Mount Pleasant, PA Weather

What Has Changed

Little change to forecast thinking through Saturday. Models continue to trend slightly downward with potential rainfall totals Sunday/Monday.

Key Messages

1) Quiet weather and above-average temperatures continue through at least Saturday. The next chance of rain may arrive Sunday.

Discussion

KEY MESSAGE 1... Confidence in the lack of measurable precipitation through Saturday remains high as surface high pressure will remain in control.

A cold front is still forecast to drop across the region tonight. Moisture and support for lift still appear to be too meager to support measurable precipitation. However, enough low-level moisture is progged to create near-surface saturation as a subsidence inversion sets up behind the boundary late tonight. Areas of fog and low stratus may develop as a result. Some spotty non-measurable precipitation in the form of drizzle cannot be totally ruled out.

The boundary then eventually lifts back northward as a warm front during the midweek period, opening the door to southwest flow aloft and a slow warming trend. By Thursday, high temperatures some 10 to 15 degrees above normal appear likely. It also appears likely that additional frost/freeze headlines will not be needed ahead of the November 1st cutoff of the growing season. A shortwave riding through WSW/ENE oriented 500mb contours across the Great Lakes later this week will most likely not produce precipitation in our CWA, although a few model scenarios paint very light precipitation north of I-80 Thursday night.

Ensembles are still suggesting that a southern Great Plains shortwave riding up the Ohio Valley could provide our next best chance of rain later this weekend While it does appear that this system may end the dry stretch for most of the area, strength and timing differences in the various members continues to cast doubt on receiving a significant, wetting rainfall.

Aviation

VFR favored through most of the TAF period with scattered to broken coverages of passing cirrus.

The exception is increasing probabilities (ranging from 20-60%) from hi- res models for a narrow band of LIFR fog/cigs to develop along a weak frontal passage overnight that stalls near to just north of the I-70 corridor. Though spotty MVFR visibilities could develop too, it's most likely an all-or- nothing fog scenario; either enough clearing plus moisture convergence along/ahead of the boundary result in 1/2mile or less visibilities, or too much cirrus prevents necessary cooling and fog doesn't develop at all.

Outlook... Surface high pressure will maintain high confidence in VFR conditions through at least Thursday (low probabilities for cigs and light precip return Friday around NW PA with another stalled boundary). More likely, these conditions continue until an upper trough/surface cold front passage sometime Sunday into early next week.