Marine Weather and Tide Forecast for Bethel Park, PA

NEAR TERM /UNTIL 6 AM SUNDAY MORNING/
KEY MESSAGES:

- Dry with decreasing cloud cover late and seasonable temperatures.
- Wind gusts up to 45 mph expected on the ridges overnight.
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Mid level clouds continue across the region under warm advection aloft. The 00Z PIT sounding showed these cloud bases just below 500mb. A low level jet will maintain at least some mixing in the lower elevations overnight. This, and the warm advection, should result in nearly steady temperatures overnight. Temperatures could even rise a couple of degrees overnight.

A 50-60 KT 850mb jet is progged to set up across the Upper Ohio Valley region overnight. An inversion aloft should keep most of this wind from reaching the ground, though occasional wind gusts from 20-30mph are expected overnight across the lower elevations with some limited mixing. The higher terrain areas could see gusts from 40-45kt, with NBM probabilities of this occurrence at 70 percent.

SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/
KEY MESSAGES:

- Gusty winds continue on the ridges through the day on Sunday.
- Rain chances increase from west to east Sunday night.
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An upper shortwave trough ejects quickly northeastward from the southern Plains into the Ohio Valley Sunday into Sunday night.
Dry weather will still dominate during the day Sunday as warm air advection under a deepening southerly flow helps high temperatures climb above seasonal levels, with the NBM showing a 50% or greater chance of exceeding 45F across most of the lowlands south of I-80. The approaching system brings increasing precipitation chances from west to east Sunday night, likely in the form of rain as temperatures will be mild given the warm air advection and lack of radiative cooling under thickening clouds.

LONG TERM /MONDAY THROUGH SATURDAY/
KEY MESSAGES:

- Above average temperatures and several rounds of rain favored for the first half of the week.
- Temperatures tumble behind a cold front Wednesday as rain transitions to snow or a rain/snow mix.
- Cold and dry weather returns to finish off the work week.
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The upper shortwave trough that brought rain back to the forecast Sunday night departs on Monday, with showers generally tapering off during the day from west to east (though potentially not ending entirely over the ridges). Guidance continues to suggest most rain totals fall between 0.25 to 0.5 inches on the low end and 0.75 to 1.0 inches on the high end.
Even with rain showers, high temps climb into the upper 40s to low 50s Monday afternoon due to persistent warm air advection in southerly flow.

Another upper wave digging across the northern CONUS on Monday will trigger low-level cyclogenesis and a deepening surface low forming in the Mississippi Valley. The upper wave continues to deepen, becoming highly amplified as it swings across the central CONUS. This is where potential solutions really start to deviate from the mean and thus uncertainty increases.
Question stems both from amplitude and timing of the wave with a notable dipole late Tuesday into Wednesday as it progresses east. Precipitation chances look to ramp back up come Tuesday as some guidance develops additional low pressure along a trailing boundary. Some ensembles point toward a track off to our east while others favor further west. Either scenario again should be supported by above freezing temperatures bringing another round of rain that could be followed by some wrap around snow in colder northerly component flow on the backside in lingering troughing. Temperatures are favored to remain above average Monday and Tuesday before tumbling back closer to normal for the rest of the week. Wednesday's highs exhibit large spread owing to timing of cold advection behind the departing low, so while the current highs represent the mean, that's not the most likely outcome. Drier and cooler weather is favored by Thursday and Friday with high pressure in place for this period.

AVIATION /04Z SUNDAY THROUGH THURSDAY/
A strong nocturnal low-level jet is expected to bring LLWS concerns to all area terminals tonight mainly between 00-14z.
Wind speeds at 2kft can be between 40-50kts. Otherwise, VFR is likely to prevail with some high clouds.

Chances of an MVFR decks increase above 50% by noon tomorrow for DUJ and FKL with northwest flow at the top of the boundary layer bringing in lake moisture, though the is some timing uncertainty as to when these clouds materialize which could result in decks filling in a bit faster or slower.

Otherwise, VFR prevails tomorrow with increasing wind gusts after the inversion breaks in the morning, mixing into the low jet. There is around an 80% chance that every port sees 20kt to 30kt gusts tomorrow morning, before gusts subside into the evening hours.

Outlook...
More widespread restrictions and rain return with a Monday warm front. Low level moisture should maintain restrictions and rain chances continue Tuesday/Tuesday night with the approach and passage of a cold front. Restrictions and rain/snow are expected Wednesday under subsequent upper troughing and cold advection.

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