Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 262256 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 556 PM EST MON JAN 26 2015 .SYNOPSIS... PERIODS OF LIGHT SNOW WILL DECREASE ACROSS CENTRAL PENNSYLVANIA TONIGHT AS A STRONG COASTAL STORM TRACKS TOWARDS NEW ENGLAND TONIGHT. THE COASTAL STORM WILL RAPIDLY INTENSIFY TONIGHT AND TUESDAY...AS IT TRACKS EAST OF NEW ENGLAND. HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE MIDDLE OF THE WEEK...FOLLOWED BY AN ALBERTA CLIPPER THURSDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 600 PM UPDATE... EXTENDED THE ADVY FOR THOSE MIDDLE SUSQ COUNTIES THRU 11 PM...AS SNOW IS STILL FALLING AND IS NOT TAPERING OFF AS QUICKLY AS 4KM NAM/RAP/HRRR HAD PORTRAYED. MDLS CONTINUE TO INDICATE THAT THIS IS THE FIRST AREA OF THE CWA WHICH WILL HAVE THE SNOW DROP TO NOTHING. SNOW HAS RE-ENTERED/DEVELOPED OVER THE SE AND CURRENT NUMBERS STILL LOOK GOOD OVER THE WHOLE REGION. PREV... ADDED TIOGA CO TO THE ADVY AS SNOW SHOULD CONTINUE TO FALL THERE FOR ANOTHER FEW HRS AND THEY ARE ALREADY PUSHING 3-5 INCHES OF SNOW OFF THEIR CARS. HOWEVER...THE RAP AND HRRR BOTH SLIDE THE BIG BAND OFF TO THE WEST /NOT EAST/ SLIGHTLY - SO LESSER CHANCE FOR SULLIVAN CO PA TO GET TOO MUCH MORE. JUST UPPED POPS SLIGHTLY TO JUST BELOW 101 PERCENT IN THE CENTRAL AND WEST. PREV... DEFORMATION BETWEEN THE INVERTED SFC TROF OVER WESTERN AND SOUTHWESTERN PA AND RAPIDLY DEVELOPING COASTAL LOW OFF OF SOUTHEAST VA IS MAINTAINING CATEGORICAL POPS/SNOW ACROSS THE LAURELS AND CENTRAL/WEST CENTRAL/NORTHWEST/NORTHERN MOUNTAINS PRESENTLY. MY SOUTHEAST COUNTIES HAVE STARTED TO SEE SOME LIGHT ACTIVITY BUT IT IS STILL REMOVED FROM THE BETTER DEFORMATION ASSOCIATED WITH THE INVERTED TROF TO THE WEST AND THE INTENSIFYING LOW TO THE EAST. LOWERED THE LOWER END OF SNOW FAR RANGES FOR THE EAST IN WSW...GENERALLY 2 TO 5 INCHES EXPECTED OVERALL BEFORE ACCUM SNOWFALL EXITS PA BY DAYBREAK TUE MORNING. OVERALL HOWEVER...WIDESPREAD LIGHT SNOW WILL CONTINUE TO FALL OVR CENTRAL PA THIS EVENING INTO LATE TONIGHT ALONG THE AXIS OF DEEP EASTERLY FLOW BTWN LOW TO THE SOUTH AND HIGH PRES OVR NEW ENGLAND...FORCED LOCALLY BY THE INCREASING AFOREMENTIONED DEFORMATION. HI RES NAM/HRRR/WRF ARW ALL SUPPORT AN ADDITIONAL 1-3 INCHES TODAY...WITH THE HIGHEST AMTS ACROSS THE CENTRAL MTNS/ALLEGHENIES. KEEPING HEADLINES AS IS FOR NOW BUT SOME MAY NEED TO BE EXTENDED OVERNIGHT DEPENDING UPON WHERE THE DEFORMATION PROPOGATES. HRRR INDICATES A SOUTHWEST SHIFT TO THE FORCING AFTER 03Z...AS THE PARENT COASTAL CIRCULATION DOMINATES AND TAKES OVER EFFECTIVELY DISRUPTING AND ELIMINATING THE DEFORMATION FORCING SNOWFALL OVER CENTRAL PA BY 12Z. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... AS MENTIONED ABOVE...DEFORMATION SNOW SHOWERS SHOULD DWINDLE EARLY TUESDAY...WHILE NNW FLOW IN WAKE OF DEPARTING COASTAL LOW DRAWS MUCH DRIER AIR INTO CENTRAL PA. 25 TO 35KT NE WIND GUSTS WILL BE FELT AS TIGHT PRES GRADIENT IS REALIZED IN WAKE OF STORM JUST OFFSHORE OF SOUTHERN NEW ENGLAND COAST. AS PREVIOUSLY MENTIONED...THERE IS THE POTENTIAL OF SOME BLOWING/DRIFTING...ESP EASTERN PA WHERE BUKFIT SOUNDINGS SUPPORT GUSTS BTWN 30-35KTS. ENS MEAN 925 TEMPS SUPPORT MAX TEMPS TUE FROM NR 20F OVR THE N MTNS...TO ARND 32F ACROSS THE LOWER SUSQ VALLEY. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... DEEP STORM WILL PULL AWAY FROM PA TUESDAY NIGHT. WITH WINDS FROM THE NORTH...TOOK OUT SNOW SHOWERS FOR JST. SKIES SHOULD CLEAR OUT BY WED MORNING. MAIN CHANGE WAS WED NIGHT...DID LOWER TEMPS...BASED ON 12Z MODEL RUNS...AND THAT WITH MAINLY CLEAR SKIES AND LIGHT WINDS...EXPECT TEMPS TO DROP...WITH FRESH SNOW COVER. NEXT SYSTEM WILL BRING SOME SNOW SHOWERS TO THE AREA LATER THU INTO FRIDAY. THIS SYSTEM NOT LOOKING LIKE IT WOULD RESULT IN A COASTAL REAL NEAR THE COAST. COLDER AIR FOR FRIDAY NIGHT. WEEKEND NOT LOOKING TOO BAD...COLDER AIR WILL TRY TO BUILD IN EARLY NEXT WEEK. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... SENT OUT MORE ADJUSTMENTS AT 22Z. NW TO SE BANDS OF SNOW STILL LIFTING NORTHWARD FROM NEAR BWI. EARLIER DISCUSSION BELOW. REDUCTIONS CONTINUE REGIONWIDE AS INVERTED TROUGH LINGERS OVER CENTRAL PA /AND AS DEVELOPING NOR`EASTER BEGINS TO DEEPEN OFF MID ATLANTIC COAST/. EXPECT WIDESPREAD LIGHT SNOW TO CONTINUE THIS INTO TONIGHT WITH VSBYS VARYING FROM 1-4SM AND CIGS OF MVFR- IFR SETTLING BACK TOWARD A MORE ROBUST IFR DECK. NE WINDS WILL BE AROUND 10 MPH TODAY...AND PICK UP A BIT TO 10-15 MPH IN THE LOWER SUSQ TONIGHT AS STORM DEEPENS TO THE EAST AND SYNOPTIC FLOW INCREASES. IMPROVING CONDITIONS ON TUES AS HIGH PRESSURE BUILDS IN. SHOULD SEE VFR CONDITIONS IN CENTRAL AND EAST...WITH MVFR CIGS IN NW FLOW UNDER SUBSIDENCE INVERSION IN THE WESTERN HIGHER TERRAIN. NORTH WIND WILL BE BREEZY...PRODUCING SPEEDS OF 10-20 MPH. OUTLOOK... WED...VFR WITH NO SIG WEATHER EXPECTED. THU...VFR TO START...WITH LATE DAY RESTRICTIONS SPREADING IN FROM THE WEST. THU NIGHT-FRI...WIDESPREAD IFR/MVFR IN SNOW. SAT...MAINLY VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR PAZ004>006- 010>012-017>019-024>026-033>036-045-058-059-064>066. WINTER WEATHER ADVISORY UNTIL 11 PM EST THIS EVENING FOR PAZ027-028-037-041-046-049>053-056-057-063. && $$ SYNOPSIS...DEVOIR/FITZGERALD NEAR TERM...DANGELO/DEVOIR/FITZGERALD SHORT TERM...DEVOIR/FITZGERALD LONG TERM...MARTIN AVIATION...DEVOIR/MARTIN

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