textproduct: Jackson

KEY MESSAGES

- Hot temperatures continue today, but lower humidity should help to reduce heat stress, with dangerous levels of heat stress confined to north of Interstate 20.

- Dangerous levels of heat stress will build back in areawide this weekend through early next week before a front with drier air, lower dewpoints and pleasant temperatures/less heat into late next week.

DISCUSSION

Issued at 219 AM CDT Fri Sep 18 2026

Through mid-late next week (Thursday)...

Through this weekend: The Gulf Coast states remain entrenched under a sprawling high at the surface and aloft (598 to 600DM). RAP analysis/water vapor imagery indicate the center of mid level high pressure gradually shifting westward today, leading anomalous warmth, some 8-15F above normal (95F to 101F). Drier air is evident in GOES East total PWs (0.9 to 1.3 inches) moving across the Gulf Coast region as the mid level high shifts westward. While it will remain hot, dangerous heat stress will be somewhat decreased and shifted northward. Lows will be seasonably warm, a touch cooler this morning in the mid to upper 60s to the southeast (66-70F along and southeast of the Natchez Trace) while low 70s (71-74F) to the northwest into the Delta, before a touch warmer tonight (69-74F).

Highs continue to moderate into the weekend, with an influx of deeper moisture. A westward propagating upper low/surface trough over the northeast Gulf will lead to an influx of deeper moisture aloft and higher boundary layer moisture, which supports less mixing and more concerns of dangerous heat. Highs will moderate into the upper 90s to around 100F (97-102F), with 101-102F possible, especially in northern observation sites. Added some targeted heat graphics in the HWO for today into the weekend (Limited north of Interstate 20 today, areawide Limited Saturday, and Elevated west of Interstate 20 late week on Sunday). Holding off on any heat headlines for now. Rain chances remain a low chance (less than 15 percent), with any chances possible southeast of the Natchez Trace into the Interstate 59 corridors. While the official forecast indicate a low chance of rain (less than 15 percent), some consensus and synoptic pattern could support higher coverage than indicated, as much as isolated/low chance rain and storm coverage in the Pine Belt late weekend on Sunday (15-30 percent).

Next week (Through next Thursday): As the upper low weakens and another shortwave/cold core low propagates into the Mid West States through middle to late next week, the mid level feature over the northeast Gulf is progged to lift northward. This feature will become absorbed in the mean flow to the north, which may become more amplified than previously anticipated (per deep cold core over the Great Lakes in 18/00Z Euro). This will lead to less focused moisture convergence but persistent deep moisture (PWs around 1.75 to greater than 2 inches).There are continued indications of weak front/convergence zone and northwesterly flow sinking into the area early next week, with drier air and lower dewpoints late week.

Dangerous heat concerns will persist into early week and will continue to message Elevated HWO heat graphics for Monday, less oppressive Tuesday and much more pleasant into late week. Combined with the ridge less stout and centered over east TX, highs will not be as seasonably warm later (10F to 16F above early week to 4F to 12F above late week). Highs peak in the 96F to 101F range early week to 88F to 96F by mid to late week. Rain and storm chances remain in the isolated/low chance range (15-25 percent) on average in east to southeast MS, with deep moisture/frontal convergence possibly driving coverage a touch higher in the scattered/medium chance range (20 to 40 percent range). There could be some cooler thermal profiles aloft, with vertical totals in the mid to upper 20s (26C to 28C); isolated strong storms cannot be ruled out at times. /DC/

AVIATION

(18Z TAFS) Issued at 1254 PM CDT Thu Sep 17 2026

VFR conditions wl prevail through the TAF period. /22/

PRELIMINARY POINT TEMPS/POPS

Jackson 96 71 98 72 / 0 0 0 0 Meridian 97 72 99 71 / 0 0 0 0 Vicksburg 96 71 97 72 / 0 0 0 0 Hattiesburg 95 70 98 72 / 0 0 0 10 Natchez 96 70 98 72 / 0 0 0 0 Greenville 99 73 100 73 / 0 0 0 0 Greenwood 99 72 100 72 / 0 0 0 0

JAN WATCHES/WARNINGS/ADVISORIES

MS...None. LA...None. AR...None.