Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 221439 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1039 AM EDT TUE JUL 22 2014 .SYNOPSIS... A RIDGE OF HIGH PRESSURE WILL REMAIN OVER PENNSYLVANIA TODAY. A POTENT COLD FRONT WILL MOVE SOUTHEAST FROM THE GREAT LAKES AND CROSS THE COMMONWEALTH LATE WEDNESDAY AND WEDNESDAY NIGHT. A REFRESHINGLY COOLER AND LESS HUMID AIRMASS WILL OVERSPREAD THE COMMONWEALTH FOR THE END OF THE WEEK INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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LOW CLOUDS STACKED UP AGAINST THE ALLEGHENIES ARE FINALLY SHOWING SIGNS OF MIXING OUT AND WILL LEAD TO A PARTLY SUNNY AFTERNOON. IT IS WARM AND HUMID AND ONCE AGAIN TODAY WE WILL BE DEALING WITH ISOLATED BUILDUPS LEADING TO A FEW SHOWERS OR THUNDERSTORMS. MESO ANAL SHOWS STABILITY ERODING OVER WESTERN PA...BUT ALSO INDICATES A TONGUE OF VERY WARM MID LEVEL AIR PUSHING INTO THE AREA. THIS WILL HELP SUPPRESS ACTIVITY DESPITE THE EXPECTATIONS OF CAPES COOKING UP INTO THE 1200-2000J RANGE THIS AFTERNOON. THE BEST CHC FOR THE ISOLATED CONVECTION SHOULD BE ACROSS SOUTHERN PA AND PERHAPS THE LOWER SUSQ VALLEY WHERE SLIGHTLY COOLER MID LEVEL TEMPS ARE FORECAST TO PERSIST. AFTER THE EARLY TO MID MORNING LOW CLOUDS AND PATCHY FOG MIXES OUT...TODAY WILL FEATURE NOTICEABLY WARMER TEMPERATURES AS AN UPPER RIDGE SLIDES EAST FROM THE GRT LKS. HIGHS MONDAY WERE IN THE M/U80S UPSTREAM OVR MICHIGAN AND EXPECT SIMILAR READINGS THROUGHOUT THE VALLEYS OF CENTRAL PA THIS AFTERNOON. THE HIGHER TERRAIN OF THE ALLEGHENY PLATEAU WILL LIKELY ONLY REACH THE L80S.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... SIMILAR /AND PERHAPS EVEN MUGGIER/ CONDITIONS ARE EXPECTED FOR TONIGHT WITH A LIGHT SOUTHERLY FLOW AND 1.5 INCH PWAT AIR KEEPING TEMPS ABOUT 6-8F ABOVE NORMAL. VERY WARM MID LEVEL TEMPS /AVERAGING 9C AT 700 MB OVER CENTRAL PENN/ WILL KEEP CONDITIONS DRY TONIGHT THROUGH MUCH OF WEDNESDAY MORNING. THE ARRIVAL OF A STRONG COLD FRONT AND UPPER LEVEL DISTURBANCE WEDNESDAY AFTERNOON AND EVENING WILL CREATE SEVERAL BANDS OF DEEP UVVEL...HELPING TO BREAK THIS CAP AND FIRE OFF ONE OR MORE BKN LINES OF STRONG TO POTENTIALLY SVR TSRA. SPC HAS THE ENTIRE CWA IN THEIR DAY 2 /SEE TEXT/ OUTLOOK. GIVEN THE PROJECTED HIGH CAPE AND WEAK-MDT DEEP LAYER SHEAR TYPE OF ENVIRONMENT THE PRIMARY STORM TYPE WILL BE PULSE AND MULTI-CELL CLUSTERS CAPABLE OF PRODUCING LOCALIZED SVR HAIL AND WET MICROBURSTS /WITH A FEW MIN-BOW ECHOES POSSIBLE AS WELL/ WEDNESDAY AFTERNOON THROUGH EARLY WED EVENING. THANKS TO A WARMING/LLVL...WSW DOWNSLOPE FLOW AHEAD OF THE CFRONT...HIGH TEMPS WED WILL BE THE WARMEST OF THE WEEK...RANGING FROM THE LOWER 80S ACROSS THE HIGHEST TERRAIN OF THE NORTH AND WEST...TO THE MID AND UPPER 80S IN THE CENTRAL VALLEY...AND LOWER 90S IN THE GREATER YORK/HARRISBURG AREA. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... OVERALL SCENARIO REMAINS UNCHANGED IN THE LONG TERM PERIOD AS A LARGE UPPER RIDGE BUILDING OVER THE FOUR CORNERS REGION IS FORECAST TO EXPAND NORTH AND EAST INTO THE ROCKIES AND PLAINS DURING THE PERIOD. DOWNSTREAM...THIS WILL LEAD TO LONG WAVE TROFFING OVER THE EASTERN THIRD OF THE COUNTRY. UPPER LOW TO THE EAST OF HUDSON BAY WILL BE STRENGTHENED AT TIMES BY SHORTWAVE ENERGY IN THE STRONGER JET STREAM FLOW ACROSS CANADA. SOUTHWARD EXTENSION OF THIS LOW/TROF WILL AT TIMES DURING THE PERIOD STRENGTHENING THE TROFFING ACROSS THE NORTHEASTERN U.S./OUR REGION. TODAYS TREND OF MEDIUM RANGE MODEL GUIDANCE IS FOR STRONGER/DEEPER TROFFING DOWNSTREAM ACROSS THE EASTERN U.S...DEVELOPING AN ALMOST FULL LATITUDE TROF EXTENDING FROM THE EASTERN CANADA LOW SWD TO FLORIDA. THIS WILL LIKELY SERVE TO EXPAND AND PROLONG THE CHANCES FOR PCPN THIS WEEKEND. GUIDANCE FORECASTS CONTINUE TO BRING A FRONT AND INCREASED CHANGES FOR PRECIPITATION TOWARD PA IN THE WEDNESDAY/THURSDAY TIME FRAME AND SHOW A SECOND...POTENTIALLY STRONGER SYSTEM LATE NEXT WEEKEND. THE TREND OF STRONGER TROUGHING MENTIONED ABOVE HAS LEAD TO SLOWER ARRIVAL AND DEPARTURE OF THE FRONTAL SYSTEM IN THE DAILY PROGS. A WARM FRONT WILL BE ON THE DOORSTEP OF PA SUNDAY MORNING...A BIT SLOWER THAN FORECAST YESTERDAY. HAVE THUS ADJUSTED POPS/TIME TO SUIT. ASSOCIATED COLD FRONT DOES NOT CROSS THE STATE TIL MONDAY AT THIS POINT...LEADING TO A POTENTIAL PROLONGED PERIOD OF SHOWERS AND THUNDERSTORMS. AT THIS TIME FRAME HOWEVER...A LOT WILL LIKELY CHANGE BEFORE WE REACH NEXT WEEKEND. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/...
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MORNING LOW CLOUDS AND FOG/HAZE WILL CONTINUE TO SLOWLY MIX OUT AND BURN OFF. EASTERN TERMINALS WILL BE SLOWEST FOR A CHANGE GIVEN THE DEEPER LAYER MOISTURE IN PLACE...BUT STILL EXPECT ALL AIRPORTS TO BECOME VFR BETWEEN 15-18Z. WARMING TEMPS ALOFT AND LACK OF SYNOPTIC FORCING SUGGESTS VERY LOW CHANCES OF AFTERNOON POP-UP SHOWERS OR THUNDERSTORMS. NO MENTION OF THUNDERSTORMS IN TAFS AS POINT PROBS/PCPN CVRG WILL BE VERY LOW/SPARSE. DIURNAL CU SHOULD FADE AFTER DARK WITH SOME PATCHY FOG AND ASSOCD LOWER CIGS/VISBYS RE-DEVELOPING OVERNIGHT. OUTLOOK... WED...SCT TSTM IMPACTS LKLY ASSOCD WITH COLD FRONT. THU...SCT TSTM IMPACTS PSBL SERN AIRFIELDS AS COLD FRONT SLOWS AS IT APPROACHES THE MID-ATLC COAST. FRI-SAT...PATCHY A.M. FOG PSBL. OTHERWISE NO SIG WX.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/LAMBERT NEAR TERM...LA CORTE/LAMBERT SHORT TERM...LAMBERT LONG TERM...LAMBERT/GARTNER AVIATION...STEINBUGL

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