textproduct: Houston/Galveston

KEY MESSAGES

- Hot and dry conditions to prevail, with temperatures skewing a little hotter than normal this week.

- Heat indices will be near Heat Advisory criteria throughout the week. Heat will be dangerous even if we remain a little below advisory criteria.

- Rain chances remain near zero through the forecast period.

DISCUSSION

Issued at 1023 PM CDT Mon Aug 17 2026

"I'm gonna keep it 100 with y'all"...is what Mother Nature told us the forecast will be for the foreseeable future. Southeast TX remains dominated by a 596-597 dam mid-level high ("heatdome") that will continue to sit overhead through at least midweek. Rain chances remain slim to none as a result...our "best" chance of rain comes Friday/Saturday but even that is only around 10% (more on that later). On Monday afternoon, we had a few locations reach the century mark, but this was aided by drier air continuing to linger north of I-10. Further south, low-level moisture began to increase in the afternoon. With elevated moisture back in place, temperatures will may actually be a degree "cooler"...but head indices will be a bit warmer. Max heat indices on Monday were mainly in the 102-105F range whereas on Tuesday we're looking more in the 104-107F range. Still anticipating enough mixing in the afternoons to keep us just below our Heat Advisory threshold. Even if a heat advisory is not in effect, it will still be dangerously hot especially for those outdoors for extended periods of time.

850 mb temperatures will approach the 99th to MAX percentiles (NAEFS/GEFS) Wednesday through Friday. While that's occuring another pocket of drier air (PW's around the 25th percentile: ~1.51") moving in on Wednesday/Thursday. The dry air we recently experienced was closer to the 10th percentile (~1.24") at its peak, so the air won't be as dry. However, it'll likely be dry enough to bring widespread high temperatures in the triple digits for the middle to latter part of the week. This drier air will likely limit heat indices like we saw on Monday, but again this heat will still be dangerous if outdoors for an extended period of time. Low temperatures for the rest of the week will be mainly in the upper 70s to low 80s, so there won't be much relief overnight from the heat. Speaking of overnight, patchy fog potential will persist for at least the next few mornings especially for areas west of I-45.

This trend unfortunately looks to continue for the remainder of the month with rain chances slim at best. Slim isn't zero though, so let's talk about where these slim rain chances come from. After midweek, the heatdome slides westward towards the Four Corners region which places us in northwest flow aloft. An upper level trough is expected to slide through the Mississippi River Valley going into the weekend with an associated frontal boundary and we may catch some PVA on the tailend of this trough. Now the front is not going to make it anywhere close to here, but it likely will serve as an initiation point for convection to develop and push southward. How far south does that convection last? Who knows! Will we have enough moisture in place and will the ridge be far enough to the west to allow for some sea breeze convection? Maybe! Ensemble guidance still favors a dry solution for the weekend, BUT there are a few members that bring measurable rain to portions of Southeast TX over the weekend. Maybe if enough of us wash our cars we can make that low probability solution a reality!

With hot conditions persisting over the next several days, please continue to keep heat safety at the top of your minds for any plans that you make (especially if outdoors). Know the signs of heat- related illnesses, stay hydrated (with water), take frequent breaks from the heat, wear loose/light-colored clothing and sunscreen, and ALWAYS ALWAYS ALWAYS LOOK before you LOCK your vehicle. Don't forget about your pets as well! If the ground is too hot for the palm of your hand, then it is too hot for their paws.

Batiste

AVIATION

(06Z TAF Issuance) Issued at 1023 PM CDT Mon Aug 17 2026

Not much change for this TAF package. VFR conditions prevail at all sites. Winds continue to gradually decrease and skies remain mostly clear. Winds become light and variable overnight, turn out of the WSW early tomorrow morning, then pick back up and turn out of the SSE by tomorrow afternoon. Once again, MVFR CIG/VIS is possible at some sites (CLL/UTS/CXO/LBX) early tomorrow morning. CIGS lift and fog burns off shortly after sunrise. VFR conditions expected for the remainder of the day tomorrow.

MLG

MARINE

Issued at 1023 PM CDT Mon Aug 17 2026

A period of benign marine conditions continues with light to occasionally moderate southerly/southwesterly winds and 2-3 ft seas prevailing over the next several days. Wind speeds approach 15 kt during the evening/overnight hours then decrease during the daytime hours.

Batiste

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 76 100 79 100 / 0 0 0 0 Houston (IAH) 79 99 80 100 / 0 0 0 0 Galveston (GLS) 83 91 83 91 / 0 0 0 0

HGX WATCHES/WARNINGS/ADVISORIES

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