textproduct: Jackson

KEY MESSAGES

- Hot and humid weather persists at quite oppressive levels through the first half of the weekend.

- Scattered showers and storms are possible today and into tonight, before convective coverage increases during the latter part of 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 735 AM EDT SAT JUL 4 2026

Updated the forecast for the ongoing convection bubbling up in the southwest parts of the area and also included the latest obs and trends for the T/Td/Sky grids. These adjustments have been sent to the NDFD and web servers along with a freshening of the SAFs and zones.

LONG TERM

(Sunday night through Friday) Issued at 430 AM EDT SAT JUL 4 2026

The main change to grids for the first part of the extended forecast this morning was to add in minimal amounts of terrain details each night on account of the still moist air mass and only partly clear skies that will be in place through Tuesday morning and beyond. Persistent troughing aloft still looks to keep things fairly active and well hydrated through the end of the work week keeping shower and storm chances in the sensible weather forecast.

The previous long term discussion follows:

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 12Z TAFS through 12Z Sunday morning) ISSUED AT 750 AM EDT SAT JUL 4 2026

Aside from the storm near KLOZ, VFR conditions prevail at the TAF sites for the 12Z issuance. The convective debris clouds around and new clouds with the redevelopment kept river valley fog from affecting all but far eastern parts of the area. Ongoing storms have been addressed with tempo groups that also extended to nearby TAF sites. We are also looking for the development of scattered thunderstorms across the entire forecast area late this afternoon, so these were handled with PROB30 groups at all of the aviation terminals. Winds may become erratic and gusty in any thunderstorm activity through the period, but otherwise, they will remain light and variable. Given the low- confidence nature of this forecast, aviation interests should monitor for potential TAF amendments during the morning and early afternoon hours.

JKL WATCHES/WARNINGS/ADVISORIES

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

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