Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 310129
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
929 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 TONIGHT/...
AS OF 01Z...MID LEVEL CLOUDS FROM AN UPR TROUGH PERSIST OVER THE
NRN AND WRN PORTIONS OF THE CWA. TROUGH DIGGING OVER THE MIDWEST
FROM A LOW CENTERED OVER THE ARROWHEAD OF MN (PER WATER VAPOR) WILL
BEGIN TO DOMINATE THE ERN CONUS TONIGHT. THEREFORE...THE CLOUDS
OVER US SHOULD GENERALLY CLEAR EAST OF THE ALLEGHENY FRONT.
DEWPOINTS IN THE MID 30S AND SOME MIXING SHOULD LIMIT FOG. 1020MB
SFC HIGH IS OVER THE ERN OH VLY. THIS HIGH CENTER WILL SHIFT TO
NEW ENGLAND BY FRIDAY MORNING. MIN TEMPS AROUND 40F INLAND...LOW
30S AT HIGHER ELEVATIONS AND MID TO UPR 40S FOR NEAR SHORE.

&&

.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 /01Z 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...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
UPDATE...JACKSON
PREVIOUS...WOOD!/KLW






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