Jackson forecast discussion

Update

Issued at 910 PM EDT THU OCT 22 2026

For tonight, colder low temperatures in the upper 30s were expanded over a little bit larger area outside of the deep valleys.

Short Term

(This evening through Friday night) Issued at 212 PM EDT THU OCT 22 2026

Northerly flow aloft will continue through Saturday morning on the downstream side of a highly amplified upper ridge over the Central US. At the surface, a dry cold front (essentially just a refresh of the air mass) moves across eastern Kentucky overnight tonight, with surface high pressure remaining in control through Saturday morning.

Subtle low-level mixing in association with the dry cold front passage tonight may keep widespread valley fog confined to the deeper river valleys and hollows. Otherwise, the renewed cold advection will keep lows tonight in the mid 30s to lower 40s. Patchy frost is possible, but again will be localized to the deeper hollows where fog does not develop, typically away from the river valleys.

Sunny and dry conditions are expected Friday with a light east to northeast wind with the cold advection behind the front. The increased mixing will offset the slightly cooler air mass, and result in high temperatures similar to today's in the upper 60s to lower 70s.

Light northeast to southeast breezes continue into Friday night and Saturday morning under continued high pressure, with good radiational cooling and associated decoupling in the valleys resulting in more widespread river valley fog compared to tonight. Ridgetop temperatures will climb a few degrees into the 40s but valleys will remain in the mid to upper 30s. Patchy frost will be possible in the deeper valleys where fog does not occur.

Long Term

(Saturday through Thursday) Issued at 153 PM EDT THU OCT 22 2026

A blocky pattern will still hold at the start of the long term period, with an expansive and amplified midlevel ridge over the center of the country. To the west of the ridge, troughing associated with a closed low initially located over California will have little ability to progress east through early next week, when this disturbance lifts north and finally begins to flatten the ridge. With this pattern in place, local conditions will vary little from day to day through Tuesday as surface high pressure remains nearby.

Through Tuesday, weather should remain sunny as high pressure dominates. Each afternoon, temperatures will rise to near or slightly above average for this time of year, with highs in the upper 60s to low 70s. Sunday does look to be the warmest day of the period, as the ridge expands east somewhat and 500 mb heights peak in roughly the 90th percentile compared to climatology. Even so, temperatures should remain mild, perhaps peaking in the mid 70s at most. Troughing off the Mid Atlantic coast this weekend will prevent any eastward progression of this ridge, keeping eastern Kentucky firmly east of the ridge axis, and by extension, the highest geopotential heights. By Monday the ridge will begin flattening, with high temperatures falling a degree or two.

Accompanying these pleasant temperatures will be plenty of sunshine. Skies should be nearly clear through the weekend, with just a slight uptick in upper level moisture by early next week as flow aloft begins to shift more westerly. With such dry air just above the surface, NBM dewpoints are almost certainly overdone, particularly in the afternoon hours. Thus, dewpoints were nudged down into the low and mid 40s, much more in line with ensemble guidance. Overnight, this dry air, in addition to clear skies and a weak pressure gradient, should allow for efficient radiational cooling. This will set the stage for ridge valley splits as valleys fall into the upper 30s and ridgetop lows remain in the low 40s through early next week.

By Tuesday, flow aloft will become more southwesterly as the ridge finally breaks down and troughing begins to dig into the central CONUS. Meanwhile, a surface low will progress across the Midwest, with a weak and poorly defined cold front extending to the southwest of this system. This front will attempt to sag toward our area somewhat, but with limited upper level support, it should lose steam and become more diffuse with time, and is not expected to make it to the Commonwealth. Thus, the forecast still remains dry, with the main change being a slight increase in cloud cover and highs cooling by a degree or two.

Aviation

(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 910 PM EDT THU OCT 22 2026

Fog will bring IFR or worse conditions in some valley locations overnight and early Friday, mainly near lakes, rivers, and large streams. KSYM was affected by mainly MVFR conditions for a few hours around dawn for the last couple of days, and the TAF has allowed for a potential for this again. Although KSME dropped to IFR or worse for about an hour early this morning, confidence in a repeat is not high enough to include it in the TAF. Otherwise, VFR conditions with clear skies and light winds will prevail during the period.

Jkl Watches/Warnings/Advisories

None.

UPDATE...HAL SHORT TERM...CMC LONG TERM...FAGAN AVIATION...HAL