textproduct: State College

WHAT HAS CHANGED

* Added fog to more valleys this morning and lowered dewpoints and temps very slightly today.

KEY MESSAGES

1) Nor'easter this weekend will stay far enough off to our east to make gusty winds Saturday and Sunday, and mainly light rain for only the eastern half of the CWA. Otherwise: dry thru Wed.

DISCUSSION

KEY MESSAGE 1: Nor'easter this weekend will stay far enough off to our east to make gusty winds Saturday and Sunday, and mainly light rain for only the eastern half of the CWA. Otherwise: dry thru Wed.

Honorable mention: Morning fog and frost will both go away quickly thanks to sunshine and a minor increase in wind.

Main story: Our weather pattern will be dominated by a deepening nor'easter off the coast. The storm is expected to move up toward the southern New England Coast and Long Island before taking a bit of a westward jog. The center of the unusually-deep (988mb) surface low is progged to get right to the NJ coastline by most models. That puts confidence high. However, the westward extent of the rain shield is still a bit uncertain. NAM and HRRR from 00Z runs are wetter west with light rain making it into UNV Sat evening. However, the dry air being brought in from the N by the storm could make a sharp cutoff, or at least make it tough for the precip aloft to make it to the ground the farther one moves west in the CWA. For now, we'll hang with the NBM PoPs and how far west it brings measurable precip with very minor hourly tweaks to make them less specific at 30-36hrs out. The wind will be noticeably breezy and gusty this weekend. But, no ill effects are foreseen from the wind.

Max temps don't change much at all for the next 4 days, and then warm up a little. Mins will be 4-5F milder tonight than Fri AM, and a little mild still Sun AM with more clouds overhead. There could still be some valley fog later tonight/Sat AM. But, the increasing clouds from the west should make that less common in the eastern half+ of the CWA.

The have-nots (or halve-nots): The western half of the CWA will stay dry through at least the middle of next week when a dying cold front approaches from the west. Precip from that system may dry up before getting half way thru the CWA as it runs into a ridge along the East Coast.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

Fog will quickly dissipate through the morning and VFR conditions are expected for the rest of the day under mainly clear skies, though high clouds will begin to move in from the east as the developing Nor'easter slowly moves northward off the coast. The tightening pressure gradient between high pressure to our north and the developing storm to our south and east will allow for northeast surface winds between 10 and 15 knots with gusts to 20 knots possible. A few gusts may reach 25 knots at MDT and LNS.

LLWS becomes a bigger concern for eastern TAF sites after 00Z tonight as a 45 to 60 knot 850 mb low-level jet moves into the area as the Nor'easter deepens and continues to track northward. Wind shear will first develop at MDT and LNS, with the threat moving north and west after 06Z. Some guidance shows light rain beginning to approach the eastern TAF sites by 12Z, though confidence is low as it will depend on the just how far west the surface low ends up.

HREF probabilities of fog formation tonight are highest in the same areas that have seen fog develop this morning. Increasing cloud cover may limit fog somewhat compared to this morning, so we will hold off on introducing any IFR restrictions for now.

Outlook...

Sat-Sun...MVFR and periods of -RA possible far eastern airfields.

Mon-Tue...VFR.

CTP WATCHES/WARNINGS/ADVISORIES

Frost Advisory until 8 AM EDT this morning for PAZ005-006-033.