textproduct: State College

WHAT HAS CHANGED

* Winter Weather Advisory issued for Potter, Tioga, N. Lycoming and Sullivan Counties 7PM Thursday to 1PM Friday

KEY MESSAGES

1) Elevation dependent wet snowfall in the Northern Tier and Endless Mountains overnight through Friday morning

2) Breezy and colder weekend with rain and snow showers downwind of Lake Erie

3) Dry and seasonal pattern returns next week

DISCUSSION

KEY MESSAGE 1: Elevation dependent wet snowfall in the Northern Tier and Endless Mountains overnight through Friday morning

In the wake of circulation rotating across south central PA this afternoon, intensifying cold air advection and increasing FGEN will eventually result in dynamic column cooling and lowering snow levels across north central and northeast PA tonight. Snow totals trended higher for this cycle especially above 1500ft elevation given colder model trends and increasing banding potential. Despite marginal temperatures, confidence has increased for up to 2 inches of wet snow across the northern tier/Endless Mtns overnight into early Friday. Locally higher amounts to 4 inches are possible especially within a comma head banded snow feature. This feature could also drag snow levels closer to the ground at lower elevations. The bulk of the accumulation may be confined to non paved surfaces which may limit winter driving impacts. Snowfall could extend farther to the south impacting higher terrain from Northern Clinton to Schuylkill Counties. Odds for accumulation decrease during the daytime hours Friday.

------------------------------------------------------------------

KEY MESSAGE 2: Breezy and colder weekend with rain and snow showers downwind of Lake Erie

Breezy and colder conditions will grip the area this weekend. Wind gusts in the 25-35 mph range are likely producing wind min wind chills in the 15-30F range. The lake effect and upslope snow is expected to produce a coating to one inch of snow across the Laurels and the northwest mountains with localized amounts pushing closer to two inches in the favored snowbelts and summits. A mix of rain/snow showers are possible at times between the I-99 and I-81 corridors. Rain/snow showers taper off by Sunday night.

------------------------------------------------------------------

KEY MESSAGE 3: Dry and seasonal pattern returns next week

All indication point to another stretch of dry, tranquil, and seasonal weather returning for next week 11/16-11/20. Temperatures will moderate and trend warmer with fcst max temps climbing 10 to 15 degrees above the historical average by late week.

AVIATION /19Z THURSDAY THROUGH TUESDAY/

Changes for the 18Z package are mainly to add the last 6 hrs to the end of the fcsts. The first 18 were fantastic thanks to the prev shifts. Just minor tweaks here and there for lowering/raising cigs/visby. The center of the low pressure area at 18Z is making it's jump to the coast. The comma head of the storm is only now moving through the western terminals. Precip much lighter, but a band of heavier precip looks like it will set up across the northern tier of PA (mainly from IPT and north). The heaviest of the snow and lowest cigs/visbys will likely be east of BFD overnight and Fri as the then-offshore low deepens more and feeds precip into NE PA. On the good side: A several (6-12hr) break in precip is expected for the western half of the CWA until the flow can back to the NW even more late tonight and on Friday. Light precip (snow on higher elevations and rain low) will continue in the eastern half of CTP's airspace until at least 12Z (KUNV) and 18-21Z (KIPT/KZER).

Wind will pick up over the next 6 hrs out of the N/NW. Frequent gusts into the upper teens and L20s are expected.

Flying conditions will remain poor for a day or so Fri and Fri night with IFR at the higher-elevation terminals (BFD, JST) and MVFR in the S.

Outlook...

Fri Night...-SHSN and ocnl IFR NW. -SHRA and MVFR SE. Gusty NW wind.

Sat...Improving, but still gusty with MVFR clouds and isold -SHSN for BFD/JST. VFR elsewhere.

Sun...VFR, gusts NW 15-25KT.

Mon-Tue...VFR.

CTP WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory from 7 PM this evening to 1 PM EST Friday for PAZ006-037-041-042.