textproduct: Jackson

KEY MESSAGES

- Dry weather with mainly clear skies, mild days, and chilly nights will persist well into week.

- Light, patchy frost may develop tonight and again late Friday night in valleys away from lakes, rivers, and larger creeks.

LONG TERM

(Friday night through Wednesday) Issued at 804 AM EDT Thu Oct 22 2026

Confidence is high that the peaceful weather described above will persist into the long term forecast period. Forecast guidance collectively resolves a mid/upper level ridge building into the Greater Ohio River Valley this weekend. Synoptic-scale subsidence downstream of the ridge axis will keep skies clear and keep a surface high pressure system nearby. The northerly orientation of the flow aloft and the light/variable nature of the surface-level winds will limit the amount of meaningful advection realized over the CWA. So, given the dryness of the antecedent airmass, there are no meaningful rain chances in the forecast for the next 7 days.

Ridging patterns like this favor efficient diurnal radiative and mixing processes, and those processes will be the primary factor governing Eastern Kentucky's sensible weather conditions through early next week. Bountiful solar insolation and nocturnal ridge- valley splits should yield 25-35 degree diurnal temperature ranges each day. Subtle geopotential height rises suggest that Saturday and Sunday's temperatures could fall on the higher end of the forecast guidance envelope, and highs should reach widespread readings in the the low/mid 70s each day. Lows will be more terrain-dependent, with ridgetops remaining in the 40s as colder air pools in the valleys after dark. The most sheltered and shaded valleys will see temperatures cool down into the mid 30s, and patchy frost cannot be entirely ruled out in these hollows. In the broader valleys, the presence of rivers, lakes, creeks, and streams will favor fog formation as lows drop into the upper 30s/lower 40s. More locations should see fog than frost amidst the aforementioned warming trend, but trends in afternoon dewpoint observations will need to be monitored closely. If diurnal mixing is deep enough to mix down the dry air aloft, the areal coverage of frost could be greater than what is currently included in the forecast grids. It would not be surprising if 20-30 degree dewpoint depressions are realized, and the blended NBM guidance used to populate the long term forecast grids is likely too moist. Small differences can make a big impact when it comes to forecasting crossover temps and fog/frost, but neither of these weather conditions would produce significant impacts.

Such quiet weather can only persist for so long though, and the ridging pattern is poised to gradually break down next week. As an upper level trough ejects into the Plains on Monday, the ridge over the Ohio Valley will flatten out. The resultant height falls point towards a slight decrease in temperatures, and the flow aloft will shift towards a more westerly and then southwesterly orientation by Tuesday. This shift will introduce relatively greater amounts of moisture to the column and thus some cloud cover back into the forecast. Model spread begins to increase beyond then, as there are differing solutions surrounding the trajectory and evolution of that ejecting trough. Hazardous weather appears unlikely with this first system, as there will not be much low-level moisture return out ahead of its arrival and it will likely lose its upper atmospheric support as time progresses. Some guidance suggests that there could be some light precipitation on Wednesday, but ensemble probabilities for measurable precipitation remain less than 15%. Thus, the greatest changes in the forecast associated with this late-period system will likely be tied to that increase in cloud cover. Expect slightly cooler highs and slightly warmer lows as those clouds modify the diurnal radiation budget, but temperatures should remain in the same general upper 60s/lower 70s and low/mid 40s range.

AVIATION

(For the 12Z TAFS through 12Z Friday morning) ISSUED AT 734 AM EDT THU OCT 22 2026

Fog is bringing localized IFR or worse conditions to many valley locations this morning, mainly away from the TAF sites. The fog should lift/burn off by mid-morning, leaving clear skies and light variable to northerly winds. Fog is possible in many valley locations again late tonight.

JKL WATCHES/WARNINGS/ADVISORIES

None.