517
FXUS64 KJAN 191745 AAA
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
1245 PM CDT Sat Sep 19 2026

...New AVIATION...

.KEY MESSAGES...

- 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 308 AM CDT Sat Sep 19 2026

Through next week (Friday)...

This weekend: Sprawling mid level high at the surface and aloft
(595 to 597DM) remains situated over the ArkLaTex, per RAP/upper
air analysis and GOES East water vapor imagery. Continued
anomalous some 8-15F above normal (95F to 101F). Drier air is
propagating westward, with GOES East total PWs showing drier air
in the west (1.2 to 1.4 inches) while a little deeper moisture to
the east. A westward propagating upper low/surface trough over
the northeast Gulf will lead to an influx of deeper moisture aloft
from east to west and higher boundary layer moisture, which
supports less mixing and increased concerns of dangerous heat.
Highs will continue to moderate into the upper 90s to around 100F
(97-102F), with 101-102F possible, especially in northern
observation sites. Continued messaging targeted heat graphics in
the HWO through the weekend (Elevated in west-central to
northeast, east and southeast MS while and Elevated west of
Interstate 55 late week Sunday into Monday). Ongoing heat advisory
looks on track but some localized expansion may be warranted
further south and west today. Additional heat headlines will
likely be needed Sunday but will hold off introduction for now. Lows
will be seasonably warm, some 6-14F above and a touch warmer this
morning (69-74F) with even more seasonable warmth tonight, 8-15F
above (72-76F).

Rain chances remain a low chance (less than 15 percent), with any
chances possible southeast of the Natchez Trace into the Highway
45 to 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 Golden
Triangle today and additionally southeast of the Natchez Trace
into the the Pine Belt late weekend on Sunday (15-30 percent).

Next week (Through next Friday): As the upper low weakens and
another shortwave/cold core low propagates into the Mid West
States into the middle of 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 but has trended
stronger with the ArkLaTex to northwest Gulf high pressure ridge
aloft. 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/suppressed heat/Elevated HWO Tuesday and much more
pleasant into late week. Combined with the ridge less stout and
centered over east TX and weak front diving southward, highs will
not be as seasonably warm later (10F to 16F above early week to
3F to 10F above late week). Highs peak in the 96F to 101F range
early week to 90F to 96F by mid week to 86F to 94F by the end of
the week. Rain and storm chances remain in the isolated/low
chance range (15-25 percent) on average in north central,
northeast to east and southeast MS, with deep moisture/frontal
convergence possibly driving coverage a touch higher in the
scattered/medium chance range (30 to 50 percent range). There
could be some cooler thermal profiles aloft (around -8C at 500mb
and vertical totals in the mid to upper 20s (27C to 29C);
isolated strong storms cannot be ruled out at times especially
early week around Monday. /DC/

&&

.AVIATION...
(18Z TAFS)
Issued at 1244 PM CDT Sat Sep 19 2026

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

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       98  73  97  72 /   0   0   0   0
Meridian      99  72  98  71 /   0  10  10   0
Vicksburg     98  73  97  73 /   0   0   0   0
Hattiesburg   98  73  97  72 /   0   0  10  10
Natchez       97  72  97  73 /   0   0   0   0
Greenville   100  74  99  75 /   0   0   0   0
Greenwood    100  73  99  72 /   0   0   0   0

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Heat Advisory until 8 PM CDT this evening for MSZ026>033-035>058.

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

$$

/DC/22