textproduct: Jackson

KEY MESSAGES

- Lower humidity and dry weather continues today.

- Unsettled weather returns to end the week and into the weekend, with rounds of showers and storms possibly producing heavy rain and a flood threat.

UPDATE

Issued at 943 AM EDT Wed Jun 24 2026

The previous forecast remains largely on track, with lingering valley fog burning off under mostly sunny skies this morning. Temperatures are quickly recovering into the upper 60s, and western locales should approach 70 by the top of the next hour. As such, have bumped MaxT grids up by a degree or two later this afternoon. Expect efficient diurnal warming/mixing processes to persist through this evening as a surface high pressure system sits directly overhead.

UPDATE Issued at 628 AM EDT WED JUN 24 2026

Increasing high clouds and even a deck of stratocumulus have helped keep fog a bit at bay, with many webcams showing low stratus instead of fog. Made some tweaks to Sky grids for the next few hours to account for these trends, and updated hourly T/Td grids likewise.

LONG TERM

(Thursday night through Tuesday) Issued at 255 AM EDT WED JUN 24 2026

The long term period will open with an upper level high located off of the southeast Atlantic coast, with additional upper level ridging over Texas, northern Mexico, and southern AZ/NM. To the north, an upper level low will be located between the Great Lakes and the Hudson Bay, with general upper level troughing over the Great Lakes region. Locally, eastern Kentucky will remain in quasi zonal flow aloft as the area is sandwiched between these features, leaving the forecast area in an active pattern going into the weekend. At the surface, an area of low pressure will be located near Lake Huron, with a cold front draped over southern Ohio and Indiana. Meanwhile, a series of 500 mb shortwaves will translate eastward into the Ohio Valley region early Friday morning. Associated height falls overspreading eastern Kentucky should provide additional lift for showers and storms, meaning Friday and Saturday are expected to be rainy, with showers and thunderstorms likely throughout the day.

Activity on Friday and Saturday will bring a risk for heavy rainfall and perhaps isolated to scattered flash flooding. There are some indications that these shortwaves could lead to the formation of a secondary surface low over the Ohio Valley, which could eventually enhance southwesterly flow over the forecast area, leading to further moistening of the environment. Regardless, PW values are expected to be high on Friday and especially overnight Friday into Saturday, when 12Z LREF mean PW values are in the range of 1.7-1.9 inches (generally in the 90th percentile or higher for the forecast area). An analysis of ensemble members reveals high confidence in this moist environment, with relatively small spread in PW beyond a slight skew in the distribution towards higher PW values in some members. As a result, instances of flash flooding cannot be ruled out with this activity, and WPC has highlighted the area with Slight Risk (Level 2/4) Excessive Rainfall Outlooks for Days 4 and 5 (Friday and Saturday) to account for this possibility.

A few questions remain regarding this flood risk. First, the exact positioning of the aforementioned front will affect the most favored corridor for higher QPF, especially given strong moisture convergence, the expectation that the front will become quasi- stationary, and general boundary-parallel southwesterly flow that could allow for training storms (with particular concern for our area on Friday). The general model trend right now is to keep the boundary north of the Ohio River before it lifts further north, relegating the highest QPF to the northern extremities of our forecast area, but this trend will bear monitoring with subsequent forecasts. Additionally, with a series of impulses aloft, complexes of storms capable of producing flash flooding may also be possible. Some machine learning guidance has highlighted a low-end risk for damaging winds with thunderstorm activity on Friday and Saturday; however, this remains contingent on the development of adequate instability (something which may be difficult to realize if showers and storms are ongoing), and shear looks to be quite marginal (generally 20-30 kts), so there is low confidence in any severe risk at this time.

By Sunday, upper level ridging will build over the Mississippi Valley, leaving eastern Kentucky in northwest flow aloft. This will allow for one more day of potentially disturbed weather before upper level ridging amplifies further and overspreads the forecast area. With height rises over eastern Kentucky, weather will be hot and rain chances will be low, with highs in the 90s returning by early next week. Without a mechanism to sweep out the moisture associated with previous activity, dewpoints should also remain high (likely in the 70s), so this will not be a dry heat; weather will be muggy into the end of the period.

AVIATION

(For the 12Z TAFS through 12Z Thursday morning) ISSUED AT 717 AM EDT WED JUN 24 2026

Fog and low stratus will lift and dissipate, possibly lifting into a cumulus field in the 12z to 14z timeframe, with all locations returning to VFR at that point. Valley fog formation will be possible again tonight, mainly after 04z, but it is uncertain whether it will impact any TAF sites at this time. Winds will remain light and variable through the period.

JKL WATCHES/WARNINGS/ADVISORIES

None.