textproduct: State College

WHAT HAS CHANGED

* Not much at all

KEY MESSAGES

1) Upper low over the Upper Great Lakes will move southeast tonight then bounce to the northeast Monday. Showers and thunderstorms will move through the region periodically through Monday night.

DISCUSSION

KEY MESSAGE 1: Upper low over the Upper Great Lakes will move southeast tonight then bounce to the northeast Monday. Showers and thunderstorms will move through the region periodically through Monday night.

Showers and thunderstorms are spread across all of the CWA, even as far S as the Turnpike, this afternoon. The convection is likely at a peak right now as the forcing from a significant short wave trough is moving through coincident with peak solar heating. A lull may be in store as we get under the influence of the NVA behind the trough. But, it will only be brief as a stronger wave rounds/warps the base of the upper low over the Great Lakes. That feature is on track to redevelop convection over the NW around or just before sunset, and drive more SHRA/TSRA through between then and midnight. All of these showers have the potential to make some small hail. A G29KT just happened at CXY as a good SHRA passed, and that shows the potential of showers (there was no TS) that may /seem/ a bit too far from the cold pool aloft.

After midnight, the coverage of showers should be lower. Without the extra help from the sun and strong forcing, the cold pool aloft won't be enough to generate more than isolated showers, and thunder will be unlikely overnight.

We expect not as much coverage to the SHRA/TSRA Monday without good PVA moving across. However, the cold pool aloft and heating should make isolated to scattered convection along the northern tier. It is very unlikely that any precip will get south of I-80. Some will linger into the night, but it gets dry on Tuesday with not muggy, but not refreshing dewpoints.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

Upper level trough swinging across the area along with a west to southwest flow over Lake Erie resulted in showers across the far northwest this morning. Low over southwestern Ontario. Weather pattern more typical of late September than late August.

Winds slowly shifting more from the west now, resulting in the activity pushing more into our area this aft. Most of the activity is in the form of showers, with leading left moving cells on the wind shift line moving over the Finger Lakes. Thus went mainly VCSH, but did target BFD for MVFR conditions.

By late afternoon and early evening, activity should taper off, as heating ends. MVFR and IFR conditions across BFD and JST expected overnight with lower CIGS. Fog potential limited with this weather pattern.

For Monday, still VCSH possible across the Mtns.

Outlook...

Tue-Wed...Patchy morning fog, otherwise mainly VFR conditions.

Thu-Fri...Chance of showers and storms again.

CTP WATCHES/WARNINGS/ADVISORIES

None.