448
FXUS64 KHGX 211125
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
625 AM CDT Tue Jul 21 2026

...New AVIATION...

.KEY MESSAGES...

- Hot conditions persist through the week with the hottest days
  Tuesday and Wednesday.

- A Heat Advisory is in effect from 11 AM - 8 PM Tuesday.

- Tropical Storm Bertha is forecast to weaken as it approaches
  southeast Texas late in the week. While forecast uncertainty
  remains fairly high, residents should monitor the latest
  forecasts and evolution of this system.

- Corresponding rain and temperature forecasts for the local area
  are subject to changes later in the week and highly dependent on
  the tropics.

&&

.DISCUSSION...
Issued at 1231 AM CDT Tue Jul 21 2026

The weather this week remains divided between the heat through
Thursday followed by what will likely be a weakening Bertha.

First, the heat. Ridging over the Rockies will build southeastward
into the southern Plains and across much of Texas. This ridge will
provide ample subsidence, which will keep rain chances very low and
raise our temperatures. While may mix out our dew points some in the
afternoon, it will still be humid enough for heat concerns. Most
areas this afternoon will rise into the upper 90s with some pockets
near 100. Only the immediate beaches will stay in the low to mid
90s. The humidity this afternoon will make it feel more like 107-112
in many areas, and the Heat Advisory remains in effect from 11 AM to
8 PM today. Wednesday looks to be even hotter with the ridge center
positioned over Oklahoma and northern Texas. Many areas away from
the coast will likely exceed 100 degrees for highs (mid 90s near the
coast). That also means our heat index values could be even higher,
perhaps in the 110-115 degree range. We`ll likely need at least
another Heat Advisory for Wednesday, but Extreme Heat
Watches/Warnings could be possible should more widespread areas
see their heat index climb to or above 113. We may eke out a
couple showers or storms Wednesday and Thursday afternoons as a
weak backdoor front moves into the area, but chances are rather
low (30% or less).

Now, the latter half of the week will hinge on the track and
evolution of Bertha. Our ridge that is bringing us the heat will be
the primary steering mechanism, dragging Bertha to the west
paralleling the Louisiana Gulf Coast. On its path, it will be
battling dry air entrainment and wind shear, likely weakening Bertha
on its approach. For more information on its potential impacts to
southeast Texas, please see the tropical discussion below.

After what is left of Bertha passes the area, ridging looks to
dominate as the pattern amplifies further across the Central US.
This means the potential for more heat and continued low rain
chances this weekend into early next week.

Young

&&

.AVIATION...
(12Z TAF Issuance)
Issued at 623 AM CDT Tue Jul 21 2026

MVFR and localized IFR conditions due to patchy fog being observed
this morning, especially at KCXO and KLBX, similar to what has
occurred the past few nights. By 14Z all terminals are anticipated
to return to VFR. Winds are expected to vary between west and
southwesterly flow throughout the day. Overnight we may have another
round of patchy fog; however, an increasing dewpoint depression may
inhibit dense fog. A few of the usual fog prone sites may drop to
MVFR during the 10Z-14Z timeframe, otherwise expect VFR conditions
to continue overnight. Light and variable winds are likely across
all regions tomorrow night.

Davis/Wingo/Bailey

&&

.MARINE...
Issued at 1231 AM CDT Tue Jul 21 2026

High pressure over the western Gulf continues to bring light to
moderate west-southwest breezes over the waters with seas around 2
to 3 feet. This should continue through Wednesday before influence
from Tropical Storm Bertha potentially begins. There remains high
uncertainty in the forecast track and intensity of Bertha, though
the official forecast calls for weakening back to a depression late
in the week. Given this, significant impacts in our waters is not
expected, but some impact to small craft is possible if higher winds
and seas materialize, mainly offshore.

Young

&&

.TROPICAL...
Issued at 1231 AM CDT Tue Jul 21 2026

As of 10 PM CT, the center of Tropical Storm Bertha continues to
slowly drift northwestward south of the Florida Panhandle. This
should gradually pick up speed and turn more toward the west late
Tuesday into Wednesday. On its forecast track, Bertha will move near
the Louisiana coast late Wednesday through Friday morning, then
potentially approach Southeast Texas late Friday. However, on its
journey westward, Bertha will be battling dry air entrainment as
well as northerly wind shear. This will likely result in a weakening
Bertha with convection displaced to the south of its center. The
official forecast from the National Hurricane Center calls for
Bertha to weaken back to a depression near southwest Louisiana and
remain that way on its approach to southeast Texas, if it survives.

Of course, this has implications for our local impacts. Regardless
of what form Bertha is in on its approach, it appears most of the
shower and thunderstorm activity will be displaced to the south. If
some of the outer bands can make it to the coast, then some locally
heavy rainfall would be possible. As it stands, the 90th percentile,
or reasonable high-end, for rain from the LREF (GFS, ECMWF, and
Canadian ensembles) around around an inch through this weekend. Some
breezy winds are also possible, mainly near coastal areas and
offshore.

Due to the high uncertainty, continue to keep up to date with the
latest forecasts for any changes in trends over the next couple days.


&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  98  78 101  81 /   0   0   0   0
Houston (IAH) 100  80 103  82 /   0   0   0  10
Galveston (GLS)  94  81  96  83 /   0   0  10  30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory from 11 AM this morning to 8 PM CDT this evening
     for TXZ163-164-176>179-195>200-210>214-226-227-235>238-300-
     313-335>338-436>439.

GM...None.
&&

$$

DISCUSSION...Young
AVIATION...Bailey/Davis/Wingo
MARINE...Young