Marine Weather and Tide Forecast for Seven Springs, PA

NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:

- Cold front approaches today and crosses tonight, providing widespread thunderstorms.
- Severe weather threat remains for this afternoon and evening, with all hazards possible.
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Currently seeing some isolated showers forming in the area, aided by a weak surface boundary/low-level convergence.
Southwest flow is quickly increasing moisture in the region as well, evidenced by rapidly rising dewpoints. In particular, the dewpoint at Zanesville has increased by 20 degrees in roughly 12 hours.

While these showers and the resultant cloud cover may briefly hinder destabilization in localized areas, the feeling is that these will not greatly hinder the environment for later, as surface-based CAPE development in the 1000-1500 J/kg range still is likely over most of the region. Combined with expectations of effective shear in the 40 to 50 knot range, widespread severe weather remains a likely outcome.

CAMs still advertise a variety of solutions regarding storm morphology and timing, but it is still thought that the most favored timing for the bulk of the severe event appears to be 20Z to 01Z. Although some discrete storms/supercells are possible north and west of Pittsburgh during the early portions of the event, presenting an all-hazards threat, a transition to line segments or a QLCS structure is still expected as cold pools combine, leading to damaging wind becoming the dominant severe type. The hail threat will decrease somewhat after the transition, but at least a low-end tornado threat will continue as hodographs do exhibit decent low-level curvature and instability will be more than sufficient. If a QLCS can form, the severe threat should continue even after sunset as the structure should have sufficient momentum for maintenance.

The cold front is forecast to sink into the region starting during the late evening and set up in a west-to-east fashion near the WV/PA border. Some additional, likely non-severe, convection is possible initially along the boundary before activity tapers to mainly scattered showers towards sunrise.

SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/
KEY MESSAGES:

- The front will be stalled south of Pittsburgh through Wednesday, with scattered showers/storms possible -------------------------------------------------------------------

The overnight frontal boundary passage should push the bulk of precipitation to our south by 12Z Wednesday, but there remains the forecast challenge as to how far south the boundary gets. The departure of the mid-level shortwave will lessen the push of the front, especially to the south where the eastward push is practically nonexistent. Thus, will expect showers along the stalled boundary through the day on Wednesday with the potential for a few thunderstorms to develop. The rain chance may begin to lift north Wednesday night as the boundary tries to push north again.

After temperatures rise into the upper 70s/lower 80s ahead of convection on Wednesday, values should drop back closer to climatology behind the front for Wednesday night.

LONG TERM /THURSDAY THROUGH MONDAY/
KEY MESSAGES:

- Another round of severe weather is possible Thursday - Multiple rounds of rain remain possible into Saturday - Cooler temperatures this weekend, with drier weather Saturday night into Monday -------------------------------------------------------------------

The end of the work week continues to look active, as shortwaves in moist southwest flow continue to impact the region Thursday into Saturday. This occurs ahead of a deepening mid-level trough, which positions itself over the Middle/Upper Mississippi Vally around 00Z Saturday. Progression will be slowed by resultant building ridging just off of the Atlantic Coast.

Severe weather still looks like a possibility on Thursday as the lead shortwave moves up the Ohio Valley. Chances appear best to the west of Pittsburgh, where the NBM continues to advertise a 40% to 70% probability of 1000 J/kg of CAPE, along with sufficient deep shear. The threat will depend somewhat on how well the warm sector can establish itself behind the northward-returning frontal boundary. Some cloudier model scenarios would lead to less instability, and thus a lower severe threat. Isolated hydro concerns remain a possibility given the convective potential and the presence of 1.2 to 1.4 precipitable water values through the period, including the passage of another shortwave Friday ahead of the main trough. Still, the NBM is not overly bullish on precip, with 20% or less probability of an inch or more over the 72 hours ending at 12Z on Saturday.

The passage of the main shortwave trough will keep some scattered showers going through the day Saturday before a cold front sweeps through later in the day. This will finally bring drier weather to the region Saturday night through Monday as surface high pressure builds ahead of Mississippi Valley ridging. Temperatures drop off to below seasonal during this period, with frost/freeze potential Saturday night if sufficient clearing can occur.

AVIATION /18Z TUESDAY THROUGH SUNDAY/
A low-end VFR cu field (cigs around 3-5kft) is developing across the area as southwest winds gust to 25-30 knots ahead of an approaching cold front. Showers and thunderstorms currently over western Ohio are expected to continue eastward, reaching ZZV between 19z-20z, PIT/AGC between 21z-22z, and LBE/DUJ after 22z. This will be the first wave of storms and carry the greatest potential for strong wind gusts, hail, and possibly a brief tornado. Gusts over 55 knots and power outages have already been reported with these storms over portions of eastern Indiana.

This first wave will be followed by a brief lull in activity early this evening until the cold front itself makes its way into the area after 00z. Another round of showers and storms will accompany the front, this time moving from NW to SE reaching FKL/BVI around 01z-03z, PIT/AGC around 03z-05z, and MGW after 06z. The frontal passage brings an end to convection as generally light north- northwest winds usher drier air into the area.

Expect locally lower ceilings and visibilities in and around all showers and storms. Outside of convection, VFR generally prevails except for possible MVFR ceilings at MGW starting after 04z and lasting through the frontal passage into early morning hours on Wednesday. Widespread VFR is expected to return by the end of the TAF period Wednesday afternoon.

Outlook...
VFR is expected on Wednesday as high pressure briefly builds in. Occasional restrictions in showers and thunderstorms return Wednesday night and Thursday as a warm front lifts north.

Showers/storms and restrictions continue Thursday night and Friday with the approach and passage of a cold front. VFR returns Saturday under high pressure.

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