textproduct: Jackson

KEY MESSAGES

- A series of cold fronts today and tonight will usher colder and drier air into the region for the weekend. - A widespread frost is likely this weekend, and a freeze is also possible. The coldest conditions will be in the deeper valleys.

UPDATE

Issued at 908 AM EST FRI NOV 6 2026

Have updated current grids to represent coverage of valley fog/low clouds this morning, and its dissipation. Also, used latest model runs to sharpen up the boundary of the low clouds as they arrive from the northwest today.

LONG TERM

(Saturday night through Thursday) Issued at 430 AM EST FRI NOV 6 2026

The extended period opens Saturday evening with an upper-level low located over southern Ontario and the Lower Great Lakes. Broad cyclonic flow around the trough will direct a colder, drier airmass into Kentucky from the northwest as surface high pressure builds in from the west. Calm to light winds under mostly clear skies would typically favor frost formation if temperatures drop sufficiently.

However, deterministic and ensemble guidance (including the RRFS, REFS, GFS, and ECMWF) remain noticeably milder than the NBM. The NBM appears to be weighting recent two-week observations where dry air and strong radiational decoupling produced colder valley lows. Given persistent CAA and lingering boundary layer mixing under northwesterly flow Saturday night, large ridge/valley temperature splits are not favored. While NBM lows in the upper 20s to low 30s were retained - which would yield widespread frost - confidence remains too low to warrant a Freeze Watch at this time. Should warmer guidance in the mid-30s verify, patchy river valley fog may develop instead.

High pressure settles overhead Sunday, bringing mostly sunny skies with seasonable highs in the upper 50s to lower 60s. For Sunday night, the forecast maintains a colder, decoupled solution with lows dropping into the lower 30s for much of the area. With high pressure overhead, clear skies and light winds will allow for efficient radiational cooling, which would support these colder valley temperatures and result in areas of frost. However, forecast confidence remains low: higher-resolution guidance, including the RRFS, suggests a more modified airmass with lows holding several degrees warmer in the mid to upper 30s. Given this spread and the recent NBM cold bias, the inherited colder numbers were kept for continuity. Should the warmer guidance verify, frost and possibly freeze conditions could be limited to isolated cold spots, with patchy river valley fog becoming the prevailing overnight feature instead.

Quiet conditions will continue through Wednesday. Thereafter, guidance suggests another upper-level cyclone digging out of the Upper Midwest into the Great Lakes, with an attendant frontal passage across the Ohio and Mississippi Valleys bringing rain chances back to the area Thursday into Friday.

AVIATION

(For the 06Z TAFS through 06Z Friday night) ISSUED AT 1231 AM EST FRI NOV 6 2026

VFR conditions are in place across the forecast area at time of the 06z TAF issuance. Valley fog is expected across the forecast area tonight which will cause IFR conditions. However, outside of valleys, VFR conditions should prevail. Ceilings are forecast to drop quite sharply from northwest to southeast as a cold front moves through the area on Friday. This ceiling change should bring widespread MVFR conditions with IFR conditions possible, but with some improvement in cigs back to low-VFR conditions through the evening for most locations. The cold front will also cause winds to veer to the northwest, but with sustained winds expected to remain below 10 kts.

JKL WATCHES/WARNINGS/ADVISORIES

Frost Advisory from midnight tonight to 9 AM EST Saturday for KYZ044-050>052-058>060-068-069-079-080.