Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 250053 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 853 PM EDT FRI OCT 24 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD OVERHEAD THROUGH SATURDAY. A REINFORCING COLD FRONT WILL PASS THROUGH THE REGION LATE SATURDAY NIGHT INTO SUNDAY BEFORE HIGH PRESSURE RETURNS FOR MONDAY. THE HIGH WILL MOVE OFF THE COAST DURING THE MIDDLE PORTION OF NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY/...
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S/WV DIGGING ACRS APPALACHIA THIS EVNG. THE H5 TROF AXIS PROVIDING A PLACE FOR CI TO CONGREGATE-- THESE CLDS HV MVD LTL SINCE LT AFTN. GDNC SUGGESTING NEARLY SATD UPR LVLS WL SHIFT EWD BTWN 06-12Z. HV ADJUSTED SKYCOVER AND WL MAKE APPROPRIATE ADJUSTMENTS TO TEMPS TOO. HIGH PRESSURE WILL MOVE FURTHER INTO THE MID-ATLANTIC SATURDAY WHILE THE SHORTWAVE TROUGH MOVES OFF THE SC/GA COAST. MOSTLY SUNNY CONDITIONS ARE EXPECTED SATURDAY WITH W-SW WINDS AROUND 10 MPH. A DRY COLD FRONT WILL APPROACH THE ALLEGHENY FRONT SATURDAY AFTERNOON AND OVC CONDTIONS ARE EXPECTED IN UPSLOPE LOCATIONS. FCST MAX TEMPS WILL BE SLIGHTLY WARMER THAN TODAY...FRIDAY...MID TO UPPER 60S EXPECTED. HV MADE AN ADDTL UPWD BUMP OF A DEGF OR TWO BASED ON FRI OBS AND 18Z GDNC.
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&& .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... VERTICALLY STACKED LOW PRESSURE WILL TRAVEL ACROSS SOUTHERN QUEBEC SATURDAY NIGHT...WITH A TRAILING COLD FRONT CROSSING THE LOCAL AREA. THIS FRONT WILL BE VERY WEAK IN NATURE AS THE MOISTURE AND FORCING WITH THIS SYSTEM WILL BE WELL TO OUR NORTH. CONDITIONS MAY BE FAVORABLE FOR UPSLOPE SHOWERS OR SPRINKLES...BUT GIVEN THE SHALLOW NATURE OF THE MOISTURE...WOULD EXPECT ANY AMOUNTS TO BE VERY LIGHT. ANY PRECIPITATION THAT DOES FALL SHOULD BE IN LIQUID FORM AS OVERNIGHT LOWS WILL BE NEAR 40 IN THE HIGHER ELEVATIONS. MUCH IN THE WAY OF CLOUD COVER MAY BE DIFFICULT TO COME BY WITH THE FRONTAL PASSAGE EAST OF THE MOUNTAINS WITH LOWS IN THE UPPER 40S TO LOW 50S. PRESSURE GRADIENT FROM SYSTEM TO THE NORTHEAST WILL RESULT IN A BREEZY SUNDAY WITH GOOD MIXING. MINIMAL THERMAL DIFFERENCES BEHIND THE FRONT...PLENTIFUL SUN AND A DOWNSLOPE FLOW WILL RESULT IN HIGH TEMPERATURES SIMILAR TO SATURDAY ACROSS MOST OF THE AREA...NEAR OR SLIGHTLY ABOVE SEASONAL NORMS. HIGH PRESSURE WILL BUILD INTO THE CENTRAL APPALACHIANS SUNDAY NIGHT AND WITH A DRY ATMOSPHERE... FAVORABLE RADIATIONAL COOLING CONDITIONS WILL DEVELOP. HAVE MID-UPPER 30S WEST OF THE METROS BUT FEEL THESE AREAS COULD SNEAK A FEW DEGREES COOLER. MENTION OF PATCHY FROST HAS BEEN MAINTAINED IN THESE AREAS. MID 40S CAN BE EXPECTED IN THE METROS. THE HIGH WILL SLIDE TOWARD THE CAROLINA COAST ON MONDAY WITH MID/UPPER LEVEL RIDGING EXPANDING TOWARD THE EAST COAST. MANY LOCATIONS WILL SEE HIGHS NEAR OR ABOVE 70. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... ECMWF INDICATES THAT A SHORTWAVE FROM NORTHERN PLAINS CROSSING GREAT LAKES BY LATE TUESDAY. 500MB TROUGH AND WEAK PVA CROSSING CWA WEDNESDAY. NEXT SHORTWAVE TO CROSS CWA FRIDAY THROUGH SATURDAY. SURFACE FRONT FROM WEST WILL CROSS THE CWA TUESDAY NIGHT INTO THURSDAY MORNING. ANOTHER FRONT FROM THE WEST WILL AFFECT THE CWA FROM LATE THURSDAY INTO FRIDAY AFTERNOON. CERTAINTY REMAINS LOW THIS FAR OUT IN THE FORECAST PERIOD. ALTHOUGH ECMWF TIMING SEEMS TO TRACK FAIRLY WELL WITH HPC ENSEMBLE HPC INDICATES THAT PATTERN WILL PRODUCE LESS PRECIPITATION THAN ECMWF. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... CI DECK CROSSING THE TERMINALS THIS EVNG. WNDS SUBSIDING...AND HV ACTUALLY DCPLD AT SVRL SITES. VFR CONDITIONS EXPECTED TONIGHT AND SATURDAY AS HIGH PRESSURE MOVES OVER THE REGION. CLOUDS WILL INCREASE FROM THE NORTHWEST SAT NIGHT INTO SUNDAY. VFR CONDITIONS EXPECTED. GUSTY NW WINDS ARE EXPECTED SUNDAY. && .MARINE... WINDS HV SUBSIDED ACRS THE ENTIRE MARINE AREA. ALLOWED THE SCA FOR MOST OF THE WATERS TO EXPIRE AT 6PM...AND HV CANCELLED THE REST. HIGH PRESSURE MOVES NEAR THE WATERS TONIGHT AND SATURDAY. W-NW WINDS ARE EXPECTED BUT WILL STAY BELOW SCA CRITERIA. A DRY COLD FRONT WILL MOVE OVER THE WATERS BY SUNDAY AND NW WINDS WILL INCREASE ACROSS THE WATERS. A SCA IS LIKELY SUNDAY AND SUNDAY NIGHT. HIGH PRESSURE WILL BUILD OVERHEAD LATE SUNDAY NIGHT INTO MONDAY BEFORE MOVING OFF THE COAST LATER MONDAY THROUGH THE MIDDLE PORTION OF NEXT WEEK. A SOUTHERLY FLOW WILL INCREASE DURING THIS TIME. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS TUESDAY AND WEDNESDAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...HAS NEAR TERM...HTS/HAS SHORT TERM...ADS LONG TERM...CEM AVIATION...HTS/HAS MARINE...HTS/HAS

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