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 241205 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 705 AM EST WED DEC 24 2014 .SYNOPSIS...
-- Changed Discussion --
AN INTENSIFYING STORM SYSTEM OVER THE LOWER OHIO RIVER VALLEY THIS MORNING WILL MOVE NORTH-NORTHEAST ACROSS THE GREAT LAKES THIS EVENING. A PLUME OF UNSEASONABLY MOIST AIR WITH GULF OF MEXICO ORIGIN WILL HELP TO CREATE A LARGE AREA OF RAIN ACROSS THE REGION TODAY. THE ASSOCIATED TRAILING COLD FRONT WILL PUSH THROUGH CENTRAL PENNSYLVANIA TONIGHT. STRONG AND GUSTY WEST WINDS WILL OCCUR BEHIND THE FRONT LATE TONIGHT AND THURSDAY. ANOTHER LESS POTENT COLD FRONT WILL MOVE ACROSS THE AREA THIS WEEKEND.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 PM THIS EVENING/... A LARGE SHIELD OF RAIN ENCOMPASSES ALL BUT THE EXTREME NW CORNER OF THE CWA ATTM. STEADY LIGHT TO MDT RAIN WILL FALL THROUGH 14Z TDY. AFTERWARD...THE PRIMARY AXIS OF THE RAIN WILL GRADUALLY SHIFT TO THE SE HALF OF THE CWA FOR THE LATE MORNING AND AFTERNOON HOURS AS A STRONG SSWRLY 850 MB JET OF 60-70 KTS LIFTS ACROSS THE SUSQ VALLEY. INCREASINGLY STRONG SOUTHERLY FLOW JUST A FEW TO SEVERAL KFT ABOVE THE SFC /PLUS 2-3 SIGMA AT 850 MB VIA THE LATEST SREF/ WILL ADVECT ABUNDANT MOISTURE INTO THE REGION TODAY IN THE FORM OF LIGHT TO MODERATE RAIN. PWATS INCREASING TO NEARLY PLUS 4 SIGMA /OR 1.25 TO 1.5 INCHES/ THIS MORNING WILL BRING WIDESPREAD 0.5 TO 0.75 INCH AMOUNTS OF RAIN ACROSS MOST OF CENTRAL AND ERN PENN BY LATE THIS MORNING. THE RAIN COULD FALL HEAVY AT TIMES NEAR AND TO THE EAST OF THE I-81 CORRIDOR...WHERE RAINFALL TOTALS OF 1-1.3 INCHES ARE LIKELY BY THIS EVENING. THE COOL...NEAR SFC EAST TO SERLY FLOW AHEAD OF THIS LLJ MAX AND SFC WARM FRONT /WITH UP TO AN 8C SFC BASED INVERSION/ WILL LEAD TO WIDESPREAD LOW STRATUS AS THE BOTTOM OF THE MULTI-LAYER CLOUD DECK. THE TOP HALF OF MOST RIDGES WILL CONTINUE TO BE OBSCURED BY THIS CLOUD DECK. TEMPS THROUGH THE MID MORNING WILL BE IN THE LOWER TO MID 40S IN MOST LOCATIONS /EXCEPT FOR THE LOWER SUSQ REGION THAT WILL SEE MID TO UPPER 40S/. WINDS WILL BE GENERALLY LIGHT FROM THE EAST TO SOUTHEAST...BUT GUSTS AROUND 20 MPH WILL BE LIKELY ON THE HIGHER TERRAIN...AND INVOF KIPT WHERE CHANNELING EFFECTS OF THE EAST/WEST VALLEY WILL ACCENTUATE SPEEDS. FOR THE MID TO LATE AFTN HOURS...THE HIGH RES WRF ARW AND HRRR INDICATES THE RAIN SHOULD TAPER OFF AS DRY SLOT WORKS IN FROM THE SW. STEADIER RAIN WILL LIKELY CONTINUE TO FALL ACROSS THE LOWER SUSQ VALLEY BETWEEN 19-23Z WHERE LOCALLY AROUND 1.5 INCHES IS POSSIBLE OVER THE PRECEDING 12-15 HOUR PERIOD. MUCH LIGHTER AMTS EXPECTED ACROSS THE NW MTNS TDY. HIGH TEMPS LATE THIS AFTERNOON WILL VARY FROM THE MID 40S ACROSS THE NRN MTNS...TO THE UPPER 50S ACROSS THE LOWER SUSQ VALLEY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... HI RES MODELS INDICATING LIKELY A SQUALL LINE TO ACCOMPANY SFC COLD FRONT...THAT WILL BE LAGGING THE UPPER FRONTAL PASSAGE THIS EVENING. EXTENT OF SURFACE DESTABILIZATION WILL ULTIMATELY DETERMINE HOW STRONG THIS SQUALL LINE CAN GET/STAY AS IT MOVES INTO THE WESTERN THIRD OF OUR CWA BETWEEN 01-04Z THURSDAY. AS NOTED BY PREVIOUS SHIFTS...THIS IS EASILY ONE OF THE BETTER SEVERE WEATHER SETUPS FOR CHRISTMAS EVE /AT LEAST ACROSS THE WRN MTNS...WHERE UP TO A FEW HUNDRED J/KG OF MU/ML CAPE IS FCST TO DEVELOP THIS EVENING/. THE POTENTIAL EXISTS FOR SCTD WIND GUSTS OF 40-45 KTS WITHIN THE ANTICIPATED NCFRB. EVEN MINIMAL CAPE COMBINED WITH STRONG /DEEP-LAYER WIND FIELDS A FEW TO SVRL KFT AGL OFTEN RESULTS IN A NCFRB WITH LOCALIZED DOWNBURST DAMAGE OCCURRING BENEATH MINI BOWS IN THE LINE. SPC HAS PLACED MUCH OF CENTRAL PA IN MARGINAL CATEGORY FOR DAY 2 AS A RESULT. MORE DETAILS BELOW. THE ALREADY MILD TEMPS LATE THIS AFTERNOON...WILL CLIMB UP TO SEVERAL DEG F...INTO THE U40S TO U50S TONIGHT...AS STRONGER SOUTHERLY WINDS DEVELOP AT THE SFC AND ALOFT. THE WARMEST READINGS OVR MUCH OF THE AREA MAY NOT BE REACHED UNTIL AFTER DARK THIS EVENING. GUSTY WESTERLY WINDS /BETWEEN 35 AND 45 MPH/ AND SCTD...MAINLY MTN SNOW SHOWERS WILL BE THE FEATURED CONDITIONS FOR CHRISTMAS DAY. TEMPS WILL BE STEADY OR SLOWLY FALLING FOR MUCH OF THE DAY THURSDAY...AFTER THE INITIAL DROP OF 10F OR SO IMMEDIATELY FOLLOWING THE CFROPA VERY EARLY ON. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... MORE TRANQUIL WEATHER DEVELOPING FOR THURSDAY NIGHT AND FRIDAY... WITH SW FLOW. DID UP TEMPS FRIDAY INTO SAT...GIVEN RISING HEIGHTS. CUT BACK PCPN FOR LATE FRIDAY. 12Z EC RUN HAS SYSTEM FURTHER NW NOW...BUT FOR NOW WENT WITH SLIGHT CHC OF SNOW FROM SUNDAY INTO EARLY MONDAY MORNING. AGAIN WITH SPLIT FLOW...THERE COULD BE SOME CHANCE FOR A SOUTHERN WAVE TO BRING SOME RAIN OR SNOW SHOWERS TO THE AREA AT TIMES...BUT IT LOOKS LIKE ANYTHING WOULD BE FAST MOVING. PERHAPS A CHANGE LATER NEXT WEEK...AS CROSS POLAR FLOW SETS UP. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
WIDESPREAD REDUCTIONS IN PLACE THIS MORNING /WITH MOST TERMINALS REPORTING IFR CONDITIONS AT 12Z/ WILL CONTINUE THROUGH THE DAY AS AN INTENSIFYING STORM SYSTEM OVER THE LOWER OHIO RIVER VALLEY MOVES NNE ACROSS THE GREAT LAKES PUSHING A PLUME OF UNSEASONABLY MOIST AIR INTO AN ALREADY MOIST AIRMASS OVER PA. AN AREA OF RAIN WILL ALSO IMPACT MUCH OF THE CWA TODAY. THE ASSOCIATED TRAILING COLD FRONT WILL PUSH THROUGH CENTRAL PENNSYLVANIA TONIGHT. STRONG AND GUSTY WEST WINDS WILL OCCUR BEHIND THE FRONT TONIGHT AND THURSDAY. INCLUDED LLWS FOR ALL TAF SITES INITIALLY THIS MORNING AS WINDS ALOFT BEING TO INCREASE AHEAD OFF APPROACHING FRONTAL SYSTEM OVER THE MIDWEST WHILE SFC WINDS REMAIN SERLY. ANOTHER BOUT OF LLWS MOVES IN TONIGHT WITH STRONG WESTERLY FLOW BEHIND COLD FRONT. OUTLOOK... THU...WINDY AND COLDER WITH SCT MVFR CIGS AND -SHSN. LLWS. FRI...FAIR AND MOSTLY VFR. SAT...FAIR AND MOSTLY VFR. SCT SHSN WITH LOCAL REDUCTIONS NW. SUN...MVFR TO IFR WITH CHC RA/SN...ESP SOUTH.
-- End Changed Discussion --
&& .CTP WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 8 PM THIS EVENING TO NOON EST THURSDAY FOR PAZ004>006-010>012-017-018-024-033. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...LAMBERT LONG TERM...LAMBERT/MARTIN AVIATION...RXR

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