textproduct: State College

WHAT HAS CHANGED

* Increased POP, QPF, Snow, and Winds over the western and northern Alleghenies Tuesday night - Wednesday night

KEY MESSAGES

1) Snow showers and gusty winds over the Alleghenies Tuesday night through Wednesday night

2) Risk managing potential for Valentine's Day weekend storm

DISCUSSION

KEY MESSAGE 1: Snow showers and gusty winds over the Alleghenies Tuesday night through Wednesday night

Initial shot of warm advection precip should stay along and north of the PA/NY border late tonight into early Tuesday. Can't rule out some passing rain or mixed precip with the occluded front Tuesday afternoon and evening. The strongest precip signal (from both a model and forecaster confidence perspective) is focused in the Tuesday night-Wednesday night timeframe. This is when seasonably cold WNWly post frontal cyclonic flow should bring lake/terrain enhanced snow showers to the western and northern mtns. Some snow showers and flurries could spill farther to the southeast over the Allegheny Front and reach the central ridge/valley region between I99/US-220 and I81. Snow showers should taper off Thursday night as high pressure slides eastward from the Ohio Valley.

Snowfall amounts through 00Z Friday are in the 1-3" range over the favored lake and upslope snowbelts in the NW mtns and Laurel Highlands. <1" is forecast elsewhere along the Allegheny Front or northwest of I99-US220. Max wind gusts Tuesday night through Wednesday night are fcst in the 25-35 mph range with some potential for gusts to exceed 40 mph and approach low end advy criteria over and immediately downwind of the Laurel Highlands.

KEY MESSAGE 2: Risk managing potential for Valentine's Day weekend storm

Aside from the 09/12Z GFS to some extent, an ensemble consensus including ECMWF, CMC, NBM, and AI runs would lean toward an increasing potential for wintry weather arriving by the second half of Valentine's Day weekend. That said, there is still plenty of time and space between now and then. Wintry weather/impacts, particularly details surrounding how much and what ptypes, are uncertain/unclear. Confidence right now is on low side, but the potential certainly exists and will need to be monitored in the coming days.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

For the overnight period into most of Tuesday, looking at VFR conditions. Perhaps a few light rain and snow showers toward the end of the period early Tuesday evening. The airmass is quite dry, so the precipitation could be mainly snow. Also while lower CIGS and visibilities will be possible, the dry air may delay how fast conditions lower.

Main concern later tonight and early Tuesday until winds pick up a bit at the sfc will be LLWS, mainly at BFD and JST. LLWS possible at AOO, but less likely, as the stronger winds aloft will be a bit further west.

Another cold front Tuesday night will bring in colder air again on gusty winds. Snow showers and low cig restrictions are most likely Tuesday night through Wednesday at KBFD and KJST.

Outlook...

Wed-Thu...Sub-VFR most likely at KBFD and KJST with periods of snow showers.

Fri-Sat...Improving conditions late week into the weekend; monitoring potential for winter weather by Sunday.

CLIMATE

Prelim record low minimum temperatures were set at Bradford (-19F) and Altoona (-3) this morning.

BFD previous record was -12 set back in 1963. AOO previous record was 1 set back in 1979.

CTP WATCHES/WARNINGS/ADVISORIES

None.