textproduct: Houston/Galveston

KEY MESSAGES

- The Flood Watch has been cancelled early. Scattered showers and storms remain possible overnight especially around the Brazos Valley and the Piney Woods.

- Increasingly summer-like weather by the second half of the week.

- Rain chances increase next weekend as a cold front moves into the region.

DISCUSSION

Issued at 1018 PM CDT Sun Apr 12 2026

Well that escalated quickly...multiple rounds of heavy rain led to instances of flooding across portions of Southeast Texas generally along and north of the I-10 corridor. Areas from northern Colorado County through northwestern Harris County received 3-5+" of rainfall with rainfall rates peaking above 4" per hour at times. For more on today's rainfall and its impacts on area streams/rivers, see the Hydrology discussion down below. The environment is fairly worked over following this afternoon's convection, so the probability of another round of rain of similar caliber overnight are on the slim side. That being said, PW values remain above the 90th percentile (~1.53"). With additional embedded shortwaves passing through, remnant boundaries lingering from earlier convection, a nearby 25-30 kt LLJ, and elevated low-level moisture remaining in place, we certainly have the ingredients for scattered showers and storms overnight. This is most likely to occur north of the Brazos Valley/Piney Woods. We'll continue to monitor radar and model trends. As I write this (around 10pm CDT), I'm looking at a cluster of storms in central Texas moving southeastward and storms just northwest of the Brazos Valley tracking northeastward. The hope is that northeastward moving convection works over the environment before the southeastward moving convection moves in to allow for a quieter night for us. That wasn't confusing at all to describe!

As a result, the flood threat overnight remains rather conditional as it'll depend on if additional convection is able to move into our area. The latest trends of the CAMs keeps the bulk of the nocturnal convection to the north of the Brazos Valley, but they've been a bit wishy washy on the placement of convection throughout the day. There remains a slight risk (level 2 of 4) of excessive rainfall for most of Southeast Texas (except right along the coast) as a result. Just remember that this is a conditional threat as all of the favorable ingredients remain in place. It's just a matter of if convection manages to move into the area and sustain itself. Since confidence is not too high on this playing out, the Flood Watch for Southeast Texas was cancelled early. Some of the CAMs do bring some convection into the Brazos Valley/Piney Woods overnight, so the chances definitely aren't zero for isolated instances of minor flooding.

Going into the work week, we remain in a pattern with southwesterly flow aloft with embedded shortwaves bringing occasional chances for showers and storms around midweek in our northern counties. May have to watch for an isolated storm or two developing to our west on Monday afternoon as it could potentially drift eastward into our area. As an upper level trough sweeps through the central CONUS around midweek, it will aid in the development of storms off of a dry line over in western Texas. It's not entirely out of the question for a few storms to clip portions of the Brazos Valley/Piney Woods, but there will be a cap that needs to be overcome (especially on Tuesday). PW values begin to increase towards the end of the work week as moisture converges along a frontal boundary that stalls out to our north, so some isolated streamer showers will be possible. Speaking of frontal boundaries, we're monitoring the potential for a cold front next weekend. Now it's too early to say it's a sure thing one way or the other...but the NBM temperature envelope (e.g. all percentiles) do trend slightly downward so that's something! We can take a look at things probabilistically as well...the probability of high temperatures below 80 degrees increases sharply to 60-90% range in the latter half of next weekend. Plenty of time for things to change and evolve, but this does look to be our next best chance of rain as well.

Speaking of temperatures, they will go a gradual upward trend throughout the week with highs on Monday mainly in the low 80s then in the mid to upper 80s by midweek and solidly in the upper 80s by the end of the work week. Isolated spots reaching the 90 degree mark aren't entirely out of the question either towards the end of the week. Low temperatures will mainly be in the upper 60s to the low 70s throughout most of the forecast period. We already discussed the potential cold front in the paragraph above, so we'll let that speak for itself even though I'm sure y'all wouldn't blame me if we talked about it twice! :)

Batiste

AVIATION

(12Z TAF Issuance) Issued at 617 AM CDT Mon Apr 13 2026

MVFR CIGS this morning should scatter/lift with VFR conditions returning by the late morning/afternoon. Breezy south to southeast winds are expected during the daytime, later easing down this evening. Isolated showers will also be possible throughout the day, though rain chances are too low to warrant a mention in the TAFs. MVFR CIGs fill in again overnight into Tuesday. IFR CIGs could briefly develop during this early morning period as well.

03

MARINE

Issued at 1018 PM CDT Sun Apr 12 2026

Moderate southeasterly winds and elevated seas (4-6 ft) persist, so small craft should continue to exercise caution through at least Monday morning. Southeasterly winds weaken a bit early this week, but there may be intermittent periods where caution flags may be necessary. Due to the persistent onshore flow, slightly elevated water levels during high tides remain possible. P-ETSS guidance continues to reflect water levels reaching 2.5-3.0 ft above MLLW during times of high tide throughout most of the work week. While coastal flooding is not a concern at this time, some wave run-up is certainly possible along Gulf-facing beaches along with increased risk of rip currents.

Batiste

HYDROLOGY

Issued at 1018 PM CDT Sun Apr 12 2026

Clusters of strong storms began to move into northern Colorado County early this afternoon and gradually drifted east-northeastward into northwestern Harris County. These storms were slow-moving at times with rainfall rates peaking above 4" per hour in the heaviest downpours. Storm total QPE shows an axis of high rainfall totals extending from northern Colorado County to southern Austin/Waller Counties and into northeastern/northern Harris County. The highest rainfall totals peaked in the 4-5" range with the winners of the day being 5.08" in southern Waller County just north of Pattison and 5.34" in northwestern Harris County near Jersey Village. This led to instances of street flooding across this corridor with numerous reports (pictures, images, etc.) sent in. Thankfully, there were no reports of flood waters entering any homes or structures.

This heavy rainfall also led to isolated instances of flood gauges reaching, or expected to reach, action stage. Langham Creek at Addicks is already in action stage this evening. Bedias Creek at Madisonville, Davidson Creek at Lyons, and the Lavaca River at Hallettsville are all forecast to crest in action stage over the next day or so. Some of these forecasts are based off of QPF, so the forecast may change based on radar/model trends. Remember that you can monitor updated river forecasts via the NWS NWPS webpage (https://water.noaa.gov/).

There is potential for additional rounds of rainfall overnight into early Monday morning. In Southeast Texas, this is most likely to occur over the Brazos Valley/Piney Woods which is well north of the axis of high rainfall totals. Isolated instances of minor flooding cannot be completely ruled out though. The Flood Watch was cancelled since confidence isn't high on this occurrence.

Batiste

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 83 68 84 69 / 30 0 0 0 Houston (IAH) 83 70 84 70 / 30 0 10 0 Galveston (GLS) 79 73 79 73 / 10 0 10 0

HGX WATCHES/WARNINGS/ADVISORIES

TX...None. GM...Small Craft Should Exercise Caution until 7 AM CDT this morning for GMZ330-335-350-355-370-375.