Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 211545 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1145 AM EDT THU AUG 21 2014 .SYNOPSIS... A WARM FRONT WILL PIVOT INTO CENTRAL PENNSYLVANIA THROUGH TONIGHT. UPPER TROUGHING MOVING EAST FROM THE GREAT LAKES ACROSS THE NORTHEAST STATES INTO THE CANADIAN MARITIME REGION WILL PUSH THE FRONT BACK TO THE SOUTH ALONG THE EAST COAST THIS WEEKEND...ALLOWING A LARGE AREA OF HIGH PRESSURE OVER NORTHERN NEW ENGLAND TO RIDGE SOUTHWEST ALONG THE EAST-SIDE OF THE APPALACHIANS THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... ISOLATED TO LOCALLY SCATTERED COVERAGE OF SHOWERS EXPECT THIS AFTERNOON AS BROAD UPPER SHEAR AXIS LIES ACROSS PA. PW IS MUCH LOWER THAN YESTERDAY...ALONG WITH STRONGER NW FLOW ALOFT. THESE TWO FACTORS SHOULD RESULT IN LITTLE CONCERN FOR HEAVY RAINERS THIS AFTERNOON...AND JUST GENERIC OVERALL SHOWER/THUNDERSTORM CHANCES THROUGH THIS EVENING. A MOIST/MODESTLY UNSTABLE AIRMASS AND RELATIVELY STEEP MID LVL LAPSE RATES WILL YIELD HIGHEST POPS /40-60%/ DURING PEAK HEATING IN THE 18-00Z TIME WINDOW. HRRR IS LESS THAN IMPRESSIVE... GENERALLY INDICATING ISOLATED TO SCATTERED COVERAGE IN MOST PLACES. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... UPPER LOW WILL BE PASSING INTO NEW ENG BY FRI MORNING. HOWEVER..SHORT TERM MDL DATA ALL TRACKING A TRAILING SHORTWAVE SEWRD THRU CENTRAL PA FRIDAY PM...WHICH WILL LIKELY BRING ANOTHER ROUND OF SHRA/TSRA TO THE AREA. HIGHEST /LIKELY/ POPS PLACED ALONG AND SW OF QUASI-STATIONARY FRONT...WHICH MDLS PLACE ROUGHLY FROM KBFD SE TO KTHV. SOUTH AND WEST OF THIS BNDRY...UNSTABLE SOUNDINGS AND HIGH PWATS COULD RESULT IN LOCALLY HVY RAINFALL IN TSRA. CONVECTION- ALLOWING MDLS PRODUCING ISOLATED SPOTS AMTS OF ARND 4 INCHES. HOWEVER...AVERAGE AMTS BASED ON BLENDED QPF SHOULD BE LESS THAN A HALF INCH. GEFS 925 TEMPS ARE SUPPORTIVE OF MAX TEMPS NR SEASONAL LEVELS FRIDAY. CONVECTION SHOULD DIMINISH AND PUSH SOUTH OF THE STATE FRIDAY NIGHT...AS SHORTWAVE DIVES SOUTH OF THE AREA. BEHIND THIS FEATURE...BACKDOOR COLD FRONT IS PROGGED TO WORK SWRD THRU CENTRAL PA FRI NIGHT. MOIST EASTERLY FLOW ASCENDING THE APPALACHIANS MAY PRODUCE LOW CLOUDS AND SPOTTY DRIZZLE LATE FRIDAY NIGHT. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... LARGE SFC HIGH OVR NEW ENG WILL BE THE PRIMARY DRIVER OF OUR WX THRU MOST OF THE EXTENDED FCST. MOIST...EASTERLY FLOW OFF THE ATLANTIC WILL LIKELY PRODUCE A DULL AND COOL SATURDAY...WITH AM LOW CLOUDS GIVING WAY TO A BIT OF BRIGHTENING BY AFTN. GEFS 925 TEMPS OF ONLY 16C-18C IMPLY MAX TEMPS FROM JUST THE U60S OVR THE HIGH TERRAIN OF THE CENTRAL MTNS...TO THE M70S OVR THE SUSQ VALLEY. MED RANGE GUIDANCE INDICATES HIGH PRES AND ASSOC DRY AIR MASS WILL DRIFT SOUTH LATE THIS WEEKEND...BRINGING FAIR AND BRIGHTER WX TO CENTRAL PA. PTSUNNY SKIES SHOULD HELP TEMPS REBOUND A BIT ON SUNDAY...BUT STILL REMAIN BLW NORMAL. EARLIER CONCERNS OF CENTRAL PA DEALING WITH RING OF FIRE CONVECTION APPEAR TO BE WANING...AS LARGE SCALE SUBSIDENCE AND DRY AIR ARE THE THEMES OF THE MED RANGE GUIDANCE EARLY NEXT WEEK BENEATH SFC RIDGE ALONG THE E COAST. FCST CONFIDENCE BEGINS LOWER BY THE MIDDLE OF NEXT WEEK...WHEN MED RANGE MDLS BEGIN TO DIVERGE. GEFS KEEPS RIDGE AND FAIR WX GOING THRU WED...WHILE ECMWF ENSEMBLE DATA INDICATES A WEAK COLD FRONT COULD PUSH SE INTO THE REGION. THUS...HAVE ADDED A LOW CHC OF TSRA WED. WHAT APPEARS CERTAIN IS THAT THE COOL TEMPS OF THIS WEEKEND WILL GIVE WAY TO A SLOW WARMING TREND THRU THE FIRST HALF OF NEXT WEEK...AS COOL AIR MASS MODIFIES UNDER STILL STRONG AUGUST SUN. GEFS AND EC ENS 850 TEMPS SUPPORT HIGH RETURNING TO ABV NORMAL BY WED. && .AVIATION /16Z THURSDAY THROUGH MONDAY/...
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HI RES MODELS CONT TO DEPICT ISOLD SHRA AND TSTMS OVER CENTRAL PA THIS AFTERNOON. SPARSE COVERAGE RESULTS IN LOW CONFIDENCE IN POINT TERMINAL IMPACTS...SO WILL INDICATE VCSH MENTION THROUGH THIS EVENING. ANTICIPATE DECREASING COVERAGE OF SHRA AND TSTMS INTO THE EVE/OVERNIGHT PERIOD WITH AREAS OF FOG/ST POSSIBLY RE- DEVELOPING WITH SOME CLEARING/LGT WINDS/MOIST AIRMASS ESP IN THE NORTH. WILL NEED TO WATCH UPSTREAM IN THE OH VLY FOR POSSIBLE CONVECTIVE COMPLEX. FOR NOW EXPECT THIS MESOSCALE SYSTEM TO STAY SW OF THE AIRSPACE FROM OH TO WV. OUTLOOK... FRI-SAT...AM LOW CIGS/FOG FOLLOWED BY SCT SHOWERS/TSTMS AND BRIEF MVFR/IFR RESTRICTIONS. SUN-MON...AM LOW CIGS PSBL. OTHERWISE MAINLY VFR.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...DEVOIR/STEINBUGL SHORT TERM...FITZGERALD LONG TERM...FITZGERALD AVIATION...DEVOIR/STEINBUGL

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