787
FXUS64 KLCH 201741
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
1241 PM CDT Mon Jul 20 2026

...New DISCUSSION, MARINE, FIRE WEATHER...

.KEY MESSAGES...

- TD2 is expected to gradually strengthen as it meanders around
  the northeast Gulf these next couple of days. It is then
  expected to move west across the north Gulf through the end of
  the week.

- An upper level ridge will strengthen over the central US,
  bringing a warming trend to our area. Afternoon highs will
  increase by a degree or two each day, hitting the upper 90s to
  100 degrees by midweek. Heat indices will range from 105 to
  112+F this week.

- Heat advisories are in effect for this afternoon for areas along
  and east of I-49, and for tomorrow across all of central and
  southwest Louisiana and southeast Texas. An additional heat
  advisory will likely be issued Wednesday.

&&

.DISCUSSION...
(This evening through next Sunday)
Issued at 1236 PM CDT Mon Jul 20 2026

Water vapor satellite imagery and 500mb analysis depict a strong
ridge centered over the Rockies to southern Plains, which will
continue to be the dominant feature affecting our weather for the
next few days. To our east, Tropical Depression Two is currently
situated in the northeast Gulf and moving slowly to the northwest,
and this will be the major factor affecting our weather for the
latter half of the week. At the surface, a weak high pressure center
is analyzed over the western Gulf, resulting in light west to
northwest winds over our areas. A moisture gradient is present
across the CWA, with GOES-derived PWAT values ranging from 1.2
inches over southeast Texas to 1.8 inches along the Atchafalaya
River.

The upper ridge will strengthen and expand to the
southeast over the next few days. This will do two things through
Wednesday: it will bring a warming trend in temperatures, and it
will allow moisture to increase from east to west across our area.
This combination will result in heat potentially reaching hazardous
levels, and the increased moisture will inhibit the potential for
drier air to mix down in the afternoons during peak heating. A heat
advisory remains in effect for today for locations along and east of
I-49, where better moisture will lead to higher heat indices.

Tuesday and especially Wednesday will be the hottest days of the
week as the ridge builds into the Deep South. A heat advisory has
been issued for the entire CWA for Tuesday, with heat index values
likely exceeding 108 region-wide and potentially reaching 110-112
along and east of I-49. Another heat advisory will almost certainly
be needed for Wednesday, when NBM probabilities of reaching 100
degree air temperatures are over 50 percent for most areas north of
the US 190 corridor, and up to 70 percent over inland SE TX and
central LA. Also of note is that increasing moisture should lead to
the return of some isolated convection for the eastern CWA,
particularly for lower Acadiana.

Attention then turns to the tropical depression in the Gulf.
Guidance from the National Hurricane Center indicates that over the
next couple days, the system should move slowly to the northwest and
strengthen into a tropical storm. The upper-level ridge will push
the system to the northwest and then west, roughly parallel to the
coast of Louisiana. Strengthening will be limited by dry air and
moderate northeasterly shear, and should keep the storm`s intensity
to weak or perhaps moderate tropical storm strength at most. By
Wednesday, the shear will increase even further and cause the storm
to gradually weaken as it approaches the Louisiana coast. This
northeasterly shear is likely to give the system an asymmetrical
structure, with the majority of impacts focusing to the south of the
center. The shear is likely to be enough to cause the system to
dissipate completely by the end of the week into the weekend.

The latest NHC track calls for the system to make landfall over
southeastern Louisiana Wednesday, then emerge over the Gulf and
track westward just south of the southwest LA/southeast TX coastline
Thursday, but there is a good deal of uncertainty in this track. As
such, especially given the likely asymmetric structure of this
system, there is significant uncertainty in the potential impacts
for our areas. A track over the northern Gulf could keep the
majority of impacts offshore, while a track much further inland
could result in more land interaction and the system fully
dissipating earlier. Overall, the most likely area to see weak
tropical storm impacts will be the immediate Gulf coastline,
particularly portions further east. Bottom line: stay tuned to
future forecasts and updates as this system continues to develop
and more details come into focus.

The tropical system or its remnants will exit the region Friday,
with mid-level ridging then dominating the picture through the
weekend. This will result in high temperatures generally in the mid
90s. Rain chances will be low owing to large-scale subsidence, but
deep moisture will remain in place (LREF mean PWATs near 1.8-2.0
inches), which may be enough for some isolated convection
particularly near the coast where seabreeze influence is greatest.

&&

.AVIATION...
(18Z TAFS)
Issued at 1200 PM CDT Mon Jul 20 2026

Conditions will remain VFR for the rest of the day. Overnight
patchy fog should form leading to MVFR impacts. After sunrise
conditions will return to VFR. Winds will remain light and
variable through this forecast cycle.

&&

.MARINE...
Issued at 1236 PM CDT Mon Jul 20 2026

High pressure over the western Gulf will drive westerly winds around
10-15 knots today, with winds increasing from east to west starting
tonight as Tropical Depression Two approaches the area. Look for
winds to increase to the 20-25 kt range by Wednesday over our
eastern waters. Tropical storm conditions will be possible at times
Wednesday night through Friday as the system passes along the
coastline.

&&

.FIRE WEATHER...
Issued at 1236 PM CDT Mon Jul 20 2026

Hot and humid conditions are expected across the CWA through
midweek. Afternoon minimum RH values will be in the 35 to 45 percent
range across inland southeast TX, and 45 to 60 percent range
elsewhere. With winds remaining light over land, no fire weather
concerns are expected. Rain chances will gradually increase from
east to west by midweek as a tropical system approaches the area.

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory from noon to 7 PM CDT Tuesday for LAZ027>033-044-
     045-055-073-074-141>143-152>154-241>243-252>254.

     Heat Advisory until 7 PM CDT this evening for LAZ028-029-032-033-
     044-045-055-143-152>154-243-252>254.

TX...Heat Advisory from noon to 7 PM CDT Tuesday for TXZ180-201-
     259>262-515-516-615-616.

GM...None.
&&

$$

PUBLIC/FIRE/MARINE...64
AVIATION...14