Area Forecast Discussion

KEY MESSAGES

- Dangerous levels of heat stress will build back in areawide through early next week before a front brings drier air and more pleasant temperatures late next week.

DISCUSSION

Issued at 210 PM CDT Sat Sep 19 2026

Through Sunday: Local radars were showing a few showers over our northeast most counties. A few storms will also be possible this afternoon in our northeast before the convection ends by early evening. Otherwise, temperatures were already climbing in the upper 90s and may top out as record highs at many of the climate sites.

Record high temperatures along with higher humidity and mostly dry weather is expected again Sunday. Latest satellite imagery/RAP analysis showed the circulation around a weakened 593dam high centered over northeast Texas. This high will remain in place and weaken further through Sunday. Latest satellite imagery also showed a closed low spinning over the eastern Gulf. Together these features will increase moisture just east of our CWA. This moisture will combine with daytime heating for a few isolated showers and storms to develop over our eastern most counties again Sunday. Record high temperatures will combine again with enough humidity to result in peak heat index values between 105-1108F over the western half of the CWA Sunday while lower heat index values approach 105F in our east./22/

Monday through next weekend...

The anomalous ridge responsible for recent record breaking heat begins to break down early next week with the approach of a shortwave trough. There is a subtle moisture return in response to this, which will increase dewpoints back into the low 70s. This should both increase dangerous heat as well as rain chances beginning Monday and persisting through Tuesday. Heat indices will range from 100-105+, with the hottest temperatures west of I-55. An elevated heat graphic continues to be advertised. Would not rule out a heat advisory for Monday and possibly Tuesday. Further east, where low (20-30%) rain chances are focused, indices are likely to remain below criteria (105), but there will still be a limited heat threat. Isolated to scattered showers and thunderstorms, in perhaps the first sign of the cool season, will not be strictly diurnal, and should continue overnight ahead of a slow moving frontal boundary. Since synoptic forcing is still weak, this frontal boundary will slowly sag south over the course of Wednesday and into Thursday as the shortwave rounds the midlevel high. There is some difference among the guidance regarding the timing of the main jet energy associated with the shortwave, but there is good agreement, and it makes meteorological sense, that shortwave ridging will be reinforced in its wake late next week into the weekend. Dry conditions will return with a continuation of above normal temperatures. /SAS/

AVIATION

(00Z TAFS) Issued at 613 PM CDT Sat Sep 19 2026

Isolated SHRA and TS may result in brief strong wind gusts and ceiling/visby reductions in east MS over the next few hours and again on Sunday afternoon. Otherwise, VFR conditions will prevail with light wind. /DL/

PRELIMINARY POINT TEMPS/POPS

JAN WATCHES / WARNINGS / ADVISORIES

MS...Heat Advisory until 8 PM CDT this evening for MSZ026>033-035>058.

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