Area Forecast Discussion
Issued by NWS State College, PA

Current Version | Previous Version | Graphics & Text | 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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KCTP 040035 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 735 PM EST TUE MAR 3 2015 .SYNOPSIS... MIXED PRECIPITATION WILL CHANGE TO AN EXTENDED PERIOD OF FREEZING RAIN THIS EVENING THROUGH LATE TONIGHT. THE PRECIPITATION WILL LIKELY TURN TO RAIN ACROSS SOUTHERN AND FAR WESTERN SECTIONS EARLY WEDNESDAY. COLDER TEMPERATURES WILL FOLLOW FOR THE LATTER PART OF THE WEEK...AND STEADY SNOW WILL RETURN WEDNESDAY EVENING INTO THURSDAY AS A WAVE OF LOW PRESSURE RIPPLES ALONG A NEARLY STATIONARY FRONT THAT WILL BE DRAPED JUST TO OUR SOUTH. HIGH PRESSURE AND COLD AIR WILL RETURN FOR FRIDAY INTO THE FIRST PART OF THE WEEKEND. && .NEAR TERM /UNTIL 10 PM THIS EVENING/... LL JET AND ASSOC PUSH OF WARM AIR ALOFT HAS CHANGED PRECIP TO PLAIN RAIN OVR PARTS OF WARREN AND SOMERSET COUNTY AS OF 23Z. MEANWHILE...MIXED FZRA AND IP CONTINUE TO FALL ACROSS THE REST OF CENTRAL PA. MDL SOUNDINGS...AS WELL AS LATEST HRRR OUTPUT...CONTINUE TO INDICATE THE LOW LVL COLD AIR WILL ERODE FROM WEST TO EAST OVERNIGHT WITH THE LAST OF THE FZRA ENDING ACROSS THE HIGH TERRAIN NE OF KIPT BTWN 06Z-09Z. BASED ON ASOS ICE ACCRETIONS THRU 23Z AND UPSTREAM RADAR TRENDS...CONFIDENCE IN WARNING TYPE ICE ACCUMS ACROSS THE N MTNS IS WANING. ACROSS THE LAUREL HIGHLANDS...KJST ALREADY REPORTED 0.36 INCHES OF ICE ACCRETION THRU 23Z...BUT TRANSITION TO RAIN UNDERWAY WITH TEMP AT 32F. WILL LET THE CURRENT WARNINGS/ADVISORIES RIDE FOR NOW...BUT WILL LKELY BE ABLE TO CANCEL THE WESTERN COUNTIES LATER THIS EVENING. && .SHORT TERM /10 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... PRECIP SHOULD TAPER OFF ACROSS THE NORTHERN COUNTIES LATE TONIGHT...AS COLD FRONT SAGS SOUTH INTO THE REGION. FURTHER SOUTH...PRECIP WILL CONTINUE TO FALL ALONG AXIS OF LL JET AND PLUME OF HIGHER PWATS. HOWEVER...ALL NEAR TERM MDL DATA SUGGESTS A CHANGEOVER TO PLAIN RAIN...AS LOW LVL COLD AIR IS SCOURED OUT. && .LONG TERM /WEDNESDAY THROUGH TUESDAY/... AN ACTIVE LATE-WINTER PRECIPITATION PATTERN WILL IMPACT CENTRAL PA THROUGH MIDWEEK FOLLOWED BY WHAT IS HOPEFULLY THE LAST SHOT OF ARCTIC AIR FOR THE SEASON THURSDAY INTO FRIDAY. THE PATTERN SHOULD DRY OUT LATE IN THE WEEK THROUGH THE UPCOMING WEEKEND WITH HIGH PRESSURE IN CONTROL MOST OF THE TIME. THE GENERAL MODEL AND ENSEMBLE CONSENSUS IS TO MAINTAIN A RIDGE IN THE WEST AND TROUGH IN THE EAST THROUGH THE WEEKEND WITH SOME SIGNS OF A PATTERN SHIFT BY THE MIDDLE OF NEXT WEEK WITH TROUGHING FCST TO DEVELOP ALONG THE WEST COAST. BELOW NORMAL TEMPS SHOULD MODERATE CLOSER TO NORMAL EARLY NEXT WEEK WITH SOME HINTS AT EVEN WARMER TEMPS LATER NEXT WEEK. MODELS CONTINUE TO SHOW AN AMPLIFIED AND MOIST SW FLOW ALOFT AND JET ENTRANCE REGION DYNAMICS SUPPORTING A BROAD STRIPE OF PCPN ALONG A WELL DEFINED BAROCLINIC ZONE AHEAD OF PHASING UPPER LEVEL ENERGY OVER THE DSW/ROCKIES ON WED AND MOVING EWD THROUGH THE OH VLY AND MID ATLC ON THURSDAY. SEVERAL WAVES OF LOW PRESSURE ARE FCST TO DEVELOP AND MOVE ENEWD ALONG A SW-NE ORIENTED COLD FRONT WHICH SHOULD PROGRESS AND SETTLE SEWD THROUGH THE MID ATLC REGION BY EARLY THURS...AS ARCTIC HIGH PRESSURE BUILDS INTO THE UPPER PLAINS. AMPLE MOISTURE IS FCST BY THE MODELS TO MOVE INTO A DEEPENING COLD SECTOR ALONG/NORTH OF THE SEWD-ADVANCING COLD FRONTAL BOUNDARY WHICH COULD RESULT IN A LATE SEASON HEAVY SNOW EVENT FOR SOUTH CENTRAL PA WED NGT INTO THURS. THERE ARE MODEL DIFFERENCES WITH THE TIMING OF THE FRONT WHICH IS LKLY TIED TO THE CONSOLIDATION OF SHORTWAVE ENERGY UPSTREAM. THAT SAID...THE CONSENSUS FCST AXIS OF MAX QPF /0.50 INCH OR GREATER/ HAS BEEN FAIRLY CONSISTENT PAINTED OVER THE SRN 1/3 OF THE CWA. SIMILAR TO YESTERDAY...USED A MULTI MODEL BLEND WITH PSEUDO BIAS CORRECTION FACTOR TO DERIVE GRIDDED QPF AMTS WHICH GENERALLY RANGE FROM 0.25 TO 0.75 INCHES ACROSS THE SRN 1/2 OF THE CWA. THE COLUMN WILL BE IN A STATE OF TRANSITION AND COOLING DOWN FROM NW TO SE WED-WED NGT AS THE COLD FRONT PUSHES SOUTHEAST ACROSS THE AREA. THIS SHOULD SUPPORT A TRANSITION FROM RAIN TO SNOW. A PERIOD OF SLEET MAY IMPACT FCST SNOW ACCUMULATIONS WITH THE DURATION A KEY FACTOR IN THIS FCST. WITH INCREASING CONFIDENCE AND GREATEST RISK IN THE POTENTIAL FOR HEAVY SNOW/6+ INCHES...WHICH IS SUPPORTED BY ROBUST WPC ENSEMBLE AS WELL AS THE GEFS MEAN...HAVE ISSUED A WINTER STORM WATCH FOR THE SOUTH-CENTRAL COUNTIES FROM WEDNESDAY EVENING THROUGH THURSDAY EVENING. WHAT IS HOPEFULLY THE LAST SHOT OF ARCTIC AIR THIS SEASON SHOULD ARRIVE BEHIND THE COLD FRONT. FRIDAY MORNING LOWS ARE LKLY TO BE 20-30F BELOW NORMAL WITH SINGLE DIGIT LOWS +/- ZERO DEGREES. SUCH READINGS MAY BREAK DAILY RECORDS. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... A WARM FRONT LIFTING NE FROM THE OH VLY WILL KEEP A LARGE AREA OF FREEZING RAIN AND SLEET ACROSS MOST OF THE AREA THIS EVENING. JST WARM ENOUGH FOR JUST RAIN...BUT GROUND AND OBJECT TEMPS LIKELY STILL COLD. THE OTHER FACTOR OVERNIGHT WILL BE LLWS. THE PRECIPITATION WILL LIKELY GO OVER TO JUST RAIN LATE TONIGHT FOR A SHORT TIME. MANY AREAS MAY JUST SEE NOTHING ONCE THE STRONGER WARM ADVECTION SHUTS OFF. FOR WED...RAIN WILL GO BACK TO SNOW FROM NW TO SE. HARD TO SEE CONDITIONS BEING VERY GOOD. VERY COLD LOW LEVEL AIR WILL BE ADVECTED BACK TO THE SOUTH LATE WED INTO THU. A SERIES OF WEAK LOW PRESSURE SYSTEMS WILL TRACK ALONG THE COLD FRONT FROM LATE WED INTO THU...LIKELY GIVING AT LEAST SOUTHERN PA SOME SNOW. THE COMBINATION OF INCREASING WINDS...SNOW...AND FALLING TEMPERATURES WILL LIKELY RESULT IN POOR CONDITIONS FOR AVIATION. IMPROVING CONDITIONS WILL SET IN FOR FRIDAY INTO MONDAY...AS COLD HIGH PRESSURE BUILDS INTO THE AREA. OUTLOOK... WED NIGHT...SIG REDUCTIONS IN SNOW DEVELOPING MAINLY ACROSS THE SOUTH. THU...SLOWLY IMPROVING CONDITIONS...LINGERING MVFR NW AND SE. FRI-SAT...MAINLY VFR. SUN...MVFR WITH CHC -SHSN MAINLY NORTH AND WEST. VFR SE. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR PAZ004- 010-017-019-024>028-033>036-042-045-046-049>053-056>059- 063>066. WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY EVENING FOR PAZ024>028-033>036-056>059-063>066. WINTER STORM WARNING UNTIL 7 AM EST WEDNESDAY FOR PAZ005-006- 011-012-018-037-041. && $$ SYNOPSIS...DEVOIR NEAR TERM...DEVOIR/FITZGERALD SHORT TERM...DEVOIR LONG TERM...STEINBUGL AVIATION...MARTIN

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