Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 261259 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 759 AM EST WED NOV 26 2014 .SYNOPSIS... A STORM SYSTEM FORMING OFF THE SOUTHEAST COAST 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. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 6 AM...THE STORM IS JUST WEST OF MYRTLE BEACH SOUTH CAROLINA. STRONGEST PRESSURE FALLS SUGGEST THE NEAR TERM TRACK UP ALONG THE NORTH CAROLINA COAST OVER OR WEST OF CAPE HATTERAS. MAIN THINKING HAS NOT CHANGED WITH A SIGNIFICANT CYCLONE EXPECTED TO DEEPEN AND MOVE UP THE EAST COAST IN RESPONSE TO A STRONG SHORTWAVE MOVING THROUGH THE SERN US 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. SATELLITE SHOWS CLOUD TOPS COOLING AND ENHANCING UNDER THE STRONG ANTICYCLONICALLY CURVED UPPER JET STREAK MOVING THROUGH THE LOWER LAKES-EASTERN CANADA. MODELS SHOW STRONG LAYERED FRONTOGENTIC FORCING UNDER THIS JET ENTRANCE REGION SLIDING UP AND OVER THE REGION TODAY...WITH THE STRONGEST FORCING EXTENDING FROM CENTRAL PA EAST AND NORTHEAST. PRECIP HAS REACHED MY SOUTHERN ZONES...SO FAR IN THE FORM OF RAIN. FORECAST SOUNDINGS SHOW QUICK EVAPORATIVE COOLING AND A CHANGEOVER TO ALL SNOW BY MID MORNING. A DELAYED CHANGEOVER AND MARGINAL SKIN TEMPS COULD LIMIT ACCUMULATIONS BUT WE STILL EXPECT A FAIRLY WIDESPREAD MODERATE TO HEAVY SNOW AND A MISERABLE DAY FOR HOLIDAY TRAVELERS. MADE SOME TWEAKS TO NEAR TERM SNOW FALL GRAPHICS AND POSTED THEM TO THE WEB AND OUR FACEBOOK PAGE. WE STILL EXPECT AN EARLY SEASON MODERATE TO HEAVY SNOW WITH THE HIGHEST ACCUMS FROM THE SOUTH CENTRAL MOUNTAINS EAST INTO THE POCONOS. THE WESTERN AND NORTHERN EDGE OF THE HEAVIEST SNOW IS ALWAYS HARD TO PINPOINT AND DEPENDENT ON THE TRACK OF THE SURFACE LOW WHICH CONSENSUS TAKES ABOUT 100 MILES EAST OF THE CHESAPEAKE ON A TRACK TOWARD THE SOUTHERN NEW ENGLAND 40N/70W BENCHMARK THIS EVENING. I WOULD LIKE TO SEE THE ENSEMBLES POINTING THE ANOMALOUS EASTERLY LOW LEVEL JET MORE INTO CENTRAL PA TO FEEL MORE COMFORTABLE HOW FAR BACK TO BRING WARNING SNOWS...BUT IT STILL LOOKS GOOD FOR MUCH OF THE AREA TO SEE THE SEASON`S FIRST SIGNIFICANT WIDESPREAD SNOWFALL. TIMING SUGGESTS A 6-9 HOUR PERIOD OF HEAVIEST PRECIP THIS MORNING INTO THE EARLY AFTERNOON BEFORE 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. HIGH TEMPS TODAY WILL BE EARLY AND WILL FALL OFF A BIT AS PRECIP BEGINS..THEN STAY PRETTY MUCH STEADY THROUGHOUT THE DAY. && .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 TUESDAY/... 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 /12Z WEDNESDAY THROUGH SUNDAY/...
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LOW PRESSURE CONTINUES TO DEVELOP OFF THE SOUTHEAST COAST THIS MORNING AND CONTINUES TO LIFT NWD. EXPECT RAPIDLY DETERIORATING CONDS FROM SOUTH TO NORTH THIS MORNING AS RAIN BANDS MOVE IN...AND THEN TRANSITION TO SNOW THAT WILL OVERSPREAD THE AIRSPACE BY LATE MORNING. SNOW HAS BEGUN AT JST AND AOO AND HAVE QUICKLY DROPPED TO IFR AND THESE RESTRICTIONS WILL DECREASE AND REMAIN THROUGH THE DAY. HIGH CONFIDENCE IN WIDESPREAD IFR COND THAT WILL OVERSPREAD THE REGION TODAY. EXPECT THEM TO CONTINUE UNTIL THE SNOW DECREASES TONIGHT. LOW CIGS SHOULD PERSIST OVER THE WRN 1/3 OF THE AREA WED NGT WITH MARGINAL IMPROVEMENT 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. -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 NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...CERU/STEINBUGL

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