Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 180224 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 924 PM EST WED DEC 17 2014 .SYNOPSIS... BRISK WESTERLY WINDS WILL USHER IN COLDER AIR ALONG WITH SCATTERED MAINLY MOUNTAIN SNOW SHOWERS THROUGH THE END OF THE WEEK. A WEAK LOW PRESSURE AREA IS EXPECTED TO MOVE WELL SOUTH OF THE REGION THIS WEEKEND. THERE ARE INDICATIONS THAT THE WEATHER PATTERN COULD TURN MORE UNSETTLED FOR NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... NO REAL CHANGES MADE WITH THIS UPDATE OTHER THAN SOME MINOR TEMPERATURE TWEAKS. BEST CHANCE OF SOW SHOWERS WILL BE OVER THE MORE TRADITIONAL HIGH TERRAIN AREAS OF THE WEST AND NORTH AS WE ESTABLISH A COLD WNW FLOW OVER THE REGION. HRRR SHOWS PRECIP REMAINING CONFINED TO MAINLY NWRN PA THROUGH THE OVERNIGHT AND LATEST OPERATIONAL GUIDANCE SUPPORTS THIS. WEST TO NW WINDS WILL AVERAGE 10-15 KTS WITH GUSTS IN THE 20S LATE TODAY THROUGH TONIGHT. LOW TEMPS AT DAYBREAK THURS WILL BE NEAR 20F ACROSS THE HIGHER TERRAIN OF THE NORTH AND WEST...AND IN THE MID TO UPPER 20S THROUGHOUT THE SUSQ VALLEY. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... COLD AIR WILL STAY IN PLACE ACROSS THE FCST AREA THURSDAY INTO FRIDAY. THURSDAY...WINDS AT THE SFC AND ALOFT WILL VEER JUST SLIGHTLY TO THE NORTHWEST. SPEEDS OF 10-15 MPH AND GUSTS INTO THE L20S ARE POSSIBLE OVER THE MOUNTAINS. LITTLE OF NO CHANGE IN THE BLANKET OF STRATUS AND STRATOCU CLOUDS IS EXPECTED THURSDAY AND THU NIGHT...AND THE RELATIVELY SHALLOW COLD AIR BLOWING OVER THE LOWER GLAKES WILL CREATE MORE SHSN ACROSS THE NRN AND WRN MTNS. ACCUMULATIONS WILL BE MINOR...AND CONFINED TO THE FAR NW AND VERY HIGHEST ELEVATIONS. AS STATED BY PREVIOUS SHIFTS NO MORE THAN 2 INCHES IS EXPECTED THROUGHOUT THE SNOWBELT OF NW WARREN COUNTY ON THE HIGH END...SO NO LES ADVISORIES PLANNED ATTM. GLIMPSES OF SUN MAY DEVELOP AGAIN ACROSS THE LOWER SUSQ...NUDGING TEMPS INTO THE LOWER 40S /NEAR NORMAL FOR MID DEC/. MAX TEMPS ACROSS THE NRN AND WRN MTNS WILL BE IN THE U20S TO L30S. SIMILAR TEMPS AND SKY COVER EXPECTED AGAIN FOR THU NIGHT WITH ISOLATED TO SCTD MTN SNOW SHOWERS. LITTLE IN THE WAY OF ADDITIONAL SNOW ACCUM IS EXPECTED THOUGH AS MOISTURE WILL CONTINUE TO BE QUITE SHALLOW WITH THE SUBSIDENCE INVERSION BASE AOB 5 KFT AGL. A FEW HIGHLY LOCALIZED AMOUNTS IN THE 2-3 INCH RANGE ARE POSSIBLE ACROSS THE FAVORED PERENNIAL SNOWBELT OF WARREN COUNTY DURING THE 24 HOUR PERIOD ENDING 12Z FRI. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... THE PATTERN WILL REMAIN SEASONABLY COLD AND BRISK THROUGH THE END OF THE WEEK. LARGE SCALE SUBSIDENCE ASSOCIATED WITH SURFACE HIGH MIGRATING EASTWARD FROM THE UPPER MIDWEST ACROSS ONTARIO/QUEBEC SHOULD BRING AN END TO NUISANCE/MINOR SNOW SHOWER ACTIVITY AND LINGERING FLURRIES OVER THE NW ALLEGHENIES BY FRI NGT. CLEAR SKIES AND CALM/LIGHT WINDS SHOULD ALLOW MIN TEMPS TO DIP INTO THE TEENS IN THE NORTHERN MTNS SATURDAY MORNING. CONCERNING THE WEEKEND SYSTEM... HOPES FOR A SIGNIFICANT STORM THIS WEEKEND CONTINUE TO FADE WITH THE LATEST MODELS CONTINUING TO SHOW A MUCH WEAKER/SUPPRESSED AND DISJOINTED SYSTEM AS THE CONSENSUS SOLUTION. IN ADDITION..THE RISK FOR ACCUMULATING LIGHT SNOW HAS ALSO NOTABLY DECREASED...BUT NOT TOTALLY EVAPORATED. THAT SAID THERE IS STILL A NON-TRIVIAL CHANCE THAT MOST PRECIP REMAINS SOUTH OF PA AND THE WEEKEND TURNS OUT DRY FOR MOST LOCATIONS. EARLY WEEK MODEL SIMULATIONS FOR A MAJOR STORM HAVE ALL BUT TRENDED TO A VIRTUAL NON EVENT FOR OUR AREA. THE PROGRESSIVE SPLIT STREAM ENERGY ALOFT MOVING EAST FROM THE MID MS VLY NEVER REALLY ORGANIZES AS IT ATTEMPTS TO OVERRUN A RETREATING AREA OF MODESTLY STRONG HP/RIDGING OVER THE NORTHEAST AND EASTERN CANADA. AS SUCH DOWNPLAYED PCPN POTENTIAL AND TRIMMED POPS BACK BY 10-20 PCT. THE NEW WRINKLE IN THIS FORECAST CYCLE IS FOR A SECOND PIECE OF ENERGY /WHAT APPEARS TO BE THE MAIN SFC LOW/ LIFTING NORTH FROM NEAR THE FL/GA COAST AND TRACKING UP/OFFSHORE THE EAST COAST SUN THRU TUE. THE SPLIT FLOW PATTERN OVER THE CONUS IS EXPECTED TO BECOME HIGHLY AMPLIFIED WITH A VERY DEEP NEGATIVELY TILTED TROUGH EVOLVING EAST OF THE ROCKIES...LIKELY SPAWNING AN INTENSE SFC LOW OVER THE GREAT LAKES/MID ATLANTIC/NORTHEAST REGIONS AROUND THE CHRISTMAS EVE TIME FRAME. FOR WHAT ITS WORTH...BOTH THE 17/12Z GFS AND EC ARE FORECASTING A RECORD LOW MSLP SUB 970MB CYCLONE INVOF LAKE HURON AT 00Z ON 25 DEC. THIS SYSTEM WILL LIKELY GATHER MORE AND MORE ATTENTION AS WE MOVE CLOSER TO THE HOLIDAY. THE GOOD NEWS FOR TRAVELERS/BAD NEWS FOR SNOW CROWS IS THAT CURRENT PROJECTIONS WOULD PLACE CENTRAL PA INITIALLY IN THE "WARM" SIDE OF THE DEEP STORM FAVORING RAIN VS. SNOW. IT ALSO LOOKS QUITE WINDY ASSUMING THE DEEP LOW VERIFIES. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... WIDESPREAD STRATO CU AND PERSISTENT MVFR TO IFR CIGS WITH ISOLATED-SCATTERED AND GENERALLY BRIEF MVFR TO IFR VSBYS IN SNOW SHOWERS WILL OCCUR ACROSS THE NW MTNS AND LAUREL HIGHLANDS /INVOF KBFD AND KJST/ THROUGH FRIDAY MORNING. CONDITIONS ACROSS THE CENTRAL MTNS AND SUSQ VALLEY WILL VARY BETWEEN LOW END VFR...AND MVFR CIGS. GUSTY WEST TO WNW WINDS /UP AROUND 25 KTS AT TIMES/ WILL ADD SOME MECHANICAL TURBULENCE DURING TAKEOFF AND FAP TO REGIONAL AIRFIELDS THIS AFTERNOON THROUGH THURSDAY. A SECONDARY COLD FRONT AND COMPACT UPPER AIR DISTURBANCE DROPPING SE ACROSS THE REGION LATE TODAY AND EARLY TONIGHT COULD BRING SOME BRIEFLY HEAVIER SNOW SHOWERS...WITH A COATING TO 1/2 INCH POSSIBLE EVEN ACROSS THE CENTRAL MTN AND SUSQ VALLEY AIRFIELDS. OTHERWISE...NOT A LOT GOING ON TILL MAYBE JUST BEFORE CHRISTMAS. THERE COULD BE WIDESPREAD RAIN SHOWER ACTIVITY AROUND AS A POTENT SFC AND UPPER LOW TRACKS NE TWD THE OHIO RIVER VALLEY. OUTLOOK... THU-FRI...MVFR CIGS POSS NW. OTHERWISE NO SIG WX EXPECTED. SAT-SUN...LIGHT SNOW/REDUCED VSBY POSSIBLE ...MAINLY ALONG THE MD BORDER. MONDAY...MAINLY VFR. HOWEVER...AREAS OF MVFR STRATO CU ARE POSSIBLE IN DEVELOPING SERLY LOW LEVEL FLOW. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LAMBERT LONG TERM...STEINBUGL AVIATION...LAMBERT/CERU

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