Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 250658 AFDCTP Area Forecast Discussion National Weather Service State College PA 158 AM EST Sat Feb 25 2017 .SYNOPSIS...
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A strong cold front will plow east across the region today accompanied by a few bands of showers and perhaps a narrow line of strong, gusty thunderstorms. Gusty westerly winds and colder temperatures will follow the frontal passage. Some snow showers are also expected late today, tonight and Sunday across the western highlands. High pressure builds in from the Ohio Valley for Sunday but weak waves of low pressure will move up the Ohio River Valley Monday into Tuesday may bring some mixed precipitation to the northern half of the area, and mainly rain in the south.
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&& .NEAR TERM /UNTIL 8 AM THIS MORNING/...
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Incredibly mild early morning temps for late February (in the upper 50s to low 60s) running some 30+ degrees above normal. All-time February record highs were set at both Williamsport (76F) and State College (PSU weather center - 74F) on Friday. Balmy southerly wind will continue prior to a strong cold frontal passage (during the mid to late morning hours across the western third of the state). Weakened squall line just ahead of the cold front has been making steady eastward progress overnight, and is pushing to near the PA/Ohio border at 0630Z. Numerous lightning strikes continue with embedded clusters of TSRA within the approx 75 miles wide band of mdt to briefly heavy SHRA over Eastern Ohio and far NWRN PA. This line should continue to slowly track across Warren County between 07-0830Z, and through ELK and McKean Counties between 0830-10Z. It will also slowly weaken overnight due to waning CAPE. But sct, embedded low-topped TSRA with G30-40kt will survive. Min temps will only reach the mid to upper 50s, except for the far west, where readings should slide into at least the L50s by 12Z.
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&& .SHORT TERM /8 AM THIS MORNING THROUGH 6 PM SUNDAY/...
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Takeaways: CFROPA expected around 12Z across the region near and just to the east of the RT 219 corridor, 14-18z across the Central Mtns, and 18Z-21Z across the eastern part of the CWA. SPC has the eastern half of PA in a Slight Risk for today with a MRGL risk for svr extending back to the far NW part of the CWA associated with the early to mid- morning convection. Confidence is increasing for several hundred J/Kg of cape (and as much as pockets of 750 J/Kg) fueling a NCFRB that will intensify and solidify across the Central mtns and Susq Valley during the late morning and early afternoon. This line will be capable of tapping and mixing down to the sfc 50kt WSW winds that are present around 5 KFT AGL on model forecast soundings at regional gridpoints. Gusty west wind are anticpated post-cold-frontal, but not Wind Advisory worthy. Widespread cloudiness will hinder destabilization during the morning - esp in the NE where some light showers or local drizzle may be found during the first part of the day. The front will push across steadily and only taking about 6 hours to cross the entire CWA. POPs will be pegged at 100s. Temps will drop very quickly and should be back into the L-M30s in the NW by the end of the aftn. SHRA will turn to SHSN there in the aftn. Winds will be gusting into the 30s with some peaks in the 40s behind the front. But, at this point, it does not look like a wind advy is necessary.
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&& .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... The mid range models all have similar timing for FROPA. the front should be east of central PA by 00Z Saturday. Cold northwesterly flow could allow for snow showers Saturday night into Sunday. However lack of moisture will only bring light accumulations with the highest amounts in the NW mtns. After some morning flurries and scattered snow showers in the NW Sunday, the trough will continue its eastward trek and a more zonal pattern will overtake the region. This will bring more tranquil conditions with some sunshine expected for Sunday afternoon, along with decreasing winds. However, max temperatures on Sunday will be back to near normal. Heights are forecast to rebuild across the eastern half of the conus early next week on broad southwesterly flow ahead of troffing developing over the Rockies. The latest 12Z runs show a warm frontal boundary moving into the region Tuesday. This will bring the next chance for precipitation with possible warmer than normal temperatures though not as high as currently. Another upper level trough moving through the Great lakes could bring another cold front through the mid Atlantic region later next week. There are inconsistencies in timing and placement. && .AVIATION /07Z SATURDAY THROUGH WEDNESDAY/... Some low clouds at LNS. Airmass is still quite dry to the west of the far east, and there is a brisk wind. Thus not expecting low clouds to advect too far to the west early this morning. 06Z TAFS sent. Earlier discussion below. 11-3.9u loop showing developing stratus across southeast Pa at 03Z in response to an increasingly moist south-southeast flow. Based on latest GLAMP/HRRR MELD data, believe odds now favor a period of IFR cigs at LNS running roughly from 07Z-15Z. Elsewhere, will maintain the idea of low MVFR stratus developing across the rest of eastern Pa overnight. Although wouldn`t rule out a period of IFR CIGs at IPT/MDT early Sat morning. A strong cold front will sweep eastward across central Pa between 15Z-21Z, accompanied by a band of showers and possible thunderstorms. Model soundings continue to suggest the potential of borderline IFR CIGs across eastern Pa (mainly MDT/LNS) early in the day. However, by midday the focus will be on line of showers/tsra accompanying the front, as it pushes across the state. Brief IFR conditions are possible with this band of showers and possible tsra. A much drier westerly flow behind the front should result in a return to VFR conditions late in the day across most of central Pa, while MVFR CIGs linger at JST/BFD. Gusty west winds will become a concern in the wake of the front late Saturday, especially in the vicinity of JST/AOO, where Bufkit soundings support gusts between 30-35kts. Another concern will be developing lake effect snow showers Sat evening at JST/BFD, where tempo IFR visibilities appear possible. Outlook... Sun-Mon...No sig wx expected. Tue-Wed...Rain showers/reduced CIGS possible. && .CLIMATE...
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***February Warmth 2017*** Updated 2/25/17 at 1 am EST Records were broken at both Williamsport and Harrisburg on Friday. High at Williamsport at 76 degrees at 337 PM. High at Harrisburg at 76 degrees at 241 PM. Also records at Bradford, Altoona, and Johnstown. High at Johnstown 72 degrees at 357 PM. High at Bradford 69 degrees at 503 PM. High at Altoona 75 degrees at 322 PM. Previous information below. Record high temperatures for select sites for Feb. 24: ---------------------------------------------------------- Harrisburg 2/24: 75 in 1985; all-time Feb record is 78F Williamsport 2/24: 71 in 1985; all-time Feb record is also 71F Altoona 2/24: 69 in 1985; all-time Feb record is 74F Bradford 2/24: 59 in 1961; all-time Feb record is 64F ----------------------------------------------------------- Most 60 degree days in February at Harrisburg. Based on the latest forecast, add 4 more days to the list and finish tied for second with 7 days. 1. 10 days in 1976 2. 7 days in 1930 3. 5 days in 1991, 1943 5. 4 days in 1997, 1985, 1954, 1939 9. 3 days in 2017, 2016, 1996, 1990, 1961, 1932, 1890 ------------------------------------------------------------ Warmest February on Record (Avg. Temperature through 2/21) Harrisburg: 2017 rank=4 (38.6) 1. 40.4 in 1998 2. 39.6 in 1976 3. 39.4 in 1954 Williamsport: 2017 rank=4 (35.4) 1. 37.0 in 1998 2. 36.1 in 1954 3. 35.6 in 2002 Altoona: 2017 rank=2 (36.5) 1. 37.4 in 1976 Evening cooling will be a little slower than last night. Bradford: 2017 rank=6 (29.3) 1. 32.3 in 1998 2. 30.1 in 2002 3. 29.6 in 2012 4. 29.5 in 1990/1976 -------------------------------------------------------------
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert NEAR TERM...Lambert SHORT TERM...Dangelo LONG TERM...Ceru/Gartner AVIATION...Fitzgerald/Martin CLIMATE...Lambert

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