Somerset, KY Weather

Key Messages

- Dry weather persists into next week, with mostly clear skies, mild days, and chilly nights expected.

- Light, patchy frost may develop late tonight and again on Sunday and Monday nights in sheltered valleys away from lakes, rivers, and larger creeks. Fog is more likely near those bodies of water.

Long Term

(Sunday night through Friday) Issued at 420 AM EDT SAT OCT 24 2026

The long-term period opens Sunday evening with the stubborn 500 hPa ridge of recent days still anchored over the region, its positively-tilted axis stretching from the Ark-La-Tex northeastward to over southern Quebec. Subsidence on the eastern side of the ridge continues to maintain expansive surface high pressure (with an ~1032 mb center over the Delmarva) from the Mid/Lower Mississippi Valley northeastward to over the Atlantic south of the Maritime Provinces. Well to our north, a trough is passing over the Hudson Bay region, supporting an ~985 mb surface low over the northern tip of Quebec. The low's cold front trails south across the province to near Ottawa and then southwest across the Upper Great Lakes and Central Plains to another weaker low along the lee of the Colorado/New Mexico Rockies. That second surface low is associated with a shortwave ejecting out of mean 500 hPa troughing found along and west of the Rockies, anchored by a vertically stacked parent low just off the Pacific Northwest coast.

The ridge aloft will flatten appreciably on Monday and Tuesday as the aforementioned cold front sags southeast and eventually stalls north of the Ohio River. Meanwhile, the upstream shortwave and surface low eject northeastward, pulling the boundary back to the north by Wednesday. That shortwave as well as the lingering ridge over the eastern CONUS will flatten and fill on Wednesday and Thursday. A small minority of the 24/00Z LREF members maintain a strong enough shortwave trough to sensibly impact the Lower Ohio Valley. However, a vast majority of solutions maintain resilient ridging as the 500 hPa axis shifts east of the Commonwealth, which would preclude anything more than periods of passing mid and high-level cloud cover. The number of ensemble members favoring 500 hPa troughing developing over the Ohio Valley grows on Friday, though ~61/100 LREF members still cluster towards lingering ridging. Materially, this suggests that upper-level ridging is still favored to remain intact and keep dry weather in place over eastern Kentucky through the long-term period, but forecast confidence does decrease noticeably by Friday. There are still no rain chances in the long-term forecast at this time.

Aside from increased cloud cover midweek, the pattern should continue to favor fair weather with sunny, mild days, and cool, clear nights. Frost will be possible again in the colder sheltered hollows on Sunday and Monday nights. Fog will also continue to be a nightly phenomenon for the typical favored valley locations. Otherwise, look for high temperatures to range in the lower to middle 70s while sharp ridge-valley splits develop each night, with minimum temperatures in the mid to upper 30s in the coldest hollows to the mid to upper 40s on thermal belt ridges. The exception could be Tuesday and Wednesday nights when more extensive cloud cover could keep nighttime temperatures a tad milder.

Aviation

(For the 06Z TAFS through 06Z Saturday night) ISSUED AT 158 AM EDT SAT OCT 24 2026

VFR conditions are currently in place at all TAF sites, but recent satellite imagery reveals radiation fog developing in the valleys of Eastern Kentucky. This fog should deepen in the coming hours, especially in places closer to the area's lakes, rivers, and streams. KSYM and KSME are the TAF sites most likely to see vsby reductions from this fog. The former has experienced fog- driven MVFR reductions around dawn for the past few days, and the same weather pattern remains in place across the area. Persistence forecasting suggests that a TEMPO group around dawn will sufficiently capture these potential vsby reductions. KSME's proximity to Lake Cumberland could bolster the fog potential there, so a TEMPO group has also been introduced there with the 06z TAF package. Once the fog mixes out by mid-morning, all terminals are forecast to return to and/or remain in VFR conditions through the end of the forecast period. A passing disturbance aloft could introduce a few high clouds in the latter half of the period, but these will not be enough to produce meaningful ceilings. Expect light and variable surface winds to persist through the end of the period.

Jkl Watches

None.