Marine Weather and Tide Forecast for Bethel Park, PA

KEY MESSAGES
1) Dry through tonight, then low rain chances Tuesday

2) Rain and severe thunderstorm chances Wednesday

3) Windy and cooler late week with rain/snow chances

DISCUSSION
KEY MESSAGE 1...
A ridge of high pressure will maintain dry weather tonight, though cloud cover should increase late tonight ahead of a weak approaching shortwave in WSW flow aloft. This wave will bring low chances for rain Tuesday, though temperatures are expected to be around 25 degrees above average.

KEY MESSAGE 2...
A surface warm front is expected to extend east of a surface low across SE MI, to Lake Erie on Wednesday morning. Increasing ascent in warm, moist advection should result in areas of rain across the region through early afternoon. Models indicate some elevated instability in place, with some embedded thunderstorms also possible. Later on in the afternoon, the surface low is expected to track ewd to southern Ontario, as a strong cold front reaches Ohio. Increasing shear (0-6km around 50kt) and instability (ML CAPE 500-1000 j/kg) ahead of this front will result in a potential for severe thunderstorm development in late afternoon and evening. Directional shear is also progged, resulting in hodographs favorable for rotation. Uncertainty exists in how any cloud cover and rain from earlier in the day affects instability and afternoon storm development. However, there is sufficient potential for severe storms that the area is in a Slight Risk from the Storm Prediction Center.

KEY MESSAGE 3...
The front will complete its passage Wednesday night, with rain possibly changing to snow before ending. Any accumulation should be minimal. Cold NW flow and a crossing upper trough should maintain cloud cover across the region Thursday, and there could be a few lingering flurries especially in the morning. An overall variable temperature pattern is then expected through the weekend, with a series of crossing cold fronts. Strong wind gusts are also possible on Friday with the approach and passage of one of those fronts.

AVIATION /15Z MONDAY THROUGH FRIDAY/
VFR is expected through most of tonight as a ridge of high pressure slides east of the region. SW wind gusts around 20kt are expected through late afternoon, until mixing and gusts both subside this evening. Clouds are expected to increase in warm, moist advection ahead of a weak crossing shortwave late tonight into Tuesday. Increasing low level moisture should result in MVFR cigs developing through much of the day Tuesday, with some improvement expected later in the afternoon as the wave exits.

Outlook...
More widespread restrictions in rain and thunderstorms are expected late Tuesday night and Wednesday with the approach and passage of a cold front. The rain could change to snow before ending Wednesday night behind the front.

Cig restrictions and gusty wind are likely Thursday in cold NW flow and with a crossing upper trough. Restrictions in rain and snow are possible Friday with another crossing cold front.

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