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National Weather Service Forecast Discussion

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240
FXUS64 KHGX 220554
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1254 AM CDT Wed Jul 22 2026

...New DISCUSSION, MARINE, TROPICAL...

.KEY MESSAGES...

- Very dangerous heat is expected today with dangerously heat
  indices across all of southeast Texas. An Extreme Heat Warning
  has been issued from 11 AM - 8 PM.

- Widely scattered showers and storms are possible late this
  afternoon. Some storms may produce frequent lightning and gusty
  winds.

- Tropical Storm Bertha is forecast to weaken as it approaches
  southeast Texas Thursday afternoon into Thursday night. While
  significant impacts are not expected, continue to monitor the
  latest forecast updates.

- 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 1248 AM CDT Wed Jul 22 2026

Very dangerous heat continues across the area today. Ridging builds
in across the southern Plains with the ridge centered over northern
Texas into Oklahoma. This coupled with the subsidence on the outer
edges of Tropical Storm Bertha will lead to very hot temperatures
across southeast Texas today. High temperatures will likely reach or
exceed the century mark away from coastal locations. Areas closer to
the coast will still reach the mid to upper 90s. Dew points in the
70s will combine with these temperatures to produce heat index
values up to 115. This heat will be extremely dangerous for those
outdoors for extended periods of time, especially without hydration
and air-conditioned breaks. Please limit your time outdoors if
possible. Lows tonight won`t provide much relief either as they
settle only in the upper 70s to mid 80s.

Outside of today`s heat, a weak boundary will slide in from the
northeast late this afternoon into the early evening. There will be
enough moisture to work with as well as plenty of instability to
produce isolated/widely scattered showers and storms along this
southwestward moving boundary. These storms will also be capable of
some strong downburst winds as DCAPE (downdraft CAPE) is in excess
of 1000 J/kg. Thus, wouldn`t be surprised to see a few strong to
perhaps an isolated severe storm late in the afternoon into early
evening.

By Thursday, we`ll have increasing influence from Tropical Storm
Bertha, but significant impacts are not expected. We still expect
Bertha to weaken on approach, if it survives the dry air, wind
shear, and land interaction over the next 24-36 hours. For more
details on Bertha, see the tropical discussion below. Increasing
clouds could help hamper the heat somewhat Thursday, but it`s
possible we may still reach advisory levels with our heat indices
around 105-110 with temperatures still in the mid 90s for most,
except lower 90s near the coast. Some rain bands from Bertha may
affect mainly coastal areas Thursday, but this remains lower
confidence.

Ridging builds across much of the central and western US again into
early next week, meaning the hot, dry weather likely rolls along.

&&

.AVIATION...
(00Z TAF Issuance)
Issued at 607 PM CDT Tue Jul 21 2026

Mainly VFR conditions expected throughout the TAF period. Winds
will be light and VRB through early Wed, turning W to NW during
the mid morning hours. Winds will be light and VRB again Wed
evening. There is some uncertainty with respect to rain chances
on Wed, will not add the mention of SH/TS for this TAF issuance
and will re-evaluate for the 06Z issuance.

Cotto

&&

.MARINE...
Issued at 1248 AM CDT Wed Jul 22 2026

High pressure over the western Gulf continues to bring gentle to
moderate breezes to the waters today. Winds may briefly approach
cautionary levels late this afternoon and early this evening over
the eastern waters. Influence from Bertha will begin Thursday with
potentially increasing winds and seas. However, Bertha is forecast
to weaken on approach, and most impacts from Bertha would be limited
to small craft operators. There is a low (near 10%) chance of
sustained tropical storm force winds (34 knots or greater) over the
open Gulf waters. Seas will build in response to about 3 to 5 feet.
All of this is dependent on Bertha`s strength and track. Beyond
Thursday, light to moderate southerly flow is expected with 2 to 3
foot seas.

&&

.TROPICAL...
Issued at 1248 AM CDT Wed Jul 22 2026

As of 1 AM CT, Tropical Storm Bertha was centered off the Alabama
coast with maximum sustained winds of 50 mph. Overall, the forecast
thoughts have not changed significantly. We still expected Bertha to
move westward along the Louisiana coastline through the day
Wednesday night into Thursday, then approach southeast Texas
Thursday evening as a tropical depression.

However, it is possible that Bertha does not survive as an organized
tropical system. It has continued to battle wind shear and dry air
with the center becoming exposed every now and then. This will
continue to be the case as it moves westward, which makes its
prospects for survival questionable, especially once adding in
potential land interaction.

As it approaches southeast Texas, significant impacts are not
expected. Winds may be a bit breezy Thursday and Friday. Chances for
tropical storm force winds (39 mph or greater) are low (10-20% for
points over the water and less than 10% for locations south of I-
10). Rainfall will also be hard to come by with totals only around
0.5 inch or less. Chances of seeing more than an inch are low (less
than 30%). Coastal flood impacts are also not anticipated.

All that being said, continue to monitor the forecast for any
changes over the next day or so.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 101  81  97  79 /  10  10   0   0
Houston (IAH) 103  82  99  82 /  10  10  10  10
Galveston (GLS)  96  83  92  82 /  10  30  30  20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Extreme Heat Warning 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...Cotto
MARINE...Young

NWS HGX Office Area Forecast Discussion