Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 182011 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 411 PM EDT SAT OCT 18 2014 .SYNOPSIS... A STRONG COLD FRONT WILL PUSH EAST OF THE STATE TONIGHT...USHERING IN THE COLDEST AIR OF THE SEASON SO FAR. HIGH PRESSURE WILL MOVE IN FOR SUNDAY AND MONDAY BEFORE A STRONG UPPER TROUGH AND ASSOCIATED SURFACE LOW DIGS SOUTHEAST ACROSS THE GREAT LAKES AND REACHES THE MID ATLANTIC COAST BY EARLY WED. THIS SLOW MOVING WEATHER FEATURE WILL BRING AN EXTENDED PERIOD OF UNSETTLED WEATHER TO THE REGION FOR THE MIDWEEK WITH SHOWERS AT BEST...AND A CHILLY STEADY RAIN FOR 24 TO 36 HOURS AT WORST. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... SFC COLD FRONT NEAR A KBGM...TO KSEG AND KMRB LINE AT 18Z WITH A FEW DEG F TEMP DROP IMMEDIATELY IN ITS WAKE ACROSS THE CENTRAL RIDGE AND VALLEY REGION. BKN AND GENERALLY HIGH-BASED STRATO CU WILL CONTINUE TO BLANKET THE CENTRAL RIDGE AND VALLEY REGION WITH OCNL SPRINKLES AND JUST A FEW STRAY RAIN SHOWERS THE REST OF THE DAY. THE NRN AND WESTERN MTNS WILL SEE FREQUENT SHOWERS AS THE COLD AIR DEEPENS THERE THROUGH THE REST OF THE AFTERNOON HOURS...AIDED BY OROGRAPHIC LIFT AND AN INJECTION OF MOISTURE OFF THE GLAKES. QPF THROUGH TONIGHT WILL VARY FROM SEVERAL HUNDREDTHS TO ONE- TENTH OF AN INCH ACROSS THE WESTERN MTNS TO BASICALLY NOTHING ACROSS THE MID AND LOWER SUSQ VALLEY. DOWNSLOPE FLOW WILL KEEP TEMPS NEARLY STEADY IN THE U50S TO LOWER 60S ACROSS THE SUSQ VALLEY THROUGH 21Z...WHILE TEMPS IN THE LOWER TO MID 40S ACROSS THE WESTERN MTNS...AND LOWER TO MID 50S ACROSS THE CENTRAL MTNS FALL SLOWLY FROM HERE ON THROUGH DUSK. MEAN LLVL FLOW VEERS AROUND ABOUT 30 DEGREES TO 315 DEG TONIGHT AND WILL KEEP NUMEROUS...LAKE EFFECT BANDS OF RAIN SHOWERS /EVENTUALLY MIXING WITH THEN CHANGING TO SNOW SHOWERS LATE ACROSS THE WESTERN MTNS/. THE RELATIVELY LOW SUBSIDENCE INVERSION SHOULD KEEP THE SHOWER INTENSITY AND QPF ON THE LOW SIDE. ELEVATIONS AOA 2000FT MSL COULD SEE THE FIRST DUSTING OF SNOW VERY EARLY SUNDAY MORNING AS TEMPS SETTLE TO BETWEEN 30-32F INVOF KBFD AND KJST. LOW TEMPS ELSEWHERE OVERNIGHT /ACCOMPANIED BY A GUSTY WNW WIND/ WILL BE IN THE LOWER TO MID 30S. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... HIGH PRESSURE OVER THE MIDDLE OHIO RIVER VALLEY WILL NOSE NE INTO THE COMMONWEALTH BY LATE AFTERNOON. MORNING CLOUDS AND SOME LIGHT RAIN/SNOW SHOWERS ACROSS THE ALLEGHENIES WILL YIELD TO SLOW CLEARING FROM SE TO NW DURING THE MIDDAY AND AFTERNOON HOURS. A GUSTY NW WIND IN THE MORNING WILL SLOWLY SUBSIDE DURING THE DAY. HIGH TEMPS IN THE LOWER TO MID 40S ACROSS THE MTNS AND LOWER TO MID 50S IN THE SE WILL BE ABOUT 10F BELOW NORMAL. THE RIDGE OF HIGH PRESSURE WILL CROSS THE STATE SUNDAY NIGHT WITH AT LEAST A SVRL HOUR PERIOD OF MAINLY CLEAR SKIES AND LIGHT WIND ALLOWING TEMPS TO DROP WELL INTO THE 30S /WITH AT LEAST AREAS OF FROST THROUGHOUT THE COUNTIES OF CENTRAL AND SRN PENN THAT ARE STILL IN THE TAIL END OF THE GROWING SEASON/. SOME UNCERTAINTY REMAINS TO THE TIMING OF LATE NIGHT CLOUD COVER /AND PERHAPS A SLIGHT INCREASE IN WIND TO WEST-SOUTHWEST BREEZE OF 5-7 KTS/... SO WILL HOLD OFF ON ISSUING A FREEZE WATCH FOR SUNDAY NIGHT AT THIS POINT. A FROST ADVISORY APPEARS TO BE THE MORE LIKELY OUTCOME AND CAN MENTION THAT ASPECT IN THE HAZ WEATHER OUTLOOK. && .LONG TERM /MONDAY THROUGH SATURDAY/... ZONAL FLOW AT BASE OF VERY BROAD TROUGH WILL TRANSITION BRIEFLY TO SW FLOW AND WAA ON MONDAY AS NEXT WAVE SLIDES THROUGH THE GREAT LAKES. AFTER A CHILLY START...HIGHS WILL CLIMB INTO THE 50S WITH CLOUDS INCREASING THROUGH THE DAY. APPROACHING WAVE/COOL FRONT MAY KICK OFF SOME SCT SHOWERS IN THE NW LATER IN THE DAY...BUT OTHERWISE IT WILL BE DRY. LARGE RIDGE BUILDS OVER THE INTERMOUNTAIN WEST AND SW CANADA FOR MIDWEEK...AS AMPLIFYING SHORTWAVE TROUGH AND WEAK SURFACE REFLECTION SLIDE OVER PA...BEFORE CLOSING OFF INTO AN INTENSIFYING LOW PRESSURE AREA OFF THE NJ COAST WED AND THU /ONCE THE WEAK CLIPPER LOW OVER THE GREAT LAKES TRANSFERS ENERGY OFF THE COAST/. MODEL SOLUTIONS ARE VERY MUCH IN LINE WITH EACH OTHER...AND THIS WILL RESULT IN A RAINY/SHOWERY AND QUITE BREEZY MID/LATE WEEK UNTIL THIS LOW LIFTS TOWARD THE CANADIAN MARITIMES ON FRI. TEMPS WILL ALSO REMAIN BELOW NORMAL IN PERSISTENT NORTHERLY FLOW. RIDGE REMAINS IN PLACE TO OUR WEST HEADING INTO NEXT WEEKEND...WHICH WILL KEEP TROUGH IN PLACE OVER THE NORTHEAST. A BRIEF WARMING TREND POSS LATE WEEK BUT MODELS HINTING AT POTENTIAL FOR ANOTHER SHOT OF COLDER AIR FOR LATE WEEKEND AS BRISK NW FLOW CONTINUES. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... SFC COLD FRONT NEAR A KELM TO KUNV AND KAOO LINE AT 1530Z WILL PUSH TO A KAVP TO KMDT LINE BY 18Z. WIDESPREAD MVFR CIGS AND OCNL MVFR VSBYS WILL PERSIST ACROSS THE MTNS NEAR AND TO THE WEST OF A KJST TO KFIG AND KELZ LINE...WITH BRIEF IFR CONDITIONS IN HEAVIER RAIN SHOWERS THIS AFTERNOON AND EARLY THIS EVENING AS DEEPENING COLD AIR SPREADS INTO THAT REGION. MAINLY MVFR BKN-OVC STRATO CU WILL PERSIST ACROSS THE CENTRAL MTNS INVOF KAOO...KUNV AND KIPT WITH CLOUD BASES BETWEEN 2-3 KFT AGL. WEST TO NORTHWEST WINDS WILL INCREASE BEHIND THE CFRONT THIS AFTERNOON WITH GUSTS IN THE LOWER TO MID 20KT RANGE. IFR WRN MTNS AND MVFR CENTRAL ZONES WILL CONTINUE TONIGHT AS SHOWERS SHOULD SPREAD ACROSS THE CENTRAL TAF SITES THIS EVENING INTO SUNDAY MORNING. THE LOWER SUSQ VALLEY AIRFIELDS WILL STAY MAINLY VFR DURING THIS SAME PERIOD. WINDS SHOULD ONLY DECREASE BY ABOUT 5 KTS OR SO OVERNIGHT...STILL STAYING QUITE GUSTY FROM THE WNW AS THE COLD AIR DEEPENS. MVFR CIGS ACROSS THE NRN AND WESTERN MTNS IN THE MORNING WILL BECOME MAINLY VFR BY THE MID TO LATE AFTERNOON. VFR CONDITIONS EXPECTED ELSEWHERE. OUTLOOK... MON...NO SIG WX. TUE-THU...MVFR/SHOWERS AS A SLOW MOVING SYSTEM MOVES IN FROM THE GR LAKES. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...LAMBERT LONG TERM...RXR AVIATION...LAMBERT

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