Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 140401 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1101 PM EST SAT FEB 13 2016 .SYNOPSIS... A STRONG BUT QUICKLY-MOVING SURFACE HIGH WILL MOVE ACROSS THE REGION TONIGHT AND SUNDAY. A STORM SYSTEM WILL BEGIN FORM TO THE SOUTH OF THE STATE ON MONDAY. A WINTRY MIX AND PERHAPS PLAIN RAIN WILL OCCUR AFTER AN INITIAL PERIOD OF SNOW. THE LOW PRESSURE CENTER SHOULD PASS OVER EASTERN PA ON TUESDAY. LATER IN THE WEEK...A RIDGE OF HIGH PRESSURE MOVES IN ALOFT WITH MUCH WARMER AIR FOR LATE IN THE WEEK. && .NEAR TERM /UNTIL 8 AM SUNDAY MORNING/... 10 PM UPDATE... A FEW DISTINCT SNOW BANDS ARE LEFT OVER THE AREA WITH A VERY PERSISTENT PAIR. BUT THEY ALL LOOK LIKE THEY WILL MIGRATE SLOWLY TO THE SOUTH THROUGH THE NEXT FEW HOURS AS THE FLOW VEERS. ANY ACCUMULATIONS WILL BE LIGHT...AND THE NARROW-NESS OF THE BANDS WILL MAKE IT HIGHLY LOCALIZED. TEMPS ALREADY BELOW ZERO IN THE NORTH AND TEMPS ON TRACK TO HIT FCST LOWS. WINDS DO NOT GO SLACK...SO THE MIXING WILL KEEP THE TEMPS FROM GOING TOO LOW. THE WIND CHILL ADVY/WARN LOOK WELL PLACED AND TIMED. THE WIND SHOULD BECOME EVEN LIGHTER THROUGH THE DAY FROM W-E AND ALLOW THE WC FLAGS TO DIE ON SCHEDULE. 8 PM UPDATE... SNOW BANDS CONTINUE RUNNING NW-SE THRU THE AREA. INTERESTING TO NOTE THAT THE HRRR AND RAP BOTH MAKE THE LONG BAND THRU THE CENTRAL MTNS REACH DOWN INTO LEBANON AND LANCASTER COUNTIES ON THE BERKS BORDER. THIS IS VERY NEARLY THE LOCATION OF THE BIG ACCIDENT EARLIER TODAY. THE SHSN DO APPEAR TO DISSIPATE BY MIDNIGHT...THO. WILL KEEP POPS IN FOR MOST PLACE FOR THE TIME BEING BUT CALL ADDTNL ACCUMS LESS THAN AN INCH EVERYWHERE. PREV... OVERNIGHT THE MASSIVE SURFACE HIGH MOVES IN SHOULD BE OVERHEAD BY SUNDAY MORNING. THIS WILL LOWER THE INVERSION HEIGHT...SHUTTING OFF THE SNOW SHOWERS THIS EVENING AND EARLY TONIGHT AND SHUTTING DOWN THE WINDS. THE LIGHT WINDS BEFORE SUNRISE COULD SQUEEZE OUT A FEW MORE DEGREES OF RADIATIONAL COOLING. GOING TO BE A VERY COLD MORNING. MANY LOCATIONS WILL LIKELY HAVE THEIR COLDEST OVERNIGHT LOW OF THE SEASON. && .SHORT TERM /8 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... HIGH PRESSURE IN CONTROL. WINDS SLACKEN AND TEMPS ONLY AS MILD AS SAT...BUT SHOULD FEEL BETTER. THE HIGH MOVES RAPIDLY TO THE EAST LATE SUNDAY NIGHT. EARLY RADIATIONAL COOLING SHOULD DROP TEMPERATURES OFF FAST SUNDAY EVENING. BUT RETURN FLOW COULD CAUSE TEMPERATURES TO BEGIN TO SLOWLY RISE SUNDAY NIGHT INTO MONDAY MORNING. GOING TO BE INTERESTING MONDAY-TUESDAY WEATHER! && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... *IMPACT WEATHER HIGHLIGHTS: POTENTIAL WINTER STORM EARLY NEXT WEEK. DID NOT CHANGE MUCH FOR MONDAY...TUE FRAME. MAIN THING WAS TO INSERT SOME ZR INTO THE GRIDS AFTER 00Z TUE...THROUGH LATE TUESDAY MORNING. BASED ON WPC GRAPHICS. ALSO DID UP POPS SOME. DID NOT DO A LOT WITH SNOW AMTS SO FAR. MAY ADJUST MORE LATER. EC MAY BE TO FAR WEST...BUT EITHER WAY...EXPECT SOME SNOW TO PILE UP ACROSS SOUTH CENTRAL PA BY LATE MONDAY AFT...ABOUT 1 TO 2 INCHES...AS SYSTEM LIFTS NE FAST...AND WARM ADVECTION WAITS FOR NO MAN. MORE DETAIL BELOW. CLOUDS AND POTENTIAL LIGHT SNOW COULD ARRIVE IN SOUTHWESTERN AREAS MONDAY MORNING AS INDICATED IN SOME ENSEMBLE FORECASTS. BULK OF MED RANGE GUIDANCE INDICATES THE LIKELIHOOD OF SOME LGT SNOW ARRIVING MONDAY...AS SFC HIGH DRIFTS OFF THE COAST AND MILDER SOUTHERLY FLOW OVERRUNS RETREATING ARCTIC AIR MASS. HOWEVER...THE BIGGER CONCERN INVOLVES DIGGING UPPER TROF OVR THE MISS VALLEY AND ASSOC SFC LOW PRESSURE LIFTING UP THE APPALACHIANS. MDL SPREAD CONTINUES TO NARROW...WITH MOST RUNS TRACKING SFC LOW ACROSS EASTERN PA TUESDAY. THIS TRACK WOULD CERTAINLY FAVOR RAIN ACROSS EASTERN PA AND RAIN OR SNOW ACROSS WESTERN PA. GIVEN INHERENT MDL UNCERTAINTIES THIS FAR OUT...WILL MAINTAIN RAIN/SNOW IN THE FCST FOR MOST OF CENTRAL PA MON NIGHT-TUES. HAVE RAISED POPS INTO THE LIKELY CATEGORY BASED ON CONVERGING MDL SOLUTIONS. WILL ALSO HAVE TO WATCH FOR THE POSSIBILITY OF FLOODING ACROSS EASTERN PA...GIVEN RAINFALL AND SNOWMELT POTENTIAL. LATEST MDL ENSEMBLE RIVER FORECASTS USING NAEFS SUGGESTS MINOR FLOODING IS A POSSIBILITY ACROSS THE LOWER SUSQ VALLEY BY TUES. WPC ALSO HAS HIGHLIGHTED SE PA FOR A SLIGHT RISK OF FLOODING TUESDAY. EXPECT BULK OF PCPN TO BE OUT OF THE AREA BY LATE TUE AM. ANOTHER COLD FRONT WED. DID UP POPS SOME ACROSS THE WEST. MOISTURE IS LIMITED. NOT A BAD DAY FOR THU OR FRI...AS HIGH PRESSURE BUILDS INTO THE AREA. PERHAPS A FEW RAIN AND SNOW SHOWERS FOR LATE IN THE WEEK WITH THE NEXT COLD FRONT. NEAR TO ABOVE NORMAL TEMPS APPEAR LIKELY LATER NEXT WEEK...AS HEIGHTS ARE FORECAST TO RISE AND A LOW PRESSURE SYSTEM LIFTS THROUGH THE GREAT LAKES TO THE WEST OF PA. && .AVIATION /04Z SUNDAY THROUGH THURSDAY/...
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ARCTIC AIR HAS BROUGHT COLD TEMPERATURES AND STRONG GUSTY WINDS TO THE REGION. SNOW SQUALLS ARE COMMON IN THE WESTERN MOUNTAINS WITH IMPACTS ON KJST AND KBFD. A BAND OF SHOWERS OVER CENTRAL PA HAS BROUGHT ONLY MVFR CIGS AND VSBYS TO UNV...SO WILL LEAVE A BRIEF TEMPO THROUGH 08Z...AS MODELS HAVE MOST SHOWERS OUTSIDE OF THE NW MTNS FADING BY 09Z. AS THE THERMAL PROFILE IS ADIABATICALLY NEUTRAL EXPECT ANY GUSTY WINDS ALOFT TO FILTER TO THE SURFACE. SO SNOW AND BLOWING SNOW IS POSSIBLE WITH THE STRONG GUSTY WINDS. GOOD GUST SPREADS TOO WHICH AFFECT TAKEOFF/LANDINGS. GUSTS OVER 30KTS HAVE BEEN OBSERVED. BFD AND JST WILL SEE IFR CIGS AND VSBYS CONTINUING UNTIL AROUND 09Z AS THE TROUGH LIFTS TO THE NORTHEAST THE WINDS WILL SHIFT TO THE NORTH AND DIMINISH. THIS WILL END THE GUSTS AND CEASE MOST BLOWING SNOW...ALSO CUTTING OFF MOST LAKE EFFECT AND TOPOGRAPHIC ENHANCEMENTS. THERE SHOULD THEN BE IMPROVED CONDITIONS. THINGS SHOULD BE MUCH NICER SUNDAY...THOUGH A TAD COLD WITH TEMPERATURES WELL BELOW NORMAL. HIGH PRESSURE SUNDAY DRIFTS EAST OVERNIGHT SO THE PERIOD OF NICE WEATHER WITH VFR WILL BE SHORT LIVED AS CLOUDS AND POTENTIAL PRECIPITATION MOVE IN FOR MONDAY AND INTO TUESDAY. SNOW AND ASSORTED WINTRY PRECIPITATION WILL LIKELY AFFECT FLYING MONDAY INTO TUESDAY. OUTLOOK... SUN...NO SIG WX EXPECTED MAINLY VFR. MON...WIDESPREAD RESTRICTIONS DEVELOP WITH SNOW DEVELOPING. MON NIGHT AND TUE...SNOW LIKELY WRN HALF OF PENN...WITH RAIN AND/OR SNOW IN THE SE. WIDESPREAD RESTRICTIONS SET IN. LLWS POSS SE. WED...ANOTHER WAVE SLIDES THROUGH KEEPING RESTRICTIONS IN PLACE ALONG WITH POTENTIAL FOR LIGHT SNOW...ESP OVER THE WEST. THU...MAINLY VFR.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... WIND CHILL WARNING UNTIL 11 AM EST SUNDAY FOR PAZ004>006-037- 041-042. WIND CHILL ADVISORY UNTIL 11 AM EST SUNDAY FOR PAZ010>012- 017>019-024>028-033>036-045-046-049>053-056>059-063>066. && $$ SYNOPSIS...GRUMM NEAR TERM...GRUMM/DANGELO SHORT TERM...GRUMM LONG TERM...FITZGERALD/GARTNER/MARTIN AVIATION...CERU/MARTIN

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