Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 272223
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
623 PM EDT MON OCT 27 2014

.SYNOPSIS...
HIGH PRESSURE WILL SLIDE OFF THE EAST COAST TONIGHT. A COLD FRONT
WILL CROSS THE STATE TUESDAY NIGHT FOLLOWED BY DRY CONDITIONS AND
SLIGHTLY BELOW NORMAL TEMPERATURES FOR WEDNESDAY AND THURSDAY. A
LATE-WEEK COLD FRONT WILL LIKELY USHER IN THE COLDEST AIR OF THE
SEASON SO FAR FOR FRIDAY NIGHT AND SATURDAY...WITH SCATTERED
MOUNTAIN SNOW SHOWERS AND FLURRIES ACROSS THE CENTRAL RIDGE AND
VALLEY REGION.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
HIGH PRESSURE RIDGE AXIS OVER THE CENTRAL RIDGE AND VALLEY
REGION...WILL DOMINATE OUR WEATHER FOR THE REST OF TODAY AND
TONIGHT...MAINTAINING SUNNY SKIES WITH JUST SOME THIN CIRRUS IN
MOST PLACES. THE FAR NW MAY SEE PERIODS OF THICKER MID AND HIGH
CLOUDS LATE TODAY...NEAR THE EASTERN EDGE OF MODERATELY
STRONG/DEEP LAYER WARM ADVECTION FROM THE SOUTHWEST.

EXPECT MAINLY SW WINDS IN THE 5-8KT RANGE LATE THIS AFTERNOON
ACROSS MUCH OF CENTRAL AND WESTERN PENN...WHILE THE SUSQ VALLEY
AND POINTS EAST WILL STILL SEE SFC WINDS FROM THE WEST FOR SVRL
MORE HOURS PRIOR TO THE RIDGE AXIS SLIDING BY.

MAX TEMPS WILL BE CLOSE TO 70F IN THE SW/SC VALLEYS AND AROUND
60F ACROSS THE NORTHERN MTNS. THESE TEMPS WILL BE ABOUT 7-10
DEGREES ABOVE NORMAL.

MAINLY CLEAR SKIES WITH JUST SOME CIRRUS WILL PREVAIL TONIGHT...
WITH MIN TEMPS RANGING FROM THE MID TO UPR 40S ACROSS THE NORTHERN
AND WESTERN MTNS...TO THE MID 50S IN THE LOWER SUSQ VALLEY.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
THE RELATIVELY FLAT UPPER RIDGE OVER PENN THIS EVENING WILL SHIFT
EAST AND OFF THE MID ATLANTIC COAST ON TUESDAY.

INCREASING DEEP LAYER SWRLY FLOW AND PLENTY OF SFC HEATING AHEAD
OF AN APPROACHING CFRONT WILL COMBINE WITH MARGINAL LOW-MID LEVEL
MOISTURE AND ENHANCED UVVEL BENEATH THE RIGHT ENTRANCE REGION OF A
120 KT UPPER JET AXIS /ACROSS SRN ONTARIO AND LAKE ERIE/ TO
PRODUCE ONE OR TWO LINE OF GUSTY SHOWERS AND SCATTERED LOW-TOPPED
TSRA.

LATEST SREF AND OPERATIONAL MODEL SFC-BASED CAPES ARE AOB 500 J/KG
ALONG AND JUST AHEAD OF THE CFRONT ACROSS NWRN PENN LATE TUESDAY
AFTERNOON...WHILE INSTABILITY IS MINIMAL ELSEWHERE /NEAR AND TO
THE EAST OF THE ALLEGHENY FRONT/.

INCLUDED ENHANCED WORDING FOR THE POTENTIAL OF GUSTY WINDS AND
SMALL HAIL ACROSS THE WRN MTNS LATE TUES/EARLY TUES EVENING. THE
MAIN ENERGY SHEARS OUT QUICKLY TO THE NE TUESDAY NIGHT AS MIXED
LAYER DIMINISHES EARLY TUESDAY NIGHT...SO A WEAKENING LINE OF
SHOWERS WITH SLOWLY DECREASING AREAL COVERAGE IS EXPECTED ACROSS
THE SE HALF OF THE CWA.

THE NEW FOR THIS FALL...SPC SEVERE THUNDERSTORM THREAT-RISK
CATEGORY OF /MARGINAL/ MAKES IT/S FIRST APPEARANCE IN THE
NORTHWESTERN PART OF THE CWA TUESDAY EVENING /WITH THE ERN EDGE OF
THE SMALL SLIGHT RISK AREA JUST TOUCHING THE WESTERN END OF WARREN
CTY/.

GUSTY SHOWERS WILL CONTINUE TO MOVE THROUGH THE REST OF THE AREA
THROUGH THE NIGHT. THE FRONT HANGS UP AS A BIG SUBTROPICAL RIDGE
EXTENDING INTO THE DEEP SOUTH THWARTS THE SOUTH/EASTWARD
PROGRESSION OF THE COLD AIR. THUS...SHOWERS WILL PROBABLY HANG ON
IN THE FAR SERN COS FOR THE FIRST PART OF WED. INITIAL CLEARING
MAY BE CLOSED UP OVER THE NW BY A GRADUAL VEER TO THE WIND AND
SOME SHALLOW...POST-FRONTAL STRATO CU. BUT THE FLOW IS NOT REALLY
OFF THE LAKE INTO PA...AND MORE INTO WRN NY.

UNSEASONABLY WARM TEMPERATURES ARE ON TAP FOR TUES AS DEEP MIXING
AND 8H TEMPS AROUND 13C ALLOW FOR HIGHS WELL INTO THE 70S IN MOST
PLACES. THE NORTHERN HILL TOPS WILL ALSO REACH RIGHT AROUND 70F.
MINS WED AM MORE THAN 10F ABOVE NORMAL WITH LOTS OF CLOUD COVER AT
FIRST AND A NOT-SO-COLD INTRUSION ON WSW WINDS POST-FRONT. MAXES
ON WED SHOULD BE PRETTY NORMAL.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
SLOW MOVING COLD FRONT TRACKS SOUTHEAST OF THE COMMONWEALTH ON
WEDNESDAY...WITH SHOWERS CLEARING THE LOWER SUSQ RIVER VALLEY BY
MID AFTERNOON. 850 MB TEMPS DROP BELOW ZERO OVER THE NORTHWEST
MOUNTAINS WEDNESDAY NIGHT INTO THURSDAY...WITH AN OUTSIDE SHOT AT
A FEW FLURRIES OR SPRINKLES AT THAT TIME.

MODEL CONSENSUS IS STILL ON TRACK FOR A QUICK MOVING CLIPPER
SYSTEM DROPPING FROM CENTRAL CANADA THROUGH THE WESTERN GREAT
LAKES AND ACROSS WESTERN AND CENTRAL PA ON FRIDAY...DELIVERING A
POTENT SHOT OF COLD AIR FOR FRIDAY NIGHT AND SATURDAY...AND
PERHAPS THE FIRST MEASURABLE SNOWFALL FOR A GOOD PART OF CENTRAL
ADN WESTERN PA. CONSENSUS WOULD BRING A CHANCE OF RAIN OR SHOWERS
TO WESTERN PA ON FRIDAY...AS FRONTAL SYSTEM AND ASSOCIATED LOW
PRESSURE SLOWLY DEEPEN WHILE TRACKING TOWARDS THE NORTHERN MID
ATLANTIC COAST. COLDER AIR ON THE BACKSIDE WOULD CHANGE MIXED RAIN
AND SNOW SHOWERS TO A PERIOD OF SNOW SHOWERS LATE FRIDAY NIGHT
INTO SATURDAY WEST AND NORTH...FOLLOWED BY BLUSTERY AND MUCH
COLDER CONDITIONS SATURDAY WITH LAKE EFFECT FLURRIES AND SNOW
SHOWERS WEST AND NORTH...AS 850 MB TEMPERATURES PLUMMET AS COLD AS
-8C TO -10C.

ALTHOUGH CONSIDERABLE UNCERTAINTY EXISTS REGARDING TIMING AND TEMPERATURES...
HAVE LEFT A CHANCE OF RAIN/SNOW MIX THROUGH THIS TIME-FRAME WITH
LITTLE TO NO ACCUMULATION.

HIGH PRESSURE BUILDS OVER CENTRAL PA SUNDAY AND SUNDAY NIGHT
PROVIDING DIMINISHING WIND AND MODERATING CONDITIONS BY MONDAY IN
RETURN SOUTHWEST FLOW.

&&

.AVIATION /22Z MONDAY THROUGH SATURDAY/...
HIGH CONFIDENCE IN VFR CONDITIONS PREVAILING THROUGH THROUGH
TUESDAY AFTERNOON/18Z. NO SIG WX CONCERNS AS HIGH PRESSURE SLIDES
OFF THE MID ATLC COAST.

SFC WINDS FROM 200-240 DEG WILL INCREASE BY TUESDAY AFTERNOON
AHEAD OF AN APPROACHING COLD FRONT...WITH GUSTS IN THE 20-25KT
RANGE EXPECTED OVER THE WESTERN TAF SITES. LAYERED MID TO HIGH
CLOUDS WILL GRADUALLY INCREASE INTO TUESDAY EVENING.

THE COLD FRONT SHOULD BE ACCOMPANIED BY A BAND OF GUSTY SHOWERS
AND POSSIBLY SOME SCT LOW-TOPPED TSTMS REACHING FAR WRN/NWRN PA
AROUND 00Z WED. LOW CONFIDENCE IN TSRA IMPACTS AT BFD/JST ATTM.

AS THE FRONT SHIFTS EWD THROUGH WEDNESDAY AFTERNOON/18Z:
LIMITED/BRIEF RESTRICTIONS TO CEILINGS AND VISIBILITY ARE LKLY
WITH A PERIOD OF SHOWERS. MAIN PERIOD OF RAIN SHOULD BE FROM
00-12Z WITH SHOWERS ENDING IN THE EAST BY THE AFTN. MEDIUM TO
HIGH CONFIDENCE IN TIMING AND WX ALONG AND AHEAD OF THIS FRONT.

POST FRONTAL LOW CIGS AND LAKE EFFECT SHWRS APPEAR LIKELY INTO
WEDNESDAY NIGHT OVER WESTERN TAFS BFD AND JST.

OUTLOOK...
THUR...MVFR CIGS WEST/VFR EAST.

FRI...VFR/MVFR EARLY WITH SHOWERS POSS WEST...BCMG MVFR/IFR FRI
NGT WITH NW WIND GUSTS 20-30 MPH AND RA/SN SHOWERS.

SAT...MVFR/IFR WITH SCATTERED SNOW SHOWERS WEST. VARYING VFR-
MVFR CONDS CENTRAL/EAST WITH OCNL -SHSN AND FLURRIES. NW WIND
GUSTS 25-35 MPH.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...DEVOIR
AVIATION...LAMBERT/STEINBUGL



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