Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 031140 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 740 AM EDT THU SEP 3 2015 .SYNOPSIS... ABOVE NORMAL TEMPERATURES WILL CONTINUE INTO NEXT WEEK WITH GRADUALLY DECREASING HUMIDITY LEVELS. ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE THROUGH THE END OF THE WEEK. HIGH PRESSURE WILL ENSURE FAIR AND DRY WEATHER FOR LABOR DAY WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... CANT RULE OUT A VERY ISOLATED SHOWER/TSTM THIS MORNING. THE MOST LKLY AREA WOULD SEEM TO BE THE LAUREL HIGHLANDS GIVEN STORMS DRIFTING SSEWD SOUTH/WEST OF KPIT. THAT SAID...RADAR SHOWS A LONE SHOWER DEVELOPING NW OF LOCK HAVEN WHICH ILLUSTRATES THE SPATIAL VARIABILITY. ANOTHER MUGGY START TO THE DAY WITH LOCALLY DENSE FOG. MODEST LARGE SCALE LIFT AHEAD OF WEAK MID-LEVEL PERTURBATION DRIFTING ESEWD OVER LOWER MI/LAKE HURON...COMBINED WITH ABUNDANT LOW-LEVEL MOISTURE...WEAK MLCINH AND STRONG DIURNAL HEATING SHOULD PROMOTE ISOLATED TO SCATTERED CONVECTION BY THE AFTERNOON. THE HIRES NCAR/SSEO MESOSCALE ENSEMBLE SYSTEMS...AND TO A LESSER EXTENT THE GLOBAL SHORT RANGE DETERMINISTIC MODELS...SEEM TO BE FAVORING A CORRIDOR FROM THE UPPER OH VLY ESEWD ACROSS NRN WV/SWRN PA WITH THE GREATEST RISK/PROBABILITY FOR STORMS LATER TODAY. HOWEVER LOW POPS WILL EXIST ACROSS THE ENTIRE CWA WITH SLIGHTLY HIGHER PROBS PAINTED OVER THE HIGHER TERRAIN OF THE N/W ALLEGHENIES. HIGH MSTR CONTENT AND FCST MODERATE INSTABILITY SUGGEST SOME LOCALLY HEAVY DOWNPOURS. THE DEEP-LAYER FLOW WILL BE RATHER WEAK UNDER BROAD UPPER RIDGING WHICH SHOULD LIMIT POTENTIAL FOR ORGANIZED SVR STORMS. HOWEVER SUB-SVR WATER-LOADING-RELATED WIND GUSTS UNDER 50KT WILL BE POSSIBLE AND MAY PRODUCE LOCALIZED/MINOR DAMAGE. NOCTURNAL BLYR STABILIZATION SHOULD REDUCE CONVECTIVE COVERAGE/INTENSITY CONSIDERABLY THIS EVENING WITH ANY LINGERING STORMS LKLY DISSIPATING INTO TONIGHT. PERSISTENCE AND TIME OF YEAR MAKE A STRONG CASE FOR OVERNIGHT FOG/REDUCED VISIBILITY INTO FRIDAY MORNING. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... UPPER LEVEL RIDGING WILL REMAIN A DOMINANT FEATURE INTO THE WEEKEND. SHORT TERM MODEL GUIDANCE STILL SHOWS A LOW TO MEDIUM CHANCE FOR ISOLATED/SCATTERED TSTMS FRIDAY AFTN AS WEAKER S/WV IMPULSES DRIFT SEWD WITHIN SHEAR/INSTABILITY/MSTR AXIS FROM THE GREAT LAKES ACROSS THE N-CENTRAL APPALACHIANS. A BACKDOOR COLD FRONT SHOULD ALIGN ITSELF NEAR THIS AXIS AND PROVIDE ENOUGH LOW LEVEL CONVERGENCE TO SPARK SOME CONVECTION OVER CENTRAL AND ESPECIALLY SRN PA PER MULTI MODEL CONSENSUS. DIURNAL COOLING SHOULD ALLOW ANY STORMS TO DISSIPATE THRU FRI EVE. THE BOUNDARY SHOULD PIVOT TO A NNW/SSE ORIENTATION ON SATURDAY WHILE BEING SHUNTED SWWD...AS A LARGE DOME OF SFC HIGH PRESSURE MOVES FROM ERN QUEBEC INTO NEW ENGLAND. RISK AREA FOR STORMS ON DAY 3 SHOULD BE POSITIONED TO THE WEST OF THE LOCAL CWA. TEMPERATURES SHOULD COOL OFF A BIT WITH NOTICEABLY LESS HUMID AIR ARRIVING BY SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... HIGH PRESSURE SHOULD MAINTAIN DRY WEATHER SUNDAY-MONDAY. LEAD COLD FRONT ADVANCING EWD FROM THE GREAT LAKES/MIDWEST AND POTENTIAL ONSHORE FLOW MSTR MAY IMPACT THE FCST BY TUESDAY...BUT A CONSENSUS SOLUTION HOLDS BACK HIGHER POPS UNTIL WED-THU IN ASSOCIATION WITH A STRONGER SHORTWAVE/SFC COLD FRONT. SO TIMING DIFFS WILL NEED TO BE RESOLVED. THE GLOBAL NUMERICAL MODELS/ENSEMBLES ARE COMING INTO BETTER AGREEMENT ON A PATTERN CHANGE DURING THE SECOND HALF OF NEXT WEEK WITH A SHUFFLING OF THE LONGWAVE FLOW ALLOWING EWD PROGRESSION OF THE WESTERN TROUGH INTO THE CENTRAL STATES AND RECENT RIDGE OVER THE EASTERN UNITED STATES OFF THE COAST INTO THE WRN ATLC. THIS SHOULD EVENTUALLY BRING AN END TO THE RECENT HOT/DRY SPELL. A RETURN TO SEASONAL TEMPERATURES AND MORE ACTIVE PCPN PATTERN SEEMS PROBABLE BY NEXT WEEKEND IN THE NEW FLOW REGIME. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... LOCALLY DENSE FOG HAS FORMED IN THE VALLEYS OF CENTRAL PA EARLY THIS AM. CONDITIONAL CLIMATOLOGY SUGGESTS IFR CIGS WILL PERSIST AT KIPT UNTIL ARND 13Z AND IFR/LIFR VSBYS WILL PERSIST AT KBFD UNTIL ARND 14Z. ELSEWHERE...ODDS OF SIG RESTRICTIONS AFTER 12Z APPEAR LOW. AFTER THE EARLY AM FOG BURNS OFF...WIDESPREAD VFR CONDS AND LIGHT WINDS EXPECTED FOR THE REST OF TODAY. HOWEVER...AN AREA OF LOW PRESSURE PUSHING IN FROM THE GRT LKS WILL PRODUCE SCT PM TSRA ACROSS THE AREA. A BRIEF VIS REDUCTION COULD ACCOMPANY ANY TSRA...WITH THE BEST CHC OVER THE WESTERN HALF OF THE STATE BTWN 18Z-00Z. PATCHY FOG WILL ONCE AGAIN BECOME THE MAIN CONCERN TONIGHT...WITH IFR CONDS LIKELY AT KBFD AND POSSIBLE AT KIPT. OUTLOOK... FRI...PATCHY AM FOG POSSIBLE. SCT PM TSRA IMPACTS POSSIBLE. SAT-MON...PATCHY AM FOG POSSIBLE...MAINLY KBFD/KIPT. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...STEINBUGL AVIATION...FITZGERALD

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