textproduct: Houston/Galveston

KEY MESSAGES

- Rain and thunderstorms likely on Sunday.

- Strong to severe thunderstorms, locally heavy rain, and gusty coastal winds will be the primary concerns on Sunday. Hazardous marine conditions are expected.

- Colder air and strong marine winds expected Sunday night into Monday. Gale Watch in the bays and Gulf during this timeframe.

DISCUSSION

Issued at 135 PM CST Sat Nov 14 2026

Taking a look at water vapor imagery along with satellite derived PW values, we can see quite the split in moisture availability. Currently, PW values are close to the 25th percentile (~0.58") over our far eastern zones. Meanwhile, over Matagorda Bay, PW values are already exceeding the 75% percentile (~1.31"). Unsurprisingly, we already have some isolated showers generally around the Matagorda Bay area and the adjacent coastal Gulf waters as the first upper level disturbances pushes into the area. The ridge axis that has been overhead the past couple of days is pushing its way out to the east. As previously mentioned, the first embedded shortwave trough is moving through the area this afternoon. The latest high-res model guidance indicates that convective coverage will gradually increase later this afternoon once daytime "heating" comes into play. I put that in parentheses for now because daytime heating for today will only peak into the low to maybe mid 70s right around Matagorda Bay. There is some modest amounts of instability off the coast, so it's not out of the question to see some occasional bouts of lightning.

There will still be a layer of dry air in the mid-levels (between 500-800mb) that this increasing moisture and lift would have to battle through. The best chances for rain remain west of I-45 (closer to the Brazos River). Some isolated heavier downpours will be possible later this afternoon into the evening around Matagorda Bay. Some of the latest high-res guidance supports this and even shows the potential for training convection right along the coast near Matagorda Bay late this evening into early Sunday morning. As a result, WPC has outlined this area (generally west of Freeport and south of Edna) in a marginal risk (level 1 of 5) of excessive rainfall for today/tonight. Due to the increasing cloud cover and increasing easterly winds, high temperatures today will mostly top out in the upper 60s to low 70s.

The next upper level disturbance is currently pushing through the Four Corners region which has led to surface low pressure development near the Texas/Oklahoma panhandles. The placement of this surface low is important to note because it will place areas generally west of I-45 and south of I-10 in the warm sector. There remains a little bit of uncertainty on how far north this warm sector will extend...there is potential for this to extend past the I-10 corridor into Harris County for instance. There'll be quite a bit of shear to work with as a LLJ moves in overhead Sunday morning as the low tracks southeastward.

If we take a look at updraft helicity, we see that there is potential for a couple of stronger updrafts to push their way into areas within the warm sector...which is why the exact placement of the warm sector is important to note. So, we'll have shear, instability, moisture, and plenty of lift to work with...so SPC has outlined areas generally south of a College Station-Conroe-Liberty line in a marginal risk (level 1 of 5) of severe weather on Sunday. Damaging winds and hail are the primary hazards, but a brief isolated tornado can't be ruled out. We'll go over the evolution of this entire event in a few paragraphs...

Heavy rainfall will also be a threat, especially as the surface low moves into our area along with the associated cold front. This will surge PW values near the MAX percentile (~1.99") along the coast. The overlap of climatologically high PW's and numerous sources of lift creates the potential for rainfall rates peaking above 2-3"/hr. The greatest potential of this remains south of I-10 and along the coast. We're still expecting widespread rainfall amounts of 1-3" north of I-10. South of I-10, rainfall totals peak in the 3-6" range with the potential for totals possibly approach 6-8" with the highest totals occurring right along the coast (especially near Matagorda Bay).

Moderate to heavy rainfall potential begins around Matagorda Bay this evening. As mentioned earlier, we could see training convection set up going into Sunday morning which will then be followed by a line of strong to possibly severe thunderstorms. As a result, WPC has outlined areas near and south of I-10 in a slight risk (level 2 of 4) of excessive rainfall for Sunday. Elsewhere (outside of portions of the Piney Woods), there is a marginal risk (level 1 of 4) of excessive rainfall. It's worth mentioning that some of the high-res guidance (including the RRFS), has rainfall amounts exceeding 15" just offshore...so we'll continue to monitor trends to make sure it doesn't trend further north.

Now for a brief overview of the evolution of this event...we begin with isolated to scattered showers this afternoon. Some training convection will be possible later this evening into Sunday morning along the coast near Matagorda Bay. Scattered showers will be possible throughout the morning all over Southeast Texas, and then a line of storms associated with a frontal boundary will begin to push into the Brazos Valley in the mid to late morning hours. It will make it into the Houston metro area in the late morning to early afternoon hours, and then off of the coast in the late afternoon hours. The strongest of the storms (if they develop) would most likely occur west of I-45.

The cold front pushes offshore Sunday evening but lingering moisture and lift may lead to our coolest day since mid-March on Monday! Lingering moisture along with lift from the nearby upper level low will result in scattered light rain showers persisting through Monday afternoon...but rain chances gradually taper out from north to south throughout the day. A widespread thick layer of low-level cloud cover will also persist throughout the day. The other part of that equation will be gusty northeasterly winds that prevail in the wake of the front throughout the day on Monday. We are expecting sustained winds near the Wind Advisory threshold along the coast. Technically, wind speeds along the barrier islands will rise enough later this evening to warrant the issuance of a Wind Advisory beginning at 6pm. For the coastal counties/zones, a Wind Advisory will go into effect at 9am Sunday and run through Monday afternoon. The barrier island Wind Advisory will run through Monday evening.

Elevated winds, lingering cloud cover, and light rain generally aren't favorable for heating...so the forecast high temperatures for Monday have continued to trend down. Most of us will not see temperatures rise above 60 degrees on Monday...so mostly highs in the upper 50s. This will likely be our coolest day that we've experienced since mid-March. As far as low temperatures go, we'll only see those bottom out in the 40s/50s Sunday night through Tuesday night.

We'll see a gradual warming trend through next week as high temperatures rise into the 60s on Tuesday and the 70s on Wednesday courtesy of ridging aloft moving in. The dry pattern looks to persist through midweek, before slight rain chances return towards the end of the work week.

Batiste/Crabb

AVIATION

(18Z TAF Issuance) Issued at 135 PM CST Sat Nov 14 2026

VFR conditions prevail throughout today and into the evening. The main flight impact are gusty ESE winds between 20-25kts inland, with an occasional gust up to 30kts. Probability remains low to see 30kts gusts inland, thus, it remains out of the TAFS for the inland sites but still possible. The coast will see gusts between 25-35kts. The prefrontal SHRA begins to enter the vicinity during the overnight before progressing S'ward through the coast. The main cold front is anticipated to arrive Sunday around 15z and march S to reach the coast by the afternoon. Some of the thunderstorms have the capability to become SVR with strong wind gusts as we remain in a Marginal Risk from SPC. These storms bring decreased VIS/CIGS to MVFR/IFR conditions. Once the front passes through -SHRA can linger into the next TAF cycle on Monday and this is when the winds back to NE. The previously mentioned MVFR/IFS CIGS are anticipated to last through Monday morning. VFR conditions are expected to return Monday late-morning to early afternoon.

CMW

MARINE

Issued at 135 PM CST Sat Nov 14 2026

A Small Craft Advisory remains in effect for the bays and Gulf waters through Sunday evening as moderate easterly to southeasterly winds persist. Winds will transition from easterly to southeasterly going into the overnight hours. Subsequently, seas will rise to 6-9 ft overnight and through most of the day on Sunday. Periods of showers/storms will begin as early as this afternoon/evening around Matagorda Bay, but the most impactful round comes on Sunday afternoon as a frontal boundary pushes off the coast. Some of the storms on Sunday could be strong to severe and produce strong wind gusts and isolated waterspouts.

Once the frontal boundary pushes off the coast on Sunday evening, strong northeasterly winds will follow with sustained winds in the 30-35kt range and gusts near or potentially exceeding 40 kt. Seas subsequently rise and begin to peak in the 10-13 ft range especially in the offshore Gulf waters. As a result, a Gale Watch is in effect for the bays and Gulf waters beginning Sunday evening thru Monday evening. Winds and seas gradually subside throughout the day on Tuesday, but may remain elevated enough for Small Craft Advisories.

We are continuing to monitor water levels as PETSS guidance reflects peaks in the 3.0-3.5 ft MLLW during times of high tide over the weekend...especially Sunday afternoon/evening. The elevated onshore flow over the weekend will also lead to moderate to high risk of rip currents along Gulf facing beaches. A Beach Hazards Statement has been issued to cover the threats of minor coastal flooding and the increased risk of rip currents.

Batiste/Crabb

HYDROLOGY

Issued at 135 PM CST Sat Nov 14 2026

With the anticipated periods of moderate to heavy rainfall coming up today into Sunday, there is some potential for action to minor stage river flooding especially along the San Bernard and Tres Palacios Rivers. This is where the greatest confidence of higher rainfall totals is expected to occur (generally around Matagorda Bay). Rainfall totals south of I-10 are expected to be in the 3-6" range with isolated totals possibly peaking closer to 6-8". Rainfall rates in the heaviest downpours will likely exceed 2-3"/hr, so flash flooding in low-lying areas and areas with poor drainage is certainly possible. The most likely impact in urban areas would be localized street flooding if heavy downpours occur for an extended period of time. We'll also be monitoring for localized rises on the Houston bayous and nearby watersheds.

Stay tuned for additional updates as we go throughout the week and remember that you can monitor updated river forecasts via the NWS NWPS webpage (https://water.noaa.gov/).

Batiste/Crabb

PRELIMINARY POINT TEMPS/POPS

College Station (CLL) 53 60 48 57 / 70 100 60 20 Houston (IAH) 55 64 50 58 / 30 100 80 40 Galveston (GLS) 65 72 58 63 / 10 100 80 50

HGX WATCHES/WARNINGS/ADVISORIES

TX...Wind Advisory from 9 AM Sunday to 3 PM CST Monday for TXZ214- 235>238-313-335>338.

Beach Hazards Statement through Monday morning for TXZ436>439.

Wind Advisory from 6 PM this evening to 6 PM CST Monday for TXZ436>439.

GM...Small Craft Advisory until 6 PM CST Sunday for GMZ330-335-350- 355-370-375.

Gale Watch from Sunday evening through Monday afternoon for GMZ330-335-350-355-370-375.