Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 221820 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 220 PM EDT TUE APR 22 2014 .SYNOPSIS... A COLD FRONT WILL CLEAR CENTRAL PENNSYLVANIA THIS EVENING...ENDING ANY LINGERING SHOWER OR THUNDERSTORM ACTIVITY BY EARLY TO MID EVENING. MUCH COLDER AIR WILL WORK INTO THE COMMONWEALTH LATER TONIGHT AND WEDNESDAY...WITH LAKE EFFECT SNOW SHOWERS OVER THE NORTHWEST AND WEST CENTRAL MOUNTAINS AND FLURRIES POSSIBLE OVER THE REST OF THE CENTRAL AND NORTHERN MOUNTAINS. COOL AND DRY WEATHER IS EXPECTED TO CONTINUE THURSDAY...AS A RIDGE OF HIGH PRESSURE SLIDES OVER THE AREA. THE NEXT COLD FRONT AND CHANCE FOR SHOWERS WILL ARRIVE ON FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... PRE-FRONTAL TROF AND SHOWER BAND PASSED WESTERN AND CENTRAL PA WITHOUT MUCH FANFARE...BUT COLD FRONT IS NOW PRESSING ESE INTO NORTHWEST AND WEST CENTRAL MOUNTAINS. ISOLATED LIGHTNING STRIKES ACCOMPANY THE SMALL STORMS...AND GUSTY WINDS TO 30 MPH AND EVEN SOME SMALL HAIL ARE POSSIBLE...AS MUCAPES OF 300-400 J/KG ARE REALIZED. STILL NOT ANTICIPATING ANY SEVERE AT THIS TIME. MUCH COLDER AIR DIVES INTO WEST CENTRAL PA BY 00Z WED...WITH 850 MB READINGS PLUNGING BELOW ZERO. GUSTY POST-FRONTAL WNW FLOW WILL INCREASE THROUGH WEDNESDAY AND HELP DIRECT AN ABNORMALLY COOL CANADIAN AIRMASS INTO THE AREA WHICH WILL LAST THROUGH THURSDAY MORNING. WELL ALIGNED NW FLOW WILL COMBINE WITH 850 MB TEMPS FALLING TO AROUND -3 TO -4C TONIGHT TO BRING SCATTERED SNOW SHOWERS TO THE NW MTNS AND LAURELS OVERNIGHT TONIGHT...WITH A LIGHT COATING POSSIBLE AT ELEVATIONS GENERALLY AOA 1500 FT MSL. A FEW FLURRIES WILL LIKELY SPILL OFF THE ALLEGHENY FRONT AND INTO THE CENTRAL RIDGE AND VALLEY REGION AFTER MIDNIGHT TONIGHT. LOW TEMPS TONIGHT WILL VARY FROM THE LOWER TO MID 30S ACROSS THE MOUNTAINS...TO BETWEEN 40-45F THROUGHOUT THE SUSQ VALLEY. && .SHORT TERM /WEDNESDAY/... STRATOCU WILL LINGER ACROSS THE NRN AND WESTERN MTNS FOR WEDNESDAY WITH SCATTERED MAINLY MORNING SNOW SHOWERS /MIXED WITH RAIN IN THE VALLEYS/...WHILE MOSTLY SUNNY SKIES DEVELOP ACROSS THE LOWER SUSQ VALLEY. VRBL AMOUNTS OF STRATO CU WILL OCCUR ACROSS THE CENTRAL RIDGE AND VALLEY REGION. IT WILL BE BREEZY TO LOCALLY WINDY WITH SUSTAINED WINDS OF 12 TO 18 MPH AND GUSTS TO 30 MPH IN THE AFTERNOON. HIGH TEMPS ON WEDNESDAY /IN THE MID AND UPPER 40S ACROSS THE NW MTNS AND LAURELS...AND UPPER 50S TO AROUND 60 IN THE SE/ WILL AVG 5-10 DEGREES BELOW NORMAL. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... SFC LOW WILL DEEPEN INTO THE CANADIAN MARITIMES THROUGH DAY 3/WED...AS THE PARENT UPPER LEVEL TROUGH AMPLIFIES SEWD ACROSS THE NORTHEASTERN CONUS AND EVENTUALLY CLOSES-OFF NEAR THE GULF OF MAINE/SOUTH OF NOVA SCOTIA BY 12Z THURS. THIS SHOULD MARK THE BEGINNING OF A LARGER SCALE PATTERN TRANSITION FROM MODERATELY PROGRESSIVE TO A BLOCKY/SLOWER-EVOLVING REGIME BY THE WEEKEND AND INTO EARLY NEXT WEEK. SFC HIGH PRES RIDGE AXIS WILL CROSS THE AREA ON THURSDAY. AT THIS TIME IT APPEARS THAT THERE WILL BE ENOUGH OF A PRES GRADIENT AND NW WIND TO PREVENT FROST/FREEZE HEADLINES FOR THE LOWER SUSQ. VALLEY THURSDAY MORNING. TEMPS WILL GRADUALLY REBOUND DURING THE DAY THURSDAY. THERE IS DECENT MODEL/ENSEMBLE AGREEMENT IN A SHORTWAVE TROUGH AND SFC LOW PRESSURE TRACKING THROUGH THE GREAT LAKES REGION BY THE END OF THE WEEK...WITH THE NEXT COLD FRONT FCST TO ARRIVE ON FRIDAY ACCOMPANIED BY THE CHC FOR SHOWERS. THERE IS INCREASING SPREAD IN THE GUIDANCE FOR THE WEEKEND AND INTO EARLY NEXT WEEK WITH HINTS OF A REX BLOCK DEVELOPING OVER THE CENTRAL NOAM AND MEAN TROUGH LINGERING OVER SERN CANADA AND PERHAPS THE NERN US. THE 21/12Z GFS ARE STRONGLY IN FAVOR OF THIS EVOLUTION WHILE THE 21/00Z ECMWF AND 21/12Z GEFS ARE NOT QUITE AS AMPLIFIED WITH TROUGHING OVER SERN CANADA/NERN US. DUE TO THE VARIABILITY IN THE GUIDANCE...OPTED FOR A CONSENSUS BLEND FOR MAX/MIN/POP WHICH RESULTED IN NEAR NORMAL TEMPS AND RELATIVELY LOW PROBS FOR RAIN. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... A STRONG COLD FRONT WILL PUSH EAST ACROSS THE STATE DURING THE MID TO LATE AFTERNOON. ISOLATED THUNDER WILL ACCOMPANY THE FRONT... WITH WINDS TURNING TO THE NW AS THEY INCREASE AND BECOME GUSTY. BEHIND THE FRONT...CIGS WILL REMAIN LOW THROUGH MID TO LATE EVENING. MVFR/IFR CONTINUES INTO WED IN WEST AND NORTH...WITH A BREEZY NW WIND. OUTLOOK... TONIGHT-WED...MVFR NORTH/WEST WITH SCT -SHRA...VFR ELSEWHERE. BREEZY NW WINDS. THU...VFR. NO SIG WX. FRI...MVFR WITH CHC SHRA. SAT-SUN. && .FIRE WEATHER...
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MIN RHS DROP TO THE UPPER 20S ACROSS PORTIONS OF THE SOUTH CENTRAL MOUNTAINS AND LOWER SUSQ RIVER VALLEY WEDNESDAY AFTERNOON. WNW WINDS OF 12 TO 18 MPH WITH GUSTS TO 30 MPH ARE EXPECTED ALONG WITH FINE FUEL MOISTURES IN THE UPPER SINGLE DIGIT PERCENTILES. THROUGH COLLABORATION WITH BOF OFFICIALS AND SURROUNDING NWS OFFICES...HAVE ISSUED FIRE WEATHER WATCH FROM 15Z WED TO 00Z THU FROM BEDFORD COUNTY EASTWARD TO LANCASTER COUNTY AND NORTHWARD TO PERRY...DAUPHIN AND LEBANON COUNTIES ON WEDNESDAY.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY EVENING FOR PAZ034>036-056-057-059-063>066. && $$ SYNOPSIS...DEVOIR NEAR TERM...DEVOIR SHORT TERM...DEVOIR LONG TERM...LAMBERT/STEINBUGL AVIATION...DEVOIR/RXR FIRE WEATHER...DEVOIR

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