textproduct: Jackson

KEY MESSAGES

- Hot and humid weather persists at quite oppressive levels through the rest of the week, likely peaking on Thursday.

- Mostly dry weather is anticipated through Thursday, before chances for showers and storms return to end the week.

UPDATE

Issued at 145 PM EDT TUE JUN 30 2026

Hourly grids were freshened up based on recent observations and trends. This led to no substantial changes at this time. Diurnally driven cumulus has formed but is expected to lack sufficient depth for any shower activity. Otherwise, temperatures were nearing 90 or in the 90s for most location and when combined with dewpoints mainly in the 70s, heat indices were in the mid and upper 90s to around 100 for most locations. As the afternoon progresses, most lower elevation locations should experience heat indices peaking between 100 and 105.

UPDATE Issued at 715 AM EDT TUE JUN 30 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. Did issue an SPS for valley fog this morning, as well. These minor adjustments have been sent to the NDFD and web servers along with a freshening of the zones.

LONG TERM

(Wednesday night through Monday) Issued at 330 AM EDT TUE JUN 30 2026

The long-term period opens Wednesday evening with an ~596 dam high centered nearly directly over eastern Kentucky and a corresponding surface high in place over the Southeastern CONUS. The low-level air mass will be oppressively hot and humid with 850 hPa temperatures of 23 to 24C and dew points in the lower to mid 70s. Upper-level troughing will be found upstream over the Western CONUS.

The hottest and muggiest air mass of the period will be over the Coalfields and vicinity Wednesday night and Thursday as the upper high lingers overhead. With strong solar heating and the air mass warming even more, expect high temperatures to soar well into the mid 90s on Thursday afternoon with some of the hottest spots flirting with the upper 90s. These values combined with torrid dew points will support heat indices in the 100 to 110F range. While forcing will be weak, a few orographically induced showers or thunderstorms could pop off. While shear will be weak, there will be plenty of instability, so any pulse storm that does go up could be briefly strong.

The upper-level high will then slowly shift east and subside on Friday and Saturday as western troughing deamplifies with a piece of shortwave energy ejecting eastward out across the Plains toward the Ohio Valley. As a result, there will be a gradual slackening in the heat and an overall trend toward increasing PoPs each day as disturbances pass aloft and a cold front eventually approaches from the northwest. Most places dip back into the 80s for highs by next Monday.

For Independence Day specifically, the daylight hours appear mostly dry at this point with higher chances for hit-and-miss showers and thunderstorms during the evening and early overnight. While not as hot as Thursday, it will still be quite oppressive with highs ranging from the lower to mid 90s while heat indices climb to between 95 and 105F.

AVIATION

(For the 18Z TAFS through 18Z Wednesday afternoon) ISSUED AT 145 PM EDT TUE JUN 30 2026

With high pressure remaining across the region, diurnally driven cumulus depth is expected to be limited today and to end the period. These diurnally driven cumulus in the 2.5 to 5kft agl range should dissipate by around 00Z and then return around 15Z. Valley fog is expected to develop again tonight and affect those locations between about 04Z and 13Z. At this point, TAF sites are not expected to be affected. Winds will remain light and variable through the period.

JKL WATCHES/WARNINGS/ADVISORIES

Extreme Heat Warning until 8 PM EDT Friday for KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120.