE OFF THE COAST MONDAY THROUGH TUESDAY. A SOUTHERLY FLOW WILL DEVELOP DURING THIS TIME. A COLD FRONT WILL PASS THROUGH THE WATERS WEDNESDAY. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS TUESDAY AND WEDNESDAY. HIGH PRESSURE WILL RETURN FOR LATE IN THE WEEK.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM EDT SUNDAY FOR ANZ530>543.
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&& $$ SYNOPSIS...BJL NEAR TERM...GMS SHORT TERM...BJL/GMS LONG TERM...BJL/GMS AVIATION...BJL/GMS MARINE...BJL/GMS

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