Marine Weather and Tide Forecast for Murrysville, PA

KEY MESSAGES
1) Dry and seasonably warm weather favored through Saturday afternoon.

2) Remnants of Hurricane Isaias results in widespread rain and gustier wind but limited hazardous risks.

DISCUSSION
KEY MESSAGE 1...
High pressure will continue to dominate the weather pattern for the region through Saturday morning. Expect abundant sunshine, above normal temperature that peaks Saturday afternoon, and dry conditions.

Rain may creep into southern zones by Saturday evening along with increasing cloud cover, but the bulk of Hurricane Isaias's remnants arrive Sunday.

KEY MESSAGE 2...
Hurricane Isaias will weaken after landfall while working generally NNE underneath the prevailing ridge Saturday into Sunday, with fairly high confidence the initial precipitation shield reaches northern WV/southeastern OH in the pre-dawn hours Sunday. The combination of warm, moist air (highlighted by 90th-95th percentile PWATS) and residual trough dynamics favors fairly widespread, all-day rain that sees narrow enhancements to precipitation totals. Ensembles remain consistent in a quick exit east Sunday night that sees lingering light rain/sprinkles coming to a stop Monday morning.

The large cloud shield associated with Isaias's remnants strongly favors a minimization of instability (less than 100 J/kg SBCAPE) that ensures severe hazards are not existent.
Impact focus then is on rainfall accumulation totals and synoptic wind gust potential. For flood concerns, ensembles still suggest scenarios where localized rainfall totals enter the 2-3" range (versus more consensus 1-1.5") that could be just enough to create localized flooding in poor drainage or flood susceptible areas; specifically, the increase of falling leaf debris in storm drains could limit effectiveness of planned mitigation efforts and aid in the creation of roadway ponding.
The prolonged drier stretch and lack in stronger buoyancy, however, should keep rates low enough to keep risks low. For wind concerns, pending 850mb/700mb depth/positioning, there is potential for a low-level easterly jet that creates a downsloping effect east of Pittsburgh. Gusts areawide between 15-30mph will be common but initial ensembles suggests a 10% probability for 50+ mph gusts sometime Sunday for portions of Tucker County as well as near Latrobe. Monitoring of these concerns will continue, especially when higher-resolution modeling starts reaching these forecast hours.

AVIATION /00Z FRIDAY THROUGH TUESDAY/
High pressure will continue VFR conditions through Friday.
Thursday night, with cooler temperatures as compared to Wednesday night, may see some more river steam fog develop.
That said, even nudging HRRR and REFS visibility down to the 10th percentile doesn't show a whole lot. So, have left out inclusion of fog at all sites for now, but FKL would be the likely site to keep an eye on through the night. Past sunrise Friday, VFR conditions continue with gradual intrusion of high clouds through the day from south to north. Wind will be less gusty tomorrow as the surface high pressure center passes over the region and remain westerly around 5 knots.

Outlook...
After another potential round of morning valley fog, VFR is favored through Saturday. Restrictions will become more likely starting Saturday night as the remnants of Isaias arrive during the latter half of the weekend. Wind gusts of 25 to 30 knots may become a concern on Sunday as well. Brief improvement to VFR Monday may be followed by more restrictions from the next disturbance Tuesday.

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