textproduct: Jackson

KEY MESSAGES

- Persistence forecasting prevails through much of the upcoming work week, with mostly to partly sunny skies, mild days, and chilly nights expected.

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

- The next chances for rain enter the forecast as the calendar changes to November, so interests with outdoor Halloween plans are encouraged to monitor for forecast updates this week.

UPDATE

Issued at 1030 AM EDT SUN OCT 25 2026

The last of the valley fog has lifted and dissipated over the past hour. A 500 mb ridge is in place from the western Gulf to the Lower OH Valley region, with an associated a sfc ridge of high pressure extending from portions of the Northeast and Mid Atlantic into the Appalachians and TN Valley. With high pressure in place today, temperatures should be similar to if not a degree or two warmer compared to Saturday. Minor adjustments were made based on recent observations, though this led to no substantial changes at this time.

LONG TERM

(Monday night through Saturday) Issued at 322 AM EDT SUN OCT 25 2026

The long-term period opens Monday evening with a flattening 500 hPa ridge extending from the Gulf of America northward across the Commonwealth and beyond to the Upper Great Lakes, then northwest into Central Canada. At the surface, the remnant of a former high will be situated over the Central Appalachians, separated from a stronger ~1034 mb surface high over Northern Ontario by a cold front. That frontal boundary extends southwestward from a low over the Labrador Sea, passing along the southern shores of the Great Lakes to a weak surface low over Nebraska. Aloft, the Nebraskan low is supported by a shortwave trough ejecting northeast out of a broader parent trough over the West Coast and Intermountain West. A second embedded shortwave trough is located over the Pacific Northwest.

The first shortwave trough will merge with the second and eject northeast into Central Canada through Wednesday, taking the surface low with them and pulling the stalled front back north of the Ohio Valley. The main effect from those features will be to significantly flatten the ridge residing over the Commonwealth. An area of energy likely ejects northeast and eventually crosses eastern Kentucky as an upper-level disturbance late Tuesday into Wednesday, bringing mid-and high-level moisture (likely manifesting as just an uptick in cloud cover at most). Behind that disturbance, the leftover broad ridging over the eastern CONUS will remain nearly steady state or strengthen slight through Friday. Surface high pressure scoots southeast to off the New England Coast by Wednesday evening and then builds southwestward into the Central/Southern Appalachians through ~12Z Friday.

Thereafter, a much more substantial shortwave ejects northeast next weekend with a plume of Gulf moisture (PWATs surge back above an inch and likely exceed the 90th percentile of climo for this time of year). The return of deep moisture with this feature will manifest as thickening cloud cover heralding rising rain chances late in the day on Saturday--potentially more of a trick rather than a treat given the delightful weather of late.

Outside of the periods of thicker cloud cover mentioned, dry air will allow for efficient radiational cooling and substantial ~10F ridge-valley splits each night. Temperatures may be just cold enough for one more night of patchy frost in the coldest hollows on Monday night. Otherwise, slightly milder temperatures should hopefully preclude further patchy frost. However, conditions will remain favorable for nighttime fog formation in the typically favored valley locales.

Thus in sensible weather terms, expect mostly clear skies for much of the upcoming week outside of a period of greater cloud cover Tuesday into Wednesday and again heading through Saturday. Additionally, temperatures will slowly moderate, warming from the mid 70s for highs on Tuesday to the mid to upper 70s by week's end. Meanwhile, nighttime lows will range from the mid 30s to near 50F on Monday night to the mid 40s to mid 50s by Friday night. Greater cloud cover on Tuesday night should favor milder temperatures than what would otherwise be expected in late October. Any rain chances will hold off until Saturday at the earliest.

AVIATION

(For the 12Z TAFS through 12Z Monday morning) ISSUED AT 740 AM EDT Sun Oct 25 2026

Persistence forecasting prevails once again for the 12z TAF package. Clear skies are noted in this morning's ASOS/AWOS observations this morning, but, as expected, valley fog has developed in the vicinity of the area's rivers and lakes. This morning's fog is not in the immediate vicinity of any TAF sites, but localized vsby reductions are occurring where it has developed. A brief reduction cannot be entirely ruled out at KSME, but the fog around Lake Cumberland appears patchy in current webcam imagery. Thus, fog is not expected to be the prevailing condition at any of the TAF sites this morning. All fog should mix out by mid morning, giving way to mostly clear skies. A few high clouds may pass aloft, but these will not yield any meaningful ceilings. So, expect VFR conditions this afternoon and evening, with light/variable surface winds and another chance for river valley fog at the tail end of the period.

JKL WATCHES/WARNINGS/ADVISORIES

None.