Area Forecast Discussion
Issued by NWS State College, PA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KCTP 300329 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1129 PM EDT WED OCT 29 2014 .SYNOPSIS... HIGH PRESSURE WILL MOVE IN FROM THE MIDWEST. A POTENT SHORTWAVE WILL THEN CARVE OUT A DEEP TROUGH OVER THE NORTHEAST CONUS AS IT DIVES ACROSS THE REGION LATE FRIDAY AND SATURDAY. THIS WILL LEAD TO A BLUSTERY AND COLD WEEKEND. THE UPPER TROUGH WILL LIFT OUT BY EARLY NEXT WEEK...REPLACED BY A RIDGE BUILDING ALONG THE EAST COAST. && .NEAR TERM /UNTIL 8 AM THURSDAY MORNING/... COLD ADVECTION IS PEAKING ABOUT NOW...AND THE RELATIVE WARMTH OF THE LAKE WATER WILL LIKELY MODIFY THE AIRMASS...AND DESPITE THE 0C LINE MOVING ALL THE WAY THROUGH THE CWA OVERNIGHT...THE COLDEST TEMPS AT 8H WILL BE ABOUT -3C. THEREFORE...EXPECT ANY PRECIP TO BE LIQUID WHEN IT GETS TO THE GROUND. IT IS WITHIN THE REALM OF POSSIBILITIES THAT SOME FLURRIES MAY MIX IN OVER THE VERY HIGHEST TERRAIN LATE TONIGHT. BUT NOT ENOUGH COVERAGE OR INTENSITY IS EXPECTED TO EVEN MENTION AT THIS POINT. MINS THERE SHOULD BE ABOVE FREEZING DUE TO THE CLOUDS. ELSEWHERE...THE USUAL POST-FRONTAL STRATOCU SHIELD SHOULD BREAK UP AS IT GOES DOWN HILL INTO THE LOWERS SUS AND SC MTNS. && .SHORT TERM /8 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... SHORTWAVE RIDGING AHEAD OF WEAK UPPER SHORTWAVES OVER THE OHIO VALLEY SHOULD PROVIDE A DRY DAY THROUGHOUT CENTRAL PA ON THURSDAY. THE DAY SHOULD START CLOUDY ACROSS THE NORTHWEST WITH A FEW SPRINKLES OR FLURRIES LINGERING INTO MID MORNING. CONTINUE TO LIKE THE EARLIER IDEA OF LAKE MOISTURE REMAINING TRAPPED BENEATH SUBSIDENCE INVERSION CAUSING A GOOD DEAL OF STRATOCU ACROSS THE ALLEGHENY PLATEAU...WHILE DOWNSLOPING NW FLOW YIELDS A BRIGHTER DAY ACROSS THE SUSQ VALLEY. ENS MEAN 925MB TEMPS SUPPORT MAX TEMPS FROM THE M40S ALLEGHENIES...TO M50S SUSQ VALLEY. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... THE BIG STORY THROUGH THE LONG TERM PERIOD REMAINS THE TRACK OF THE LARGE UPPER LEVEL LOW THAT WILL PROGRESS THROUGH THE GREAT LAKES REGION ON FRIDAY...AND ITS PROGRESSION EASTWARD THIS WEEKEND. ALL MEDIUM RANGE GUIDANCE STILL SHOWS A POTENT SHORTWAVE DIVING SE FROM CANADA AND CARVING OUT A DEEP TROUGH OVR THE NORTHEAST CONUS BY SATURDAY. THE GFS ENSEMBLES VARY ON THE STRENGTH AND POSITION OF THIS LOW...THROUGH ALL SHARE SIMILAR TIMING. THE OPERATIONAL GFS AND EC ARE IN LINE WITH ONE ANOTHER AND HAVE THE UPPER LOW DIG SOUTH OF THE REGION AND ACTUALLY MOVES THROUGH THE CAROLINAS BEFORE MOVING OFF COAST. THE EC HAS TRENDED TOWARDS THE GFS...AND BOTH HAVE THE LOW FURTHER EASTWARD INTO THE ATLANTIC BEFORE IT TRAVERSES NORTHWARD. THE ASSOCIATED SFC CLIPPER LOW IS PROGGED TO TRACK ACROSS EASTERN OHIO/WESTERN PA LATE FRIDAY AND FRIDAY NIGHT...BRINGING THE BEST CHANCE OF PRECIP TO THAT AREA. BOTH GEFS AND OPER ECMWF/CANADIAN MDLS ALL POINT TOWARD A MAINLY RAIN EVENT FRIDAY. HOWEVER...AS UPPER LOW CUTS OFF SOUTH OF PA EARLY SATURDAY...THERMAL PROFILES...COUPLED WITH MOIST EASTWARD UPSLOPE FLOW MAY BECOME COLD ENOUGH TO PRODUCE A LIGHT COATING OF SNOW ACROSS THE HIGH TERRAIN OF THE ALLEGHENIES. EXPECT A RAIN...SNOW MIX POSSIBLE THROUGH THIS TIMEFRAME...AND ANY SNOWFALL WILL BE WET. AS THE DEVELOPING COASTAL LOW MOVES UP THE COAST LATE SATURDAY...A TIGHTENING PRESSURE GRADIENT AND NW FLOW WILL DRAW MUCH COLDER/DRIER AIR INTO THE REGION. OPERATIONAL RUNS AND NEARLY ALL ENSEMBLE MEMBERS KEEP COASTAL LOW FAR ENOUGH OUT TO SEA TO NOT DIRECTLY IMPACT CENTRAL PA. HOWEVER...COLD NW FLOW MAY PRODUCE LAKE EFFECT SNOW SHOWERS ACROSS THE NW MTNS SATURDAY NIGHT...EARLY SUNDAY MORNING. ESPECIALLY GIVEN THE STRONG...MOIST 850MB FLOW. TEMPS THIS WEEKEND WILL ALMOST CERTAINLY BE THE COLDEST YET THIS SEASON. ENSEMBLE MEAN 8H TEMPS POINT TOWARD DAYTIME HIGHS FROM THE UPPER 30S OVR THE ALLEGHENIES TO THE 40S ELSEWHERE. THE COLDEST NIGHT OF THIS OUTBREAK WILL LIKELY BE SUNDAY NIGHT...WHEN SFC HIGH BUILDS OVR THE REGION. THOSE LOCATIONS THAT HAVE YET TO SEE A FREEZE WILL LIKELY GET IT BY MONDAY AM. HIGH CONFIDENCE IN A PERIOD OF DRY WEATHER SUNDAY/MONDAY...WHEN ALL GUIDANCE BUILDS SFC HIGH AND ASSOC DRY AIR MASS ACROSS PA. AN APPROACHING COLD FRONT WILL BRING THE NEXT CHC OF SHRA BY MIDWEEK. && .AVIATION /04Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
SOME FOG ACROSS THE SE AT MDT AND LNS. TAFS UPDATED SEVERAL TIMES THIS EVENING. EXPECT SOME WIND TO PICK UP LATE. EARLIER DISCUSSION BELOW. NO BIG CHANGE TO 00Z TAFS...FROM 21Z SET...WHEN I MADE SIGNIFICANT CHANGES. MAIN CHANGE WAS TO GO WITH BKN DECK AT AOO AND UNV. COLD FRONT AND SHOWERS NOW EAST OF THE AREA. FLOW TOO WESTERLY FOR MUCH LAKE EFFECT. PERHAPS A FEW SPRINKLES AT BFD LATER TONIGHT AND LOWER CIGS AT JST...GIVEN UPSLOPE FLOW. OTHERWISE...MAINLY DRY AND VFR CONDITIONS INTO FRIDAY MORNING. MORE IN THE WAY OF ADVERSE CONDITIONS FOR LATER FRIDAY INTO EARLY SUNDAY...AS MODELS HINT AT A DEEP SYSTEM CUTTING OFF ACROSS THE SE. ASIDE FROM A CHC OF RAIN AND SNOW SHOWERS...GUSTY WINDS WILL BE OF CONCERN. OUTLOOK... FRI...VFR/MVFR EARLY WITH SHOWERS POSS WEST...BCMG MVFR/IFR FRI NGT WITH NW WIND GUSTS 20-30 MPH AND RA/SN SHOWERS. SAT...MVFR/IFR WITH SCATTERED SNOW SHOWERS WEST. VARYING VFR- MVFR CONDS CENTRAL/EAST WITH OCNL -SHSN AND FLURRIES. NW WIND GUSTS 25-35 MPH. SUN...BECOMING VFR...WINDS DECREASING. MON...VFR.
-- End Changed Discussion --
&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DEVOIR/FITZGERALD LONG TERM...FITZGERALD/CERU AVIATION...MARTIN

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