Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 281907 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 207 PM EST SAT FEB 28 2015 .SYNOPSIS... HIGH PRESSURE OVER PENNSYLVANIA WILL PASS OFF THE NEW ENGLAND COAST THIS EVENING. LOW PRESSURE TRACKING UP THE OHIO VALLEY SUNDAY WILL CROSS PENNSYLVANIA SATURDAY NIGHT...BRINGING SNOW AND MIXED PRECIPITATION TO CENTRAL PA THROUGH EARLY MONDAY MORNING. A STRONGER AREA OF LOW PRESSURE WILL LIKELY TRACK WEST OF PENNSYLVANIA LATE TUESDAY AND EARLY WEDNESDAY. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... TEMPS HAVE REBOUNDED NICELY UNDER SUNNY SKIES AFTER A FRIGID EARLY MORNING UNDER THE 1044 MB RIDGE. EARLY AFTERNOON READINGS RANGE FROM MID TEENS NORTH TO AROUND 20 SOUTHEAST. FAIR AND STILL COLD CONDITIONS EXPECTED THROUGH THIS EVENING AS SFC HIGH DRIFTS OVR THE REGION. REGIONAL IR LOOP INDICATES MID LEVEL CLOUDS ASSOCIATED WITH AN UPPER SHORTWAVE OVER INDIANA AND OHIO...WHICH WILL TRACK INTO THE WEST CENTRAL MOUNTAINS AND LAUREL HIGHLANDS MID TO LATE AFTERNOON. ONLY IMPACT WILL BE TO DIM THE BRIGHT SUNSHINE LATE THIS AFTERNOON...AS HIGHS REACH 20-25 IN MOST AREAS. && .SHORT TERM /8 PM THIS EVENING THROUGH SUNDAY NIGHT/... UPCOMING PRECIP WILL EXTEND BETWEEN A 12-24 HOUR EVENT... MEANING THAT 24 HOUR WATCH/WARNING CRITERIA MUST BE USED TO VERIFY AMOUNTS. HERE IN CENTRAL PA...THAT MEANS A MID POINT OF 8" MUST ACCUMULATE IN 24 HOURS FOR WARNING CRITERIA TO BE MET...AND THE OVERWHELMING CONSENSUS AFTER LOOKING AT MORNING DATA SUITE IS THAT WE WON`T SEE THAT EXCEPT FOR SPOT AMOUNTS ACROSS THE NORTHWEST OR WEST CENTRAL MOUNTAINS WHERE WATCHES WERE IN EFFECT. COLLAB WITH ALL SURROUNDING OFFICES HAS PROMPTED ADVISORY ISSUANCES FOR ALL OF MY COUNTIES. ACROSS THE NORTHWEST...A GENERAL 6 TO 8 INCHES IS EXPECTED...WHILE ELSEWHERE 2 TO 4 INCHES AND A COATING OF ICE WILL BE COMMON. FOR THE FAR SOUTH AND SOUTHEAST... A COATING TO LESS THAN TWO INCHES OF SNOW IS EXPECTED TO BE FOLLOWED BY ONE TO TWO TENTHS OF AN INCH OF FREEZING RAIN. LITTLE IN THE WAY OF WIND MEANS THIS SHOULD NOT BE A PARTICULARLY DAMAGING OR DISRUPTIVE EVENT (IN TERMS OF POWER, ETC). BLEND OF MORNING MDL OUTPUT BRINGS LIGHT SNOW INTO THE WEST CENTRAL MOUNTAINS BEFORE DAWN SUNDAY. FOR THE REST OF CENTRAL PA...LGT SNOW IS LIKELY TO ARRIVE BY LATE AM. AGREE WITH PREVIOUS THINKING THAT HEAVIEST PRECIP WILL LIKELY HOLD OFF UNTIL STRONGER FORCING ARRIVES WITH APPROACH OF N STREAM SHORTWAVE DIVING ACROSS THE GRT LKS SUNDAY PM. ASSOC LL JET AND SURGE OF WARMER AIR ALOFT WILL LKLY CHANGE LGT SNOW TO A WINTRY MIX ACROSS SOUTHERN PA LATE SUNDAY AND SUNDAY EVENING...WHILE MDL SOUNDINGS AND ENSEMBLE PTYPE PLUMES INDICATE ALL SNOW ACROSS AREAS NORTH OF I-80. THE TRANSITION TO FREEZING RAIN SHOULD TAKE PLACE FROM LATE AFTERNOON THROUGH LATE EVENING SUNDAY ACROSS THE SOUTHERN HALF OF MY CWA. PRECIP LOOKS TO TAPER OFF IN ALL AREAS DURING THE PRE DAWN HOURS MONDAY MORNING. && .LONG TERM /MONDAY THROUGH SATURDAY/... BLUSTERY AND COLDER CONDITIONS WILL MAKE A RETURN ON MONDAY AS SYSTEM NUMBER ONE SLIDES OFF TO OUR EAST. OTHER THAN THE USUAL POST FRONTAL SNOWS SHOWERS...FAVORING WESTERN HIGHER ELEVATIONS...CONDITIONS WILL BE IMPROVING OVERALL. HIGH PRESSURE WILL BE SHORTLIVED MONDAY NIGHT INTO TUESDAY WHEN THE NEXT IN THE SERIES OF STORM SYSTEMS IS SLATED TO ENTER THE LOCAL WEATHER SCENE. THIS ONE PROMISES MORE OF A MESSY OUTCOME AS IT SHOULD TRACK WELL TO OUR NW...MEANING WARM AIR EVENTUALLY INVADING THE REGION...WITH A SNOW TO SLEET/FREEZING RAIN AND EVEN RAIN SCENARIO. SNOW AMOUNTS DO NOT LOOK TO BE THE BIGGEST PART OF THE MIDWEEK STORM AS WE ARE PROGGED TO WARM ALOFT RATHER QUICKLY. WITH A DEEP SNOW PACK AND A LOT OF COLD AIR TO DISPLACE...WE WILL LIKELY SEE A PERIOD OF ICING BEFORE WARM AIR EVENTUALLY CHANGES EVERYTHING TO RAIN TUESDAY NIGHT INTO WEDNESDAY. RAIN SHOULD TAPER OFF TO SCATTERED SHOWERS WITH THE PASSAGE OF THE TRAILING COLD FRONT EARLY WEDNESDAY. EARLIER MODEL RUNS SUGGESTED LATER WEDNESDAY INTO THURSDAY THERE COULD BE A RETURN OF SNOW TO SRN PA ASSOCIATED WITH A FLAT SRN STREAM WAVE...BUT LATEST OPERATIONAL ECMWF/GFS NOW KEEP THE SURFACE WAVE SUPPRESSED MAINLY SOUTH OF THE REGION..HINTING THAT ONLY FAR SERN AREAS WILL BE AT RISK FOR A PERIOD OF OVER RUNNING SNOW. THE 06Z GEFS IS A LITTLE MORE GENEROUS WITH THE POPS SO IT`S NOT OUT OF THE QUESTION THAT SOMETHING WILL YET HAPPEN AS MODELS TRY AND RESOLVE SMALL SCALE FEATURES DROPPING OUT OF CENTRAL CANADA INTO THE EASTERN US LONG WAVE. TOO FAR OFF TO LEAN ONE WAY OR ANOTHER FOR A SOLUTION. BEHIND THE MID WEEK SYSTEM...ANOTHER PUSH OF ARCTIC AIR WILL BRING TEMPS AND POPS BACK WELL BELOW NORMAL FOR LATE THURSDAY INTO FRIDAY. THE ONLY GOOD THING SEEMS TO BE EACH ARCTIC SHOT IS A LITTLE LESS POTENT THAN THE LAST AS WE LEAVE THE RECORD COLD OF FEBRUARY BEHIND. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... SURFACE HIGH PRESSURE WILL DRIFT SLOWLY EAST THROUGH TONIGHT. CONDITIONS WILL REMAIN VFR INTO TONIGHT...WITH LITTLE MORE THAN SOME HIGH CLOUDINESS PASSING OVERHEAD DURING THE DAY BEFORE MID DECK THICKENS THIS EVENING. WINDS WILL BE LIGHT THROUGH THIS PERIOD. CONDITIONS WILL BEGIN TO DETERIORATE LATE TONIGHT INTO SUNDAY...AS A WAVE OF LOW PRESSURE SLIDES FROM OKLAHOMA THROUGH THE MIDWEST AND INTO PA AT THE SAME TIME THE NORTHERN STREAM TROUGH BEGINS TO DIG. AN EXPANDING AREA OF WAA TYPE SNOWFALL WILL SPREAD IN FROM THE OHIO VALLEY STARTING AROUND 09Z. AT THE SAME TIME...CLOUDS WILL THICKEN AND LOWER WITH WIDESPREAD RESTRICTIONS DEVELOPING FROM W TO E. THE SNOW IS EXPECTED TO CHANGE TO A WINTRY MIX ACROSS SRN PA LATER SUNDAY. CONDITIONS SHOULD BEGIN TO IMPROVE ON MONDAY AND REMAIN GOOD INTO EARLY TUESDAY...BEFORE THE NEXT SYSTEM PUSHES ANOTHER ROUND OF PRECIP AND REDUCED FLYING CONDS INTO THE AREA. OUTLOOK... TONIGHT...SNOW OVERSPREADING THE AREA FROM W TO E AFTER MIDNIGHT. RESTRICTIONS DEVELOPING FROM W TO E. SUN...WIDESPREAD RESTRICTIONS. PRECIP SHOULD REMAIN ALL SNOW ACROSS NRN PA...WHILE MIXING W/ SLEET AND FREEZING RAIN ACROSS THE SOUTH. MON...CONTINUED CIG/VIS REDUCTIONS POSSIBLE...MAINLY AM. TUE...VFR AM. MIXED PRECIP WITH CIG/VIS REDUCTIONS POSSIBLE LATE. TUE NIGHT-WED...CIG/VIS REDUCTIONS CONTINUE IN WINTRY MIX/RAIN. && .CLIMATE... THE COLDEST FEBRUARY ON RECORD IS STILL LOOKING LIKELY. MONTHLY MEAN TEMPERATURES THROUGH THE 27TH...IPT 18.2...MDT 20.9. THE CURRENT RECORD COLDEST FEBRUARY..IPT 19.3...MDT 21.4 BOTH SET IN 1934. SO FAR...THIS MONTH IS THE THIRD COLDEST EVER AT IPT...AND FOURTH COLDEST EVER AT MDT. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 7 AM SUNDAY TO 7 AM EST MONDAY FOR PAZ006-012-018-019-024>028-033>037-041-042-045-046-049>053- 056>059-063>066. WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO 7 AM EST MONDAY FOR PAZ004-005-010-011-017. && $$ SYNOPSIS...DEVOIR NEAR TERM...DEVOIR SHORT TERM...DEVOIR LONG TERM...LA CORTE AVIATION...DEVOIR/RXR CLIMATE...LA CORTE

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