Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 280036 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 836 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 /01Z TUESDAY THROUGH SATURDAY/...
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HIGH CONFIDENCE IN VFR CONDITIONS PREVAILING THROUGH TUESDAY AFTERNOON/18-21Z. NO SIG WX CONCERNS AS HIGH PRESSURE SLIDES OFF THE MID ATLC COAST. ADDED MARGINAL LLWS TO WRN/CNTRL TAFS WITH THE 28/00Z SCHEDULED ISSUANCE. LOW PRESSURE OVER WI WILL DEVELOP NNEWD AND REACH NERN ONTARIO BY TUESDAY EVENING/00Z WED. SFC WINDS FROM 200-240 DEG WILL INCREASE INTO TUESDAY AFTERNOON AHEAD OF THE TRAILING COLD FRONT PUSHING THROUGH THE GREAT LAKES/OHIO VALLEY...WITH GUSTS IN THE 20-25KT RANGE EXPECTED OVER THE WESTERN TAF SITES. LAYERED MID TO HIGH CLOUDS WILL GRADUALLY INCREASE INTO TUESDAY EVENING WITH CIGS REMAINING AOA 10KFT AGL. THE COLD FRONT SHOULD BE ACCOMPANIED BY A BAND OF GUSTY SHOWERS AND POSSIBLY SOME SCT LOW-TOPPED TSTMS REACHING THE WRN 1/3 OF THE AIRSPACE BY LATE TUESDAY EVE/00-03Z. LOW CONFIDENCE IN TSRA IMPACTS AT BFD/JST. AS THE FRONT SHIFTS EWD TUESDAY NIGHT THROUGH EARLY WEDNESDAY: EXPECT LIMITED/BRIEF RESTRICTIONS TO CEILINGS AND VISIBILITY WITH A PERIOD OF SHOWERS. THE MAIN PERIOD OF RAIN SHOULD BE FROM 00-12Z WITH SHOWERS ENDING IN THE EAST BY WED AFTN. MEDIUM TO HIGH CONFIDENCE IN TIMING AND WX ALONG AND AHEAD OF THIS FRONT. POST FRONTAL NW FLOW SHOULD YIELD LOW CIGS AND SCT LAKE EFFECT/UPSLOPE SHOWERS 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.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/LAMBERT NEAR TERM...LA CORTE/LAMBERT SHORT TERM...LAMBERT LONG TERM...DEVOIR AVIATION...STEINBUGL

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