Area Forecast Discussion
Issued by NWS State College, PA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KCTP 220024 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 824 PM EDT THU AUG 21 2014 .SYNOPSIS... AN UPPER TROF WILL SLOWLY TRACK EAST OF THE REGION BY FRIDAY EVENING...ALLOWING A LARGE AREA OF HIGH PRESSURE OVER NORTHERN NEW ENGLAND TO BUILD ACROSS THE REGION THIS WEEKEND. WARMER AND DRIER CONDITIONS ARE EXPECTED NEXT WEEK...AS HIGH PRESSURE EXPANDS OVER THE EASTERN UNITED STATES. && .NEAR TERM /UNTIL 7 AM FRIDAY MORNING/... STILL SOME LINGERING SHOWERS AND THUNDERSTORMS ALONG A BROKEN LINE IN THE NORTHERN TIER COUNTIES. CENTRAL AND SOUTHERN AREAS HAVE SETTLED DOWN AFTER A BUSY AFTERNOON WITH ISOLATED SUPERCELLS AND HEAVY RAIN CORES. IR SHOWS TOPS WARMING IN THE NORTHERN TIER CONVECTION SO IT SHOULD...FAMOUS LAST WORDS...DISSIPATE OVER THE NEXT 1-3 HOURS. GUIDANCE AND 3KM MODELS SHOW QUITE PERIOD OVERNIGHT. NOT ORGANIZED RAINFALL AND THE NORMALLY WET SREF IS DRY. ALL THE RAIN AND HUMIDITY ABOUT...EXPECT A GOOD AMOUNT OF FOG. && .SHORT TERM /7 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... FRIDAY IS A CONTEST OF GUIDANCE...HIGH RESOLUTION VERSE LOW RESOLUTION. THE 16KM SREF AND THE 18Z NAM SEEM TO THINK SOME AREAS OF PA WILL BE RAIN FREE. THE GEFS SAYS BETWEEN 8 AM AND 8 PM EVERYONE GETS AT LEAST 0.10 INCHES OF QPF. THE NAM AND SREF SHOW SOME MESOSCALE DRYING. THE PW VALUES DROP TO NEAR NORMAL AND ARE SLOW TO RISE FRIDAY INTO SATURDAY EVENING. THIS OPTIMISTICALLY KEEPS THE PW PLUME OVER THE MIDWEST...AND THAT MCS OVER INDIANA TONIGHT WHICH DEVELOPED IN IT...TO OUR WEST. KEPT MOSTLY LOW POPS 3 AM TO NOON. PUT SLOW INCREASE IN MOST AREAS LATE MORNING AND AFTERNOON. THE 27KM GFS IS ON THE DRY SIDE DURING THE DAY. THE 55 KM GEFS IS PROBABLY TOO WET. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... FRIDAY NIGHT INTO SATURDAY MOST FORECAST SYSTEMS SHOW A CHANCE OF RAIN/SHOWERS BUT ALSO SUGGEST THERE COULD BE A SURGE OR BEGINNING OF A SURGE OF WEAK HIGH PRESSURE AT THE SURFACE AND LOWER PW AIR MOVING INTO THE REGION. THE BACKDOOR FRONT COULD BE COMING TO DRY US OUT. PREVIOUS: 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 LATE FRIDAY NIGHT...EARLY SATURDAY. MOIST EASTERLY FLOW ASCENDING THE APPALACHIANS COULD PRODUCE LOW CLOUDS AND SPOTTY DRIZZLE TO LIGHT RAIN FRIDAY NIGHT INTO SATURDAY. THE LARGE UPPER LEVEL LOW SHOULD STAY QUASI-STATIONARY AS THE UPPER LEVEL RIDGE OVER THE MIDWEST WILL CONTINUE BUILD AND TILT OVER THE NORTHEAST THROUGH THE WEEKEND. THE LOW MOVING UNDERNEATH THE RIDGE SHOULD ALLOW FOR A SLIGHT CHANCE FOR SHOWERS SATURDAY INTO SATURDAY NIGHT. THE BUILDING RIDGE WILL BE THE PRIMARY DRIVER OF OUR WX THRU MOST OF THE EXTENDED FCST. 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. LARGE SCALE SUBSIDENCE AND DRY AIR SHOULD PERSIST...AS THE MID RANGE MODELS ARE IN FAIR AGREEMENT OF A BUILDING RIDGE OVER THE REGION THROUGH EARLY NEXT WEEK. BY MID NEXT WEEK THE FCST CONFIDENCE BEGINS TO 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...THE MODELS SEEM TO BE OFF WITH THEIR TIMING. HAVE KEPT A LOW CHC OF TSRA WED INTO THURSDAY. 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 /00Z FRIDAY THROUGH TUESDAY/... STILL A CHANCE OF THUNDER AT BFD FOR A FEW MORE HOURS. MOST OF THE ACTIVITY IS NOT NEAR OTHER TAF SITES AT THIS POINT. MAIN ISSUE OVERNIGHT WILL BE LOW CIGS AND VISIBILITIES. PATTERN FOR FRIDAY AND SATURDAY LOOKS SIMILAR TO TODAY. THUS WENT WITH VCSH IN THE TAFS FOR FRIDAY AFT 16Z. PERHAPS SOME IMPROVEMENT FOR NEXT WEEK...AS HIGH PRESSURE SFC AND ALOFT STARTS TO BUILD TOWARD PA. OUTLOOK... FRI-SAT...AM LOW CIGS/FOG FOLLOWED BY SCT SHOWERS/TSTMS AND BRIEF MVFR/IFR RESTRICTIONS. SUN-TUE...AM LOW CIGS PSBL. OTHERWISE MAINLY VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DEVOIR/STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...GRUMM/DEVOIR LONG TERM...FITZGERALD/CERU AVIATION...DEVOIR/MARTIN/STEINBUGL

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.