textproduct: Jackson

KEY MESSAGES

- There is a Marginal Risk for isolated strong to severe storms across the eastern 2/3rds of Mississippi through this evening.

- Dangerous heat stress conditions are expected across at least portions of the forecast area through the end of this week.

DISCUSSION

Issued at 130 PM CDT Tue Aug 18 2026

The persistent heat remains the main concern over several days into early next week, but today the combination of heat and humidity will aid in development of isolated strong to severe thunderstorms. South of a stalled frontal boundary in the region, pooled deep moisture and abundant sunshine have increased analyzed SBCAPE values to around 3000-4000 J/kg this afternoon. Heating and weak convergence in the frontal zone are expected to trigger thundestorm development in the next 2-4 hours, with activity then spreading south and east through the instability axis. Deep layer wind shear is only around 15 kts, so severe storm activity may not be highly organized. Damaging wind gusts and locally heavy downpours are the primary hazards, but small hail cannot be ruled out.

In case you forgot about the heat, it is still hot. Several sites in the area have already reached 100 degrees again today, and widespread heat index values in the 105-110 degree range are being observed as of the current moment. A Heat Advisory remains in place through this evening and picks back up again tomorrow. Rain and the frontal boundary may keep max values just below Excessive Heat Warning criteria, but will continue to monitor for any needed upgrades.

Steepening northwest flow aloft, associated with a building ridge over the western CONUS, will allow for a couple of disturbances to bring rain chances into our forecast area through early next week. Will also nudge temperatures slightly cooler, but still August- level heat. /NF/

AVIATION

(18Z TAFS) Issued at 1257 PM CDT Tue Aug 18 2026

VFR conditions will prevail throughout the forecast period. Isolated to scattered TSRA will affect sites this afternoon briefly lowering conditions. /KP/

PRELIMINARY POINT TEMPS/POPS

Jackson 76 100 77 99 / 30 20 10 10 Meridian 74 99 75 98 / 30 20 10 30 Vicksburg 77 98 77 98 / 20 10 10 10 Hattiesburg 75 98 76 98 / 60 30 20 30 Natchez 77 99 76 99 / 20 0 10 0 Greenville 77 102 79 100 / 20 10 10 20 Greenwood 75 100 77 98 / 20 10 10 10

JAN WATCHES/WARNINGS/ADVISORIES

MS...Heat Advisory until 8 PM CDT this evening for MSZ018-019-025>066- 072>074.

Heat Advisory from 11 AM to 9 PM CDT Wednesday for MSZ018-019- 025>066-072>074.

LA...Heat Advisory until 8 PM CDT this evening for LAZ007>009-015-016- 023>026.

Heat Advisory from 11 AM to 9 PM CDT Wednesday for LAZ007>009- 015-016-023>026.

AR...Heat Advisory until 8 PM CDT this evening for ARZ074-075.

Heat Advisory from 11 AM to 9 PM CDT Wednesday for ARZ074-075.