textproduct: Jackson

KEY MESSAGES

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

- Isolated severe storms capable of damaging wind gusts are possible across portions of the area again today.

MESOSCALE UPDATE

Issued at 807 PM CDT Wed Aug 19 2026

Rest of this evening into tonight...

Dangerous heat continues to be the main story, but ongoing storms continue to fester into central MS, with a few exhibiting efficient cold pools and causing some gusty winds and resultant damage. Evening analysis indicates the ridge breaking down, with heights falling from near 600DM at the peak of the heatwave to around 592-593DM. This combined with deeper moisture (1.6 to 2 inch precipitable water) and steep lapse rates (26C to 27C vertical totals, 3500-4500 SB/MLCAPE and 1300-1600 DCAPE) led to scattered strong to severe storms through this evening. This has been driving the stout pulse microburst nature of convection today. These will continue the next hour or two before subsiding. Temperatures and heat remain dangerous even around 8PM, with most areas still between 88F to 93F and heat indices in upper 90s to low 100s. Current heat headlines fall off at 9PM with additional heat advisories in effect for Thursday. Seasonably warm lows, some 6F to 10F above, remain on tap again, with some record warm lows possible. Updates are out. /DC/

DISCUSSION

Issued at 244 PM CDT Wed Aug 19 2026

Dangerous heat remains a persistent concern over the next several days into early next week, but steady moisture content (as seen by dew points remaining in the low to mid 70s this afternoon) is increasing the risk for isolated strong to severe thunderstorms today and tomorrow. Analyzed SBCAPE values are near 5000 J/kg this afternoon across northeastern parts of Mississippi where moisture is greatest. Heating and weak convergence in the frontal zone will support thundestorm development particularly in that zone, with activity then spreading south and east through the instability axis. Isolated shower and storm development is possible elsewhere. DCAPE is 1100+ J/kg across the forecast area, so any substantial convection will carry the risk for damaging wind gusts from microbursts. Similar conditions will be in place, and a Marginal Risk for severe storms is in place for the northeastern 2/3rds of the forecast area.

Heat remains dangerous. Several sites continue to reach air temperatures of 100 degrees, with peak heat index values near 110- 115 degrees. Gradual easing is expected as this frontal boundary and drier air edge southward into the weekend, but afternoon heat index values are still expected to peak near or above 105 degrees into early next week especially in the southwestern half of our forecast area. /NF/

AVIATION

(06Z TAFS) Issued at 1249 AM CDT Thu Aug 20 2026

Isolated to scattered TSRA are psbl again this aftn over most of the TAF sites with the exception of GLH and HEZ. Any TSRA will likely bring lower flying conditions and gusts in excess of 30kts. Otherwise, VFR conditions will prevail areawide through the end of the TAF period. /22/

PRELIMINARY POINT TEMPS/POPS

Jackson 75 98 73 98 / 10 30 20 10 Meridian 74 97 72 97 / 20 30 40 0 Vicksburg 76 99 73 98 / 10 30 20 10 Hattiesburg 75 98 73 97 / 20 50 40 10 Natchez 76 99 74 99 / 0 30 30 10 Greenville 76 99 73 100 / 40 10 10 10 Greenwood 74 97 71 98 / 40 20 10 10

JAN WATCHES/WARNINGS/ADVISORIES

MS...Heat Advisory from 11 AM this morning to 8 PM CDT this evening for MSZ018-019-025>066-072>074.

LA...Heat Advisory from 11 AM this morning to 8 PM CDT this evening for LAZ007>009-015-016-023>026.

AR...Heat Advisory from 11 AM this morning to 8 PM CDT this evening for ARZ074-075.