Marine Weather and Tide Forecast for Prospect, PA

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

- Mostly quiet conditions this afternoon/evening with a building ridge - A passing warm front will return thunderstorms to the area overnight, some of which could be severe

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A few stray showers are noted northeast of Pittsburgh with a passing shortwave near Lake Erie. However, convection is below 10kft and only poses an isolated lightning threat through 4pm.

To our west, a warm front is currently draped across southern Ohio and central Indiana. Temperatures have jumped into the upper-80s and mid-70s behind the warm front. A surge of moisture is expected to advance late this evening as low-level winds (950mb to 850mb) increase to 40kts.

Showers and thunderstorms are expected to accompany a warm front after 10pm tonight, some of which could become strong to severe. All threats are on the table, with noted dry air above (DCAPE over 1000J/kg) and sufficient mid-level lapse rates (+7.0C/km) to prompt strong downdrafts and large hail. Effective low- level shear near 30kts and curved hodographs may also promote rotating updrafts for tornadoes. There is a noted low- level stable layer on model soundings. However, with ongoing energy from an upstream mesoscale convection system (MCS), severe storms will easily plow through that environment.

As for flooding, storm motion should be fast enough to avoid a widespread flood threat, though heavy downpours will still be likely, given PWATs near 1.50 inches. Any vulnerable locations could still experience localized flooding issues (e.g., urban and low-lying areas, and any locations that experienced flooding from recent rains).

SHORT TERM /6 AM THIS MORNING THROUGH 6 AM SATURDAY/
KEY MESSAGES:

- Storms likely ongoing early Friday with the passage of a warm front - A break in severe storms expected between 10am and 5pm Friday; isolated thunderstorms can't be ruled out - Severe storm potential increases with an approaching mesoscale convection system after 6pm Friday

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Between midnight and 9am Friday, strong to severe storms are expected to be passing through the region from west to east with the remnants of convection initiated off the warm front (see near term discussion).

By late Friday morning the environment will likely need some time to recover, rebuild instability, to initiate organized storms once again. However, a isolated storm can't be ruled out from lingering outflow boundaries.

High resolution model guidance has been consistent that by late evening (between 6pm to 8pm) a mesoscale convection disturbance will initiate to our west, just ahead of a cold front. The disturbance will potentially track east into the Ohio River Valley. Machine learning and sounding analogs support damaging wind gusts, hail, and tornadoes with this new round of severe weather Friday night into early Saturday. Over the last 12 hours, the Storm Prediction Centers has expanded the threat east to support high resolution model trends. A large portion of the region is now under a Slight Risk (2/5 on the severity scale index). Probability of severe weather appears promising between 9pm and 2am Saturday morning.

LONG TERM /SATURDAY THROUGH THURSDAY/
KEY MESSAGES:

- Cooler and drier pattern returns Sunday through Tuesday.
- Precipitation chances return Tuesday into Wednesday with a new low - Potential for heavy rain mid-week -------------------------------------------------------------------

Increasing mid-level subsidence and decreasing dew points in the wake of the cold front Saturday afternoon will likely decrease the potential for thunderstorms.

Models have been consistent that troughing over the Great Lakes and northwest flow will keep temperatures seasonable Sunday into Monday.

Probability of precipitation increases late Tuesday into Wednesday with a new low ejecting out of the Rockies and tracking east. A few model scenarios note a stationary boundary straddling south of Pittsburgh with this passing low. If this scenario plays out, heavy rain could pose a threat for portions of the region.

AVIATION /06Z FRIDAY THROUGH TUESDAY/
A shortwave trough will continue to track across the Upper Ohio Valley region early this morning. Mid level capping has limited the southern extent of a line of thunderstorms. It appears some erosion to this cap is likely as the trough approaches, though the southern extent of the line of storms remains in question.
Included IFR restrictions for FKL and DUJ, where the more favorable conditions for convection exist.

A brief period of MVFR is possible after the passage of the wave this morning, though VFR should quickly return by mid morning.
Scattered diurnal cu is expected to develop through the day.
With the thunderstorms not developing as far south as expected early this morning, this will result in more destabilization later today as another shortwave crosses the region. Added a prob30 mention of thunder for most airports south of Rt 422, though considerable uncertainty exists in this scenario.

Another round of thunderstorms, possibly an MCS, is expected to cross the region late this evening with a crossing cold front.
Models differ on the northern extent of this potential, which could also be impacted by any afternoon convection. Included a prob30 for thunder for now until forecast details become more clear.

Outlook...
Patchy restrictions in scattered showers are expected Saturday and Saturday night under a crossing upper trough. VFR returns Monday under high pressure. Restriction and rain potential returns with a Tuesday warm front.

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