textproduct: Jackson

KEY MESSAGES

- Hot and humid weather persists at quite oppressive levels to begin the weekend.

- Isolated showers and storms are possible this evening, before convective coverage increases over the weekend.

- Storms through the middle of next week may produce strong to locally damaging wind gusts along with heavy rainfall and isolated instances of flooding.

UPDATE

Issued at 900 PM EDT Fri Jul 3 2026

A better defined cluster of storms and its attendant ouflow boundary is working its way into Wayne and McCreary Counties. Model spread remains high, and it is unclear how long this activity will be able to sustain itself given the waning diurnal instability. However, the CONSSHORT is handling this set up quite well, and in collaboration with neighboring WFOs, it was used to update PoP, wind gust, and sky grids through the overnight hours. Expect wind gusts up to 30mph with the outflow ahead of these storms and then heavy rain, lightning, and gusts in the 40-55mph range with storms developing along/just behind the boundary. These storms have been undercut by the outflow, so they are struggling to become as deep as they were across the state line in TN earlier. This, plus the marginal thermodynamic/kinematic environment, will prevent there from being much of a hail threat and will likely limit there from being many severe (60+mph) wind gusts. Storm chances are greatest in locations along/south of the Hal Rogers Parkway. Ridge-valley splits and river valley fog are expected to develop further to the NE after sunset, and any convective activity is likely to weaken as moves to the NE of KY-15. Fog may also develop where grounds are wet by showers/storms, but this is contingent on any convective cloud debris clearing after midnight.

UPDATE Issued at 636 PM EDT FRI JUL 3 2026

The forecast for this evening generally remains on track, with a few stronger updrafts noted in recent satellite and radar imagery. The majority of this convection will be confined to southern portions of the forecast area, and the most robust cell appears to be developing in Harlan County as of 615 PM. We will need to monitor the potential for additional activity to develop off of any outflow boundaries this evening. This convection may produce lightning, downpours, and localized bursts of heavy rainfall as their cores collapse and produce said outflow boundaries. Once diurnal instability subsides after sunset, our attention turns to potential overnight ridge/valley temperature splits and subsequent fog development. The humid nature of the antecedent airmass means that these splits will not be particularly robust in magnitude, but MOS guidance indicates that some of the typical cool spots could approach the upper 60s. Otherwise, expect MinTs in the lower 70s. Fog coverage will be greatest where there are nearby water sources, but if wet grounds are realized in the wake of evening storms, fog could develop outside of the typical valleys. Interests with outdoor evening plans or overnight travel plans are accordingly encouraged to stay tuned for future forecast updates and have multiple means of receiving weather alerts.

LONG TERM

(Sunday through Friday) Issued at 406 PM EDT FRI JUL 3 2026

The long-term period opens Sunday morning with a pattern change underway from a hot and mostly dry pattern this week to near normal temperatures and unsettled weather for next week. The 03/12Z model suite analysis beginning at 12Z Sunday shows split flow over the Great Lakes with troughing prevailing to the south over the Ohio, Mississippi, and Tennessee Valleys while ridging extends northward from the Great Lakes into northwest Greenland. The remnants of the upper-level high that dominated this week will have retreated to the far southeastern CONUS and out over the Central Atlantic. Meanwhile, an ~593 dam high will reside over the Upper Rio Grande Valley beneath a robust trough over Western Canada. At the lower levels, the pattern is messy, though there is likely to be some kind of a weak surface low near or over Indiana with an associated subtle warm front extending eastward toward the Mid-Atlantic and a decaying cold front extending back into the Ozarks. A second weak low should be found near or over Lake Michigan.

Heading into the upcoming week, guidance generally shows the troughing aloft propagating eastward with time, with the southern low fading and the more northerly low predominating and shifting east toward the Mid-Atlantic by Tuesday and dragging a weak cold front south of the Ohio River. As the trough and weak surface reflection depart, that front stalls by Wednesday as heights aloft rebound slowly. While spread increases, models suggest that the western ridge will also break down fairly quickly by midweek as another shallow shortwave trough (associated with the Western Canada trough from the start of the period) drops southeast into the Northeastern CONUS. PWATs will be seasonably moist (75th to 90th percentile relative to climo) to start the period, ranging from 1.5 to 1.8 inches in the LREF mean on Sunday and Monday, dropping off to around 1.5 on Tuesday as the cold front settles through, and remains in the vicinity on Wednesday. Gradual moisture recovery is then likely heading later in the week as the next trough approaches. Given the synoptic features as well as numerous weaker perturbations passing aloft, a generally unsettled pattern is expected to persist throughout the week with diurnally modulated convection (most widespread in the afternoon and early evening, least widespread in the early morning) as the norm. The driest day of the period appears likely to be Wednesday, but even then isolated to scattered convection still appears probable.

In terms of heavy rainfall, a Marginal (level 1 of 4) ERO is in place from Sunday through Monday night to highlight the threat of isolated flash flooding should storms become persistent over a given location. Temperatures through the period again start on the warm side Sunday with highs close to 90F before settling back into the mid to upper 80s for daily highs each afternoon from Monday onward. Nighttime lows retreat into the 65 to 70F range for most locales.

AVIATION

(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 758 PM EDT FRI JUL 3 2026

VFR conditions prevail at all TAF sites as of the 00z issuance, but there are three distinct chances for categorical reductions during the TAF period. Confidence in the first two meteorological phenomena responsible for these potential reductions is quite low, so only the third is explicitly mentioned in this TAF package. The first is the low-end chance for CB clouds to develop off of outflow from thunderstorms currently located to the south in Tennessee. By the time that outflow reaches our southwestern terminals (KSME and KLOZ), it will be working against decreasing instability. A 15-20% chance of thunderstorms was added to the forecast grids through late this evening, but this was not enough to mention in the TAFs. Once that activity subsides, river valley fog development is possible. Based on LAMP probability guidance and model consensus, KSME and KLOZ are the TAF sites that are most likely to experience fog-related MVFR vsby reductions, but convective cloud debris from the evening storms to our south may prevent this from happening. At NE terminals like KJKL and KSJS, fog may lift out of the valleys tomorrow morning and briefly yield reductions, but confidence in this was once again too low for an explicit mention. Confidence is higher in the development of scattered thunderstorms across the entire forecast area tomorrow afternoon, so these were handled with Prob30 groups at all terminals. Winds may become erratic and gusty in any thunderstorm activity tonight tomorrow, but otherwise, they will remain light and variable. Given the low-confidence nature of this forecast, aviation interests should monitor for potential TAF amendments later this evening and overnight.

JKL WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 9 PM EDT Saturday for KYZ044-050>052-058>060- 068-069-079-080-083>085.

Extreme Heat Warning until 9 PM EDT Saturday for KYZ086>088-104- 106>120.