textproduct: Houston/Galveston

KEY MESSAGES

- Dangerously hot conditions through 4th of July weekend, with heat index values approaching advisory criteria.

- Widespread heat indicies of 105-107F (41-42C) with locally higher values over 108F (43C +) are likely this weekend.

- Isolated to widely scattered showers/thunderstorms today. Drier over the weekend. Chance of isolated to scattered sea breeze showers/storms increases early next week.

DISCUSSION

Issued at 1146 AM CDT Fri Jul 3 2026

The weather pattern over SE Texas continues to be dominated by a large mid/upper ridge that is centered over eastern CONUS. The ridge has expanded somewhat, with the atmosphere over SE Texas becoming drier and hotter than yesterday. That being said, the ridge has not been suppressive enough to prevent the development of isolated to widely scattered showers/thunderstorms, particularly over our coastal zones. Temperatures today will be well into the 90s (easily 34-37 celsius) with peak heat index values averaging around 105F (41C). The pattern looks similar this weekend, but with slightly stronger ridging and a somewhat drier atmospheric profile. This may allow afternoon temperatures to warm a degree or two or three higher than today. However, the drier profile may also allow for lower dew points to mix to the surface, resulting in similar heat indicies as today. Though our current forecast keeps heat index values below Heat Advisory criteria, it is highly likely that there will be locally higher heat indicies. This is especially true within Houston's urban heat island, where peak indicies could easily surpass 108F (43C +) in hot spots today through the weekend. It is important to emphasize that even "normal" SE Texas summer temperatures are dangerous, especially when spending extended times outdoors. Temperatures this weekend will skew a little hotter than normal.

A mid/upper trough over the Great Lakes / Midwest should extend its axis sufficiently southward to result in a weakness in the aforementioned ridge across the Mississippi River Valley and into SE Texas. We don't expect much relief from the heat as a result of this weakness. Perhaps we can nudge temperatures down slightly. But the less suppressive environment may allow for more sea breeze shower/thunderstorm activity by Monday or Tuesday. However, ridging may attempt to build back over the area later in the week.

Self

AVIATION

(12Z TAF Issuance) Issued at 600 AM CDT Fri Jul 3 2026

Very little change with this aviation update. GOES nighttime microphysics imagery reveals low level stratus off to our west. MVFR ceilings have struggled to develop across southeast Texas this morning. However, will maintain a TEMPO group for the next couple of hours for our more inland locations as they are most likely to experience MVFR conditions. A few streamer showers may move inland over the next couple of hours, mainly at GLS/LBX. Sea-breeze activity does not look too impressive today with the greatest chances for TSRA closer to the coast. If any activity makes it a bit further inland, we will make adjustments to the TAFs as needed.

Looking at tonight, will maintain VFR conditions for all sites. The latest HREF probs hint at MVFR ceilings develop again. However, will lean towards persistence with this update as they have struggled to develop this morning. If any low level ceilings develop, would expect them to be brief.

MARINE

Issued at 1146 AM CDT Fri Jul 3 2026

Light onshore flow will continue over the next several days. Gulf seas are expected to average 1 to 3 feet. Isolated coastal and Gulf showers will be possible each morning, with a chance of isolated thunderstorms along the sea breeze in the afternoon. By the middle to later part of next week, a gradually steepening gradient may allow for an increase in south to southeast winds, along with a corresponding increase in the seas. For now, the forecast shows onshore winds increasing to 10-15 knots by Tuesday/Wednesday, before increasing further to the 15-20 knot range by Thursday. Seas may increase to 3-4 feet by week's end.

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 77 96 77 95 / 0 0 0 0 Houston (IAH) 79 97 79 96 / 0 10 0 10 Galveston (GLS) 83 90 83 90 / 0 10 10 0

HGX WATCHES/WARNINGS/ADVISORIES

TX...None. GM...None.