Marine Weather and Tide Forecast for Murrysville, PA

NEAR TERM /UNTIL 6 PM THIS EVENING/
KEY MESSAGES:

- Dry with clearing skies through the day.
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High pressure will slide across our south today extending ridging into our region and even returning some sunshine this afternoon as clouds gradually erode from the south in drier air. NBM advertises 70-90% probability for total cloud coverage <50%. Warm advection in southwesterly flow will help rebound highs back above freezing with high probability south and west of Pittsburgh, highest across southeast Ohio. Ensembles depict a weak, relatively flat wave sliding through the mid- level northwesterlies that may spark off low probability light snow showers with a 15-25% chance across Forest and Venango Counties. With it fighting increasingly dry air, it's going to be very difficult for anything more than a few flurries to reach the ground.

SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/
KEY MESSAGES:

- Gusty winds expected on the ridges tonight and through the day on Sunday -------------------------------------------------------------------

By tonight, skies will begin top clear out with overnight temperatures plummeting into the mid 20s but this will be right around normal for this time of year. Winds could remain elevated into the overnight with especially the ridges seeing some 35 mph to 45 mph winds. In fact, the NBM is giving some 80% to 90% of 40 mph wind gusts or more for E. Tucker County and around 60% for the Laurel Summit area. Have mentioned this in the HWO.

Sunday looks to be a transition day with an overall high confidence evolution between a departing upper trough and brief shortwave ridging traversing overhead within more zonal flow. Ridging from high pressure across the southeast will maintain dry weather Sunday with deep southerly flow inducing warm advection allowing for temperatures to rise into the 40s (50-80% chance of >45F for Pittsburgh and south). With the southerly flow will come increasing moisture as well setting the stage for the return of precipitation, this time likely in the form of rain, come Sunday night.

LONG TERM /MONDAY THROUGH FRIDAY/
KEY MESSAGES:

- Above average temperatures favored for the first half of the week.
- Temperatures tumble for the latter half.
- Several rounds of rain chances beginning Monday.
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Another upper wave digs across the northern CONUS as surface low pressure develops across the Mississippi Valley. Latest clustered ensembles suggest that uncertainty with the approaching wave has decreased a bit with still some question on the departure of the trough across New England. One solution presents the wave phasing with a parent trough axis further to the north with quicker progression while another keeps it unphased and flatter.
What appears to be the more dominant factor in its progression is the amplitude of the departing downstream trough. If it's deeper, precipitation onset isn't until closer to the morning hours on Monday. If it's flatter, precipitation reaches our eastern Ohio counties overnight Sunday night. Given continuing strong deep layer warm advection ahead of the approaching attendant surface low, profiles indicate that this should be a rain event areawide even with potential onset in the overnight hours. The takeaway message here is that the occurrence of rain for the beginning of the week is high confidence, but the timing of it is still lower confidence. The goal posts for total rainfall through Monday night sit around 0.8-1 inch on the high end and a quarter inch on the low end.

On Tuesday, a longwave trough axis sweeps through the central CONUS on the heels of the initial shortwave. 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 /10Z SATURDAY THROUGH WEDNESDAY/
Mainly VFR stratocu was across the area this morning under ascent with warm advection aloft. Cigs heights will continue at MVFR levels for DUJ and FKL this morning where more favorable low level moisture is in place.

The lower clouds will exit the region by mid morning for airports other than FKL and DUJ, with mid level cigs overspreading most airports with continued warm advection aloft.
A tightening surface pressure gradient between high pressure to our south, and low pressure to the north, will result in gusty SW wind to around 20kt by mid morning. VFR and mid level cigs will continue Saturday night, with LLWS as a 40-50kt jet at 2kft sets up across the region.

Outlook...
LLWS should end Sunday morning as the low level jet diminishes.
Otherwise, VFR is expected under a ridge of high pressure.
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.