876
FXUS64 KJAN 200556 AAA
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
1256 AM CDT Thu Aug 20 2026

...New AVIATION...

.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.

&&

$$

DC/NF/22