textproduct: State College

SYNOPSIS

* Warming trend continues through Thursday, trending a few to several degrees above average this afternoon, and 6 to 12 deg F above normal on Thursday. * Winds will pick up this afternoon with gusts of 25 to 35 mph across much of the area. * A period of rain is expected late Thursday/Thursday night, tapering off as snow showers Friday with the next shot of cold air and wind with gusts over 40 mph possible.

NEAR TERM /THROUGH TONIGHT/

Moderate isentropic lift in the 285-295K layer will sustain a stratus deck over central PA this morning ahead of a decaying cold front that will pass through the area this afternoon. The front may trigger a few light sprinkles or a flurry, but most likely the front will not produce any precip. Skies will clear a bit behind the front, especially in the Lower Susq Valley, but stratus will build back in across the NW in upslope westerly flow. Westerly winds behind the front this afternoon will gust 25-35 mph for much of the area, with a few gusts to 40 mph possible in the Laurel Highlands. Temps are expected to rise above freezing CWA-wide for the first time in a while, leading to snowmelt.

Wind gusts will diminish quickly this evening as a surface stable layer develops. With skies clearing and high pressure building overhead, this setup will favor the development of at least patchy fog, and possibly more widespread fog starting before midnight and continuing through much of the rest of tonight. With temperatures forecast to drop below freezing tonight, freezing fog could result in some slick spots on untreated roadways.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/

With warm air advection strengthening the existing temperature inversion Thursday morning, any fog and low stratus may be slow to dissipate. Robust surface low pressure tracking across the northern Great Lakes will bring about the next chance for precip. The bulk of model guidance indicates widespread rainfall is expected to enter central Pennsylvania beginning late Thursday afternoon or Thursday evening and continue overspreading the area into Thursday night. Precipitation continues through much of Friday across the northwestern Pennsylvania while gradually tapering off west- to- east elsewhere during the morning. A transition to rain/snow mix will be possible west of the Allegheny Front near/slightly after sunrise before snow becomes the dominant precipitation type after the cold frontal passage.

On Friday, a combination of the aforementioned potent low pressure system deepening as it departs, coupled with a building high across the southeast, will lead to an increasing surface pressure gradient that will allow for gusty winds. Widespread 35-45 mph wind gusts remain possible with locally higher wind gusts across the Laurel Highlands. Wind Advisory potential continues in this timeframe with highest probabilities of exceeding advisory criteria across the higher elevations of central Pennsylvania. Can't rule out High Wind Warning criteria being met in the Laurels, but for now the chance is too low too warrant a High Wind Watch.

LONG TERM /SATURDAY THROUGH TUESDAY/

Model consensus has a warm front crossing through the region on Saturday followed by a cold front on Sunday. These systems appear to be moisture starved, but there could be some rain or snow showers on Sunday with the cold front. Prior runs of the GFS suggest snow squalls can't be ruled out depending on the timing and track of the front and associated low pressure system. Ensemble models suggest high pressure and dry weather Monday followed by a warm front with the next chance for rain or mixed precip on Tuesday.

AVIATION /09Z WEDNESDAY THROUGH SUNDAY/

MVFR ceilings continue at JST and BFD this morning with VFR everywhere else. This morning's clouds will drift east/dissipate as high pressure approaches with VFR conditions prevailing areawide for much of the morning. LLWS will linger through midday as a 45-50kt low level jet lifts through the region. Southwest winds may gust 20 to 30kts through the afternoon.

A moisture- starved cold front will usher in lowering ceilings across the northwest in the vicinity of BFD later this afternoon. Recent guidance has trended slower with the onset of these restrictions, perhaps not happening until after 18Z. The low clouds will likely get down to JST/UNV/IPT this evening, while AOO, MDT, and LNS should maintain clear skies.

High pressure builds in tonight, helping support calm winds across southeast PA. The combination of calm winds and clear skies provides increasing confidence in some visibility restrictions. LNS, MDT, UNV, IPT, and AOO are most likely to see restrictions, with IFR or LIFR possible.

Outlook...

Thu...Fog/low clouds slow to clear as MVFR/IFR restrictions linger. Widespread -SHRA and isolated -TSRA Thursday night ahead of and along a CFROPA.

Fri...Gusty W wind (40+ kts possible). MVFR w/SCT SHSN at JST/BFD. Mainly VFR elsewhere.

Sat-Sun...MVFR-IFR BFD in SCT -SHSN. VFR cigs favored elsewhere.

CLIMATE

Astronomical winter (solstice) begins at 10:03 a.m. on Sunday, December 21st.

CTP WATCHES/WARNINGS/ADVISORIES

None.