Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 291153 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 753 AM EDT MON SEP 29 2014 .SYNOPSIS... A WEAK UPPER LEVEL DISTURBANCE WILL MOVE NORTHEAST ACROSS THE REGION THIS MORNING WITH PLENTY OF MID AND HIGH CLOUDS...AND PERHAPS A FEW SPRINKLES. OTHERWISE...HIGH PRESSURE AT THE SURFACE WILL BE CENTERED OVER THE COMMONWEALTH AND PROVIDE AT LEAST ONE MORE NICE DAY BEFORE A WEAK COLD FRONT AND AN UPPER LEVEL DISTURBANCE MOVES SOUTHEAST FROM THE GREAT LAKES REGION AND BRINGS AN INCREASE IN CLOUDS AND THE CHANCE FOR SOME SHOWERS FOR TUESDAY INTO WEDNESDAY. A STRONGER COLD FRONT WILL PUSH EAST INTO THE COMMONWEALTH LATE FRIDAY NIGHT OR SATURDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... EAST-WEST RIDGE OF HIGH PRESSURE AND ASSOC DRY AIR MASS AT LLVLS OVER THE REGION WILL MAINTAIN FAIR AND MILD CONDITIONS THROUGH TODAY. A FEW WEAK MID/UPPER LEVEL SHORT WAVES WERE LIFTING NE ACROSS THE MID-ATLANTIC REGION JUST AHEAD OF A 700-500MB SHEAR AXIS LOCATED OVER THE ALLEGHENIES OF WESTERN PENN AND WVA. AS THIS TROUGH AXIS CROSSES THE STATE TODAY...EXPECT A GRADUAL DECREASE IN CLOUDS FOR MUCH OF CENTRAL PENN THIS AFTERNOON. THE BEGINNING OF THIS CLEARING HAS ALREADY OVERSPREAD THE NW MTNS...WHERE PATCHY 1/4-1/2SM FOG HAS FORMED INVOF KFIG. TEMPS TODAY WILL START OUT IN THE U40S TO L50S ACROSS THE NW MTNS...AND MID TO UPPER 50S AT MOST OTHER LOCATIONS. AFTERNOON HIGHS IN THE L70S NRN AND WRN MTNS...AND MID TO UPPER 70S ELSEWHERE WILL BE 8-10F ABOVE NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... LINGERING MID LEVEL CLOUDS ARE LIKELY TONIGHT ACROSS THE FAR ERN ZONES...NEAR AND JUST TO THE EAST OF THE AFOREMENTIONED MID/UPPER LEVEL TROUGH. ELSEWHERE...WEAK RIDGING AT THE SURFACE AND ALOFT WILL MAINTAIN PARTLY TO MOSTLY CLOUDY SKIES...LEADING TO ANOTHER RELATIVELY MILD NIGHT WITH MIN TEMPS EARLY TUESDAY SIMILAR TO THOSE THAT OCCURRED AROUND SUNRISE MONDAY. A RIBBON OF SLIGHTLY HIGHER PWATS OF 1-1.25 INCHES COMBINED WITH WEAK ISENTROPIC LIFT IN THE 300-305K THETA LAYER WILL MOVE OVER THE WESTERN HALF OF THE STATE TONIGHT. A FEW STRAY SHOWERS /DRIFTING NE ACROSS THE REGION/ CAN`T BE RULED OUT...BUT AT THE PRESENT TIME WILL KEEP POPS MINIMAL TO NIL FOR THE 00Z-12Z TUESDAY PERIOD. A POTENT BUT RATHER COMPACT UPPER SHORTWAVE WILL DROP SE TO THE LOWER GLAKES REGION BY MIDDAY TUESDAY. CLOUDS WILL INCREASE THROUGH THE DAY TUESDAY...AND SO WILL THE CHC FOR MAINLY SCATTERED SHOWERS. SREF SHOWS GENERALLY LOW PROBABILITIES FOR CAPES AOA 1000 J/KG NEAR AND JUST TO THE WEST OF AN ILL-DEFINED WARM FRONT THAT IS FORECAST TO EXTEND FROM NEAR KELZ...SE TO KIPT AND KRDG. MENTIONED ISOLATED AFTERNOON TSRA FOR TUESDAY. BASIN AVERAGE RAINFALL IS EXPECTED TO BE MAINLY 0.10 OF AN INCH OR LESS...BUT AMOUNTS COULD BE SLIGHTLY HEAVIER /0.15 TO 0.25 OF AN INCH/ ACROSS THE FAR NW ZONES TUESDAY AFTERNOON AND EVENING. MAX TEMPS TUESDAY ARE EXPECTED TO BE JUST A FEW DEG F COOLER AND IN THE LOWER TO MID 70S. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... EXPANSIVE UPPER RIDGE OVER THE EASTERN HALF OF THE CONUS WILL REMAIN IN CONTROL TO A LARGE DEGREE THROUGH MUCH OF THE PERIOD. SEVERAL SHORTWAVES IN THE NRN STREAM WILL SLOWLY BREAK DOWN THE RIDGE...WITH A LARGE SCALE UPPER TROF FORECAST TO MOVE INTO THE EASTERN PART OF THE COUNTRY BY NEXT WEEKEND. MODELS CONTINUE IN FAIR AGREEMENT AS BOTH THE EC AND THE GFS BRING A SHORT WAVE TROUGH THROUGH THE REGION MONDAY NIGHT INTO WEDNESDAY....WITH THE EC STRONGER WITH THE MID LEVEL LOW. A WEAK FRONT SHOULD BE ASSOCIATED WITH THIS TROUGH...HOWEVER LACK OF MOISTURE SHOULD ONLY ALLOW FOR POTENTIAL FOR LIGHT PRECIPITATION THROUGH THE NW MTNS LATE MONDAY NIGHT/TUESDAY MORNING DUE TO LAKE MOISTURE AND UPSLOPE FLOW. LATEST...00Z U.S. AND EC MODEL GUIDANCE /AND GEFS/ STILL SHOW A GREAT DEAL OF SPREAD IN THEIR SOLUTIONS WITH RESPECT TO THE LOCATION AND STRENGTH OF THE AFOREMENTIONED UPPER TROUGH THAT WILL BECOME CARVED OUT ACROSS THE ERN U.S DURING THE TUES-THUR TIME- FRAME. MOST SOLUTIONS WARRANT AT LEAST A LOW CHC FOR SHOWERS EACH OF THOSE 3 DAYS...WITH THE GREATEST CHC FOR SHOWERS BECOMING CONFINED OVER THE EASTERN HALF OF THE CWA TUESDAY NIGHT THROUGH THURSDAY AS AN ANOMALOUS EASTERN LLVL FLOW DEVELOPS BETWEEN 1030 MB SFC HIGH PRESSURE OVER QUEBEC...AND A RELATIVELY WEAK 1008-1010MB LOW NEAR THE CAROLINA OR DELMARVA COAST. TRIMMED TEMPS BY A FEW DEG F TUESDAY THROUGH THURSDAY. IT APPEARS LIKELY THAT THE INCREASING EASTERLY FLOW AT LLVLS WILL BRING INCREASING CLOUDS AND WITH SLIGHTLY COOLER DAYS AND MILDER NIGHTS. EVEN MORE UNCERTAINTY IN FURTHER REACHES OF EXTENDED FORECAST. RIDGING SLIPS BACK IN FOR LATE WEEK AS A DECENT WAVE SLIDES SE FROM CANADIAN ROCKIES IN WAKE OF WEAKENING UPPER LOW /THAT LIFTED INTO CENTRAL CANADA FROM CALIFORNIA/. AT THIS TIME...EC WEAKER AND MORE PROGRESSIVE WHILE GFS DEEPER AND SLOWER. APPEARS TO BE SOME CONSENSUS THAT PCPN ARRIVES INTO WRN PA ON FRIDAY...AND SIG PCPN WITH THE SFC FRONT EXITS THE STATE EARLY ON SAT. && .AVIATION /12Z MONDAY THROUGH 12Z TUESDAY/... LYRD MID TO HIGH CLOUDS FROM 100-250KFT ARE COVERING THE ERN 1/2 TO 3/4 OF THE AIRSPACE THIS MORNING...AND HAVE CONFINED FOG TO WHERE SKC IN THE FAR NW PRTNS OF THE AREA. EXPECT VLIFR CONDS AT BFD TO RETURN TO VFR BY 13Z. SOME VERY LIGHT RAIN /SPRINKLES/ HAVE BEEN OBSERVED FALLING OUT OF THE MID LVL CLOUD DECK. THE HIGH LEVEL CLOUDS SHOULD GRADUALLY SHIFT EWD TNGT WITH CENTRAL AREAS LKLY SEEING SOME CLEARING. FOG MAY AGAIN BE A CONCERN BUT WILL ALLOW LATER ISSUANCES TO ADDRESS POTENTIAL ALONG WITH SPECIFIC FLIGHT CATS. CLOUDS SHOULD INCREASE THROUGH TUESDAY AS AN UPPER TROUGH DIGS SEWD FROM THE ERN GRT LKS. OUTLOOK /TUESDAY THROUGH FRIDAY/... TUE-WED...AN UPPER TROUGH DIGGING INTO THE MID-ATLANTIC REGION SHOULD BRING SCT RAIN SHOWERS. LOW CIGS PROBABLE AT NIGHT. THU...LOW CIGS PSBL AS HP WEDGES ALONG/E OF THE APPLCHNS. FRI...SHOWERS AND THUNDERSTORMS PSBL ASSOCD WITH GUSTY FROPA. && .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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