textproduct: Houston/Galveston

KEY MESSAGES

- A Heat Advisory remains in effect through 8 PM this evening.

- Even hotter conditions are expected on Wednesday with dangerously heat indices across all of southeast Texas. An Extreme Heat Warning has been issued from 11 AM - 8 PM Wednesday.

- 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 217 PM CDT Tue Jul 21 2026

No major changes to the forecast... The main weather concerns are dangerously hot conditions as we continue to monitor the westward progress of Tropical Storm Bertha over the northern Gulf.

Now through Wednesday: A mid to upper level ridge centered over the Rockies continues to dominate weather conditions across the region by providing strong subsidence and dry air across the area. As Bertha moves into the northwestern Gulf, even hotter conditions will be in place by Wednesday, with highs mostly in the triple digits. The first 100-degree day may occur on Wednesday in some locations. With increasing Gulf moisture, expect dangerous heat index values in the 108 to 115F range. A Heat Advisory remains in effect for all of Southeast TX through 8 PM this evening. An Extreme Heat Warning has been issued for all of Southeast Texas on Wednesday from 11 AM through 8 PM. Remember, heat-related illnesses increase significantly during extreme heat and high humidity events. Please, stay cool, hydrated and informed. Wednesday night into Friday... Weather conditions will be mainly influenced by the eventual track and intensity of Tropical Storm Bertha. Dry air entrainment and increased wind shear will continue to play a big role in its development once it moves near the Louisiana coast and heads westward toward the TX coast. Current observations and forecasts show the heaviest precipitation and strongest winds for this system are located on the south side of this asymmetrical storm. Therefore, no significant impacts are anticipated for Southeast TX at this time. Isolated to scattered showers and thunderstorms are possible, with the best chances over the coastal counties and coastal waters. Please continue to monitor for forecast updates as Bertha evolves over the northern Gulf. See the TROPICAL section below for more details on Bertha.

Saturday through early next week... Depending on the track/intensity of Bertha, a few showers/storms will be possible on Saturday. Otherwise, the mid to upper level ridge re- establishes over the central CONUS through the weekend, leading again to drier and hotter conditions. Heat headlines may be needed late this weekend into early next week as heat indices rise into the 105-108 degF range.

JM

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 217 PM CDT Tue Jul 21 2026

Light to occasionally moderate west to southwest winds and low seas will continue across the Upper TX coast through at least late Wednesday. Mariners should continue to monitor weather conditions, especially Thursday and Friday as Tropical Storm Bertha moves westward along the northern Gulf. There still remains high uncertainty in the forecast track and intensity of Bertha. However, Bertha is expected to weaken back to a depression before it reaches our coastal waters. While forecast confidence remains low given this uncertainty, significant impacts are not anticipated across our coastal waters. However, Small Craft Advisories could potentially be issued for elevated winds and seas up to 6 ft.

JM

TROPICAL

Issued at 217 PM CDT Tue Jul 21 2026

The National Hurricane Center continues to track Tropical Storm Bertha, currently centered off the Florida Panhandle coast. It is slowly moved NNW to NW today at around 3-5mph, but a building high pressure to the north is expected to force Bertha on a more westward track later today into Wednesday morning. Bertha has strengthened through the day today with maximum sustained winds of 60 mph as of the 1pm CDT Update. However, strong northerly shear has displaced most of the thunderstorms and winds to be located on the south side of the storm. Environmental conditions continue to look unfavorable for future strengthening/organization as Bertha deals with the high wind shear, increasing subsidence from the building high pressure, and deals with land interaction along the central Gulf Coast over the next few days. The current forecast has Bertha approaching the Upper Texas coast as a weak tropical depression late Thursday into Friday morning - if it survives.

We are not anticipating significant impacts to Southeast Texas from Tropical Storm Bertha. The lop-sided nature of the showers and thunderstorms is expected to keep the bulk of the rainfall offshore. Some shower and thunderstorms could be possible along the coast Thursday into Friday as the system approaches from the east, but not anticipating any significant rainfall totals. NBM shows about a 10% chance of rainfall greater than 1" near the barrier islands, but otherwise is <5% across inland portions of the region. The 90th percentile rainfall totals (which is the reasonable worst case scenario) around 0.5-0.8" south of I-10. Gusty winds will be possible over the coastal waters and along the immediate coast Thursday into Friday, but chance for tropical storm force winds inland is <5% at this time. And no significant coastal flood impacts are expected at this time with forecasted high tides around 2-2.5ft above MLLW - we typically start to see minor coastal flooding around 3.5ft. There will likely be an increased risk of rip currents along area beaches.

Please continue to monitor the latest forecast on Bertha at www.hurricanes.gov.

Fowler

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 79 101 81 97 / 0 10 10 0 Houston (IAH) 80 103 82 99 / 0 10 10 10 Galveston (GLS) 81 96 83 92 / 0 10 30 30

HGX WATCHES/WARNINGS/ADVISORIES

TX...Heat Advisory until 8 PM CDT this evening for TXZ163-164-176>179- 195>200-210>214-226-227-235>238-300-313-335>338-436>439.

Extreme Heat Warning from 11 AM to 8 PM CDT Wednesday for TXZ163- 164-176>179-195>200-210>214-226-227-235>238-300-313-335>338- 436>439.

GM...None.