Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 310333 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1133 PM EDT THU OCT 30 2014 .SYNOPSIS... HIGH PRESSURE LOCATED OVER THE EASTERN OHIO VALLEY WILL TRACK NORTHEAST TONIGHT. DEEP LOW PRESSURE WILL DESCEND FROM THE GREAT LAKES FRIDAY...CROSSING THE CAROLINAS SATURDAY BEFORE STRENGTHENING ALONG THE NEW ENGLAND COAST SUNDAY. HIGH PRESSURE WILL THEN RETURN INTO MONDAY FOLLOWED BY ANOTHER COLD FRONT DURING MIDWEEK. && .NEAR TERM /THROUGH FRIDAY/...
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UNDER SVRL HRS OF CLRG...TEMPS RADIATED EFFECTIVELY...RIGHT PAST PRVS MIN-T FCST. HV SVRL SITES IN THE MID-UPR 30S IN THE CENTRAL SHEN VLY AND FOOTHILLS. DEWPTS INT HE LWR-MID 30S. HV UPDTD MIN-T FCST BASED ON DEWPTS AND LAMP. WITH THAT IN MIND...FROST SEEMS LKLY IN THESE LOCATIONS SINCE TEMPS WL BE IN THE APPROPRIATE RANGE ALL NIGHT. A FREEZE ISNT OUT OF THE QSTN...BUT HV LWR CONFIDENCE IN THAT-- CERTINALY IN TERMS OF A WIDESPREAD OCCURENCE. HV ADDED A LATE-BREAKING/SHORT FUSED FROST ADVY TO MOST OF CENTRAL VA. HAZARD POSTED. GRIDS HV BEEN SENT.
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&& .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/... CHALLENGING FCST FOR THE FOLLOWING 36 HRS. N AMERICAN W.V. STLT SHOWS A DIGGING TROF IN THE ERN PACIFIC...RIDGING W OF THE ROCKIES W/ A SHORT WV NEAR LAKE WINNIPEG HEADING TOWARDS N DAKOTA. THE RDG WL BE TRACKING E OF THE ROCKIES FRI...W/ THE SHORT WV REACHING THE NRN GRT LAKES FRI MRNG. THIS WL BECOME THE PRIMARY PLAYER IN THE FCST FOR FRI NGT. AHEAD OF THAT FRI SHOULD SEE INCRSG CLDS W/ RLVTVLY WARM TEMPS TO END OCT - HIGHS CLOSE TO 60 WHICH IS CLOSE TO CLIMO NORMS. HALLOWEEN EVENING SHOULD BE FAIRLY PLSNT W/ TEMPS IN THE LM50S ACROSS MOST OF THE AREA. THERE WL BE CHCS OF RAIN W/ OF I-81 DURG THE EVE. MDLS ARE IN GOOD AGREEMENT THAT THE SHORT WV SHOULD BE DIVING ACROSS KY/TN FRI NGT...REACHING THE MTNS OF WRN NC BY SUNRISE SAT. AS MENTIONED PCPN XPCTD TO BEGIN IN THE W DURG THE LATE AFTN FRI...BUT BETTER CHCS WL DVLP FRI NGT W/ THE DEEPENING UPR LOW. QUSTN TURNS TO THREAT OF WINTRY PCPN: AT THIS TIME THINK THIS WL BE PRIMARILY DRIVEN BY ELEVATION - THE 850-1000 TCKNS LN IS STILL WELL ABV 1300M ACROSS THE ENTIRE FA FRI NGT. BLV THAT WINTRY PCPN THAT FALLS FRI NGT COULD BE A RA/WET SNOW MIX THAT BECOMES LARGE WET FLAKES AT THE HIGHER ELEVS. LOWS FRI NGT IN THE LM40S. L30S IN THE HIGHLANDS. ON SAT THE UPR LOW WL BE PUSHING OFF THE SC CST. THIS WL KEEP THE MID ATLC CLDY AND SHOWERY. MOISTURE WRAPPING ARND THE BACKSIDE OF THE LOW WL CONT TO SPAWN SNSH AT THE HIGHER ELEVS DURG THE DAY. BY LATE SAT SVRL INCHES OF ACCUMULATION WL BE PSBL...BUT ONLY IN THE HIGHLANDS. HIGHS SAT IN THE L50S E OF I-81...MU30S IN THE HIGHLANDS. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... UPSLOPE SNOW CONTINUES INTO SATURDAY NIGHT...SNOW TOTAL GRID EXTENDED. A COASTAL STORM SYSTEM ALONG THE COAST OF NORTH CAROLINA WILL TRACK TOWARD THE NORTHEAST OFFSHORE AND INTENSIFY SATURDAY NIGHT AND SUNDAY. RAIN SHOWERS WILL MOVE ACROSS THE CHESAPEAKE BAY SATURDAY EVENING BEFORE COMING TO AN END SATURDAY NIGHT. SOME LINGERING RAIN AND SNOW SHOWERS COULD STILL EXIST AT THE HIGHER ELEVATIONS OF THE POTOMAC HIGHLANDS AS WE WILL HAVE A GOOD UPSLOPE COMPONENT TO THE WIND FROM THE WEST-NORTHWEST AND COLDER AIR FILTERING IN AHEAD OF A BUILDING RIDGE OF HIGH PRESSURE. LITTLE ADDITIONAL SNOW ACCUMULATION AT THE HIGHER ELEVATIONS...PERHAPS AN ADDITIONAL TENTH OF AN INCH OR TWO. STRONG GUSTY WINDS ARE EXPECTED SATURDAY NIGHT. TEMPERATURES SATURDAY NIGHT WILL BE ABOUT 10 DEGREES COLDER THAN FRIDAY NIGHT WITH LOWS DROPPING INTO THE 20S IN THE MOUNTAINS AND MIDDLE 30S ALONG THE BAY. HIGH PRESSURE WILL BUILD IN FROM THE OHIO VALLEY TO THE MID ATLANTIC REGION...USHERING IN A RE-ENFORCING SHOT OF CHILLY AIR TO ONLY ALLOW OUR HIGH TEMPERATURES TO REACH THE MIDDLE 40S AS FAR EAST AS THE CHESAPEAKE BAY. STRONG GUSTY WINDS EXPECTED SUNDAY MORNING THROUGH MID AFTERNOON WILL GRADUALLY DIMINISH SUNDAY NIGHT. AS A MATTER OF FACT...DUE TO DIMINISHING WINDS AND CLEARING SKIES...TEMPERATURES WILL ALSO FALL TO A RESULT OF WIDESPREAD LOWER 30S ACROSS THE BOARD. AS THE HIGH SLIDES SOUTHEAST ACROSS THE CAROLINAS AND NEAR THE SOUTHEAST COAST MONDAY AND MONDAY NIGHT. TEMPERATURES WILL MODIFY SOME DURING THE DAY BUT REMAIN A LITTLE ON THE CHILLY SIDE MONDAY NIGHT. HIGH PRESSURE SLIDES OFFSHORE TUESDAY THROUGH WEDNESDAY NIGHT TO ALLOW A COLD FRONT TO GRADUALLY SLIDE INTO THE REGION AND BRING A CHANCE FOR RAIN SHOWERS MAINLY LATE TUESDAY INTO TUESDAY NIGHT. A SECONDARY SURGE OF COOLER AIR WITH UPPER LEVEL SUPPORT WILL PUSH THE FRONT THROUGH THE REGION AS WELL AS BRING A FEW ADDITIONAL RAIN SHOWERS. THIS HIGH WILL BUILD IN ON THURSDAY. && .AVIATION /04Z FRIDAY THROUGH TUESDAY/... CIGS AROUND 5 KFT SLOWLY ERODE TONIGHT. VFR CONDS TNGT AND FRI. CIGS INCREASE FRIDAY AND PERSIST THROUGH SATURDAY. MVFR CONDS XPCTD SAT AS RAIN FILLS IN ACROSS THE DC METROS. MVFR OR IFR CONDITIONS MAY DEVELOP NEAR BWI AND MTN TERMINALS SATURDAY EVENING WITH LINGERING RAIN SHOWERS. VFR CONDITIONS EXPECTED SUNDAY THROUGH MONDAY AT ALL TERMINALS. NORTHWEST WINDS WILL AVERAGE 15 TO 25 KNOTS GUSTING 30 TO 35 KNOTS. && .MARINE... NLY FLOW THROUGH TONIGHT AS HIGH PRESSURE MOVES NORTH ALONG THE APPALACHIANS. ONSHORE FLOW FRIDAY. WINDS XPCTD TO RMN BLO SCA VALUES TNGT THRU FRI NGT. SCA LKLY NEED SAT. SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED SATURDAY NIGHT AND SUNDAY AS LOW PRESSURE STRENGTHENS AS IT SHIFTS NORTH ALONG THE MID- ATLANTIC COAST. GALE CONDS PSBL FOR PORTIONS OF THE WATERS SAT EVE AND SUN. SMALL CRAFT ADVISORIES MAY BE NEEDED SUNDAY EVENING AS WELL. NO MARINE HAZARDS EXPECTED SUNDAY NIGHT AND MONDAY. && .TIDES/COASTAL FLOODING... A DEEP AREA OF LOW PRESSURE WILL CROSS THE CAROLINAS SATURDAY MORNING AND THEN TRACK NORTHEAST ALONG THE MID-ATLANTIC COAST SATURDAY NIGHT. THERE MAY BE A PERIOD OF HIGHER THAN NORMAL TIDES FRI NIGHT INTO SAT...FOLLOWED BY BLOWOUT CONDITIONS SAT AFTERNOON THROUGH SUNDAY. && .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE. MD...NONE. VA...FROST ADVISORY UNTIL 9 AM EDT FRIDAY FOR VAZ025>027-029- 036>040-050>052-502. WV...NONE. MARINE...NONE.
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&& $$ SYNOPSIS... NEAR TERM...HTS SHORT TERM...WOODY! LONG TERM...WITT AVIATION...BAJ/WOODY!/WITT MARINE...BAJ/WOODY!/WITT TIDES/COASTAL FLOODING...HTS/WOODY!

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