Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 262014 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 314 PM EST WED NOV 26 2014 .SYNOPSIS...
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A STORM SYSTEM WILL DEEPEN SIGNIFICANTLY AS IT MOVES UP THE EAST COAST TODAY...BRINGING WIDESPREAD MODERATE TO HEAVY SNOW TO MUCH OF CENTRAL PENNSYLVANIA. ANOTHER SHOT OF COLDER AIR WILL FOLLOW FOR THE END OF THE WEEK...BEFORE TEMPERATURES MODERATE OVER THE WEEKEND AND INTO EARLY NEXT WEEK.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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AT 10AM /15Z/...CENTER OF DEEPENING STORM NEAR MOREHEAD CITY NC. STRONGEST PRESSURE FALLS CONTINUE TO SUGGEST THE NEAR TERM TRACK WILL BE SLIGHTLY EAST OF NORTH TAKING IT OVER THE OUTER BANKS AND THEN JUST EAST OF SOUTHERN DELMARVA BY 18Z...AND LEANING A BIT FURTHER EASTWARD OFF THE NJ COASTLINE AT 00Z THU. MAIN THINKING HAS NOT CHANGED WITH A SIGNIFICANT CYCLONE DEEPENING AND MOVING UP THE EAST COAST IN RESPONSE TO A STRONG SHORTWAVE MOVING THROUGH THE SERN U.S. ON ITS WAY TOWARD TAKING ON A STRONG NEG TILT AS IT EJECTS UP THE EAST SIDE OF THE LARGER SCALE TROUGH DIGGING INTO THE OHIO VALLEY. STRONG UPPER JET /300MB SPEEDS >150KTS/ SLIDING EASTWARD ACROSS PA THIS AFTERNOON WILL KEEP WIDESPREAD SNOWS ONGOING...WITH COLDEST CLOUD TOPS SHIFTING EASTWARD AS WELL. MODELS SHOW STRONG LAYERED FRONTOGENTIC FORCING UNDER THIS JET ENTRANCE REGION...WITH THE STRONGEST FORCING EXTENDING FROM CENTRAL PA EAST AND NORTHEAST. PRECIP DID START OUT AS A SEVERAL HOUR PERIOD OF RAIN IN THE LOWER SUSQ BEFORE QUICK EVAPORATIVE COOLING BROUGHT A CHANGEOVER TO ALL SNOW BY MID MORNING. ON THE NW EDGE OF PRECIP BAND...HEAVIER SNOW DEVELOPED WITH A NARROW CORRIDOR RECEIVING SEVERAL INCHES OF SNOW OVER JUST A COUPLE OF HOURS IN PORTIONS OF SOUTHERN AND CENTRAL MTNS. ITS BEGINNING TO LOOK LIKE THAT BAND WILL BE THE WESTERN EXTEND OF THE HEAVIEST ACCUMULATIONS AS COLDEST CLOUD TOPS NOW SHIFTING E/NE. THOUGH SNOW WILL PERSIST THROUGH THE AFTERNOON ACROSS THE WEST...RAPID ACCUM RATES LIKE WE/VE SEEN OVER PAST COUPLE OF HOURS /1-3 INCHES PER HOUR/ WILL DROP OFF NOTICEABLY. FOCUS FOR HEAVIEST SNOWS OVER NEXT 6 HRS WILL BE EASTERN HALF OF CWA...ESP IN THE CORRIDOR THAT HIGHEST AMOUNTS HAVE BEEN FORECAST LEADING UP TO THE EVENT. A BAND OF 6 TO LOCALLY AS MUCH AS 9-10 INCHES STILL LOOKS REALISTIC...WITH LESSER AMOUNTS TO THE NW AND SE OF THAT BAND /IN PLACES LIKE STATE COLLEGE AND HARRISBURG METRO/. ACTIVITY STARTS TO TAPER OFF FOR THE LATTER HALF OF THE DAY. AN OLD RULE OF THUMB HAS PRECIP WINDING DOWN RAPIDLY ONCE THE SURFACE CYCLONE MOVES NORTH OF OUR LATITUDE SO BY EVENING MOST OF THE AREA SHOULD HAVE SEEN THE WORST OF THE STORM. TEMPS TODAY HAVE/WILL FALL OFF A BIT AS PRECIP BEGINS..THEN STAY PRETTY MUCH STEADY THROUGHOUT THE DAY.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... HI RES MODELS SHOW PRECIP WINDING DOWN RAPIDLY EARLY THIS EVENING AS DISCUSSED BEFORE WHEN STORMS REACH THEN EXCEED OUR LATITUDE. NOT MUCH MORE THAN THE USUAL LEFT-OVER SNOW SHOWER ACTIVITY IS EXPECTED IN THE DEVELOPING COLD ADVECTION THAT WILL MOVE IN BEHIND THE DEPARTING STORM SYSTEM. THE AIR THAT WILL MOVE IN BEHIND OUR STORM WILL BE COLDER BUT NOT ESPECIALLY SO...WITH LOWS IN THE 20S IT WILL ONLY BE A TAD BELOW NORMAL. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... ANOMALOUSLY LOW HEIGHTS OVER THE EASTERN US EARLY IN THE PERIOD WILL FLATTEN OUT INTO A BROAD ZONAL FLOW DURING THE WEEKEND. THIS WILL PROMPT A WARM-UP AS THE CYCLONE TRACK SHIFTS TOWARD THE GREAT LAKES AND HIGH PRESSURE MOVES OFF TO OUR SOUTHEAST. THE SHOT OF COLD AIR THAT WILL MOVE INTO THE REGION IN THE WAKE OF OUR STORM WILL BEGIN MODERATING BY SATURDAY...WITH READINGS IN THE MILD RANGE TAKING OVER BY SUNDAY. MODELS IN DECENT AGREEMENT IN DROPPING A WEAK COLD FRONT THROUGH THE AREA SOMETIME SUNDAY NIGHT OR MONDAY. THIS WILL BE THE BEST CHANCE OF PRECIP DURING THE PERIOD...AND EVENTUALLY COOL US OFF A BIT FOR EARLY NEXT WEEK. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
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LOW PRESSURE OFF THE CAROLINA COAST WILL CONTINUE TO PRODUCE PERIODS OF LIGHT TO MODERATE SNOW OVER CENTRAL PA INTO THE EARLY EVENING HOURS. HOWEVER...CIGS AND VSBYS ARE GENERALLY IMPROVING ATTM AS THE HEAVIEST SNOW BANDS HAVE MOVED NORTH OF THE STATE. EXPECT LOW CIGS TO PERSIST OVER THE WRN 1/3 OF THE AREA TONIGHT WITH IMPROVEMENTS TO VFR ELSEWHERE. AFTER 03Z THURSDAY...CIGS AND VSBYS SHOULD IMPROVE...BUT SHOULD REMAIN MVFR AT MOST TAF SITES LATE WEDNESDAY NIGHT. NORTHWESTERLY FLOW BEHIND THE LOW SHOULD ALLOW IFR TO CONTINUE AT BFD AND JST. OUTLOOK... THU...IFR/MVFR WITH OCNL -SHSN WRN 1/3. VFR TO MVFR CIGS CNTRL/EAST. FRI...AM MVFR/-SHSN NW...OTHERWISE BCMG VFR. SAT-SUN...MAINLY VFR. ISOLD -SHRA PSBL. MON...COLD FROPA. MAINLY VFR. SCT -SHRA PSBL.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 4 AM EST THURSDAY FOR PAZ019-042- 045-046-049>053. WINTER WEATHER ADVISORY UNTIL 4 AM EST THURSDAY FOR PAZ012-017- 018-037-041. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR PAZ024>028- 033>036-056>059-063>066. && $$ SYNOPSIS...LA CORTE/RXR NEAR TERM...LA CORTE/RXR SHORT TERM...LA CORTE LONG TERM...LA CORTE/GARTNER AVIATION...CERU/GARTNER

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