487
FXUS64 KJAN 220219 AAA
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
919 PM CDT Fri Aug 21 2026

...New MESOSCALE UPDATE, AVIATION...

.KEY MESSAGES...

- Dangerous heat stress across at western portions of the
  forecast area again Saturday.

&&

.MESOSCALE UPDATE...
Issued at 919 PM CDT Fri Aug 21 2026

Rest of tonight...

Frontal zone is draped just north of Interstate 20, with
expectations that this will continue to dive southward into the
overnight hours. Synoptic pattern remains with deep broad
troughing and stout ridge (597-600DM at 500mb) over the Four
Corners. Drier air is situated north of the frontal zone, with
deeper moisture to the south. Earlier rain and active storm period
has shifted southward, so rest of the evening should remain much
quieter. There will remain some cloud cover overnight for areas ,
but clearing to the north. Lows will remain seasonably warm
(70-74F). Updates are out. /DC/

&&

.DISCUSSION...
Issued at 315 PM CDT Fri Aug 21 2026

Through Saturday: A frontal boundary will sag slowly southward
toward the coast and help to focus scattered diurnally driven
storms for the remainder of the afternoon and into the early
evening over the southern half of the area. Given how hot and
unstable the boundary layer conditions are, steep low level lapse
rates are supporting microburst winds (e.g., 58 mph gust at TVR
just now), and have continued to message for a slight severe
weather risk this afternoon/evening. This threat may shift into
northwest portions of the area Saturday afternoon as stronger mid
level flow potentially brings organized convection, so stay tuned
for additional severe weather messaging. Of course the dangerous
heat threat continues as well and have issued an additional heat
advisory for Saturday. The heat will gradually become more
focused over southwest portions of the area, and have adjusted our
messaging to reflect this.

Sunday through next week: Global model guidance indicate that a
northwest flow pattern will evolve and persist through the
remainder of the forecast. A NW-SE oriented thermal gradient will
support the greatest heat stress over southwest portions of the
forecast area, but this doesn`t appear it will be more than a
limited to elevated dangerous heat situation. This pattern would
continue to support an occasional MCS threat, but timing details
are very uncertain, and overall rain chances are not great in the
mean. Unfortunately for those needing rainfall, there are no
strong signals for significant rainfall at this point aside from a
gradual uptick in rain chances as we go later into next week. All
global model ensembles point to dry anomalies. Given the
continued vegetative stress, the forecast area will become more
vulnerable to fire danger should wind/RH thresholds be met. As of
now the weather pattern isn`t supporting this, but all fire
related interests should monitor closely. /EC/

&&

.AVIATION...
(00Z TAFS)
Issued at 919 PM CDT Fri Aug 21 2026

VFR flight conditions will prevail through the period. Winds will
be light and variable tonight and gradually shifting northerly but
remaining light (sustained/gusts under 10mph) into Saturday. /DC/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       73 100  74  99 /   0   0  10  10
Meridian      73  99  73  98 /  10   0  10  10
Vicksburg     73 100  73  98 /   0  10  10  10
Hattiesburg   74  99  74  99 /  40   0   0  10
Natchez       74 101  75  99 /  10   0   0  10
Greenville    73  99  73  98 /   0  10  20  10
Greenwood     72  98  72  97 /   0  10  10  10

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Heat Advisory from 11 AM to 8 PM CDT Saturday for MSZ018-019-025-
     034>036-040>043-047>049-053>055-059>064-072.

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

AR...Heat Advisory from 11 AM to 8 PM CDT Saturday for ARZ074-075.

&&

$$

DC/EC/DC