Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 252120 AFDCTP Area Forecast Discussion National Weather Service State College PA 420 PM EST Sat Feb 25 2017 .SYNOPSIS... A line of thunderstorms capable of damaging winds are forecast this afternoon across east-central Pennsylvania. Gusty winds and noticeably colder temperatures will follow behind a cold front later today into tonight with scattered snow showers across the Alleghenies. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Severe thunderstorm risk is now focusing on the Lower Susq. Valley. SPC issued Severe Thunderstorm Watch #39 through 26/01z. Latest radar trends indicate a substantial increase in coverage and intensity of thunderstorms and lightning across NVA/MD tracking ENEWD toward/into southeast PA. 18z SPC mesoanalysis shows an area of 500 J/kg of MLCAPE over the LSV with dewpoints near 60F. Strong winds aloft and focused forcing along cold front is supportive of fast-moving bowing structures capable of producing damaging winds. Risk for severe storms ends by 22z as the cold front pushes east of the area. The watch will likely need to be cancelled a few hours early. A period of brisk and colder west winds will follow behind the FROPA with peak gusts 45-50mph on the highest ridges in Laurels. A few snow showers will also spill downwind of Lake Erie and over the higher terrain along the Alleghenies. Little to no accumulation is expected. Low temps will bottom out in the 20s north to around 30 in the south -- a remarkable 30 to 40 degrees colder than yesterdays record warmth. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... Morning flurries and scattered snow showers will come to an end by the afternoon over the NW mtns with winds continuing to decrease as high pressure moves over the area. Temperatures will return to near or slightly below average for late February - but it will feel much colder given the recent run of magnificent spring-like warmth. High pressure shifts off the Mid Atlantic coast Sunday night with clouds increase ahead of shortwave tracking through the Mid MS/OH Valley. Model blend keeps pcpn well to the SW of the area through daybreak Monday. && .LONG TERM /MONDAY THROUGH SATURDAY/...
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Weak shortwave brings chance for light precip on Monday, though lower levels look fairly dry as surface high exits eastward. Elongated low developing over the central U.S. on Tue will edge a warm frontal boundary toward the region, bringing chance for light precipitation and ushering in another round of warmer than normal temperatures (though not as high as the past few days). By Wed, upper wave catches up to the low, bringing a more significant rainfall, followed by a cold frontal passage. Colder and very breezy conditions then in store for late week in NW flow, along with sct lake effect snow showers in the NW Mtns. Cooler air lingers into the weekend as upper flow remains from the NW while 1037mb surface high pressure slides through. Yet another weather system slides through the Great Lakes this weekend, with center of low remaining to our north. But shower chances increase for the NW half.
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&& .AVIATION /21Z SATURDAY THROUGH THURSDAY/... 25/18z| Coverage and intensity of thunderstorms is increasing early this afternoon from NVA into SE PA with main focus for severe storms now over the southeast 1/4 of the airspace. Main risk is for strong to locally damaging winds (40+KT) impacting KMDT/KLNS airspace 19-21z. Gusty winds (25-35KT) expected behind cold front with wind shift to 250-300 degrees by this evening. Expect shower activity to taper off from west to east behind the front later this afternoon into the evening. Colder air will filter into the area with scattered light snow showers/flurries developing downwind of Lake Erie and across the higher terrain of western PA with some lower CIGs and brief visby reductions psbl into Sunday. Outlook... Sun...MVFR/-shsn west bcmg VFR. Mainly VFR central-east. Decreasing winds. Mon...Mainly VFR. Chance of rain. Tue-Wed...Rain showers/Sub-VFR reductions likely. Thu...Strong FROPA with gusty winds. Sub-VFR likely west. && .CLIMATE... **Updated 11am 2/25/17** New Record high temperatures for Feb. 24: Harrisburg 2/24: 76. Previous 75 in 1985; all-time Feb record is 78F. Williamsport 2/24: 76. Previous 71 in 1985; New record high temperature for the month of February. Altoona 2/24: 75. Previous 69 in 1985; New record high temperature for the month of February. Bradford 2/24: 69. Previous 59 in 1961; New record high temperature for the month of February. State College 2/25: 74. New record high temperature for February and meteorological winter (DJF). ----------------------------------------------------------- Warmest February on Record (Avg. Temperature through 2/24) Harrisburg: 2017 rank=1 (40.8) 2. 40.4 in 1998 3. 39.6 in 1976 4. 39.4 in 1954 Williamsport: 2017 rank=1 (37.6) 2. 37.0 in 1998 3. 36.1 in 1954 4. 35.6 in 2002 Altoona: 2017 rank=1 (39.3) 2. 37.4 in 1976 3. 36.2 in 1998 4. 35.9 in 1990/1954 Bradford: 2017 rank=T1 (32.3) 1. 32.3 in 1998 2. 30.1 in 2002 3. 29.6 in 2012 4. 29.5 in 1990/1976 ------------------------------------------------------------- && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Steinbugl NEAR TERM...Steinbugl SHORT TERM... LONG TERM...RXR AVIATION...Steinbugl CLIMATE...

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