174
FXUS64 KJAN 191758
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
1258 PM CDT Wed Aug 19 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 today and tomorrow.

&&

.MESOSCALE UPDATE...
Issued at 942 AM CDT Wed Aug 19 2026

Forecast has been updated through the daytime tomorrow based on
latest guidance. Changes primarily to updated POPs and weather
through this evening, with an adjustment to expand the Marginal
Risk for severe storms today. Overall forecast reasoning remains
on track. /NF/

&&

.DISCUSSION...
Issued at 448 AM CDT Wed Aug 19 2026

Through tonight: Heat and humidity will remain the main concern in
the short term although there will be the potential for isolated
strong to severe storms across the northeast half of the CWA this
afternoon. Early morning satellite imagery/RAP analysis showed our
CWA on the eastern periphery of a weakened 592dam ridge that will
continue to provide northwest flow aloft through tonight. At the
surface a nearly diffuse stalled frontal boundary was noted just
north of our CWA. Similar to Tuesday, convection is expected to
initiate along this stalled boundary spread to the southeast across
the northeast half of our CWA into this evening. Latest guidance
suggest the environment will support isolated strong to severe
storms capable of damaging wind gusts. This may bring some relief to
the heat today in the areas that receive rain but otherwise,
temperatures in the upper 90s to lower 100s will combine with
relatively high humidity to result in heat indices just above 110F
along the Mississippi river and southern zones with 105-110F
expected again elsewhere. Thus, an Extreme Heat Warning has been
issued for the area along the Mississippi river while the Heat
Advisory remains in effect for the remainder of the CWA today. The
convection will taper off this evening but the warm and humid
conditions will continue tonight. /22/

Thursday through next Wednesday...

What`s a three letter word that starts with `h` and ends with `t`?
Here`s a quick little hint, it rhymes with dot. If you guessed the
word `hot` then you would be correct because that is what we`re
going to be dealing with for the entire extended forecast period.
Hot and humid conditions will prevail across our entire forecast
area for Thursday. Similar to the last few previous days, afternoon
highs across our CWA will peak into the upper 90s to the low 100s.
This combined with mostly sunny skies combined with increased
humidity will cause heat index reading values to peak in the 105-110
degree range. Several areas west of I-55 could see heat indices
exceed 110 degrees. A Heat Advisory will likely be needed for the
entire area for Thursday and again on Friday. Late afternoon rain
and the frontal boundary may keep max values just below Extreme Heat
Warning criteria. Will continue to closely monitor heat trends for
any potential upgrades.

Regarding the rain chances, guidance shows a weak sfc trough that
will develop eastward across AR into northern MS. This combined with
increased deeper moisture, increased convergence from frontal zone
sagging southward will allow for better rain coverage over portions
of east MS and north MS over the next several days particularly
during the late afternoon/early evening hours. Storm coverage will
be scattered as we go through the late week and into the weekend.
Given the increased heat and humidity, scattered strong to
marginally severe storms cannot be ruled out.

Steepening northwest flow aloft, associated with a building ridge
over the western CONUS, will allow for a couple of disturbances to
bring rain chances into our forecast area through early next week.
Will also nudge temperatures slightly cooler, but still August-level
heat. A slight chance for showers and storms (PoP around 20%) will
cannot be ruled out across much of our area by Wednesday. /CR/

&&

.AVIATION...
(18Z TAFS)
Issued at 1255 PM CDT Wed Aug 19 2026

VFR conditions will prevail throughout the forecast period.
Isolated to scattered TSRA will affect sites this afternoon
briefly lowering conditions. Winds will remain light throughout
the period./KP/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       76  99  76  99 /  20  10  10  30
Meridian      75  99  74  97 /  20  20  20  40
Vicksburg     77  98  76  99 /  10  10  10  10
Hattiesburg   76  99  75  99 /  30  20  20  50
Natchez       76  99  76 100 /  10  10   0  10
Greenville    79 100  77 100 /  10  10  20   0
Greenwood     77  98  74  98 /  10  20  30  10

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Heat Advisory until 9 PM CDT this evening for MSZ026>033-037>039-
     044>046-050>052-055>058-062>066-072>074.

     Heat Advisory from 11 AM to 8 PM CDT Thursday for MSZ018-019-
     025>066-072>074.

     Extreme Heat Warning until 9 PM CDT this evening for MSZ018-019-
     025-034>036-040>043-047>049-053-054-059>061.

LA...Heat Advisory until 9 PM CDT this evening for LAZ007-015-023.

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

     Extreme Heat Warning until 9 PM CDT this evening for LAZ008-009-
     016-024>026.

AR...Heat Advisory until 9 PM CDT this evening for ARZ074.

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

     Extreme Heat Warning until 9 PM CDT this evening for ARZ075.

&&

$$

NF/CR/22/KP