textproduct: Jackson

KEY MESSAGES

- Mainly dry weather is expected into Friday, with temperatures averaging around 5 degrees below normal.

- Unsettled weather is forecast to return this weekend, with temperatures warming to near normal by early next week.

UPDATE

Issued at 1042 PM EDT WED JUL 22 2026

The cold front has settled into Tennessee and Virginia late this evening, taking any substantive rainfall with it. However, still cannot entirely rule out a sprinkle or brief light shower over the Bell/Harlan county vicinity through 1 AM EDT. Otherwise, weak northerly flow continues to bring cooler and drier air overnight. Occasional mixing should inhibit fog formation in all but the deepest and most sheltered mainstream river valleys. Temperatures are forecast to settle back into the 50s to around 60F by daybreak.

LONG TERM

(Friday night through Wednesday) Issued at 446 AM EDT Thu Jul 23 2026

The long term forecast period continues to be defined by an amplified mid/upper-level synoptic weather pattern. The antecedent ridging over the west-central CONUS is progged to strengthen this weekend, with 500mb heights over the Great Plains states rising towards the 99th percentile of LREF model climatology on Saturday and Sunday. At the same time, troughing will dig deeper into the Eastern Seaboard, with heights off the Carolina coast plummeting down below the 10th percentile early next week. Eastern Kentucky will be positioned in between these two anomalously strong features for the rest of the period, and guidance collectively resolves a prolonged regime of northwesterly flow aloft as a result. A series of shortwave disturbances is progged to navigate through this flow and approach the forecast area over the course of the next week. As they arrive, they will interact with increasing temperatures and greater low-level moisture to produce periodic shower/storm chances. Confidence in specific timing/intensity details decreases with time though.

Forecast confidence is at its highest this weekend, during the pattern's transition period. As the influence of the midlevel ridging to our west grows on Friday, the surface high pressure system responsible for today and tomorrow's pleasant will shift east for Saturday. This allows low-level flow to adopt a more west- southwesterly orientation and gradually return moisture to the atmospheric column from SW to NE. Generic rain shower chances accordingly re-enter the forecast in the southern half of the forecast area after midnight on Saturday morning, when the first shortwave impulse is expected to arrive aloft. This initial round of activity is not expected to pose a risk for hazardous weather, but the related cloud cover should keep Saturday morning's MinTs insulated within the mid/upper 60s. It may also prevent the area's conventional overnight ridge-valley temperature splits from coming to fruition. Filtered diurnal warming and continued low-level WAA yields high temperatures in the low/mid 80s on Saturday afternoon, when relatively deeper moisture will begin spreading across the CWA. LREF mean PWATs rise to between 1.5 inches in the Big Sandy region and 1.8 inches closer to Lake Cumberland on Saturday evening, and the arrival of the next impulse aloft should spark more meaningful showers and storms by then. Saturday's PM activity is more likely to come in the form of thunderstorms than anything that develops on Friday night/Saturday morning, but that convection is still not expected to be severe. While it may still produce frequent lightning and heavy rainfall, it is generally expected to wind down overnight with the loss of diurnal heating. If there is enough clearing in its wake, the area's conventional ridge/valley temperature splits could materialize by Sunday morning. Likewise, and especially if grounds are wet across the area, nighttime radiation fog is plausible.

The pattern continues to amplify headed into next week, and the growing influence of the ridging to our west should allow temperatures to warm into the upper 80s on Sunday and then towards the lower 90s on Monday and Tuesday. This corresponds with a return to seasonably appropriate dewpoints in the upper 60s/lower 70s, and together, this establishes a favorable thermodynamic environment for relatively stronger thunderstorms next week. Additional disturbances working their way around the ridge via the persistent NW flow will provide the dynamic forcing necessary for storm initiation, but there is considerable forecast uncertainty surrounding the arrival time of each wave. Pattern recognition suggests that some of this convective activity could take the form of more organized ridge- riding MCSes, but the intensity of that activity would be highly sensitive to both the evolution of upstream activity and its relation to the diurnal instability cycle. The currently-available deterministic model data lacks the resolution to resolve these finer- scale convective details, but there are some useful signals showing up in ensemble, analog, and AI/ML guidance.

Various machine learning outlook models continue to paint severe hazard probability contours across our CWA early next week. There is noticeably less of a signal with the experimental output for Sunday's setup, but recent guidance suggests that there may be a consensus time frame emerging between Monday night and Tuesday night. There was a slight uptick in the latest ECMWF EFI/SOT joint CAPE-shear output across our forecast area during the 8PM Monday to 8 PM Tuesday period. 70 to 80% of the ECMWF ensemble members are resolving CAPE and shear values above what is considered normal for this area in July, and 10% of the ensemble members are near the model climatology's maxima. Trends in the above data will need to be monitored closely in the coming days, as LREF mean ensemble soundings depict favorable convective parameter spacing (1500+ J/kg SBCAPE and 30-40 knots of effective bulk shear) during the afternoon and evening hours on both Monday and Tuesday. However, these soundings also show radiation inversions developing after sunset each night, and if storms trend towards a late-night arrival, they could certainly be in a weakening state.

The Storm Prediction Center has introduced a Day 5 (Monday) Slight Severe Weather Outlook for upstream areas like Illinois, Indiana, and Ohio. In the related forecast discussion, SPC mentions the potential for an organized MCS to develop and then drop south- southeast into the Appalachians into Tuesday. It would be working against the diurnal instability cycle as it does so, but it should be noted that the highest PoPs in the long term period now fall in the aforementioned Monday night to Tuesday night time frame. If the blended model data used to populate the long term grids continues to increase PoPs around then and a consensus emerges, the evolution of that upstream activity will need to be watched closely. It is plausible for an additional wave of storms to develop later in the day on Tuesday, but the quality of that wave's convective environment would depend on the evolution of the previous night's activity. It is far too soon to determine the effects of any mesoscale/residual boundaries upon the setup, and the favored time frame may shift in subsequent model runs. Given the potential for multiple rounds of stronger thunderstorms, WPC has already gone ahead and introduced a Marginal Excessive Rainfall Outlook to portions of the forecast area early next week. So, we will also have to monitor the potential for heavy rain to yield localized hydrological impacts as the effects of the persistent pattern accumulate. Altogether, this makes for a very active, but very complex forecast for the end of July, and interests are encouraged to monitor for further updates.

AVIATION

(For the 06Z TAFS through 06Z Thursday night) ISSUED AT 225 AM EDT THU JUL 23 2026

Clouds at the low, mid, and high level levels lingering behind a cold front over much of eastern KY at issuance. VFR was present at the TAF sites, though some MVFR lingered at non TAF site locations near the VA border at places such as K1A6 and KI35. High pressure will build into the area as it moves across the Great Lakes during the period with all locations remaining or trending to VFR (in the case of areas along the VA border) through 12Z. Once VFR develops in all locations it should remain through the end of the period. The only exception will be the chance for a few patches of valley fog through 13Z with reductions to MVFR. If this fog materializes it would not affect TAF sites and be confined to the deepest southeastern river valleys. Generally light and variable to north to northeast in more exposed locations at 10KT or less.

JKL WATCHES/WARNINGS/ADVISORIES

None.