Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 170503 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1203 AM EST WED DEC 17 2014 .SYNOPSIS... A COLD FRONT WILL PASS THROUGH THE FORECAST AREA THIS EVENING. SCATTERED MOUNTAIN SNOW SHOWERS ARE EXPECTED WEDNESDAY THROUGH THE END OF THE WEEK. A WEAK LOW IS EXPECTED TO MOVE SOUTH OF THE REGION LATER IN THE WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... THE FRONT AT 10PM EXTENDS FROM BRADFORD TO STATE COLLEGE TO JUST WEST OF HAGERSTOWN. IT IS SLOW MOVING AND RATHER WEAK...BUT AS A NEW LOW FORMS OFF THE NJ COAST...WESTERLY FLOW WILL ESTABLISH AT ALL LEVELS AND COOLER-DRIER AIR WILL BEGIN TO MOVE IN OVER THE NEXT FEW HOURS. RADAR SHOWS THE MOST ORGANIZED SHOWERS MOVING OVER MY EASTERN ZONES...WITH LIGHTER RETURNS FROM THE NW MOUNTAINS DOWN INTO CENTRAL AND SOUTHERN AREAS. T- MODERATE RAIN MARCHING THROUGH THE LAUREL HIGHLANDS INTO THE CENTRAL MOUNTAINS. SHORT RANGE HIGH RES MODELS CONTINUE TO SLOWLY DIMINISH THE SHOWER ACTIVITY THE DEEPER WE GET INTO THE OVERNIGHT. BEHIND THE FRONT AS WINDS TRANSITION TO A WSW DIRECTION...PRECIP WILL BECOME CONFINED TO HIGHER ELEVATIONS OF THE WEST AND NORTH...ENHANCED BY OROGRAPHIC FLOW. PLUS...AS COLDER AIR GRADUALLY FILTERS IN OVERNIGHT...PRECIP WILL TRANSITION OVER TO LIGHT SNOW SHOWERS. TEMPERATURES TONIGHT WILL LINGER NEAR LATE AFTERNOON VALUES FOR A WHILE...BEFORE DROPPING INTO THE 30S AREAWIDE AFTER MIDNIGHT. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... BY WED MORNING...INCREASING WESTERLY FLOW ASSOCIATED WITH A TROUGH SLIDING EASTWARD FROM THE GREAT LAKES WILL BRING COOLER AIR AND SCT SNOW SHOWERS TO THE REGION. MOISTURE PULLED AROUND THE SYSTEM AND PULLED FROM THE GREAT LAKES WILL ASCEND THE WRN HIGHLANDS BRINGING SCT LIGHT SNOW SHOWERS...AND CONTINUE THROUGH WEDNESDAY NIGHT AS THE UPPER LOW CENTER SLIDES EAST. DOWNSLOPE COMPONENT TO WINDS SHOULD KEEP IT PARTLY TO MOSTLY SUNNY IN THE SE. SOME VERY LIGHT ACCUMS COULD OCCUR ON THE WRN MTS. IT WILL GET BREEZY ON WED - ESP IN THE LAURELS WHERE GUSTS COULD GET INTO THE 30S. && .LONG TERM /THURSDAY THROUGH TUESDAY/... CYCLONIC FLOW ALOFT WILL WEAKEN ON THURSDAY AS UPPER LOW SHIFTS EWD ACROSS THE CANADIAN MARITIME REGION AND RIDGE ALOFT BUILDS OVER JAMES BAY. DESPITE A WELL ALIGNED WNW FLOW AND FAIRLY STRONG LOW LEVEL COLD AIR ADVECTION EARLY IN THE DAY...MODEL SOUNDINGS SHOW RATHER SHALLOW MOISTURE AND CAPPING INVERSION HGTS GENERALLY BELOW 850MB WHICH SHOULD LIMIT SNOW ACCUMS TO AROUND 1 INCH IN MOST AREAS IN THE NW MTNS. LOCALLY HIGHER AMOUNTS ARE POSSIBLE (2-4" MAXIMUM ACCUMULATION POTENTIAL) OVER THE FAVORED PERENNIAL SNOWBELT DURING THE 24 HOUR PERIOD ENDING 12Z FRI. THE PATTERN WILL REMAIN SEASONABLY COLD AND BRISK THROUGH THE END OF THE WEEK. LARGE SCALE SUBSIDENCE ASSOCIATED WITH SURFACE HIGH MIGRATING EAST FROM THE GREAT LAKES/MIDWEST INTO EASTERN CANADA SHOULD BRING AN END TO NUISANCE/MINOR SNOW SHOWER ACTIVITY AND LINGERING FLURRIES OVER THE NW ALLEGHENIES BY FRI NGT. CONCERNING THE WEEKEND SYSTEM... THE MODELS SHOW A SOUTHERN STREAM TROUGH DEVELOPING TOWARD THE SOUTHERN ROCKIES AND PLAINS ON FRIDAY WITH THE ASSOCIATED HEIGHT FALLS INVIGORATING A WAVE OF LOW PRESSURE OVER THE WESTERN GULF COAST STATES BY 00Z SAT. THERE REMAINS A BROAD MODEL CONSENSUS IN TRACKING THE DEVELOPING SFC WAVE EAST-NORTHEAST ACROSS THE SOUTHEAST PIEDMONT BEFORE EXITING THE LOWER 48 INVOF THE CAROLINA COASTAL PLAIN---BETWEEN HATTERAS AND MYRTLE BEACH. WHILE THERE IS MUCH BETTER MODEL AGREEMENT AND CONVERGENCE TOWARD A WEAKER/MORE SUPPRESSED SOLUTION OVER THE LAST 2 MODEL CYCLES...THERE IS STILL ENOUGH SPREAD/UNCERTAINTY IN THE EVOLVING SPLIT-FLOW PATTERN THAT A MORE SIGNIFICANT STORM SYSTEM STILL CANNOT BE RULE OUT. HOWEVER CONFIDENCE IN A MAJOR STORM HAS LARGELY DIMINISHED SINCE YESTERDAY WITH THIS SCENARIO NOW LOOKING LIKE A LOW PROBABILITY OUTCOME. CONFIDENCE REGARDING THE STORM TRACK AND ASSOCIATED WEATHER IMPACTS HAS INCREASED SOMEWHAT (FROM LOW TO AVERAGE) GIVEN THE CONVERGENCE TOWARD A MORE COMMON SOLUTION...WITH A LIGHT RAIN/SNOW EVENT EMERGING AS THE MOST LIKELY AND PROBABLE OUTCOME. HIGH PRESSURE SHOULD PROVIDE A QUIET WEATHER PERIOD EARLY NEXT WEEK BEFORE THE PATTERN TURNS INCREASINGLY UNSETTLED AND POTENTIALLY STORMY HEADING INTO CHRISTMAS EVE/DAY. && .AVIATION /04Z WEDNESDAY THROUGH SUNDAY/... WARM MOIST AIR THROUGHOUT THE LOWER SUSQUEHANNA HAS ALLOWED FOR PATCHY FOG TO SET UP OVER THE REGION...GIVING LIFR VSBYS AND CIGS TO IPT...AND THV. THE CONDITIONS ARE SLOWLY IMPROVING...THOUGH IFR CIGS REMAIN AT AT BFD...JST...UNV...MDT...LNS...UNV. THE PRECIP HAS SLIGHTLY INCREASED DUE TO UPSLOPE AT JST CAUSING THEM TO GO IFR. AOO REMAINS JUST OUTSIDE THE MOST INTENSE PORTION OF THE AIRMASS AND ARE MVFR. BFD IS IN AND OUT OF THE IFR BUT SHOULD PREDOMINATELY BE AT IFR THROUGH SUNRISE. EXPECT THE MODERATE RAIN TO SUBSIDE OVERNIGHT...WITH THE EASTERN TAF SITES BECOMING CLEARER TOWARDS MORNING. THE WESTERN TAF SITES WILL HAVE SHOWER ACTIVITY CONTINUE OVERNIGHT AND THROUGH AT LEAST THE FIRST HALF OF TOMORROW MORNING DUE TO THEIR PROXIMITY TO THE UPPER WAVE AND AS THE COLD/OCCLUDED FRONT PUSHES SLOWLY EASTWARD. WIDESPREAD RESTRICTIONS WILL CONTINUE ACROSS THE ENTIRE CWA OVERNIGHT. BEHIND THE FRONT AS WINDS TRANSITION TO A SW DIRECTION...MAINLY AFTER 06Z. PRECIP WILL TRANSITION OVER TO LIGHT SNOW SHOWERS. RESTRICTIONS OVER THE SE HALF OF CWA WILL GRADUALLY ABATE AS DOWNSLOPE COMPONENT TO WINDS BECOMES ESTABLISHED. OUTLOOK... WED...LOW CIGS/SHSN LIKELY W MTNS. OCNL MVFR CIGS POSS CENTRAL MTNS. VFR SE. THU-FRI...MVFR CIGS POSS NW. OTHERWISE NO SIG WX EXPECTED. SAT-SUN...SNOW/REDUCED VSBY POSS ESP SOUTHERN PA. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...RXR LONG TERM...STEINBUGL AVIATION...CERU/RXR

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