Marine Weather and Tide Forecast for Thornburg, PA

KEY MESSAGES
1) Showers and a few thunderstorms will continue into tonight

2) Great Lakes and eastern CONUS troughing will maintain near to below average temperature and periodic rain chances into next week, with potential for frost/freeze concerns Monday night.

DISCUSSION
KEY MESSAGE 1...
A line of showers and a few thunderstorms continue to move southeast across the region ahead of an approaching cold front.
Mixing earlier in the day resulted in dew points dropping into the 40s and 50s across the region. The latest mesoanalysis shows the ML CAPE has diminished to less than 250 j/kg, and this trend will continue this evening. The 00Z PIT sounding showed waning support for storms/severe storms as well. Effective shear remains elevated in the vicinity of the line, with around 40 kt on the latest mesoanalysis. While this should maintain the showers/storms through late evening, the severe potential will continue to diminish.

The showers should become more scattered overnight as the front drops slowly south across the region.

KEY MESSAGE 2...
Ensembles remain in good agreement that large-scale troughing remains in place over the Great Lakes/northeast CONUS through at least the end of the next work week, with near to below- normal temperatures throughout. A few shortwaves move through the larger trough through the period, providing shower chances. Minor strength/timing differences remain in the various solutions.

One such wave completes passage on Monday, with surface high pressure building in its wake Monday night, along with 850mb temperatures dipping below zero. There is fairly high confidence in clear and calm conditions as the high center moves overhead. This will represent our next (potentially last until fall?) chance at frost/freeze conditions. NBM probabilities of minimum temperatures 36 or below are 50 percent or greater to the north and east of Pittsburgh, as well as in valley locations in the terrain. Headlines may eventually be needed.

AVIATION /00Z SUNDAY THROUGH THURSDAY/
Areawide VFR begins the TAF period. A line of currently non- severe thunderstorms is on the doorstep of the area. At this time only one or two embedded thunderstorms look to be severe but these trends will be monitored. The low levels are expected to decouple here shortly with gusts abating, but heavier thunderstorms can still bring wind gusts between 40-50 mph.
Cloud bases in these storms are still VFR and it seems possible that all ports, even those that see thunderstorms, could remain VFR through the evening with a possible reduction in CIGs to MVFR overnight.

Storms advance southeast between now and 06Z, with decaying lightning chances as a transition to broken showers becomes increasingly. After 6Z Sun, brief periods of MVFR are favored for all airports save for MGW and ZZV where they should remain VFR through the rest of the night. Wind will be less than 10 knots.

MVFR may still be holding on by sunrise on Sunday, but continued dry advection behind the front and subtle high pressure intrusion favor scattering and raising of CIGs north of I-70 by early afternoon. South of I-70 there could be another round of spotty showery activity Sunday afternoon for MGW.

Outlook... VFR should return areawide Monday/Tuesday under high pressure. Restriction chances return in rainfall with a crossing low pressure system on Wednesday.

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