Marine Weather and Tide Forecast for Seven Springs, PA

KEY MESSAGES
1) There is a marginal risk for damaging winds and large hail with a decaying line of thunderstorms entering northwest PA this evening.

2) Great Lakes and eastern CONUS troughing will maintain near to below average temperature and periodic rain chances into next week, with potential for frost/freeze concerns Monday night.

DISCUSSION
KEY MESSAGE 1...
Breaks in the cloud cover have occurred over the region this afternoon, which has resulted in some surface heating through the day. Current mesoanalysis shows ML CAPE around 500 j/kg across northern OH and NW PA, ahead of an approaching cold front.

A line of showers and thunderstorms has developed along and ahead of this front across southern Ontario through SE lower MI and NW OH. Extrapolation of this line indicates it should reach Mercer county around 8 PM, and continue ESEwd thereafter through the evening. Expect current instability levels to remain nearly steady through the early evening hours, before quickly waning after 9-10pm. 0-6km shear is expected to reach 40-50kt this evening in advance of the front. With the later arrival of the storms, and diminishing instability later this evening, it appears there is a brief window for the potential for severe storms, generally from 7-8 pm through 10-11pm. It still appears that damaging wind is the main hazard from these storms, though large hail is also possible. The linear nature of the line should preclude a more significant tornado threat, though directional shear indicates some rotation in embedded cells is not out of the question.

Storms should decay to sub-severe levels as they sink south towards east-central OH/far southwest PA late this evening.
Rapid weakening should then continue, with the line nearly totally dissipating as a few showers along the I-70 corridor overnight.

KEY MESSAGE 2...
Ensembles remain in good agreement that large-scale troughing remains in place over the Great Lakes/northeast CONUS through at least the end of the next work week, with near to below- normal temperatures throughout. A few shortwaves move through the larger trough through the period, providing shower chances. Minor strength/timing differences remain in the various solutions.

One such wave completes passage on Monday, with surface high pressure building in its wake Monday night, along with 850mb temperatures dipping below zero. There is fairly high confidence in clear and calm conditions as the high center moves overhead. This will represent our next (potentially last until fall?) chance at frost/freeze conditions. NBM probabilities of minimum temperatures 36 or below are 50 percent or greater to the north and east of Pittsburgh, as well as in valley locations in the terrain. Headlines may eventually be needed.

AVIATION /20Z SATURDAY THROUGH THURSDAY/
Light rain has cleared the region to the east, only DUJ is feeling the lingering effects of this rain. Skies are beginning to scatter out and CIGs are on the rise early this afternoon.
Even as skies clear, it is possible that moisture below 3kft keeps BKN MVFR skies around a little longer through the afternoon. By this evening most ports are expected to be VFR.
Occasional wind gusts up to 20kts will be possible out of the southwest this afternoon.

Saturday evening, a line of storms is favored to drop south from Lake Erie, with the high chance of lightning at FKL. Storms advance southeast between 00Z and 06Z, with decaying lightning chances as a transition to showers is most likely for now as the rain approaches PIT. After 6Z Sun, brief periods of MVFR are favored for all airports save for MGW and ZZV where they should remain VFR through the rest of the night. Wind will be less than 10 knots.

MVFR may still be holding on by sunrise on Sunday, but continued dry advection behind the front and subtle high pressure intrusion favor scattering and raising of CIGs north of I-70 by early afternoon.

Outlook... VFR should return areawide Monday/Tuesday under high pressure. Restriction chances return in rainfall with a crossing low pressure system on Wednesday.

PBZ WATCHES/WARNINGS/ADVISORIES
PA...None.
OH...None.
WV...None.