textproduct: Jackson

KEY MESSAGES

- Warmer temperatures and a greater potential for showers and thunderstorms will start the new week.

- These storms could be more organized and strong to severe tonight depending on the development of thunderstorm clusters to the north of Kentucky and their evolution.

- Drier weather returns for the second half of the week.

UPDATE

Issued at 725 AM EDT MON JUL 27 2026

No significant changes were made to the forecast with mainly just the inclusion of the latest obs and trends for the T/Td/Sky grids. The fog was beefed up more in the past couple of hours along with the issuance of an SPS addressing valley visibility restrictions through the morning commute. These adjustments have been sent to the NDFD and web servers along with a freshening of the zones.

LONG TERM

(Tuesday night through Sunday) Issued at 455 AM EDT MON JUL 27 2026

The main change to the grids for the first part of the extended forecast this morning was primarily to include some slight terrain distinctions into temperatures for Wednesday night, though some uncertainty remains as to the sky cover. Strong 5h ridging to the west still looks to support a persistent glide path for mid-level shortwaves to dive into eastern Kentucky through the work week, though visiting sfc high pressure from Wednesday through Friday look to keep the weather calmer and drier.

The previous long term discussion follows:

The long-term period opens Tuesday morning with a pronounced ~596 dam high over the Southern Rockies with a ridge axis extending northward into Central Canada. Meanwhile, troughing extends southward from an around 540 dam low over northern Quebec to along the Mid-Atlantic Coast. An embedded shortwave trough is present over the Lower Great Lakes. This will be mirrored at the surface by a 997 mb surface low over Lake Erie. A warm front extends southward from that low to over the Southern Appalachians while a cold front arcs southwest from the surface low over southern Indiana and Illinois and then beyond to over the High Plains of Montana. This will leave eastern Kentucky in the low's warm sector at daybreak Tuesday morning with a seasonably moist air mass (PWATs around 1.8 inches).

The surface low will shift eastward along the PA/NY Twin Tiers through the day and evening on Tuesday, dropping the cold front across the Commonwealth. Substantial uncertainty remains as to instability recovery ahead of this boundary given the likelihood for convection early in the day, and especially prior to sunrise with a potential MCS. If the frontal arrival is slower and greater destabilization occurs, unseasonably strong northwesterly flow aloft would support robust shear and organized convection. Conversely, a quicker frontal passage would tend to favor keeping any stronger organized convection confined to far southeastern Kentucky or perhaps entirely southeast of our CWA. In addition to the convective potential, Tuesday does appear breezy with some momentum transfer mixing to the surface from a low-level jet (30+ kt at 850 hPa). The high PWATs could also favor some isolated heavy rainfall. Any hydro problems would probably occur where substantial rainfall occurred during the last 12 hours of the short-term period; by Tuesday, the strong flow aloft should keep cell motions quite progressive.

Once the front clears the area, cooler and drier air will filter in on Tuesday night and Wednesday, with LREF mean precipitable water values dropping to between 0.75 and 1.00 inch, or near the 10th percentile relative to climatology. Aloft, ridging will remain over the West while troughing lingers over Eastern Canada and much of the Eastern CONUS. Surface high pressure drifting south from Ontario and Quebec will ensure dry conditions through Friday. Another shortwave trough drops into the broader trough during the upcoming weekend. This will foster another surface low developing over the Plains and drifting toward the Tennessee Valley vicinity, bringing back higher PWATs and the renewed threat of convection for Saturday and Sunday.

In sensible weather terms, look for a high chance of showers and thunderstorms (PoPs of 60 to 90 percent, highest in far eastern and southeastern Kentucky) on Tuesday. If substantial sunshine materializes, some of the storms could be strong to severe and also produce heavy downpours. It will be warm and humid with highs in the 80s. Fair weather follows for Tuesday night through Friday with highs in the low to mid 80s and lows mostly from 60 to 65F. As the threat of showers and thunderstorms returns for Saturday and Sunday, daily high temperatures will remain at similar levels, but nighttime lows will moderate to between 65 and 70F with higher humidity levels.

AVIATION

(For the 12Z TAFS through 12Z Tuesday morning) ISSUED AT 800 AM EDT MON JUL 27 2026

Most of the TAF sites have gone down hard with the valley dense fog and low CIGs working over their terminals this morning at the 12Z issuance. All the fog will clear out over the next couple of hours allowing VFR conditions to return with light and variable winds. Late this evening into the overnight, a cluster of thunderstorms may start to impinge on the northern terminals working south through the rest of the aviation forecast area with time. Have included a robust PROB30 TSRA group at all sites for this.

JKL WATCHES/WARNINGS/ADVISORIES

None.