Expect another day of widespread moderate to heavy rainfall as wet pattern persists for a little longer

In brief: With low pressure and plenty of moisture in the atmosphere, expect another wet day for much of Houston. Due to the potential of flash flooding, we are maintaining a Stage 2 flood alert for coastal counties through Thursday night, and a Stage 1 flood alert for areas further inland, including Harris County. This pattern should start to change later on Friday and this weekend. Next week looks sunny.

Thursday

Areas generally to the south and east of Houston have seen 0.5 to 1.5 inch of rain overnight, totals which have mostly been manageable, but which have contributed to waterlogged soils. We are likely to see additional rounds of moderate to heavy rainfall later this morning and into the afternoon hours, with areas closer to the coast continuing to see higher rainfall. For the most part, these showers should be a nuisance rather than a genuine hazard.

Coastal areas are at the highest risk of excessive rainfall today. (NOAA)

However, the atmosphere retains the potential for heavy rainfall through today and tonight. By this I mean some storms could drop 2 to 4 inches per hour, which given our soils will back streets up quickly. Because the potential for these higher rainfall rates is greater near the coast, we are maintaining a Stage 2 flood alert for all coastal counties. Please remain weather aware today, with an eye on the radar. We will update the site this afternoon, if warranted. In this case, no news would be good news.

High temperatures today, due to persistent cloud cover and rain-cooled air, should remain in the vicinity of 80 degrees. This is decidedly not the norm for late July in Houston, and we’ll soon see a turn toward hotter weather. Winds remain light, from the east or southeast, at 5 to 10 mph. Lows tonight will only fall a few degrees from daytime highs.

Thursday night and Friday

Consistent with the pattern we’ve seen in recent days, we may see a lull in showers this evening. However, it seems most likely that we’ll see another round of showers develop near the coast after midnight, and that these will progress northward throughout the morning hours on Friday. I don’t want to jinx anything, but I think this probably will be the last “round” of showers we see from this system as the upper-level low finally lifts out of the area. Accordingly, I expect highs to be a little warmer on Friday afternoon, perhaps reaching the mid-80s.

Saturday and Sunday

Although the threat of heavy rainfall will largely have passed by this weekend, we’re still likely to see mostly cloudy skies with periodic light to moderate showers. High temperatures both days will push into the upper 80s, with a few inland areas possibly reaching 90 degrees.

After cloudy weather through the weekend, we should expect a lot of sunshine next week. (Weather Bell)

Next week

Most of next week should yield mostly sunny skies. High temperatures look fairly typical for this time of year, pushing into the mid-90s. At least right now there is not any sign of going much higher than that. In any case, aside from the warm days and humidity, next week should offer a period of relatively calm weather in Houston. Are we allowed to have such things in the year 2024?

Mostly manageable rain today, but additional waves of rain in our future

In brief: Rain has been manageable so far today. We expect more rain this evening, with scattered heavy downpours. Another round of potentially heavier rain is possible on Thursday morning. We’ll maintain our flood alerts as is for now.

Rain has been mostly under control since this morning thankfully. The next wave is coming ashore now at the coast, and even this one is checking in a bit more manageable than it looked this morning.

Rain is moving back in on the coast, with scattered downpours elsewhere. Heavier rain is moving toward Beaumont and Port Arthur. (RadarScope)

Still, rain rates around 1 inch an hour or so are likely as this pushes ashore. As it moves north and east, we’ll see most rain impacts on the southeast side of Houston, with isolated to scattered downpours north and west. Total rainfall will be an additional inch or two at the coast and less inland (except in isolated heavier downpours) through this evening. Any street flooding is expected to be more nuisance in nature.

Looking ahead, modeling is suggesting another rather beefy area of rain and storms approaches the area overnight or early on Thursday morning. This would be capable of perhaps another 1 to 4 inches of rain.

An additional 1 to 4 inches of rain is possible near the coast through Thursday morning, with isolated higher amounts also a possibility. (Pivotal Weather)

There remains enough uncertainty in the models that we use for these type of rain events that I think maintaining the Stage 2 alert for the coastal areas and Stage 1 inland is the right move. One model we track closely during these events suggests as much as 7 to 10 inches could fall in a worst case scenario between Galveston and Port Arthur and southwest Louisiana. I would especially watch the Beaumont-Port Arthur area in this setup. We don’t expect that outcome, but we can’t rule it out entirely. For the majority of metro Houston and suburbs, another inch or two, with some seeing more and some less seems reasonable.

Eric will update us on Thursday morning with the latest regarding the rainfall.

Heavy rainfall threat shifts to the coast, where we’re increasing our flood alert to Stage 2

In brief: Although the coast has largely been spared heavy rainfall for the last two days, it now appears that the axis of strongest storms will shift there on Wednesday and Thursday. Due to this heightened threat for widespread street flooding, we are elevating coastal counties to a Stage 2 flood alert for now through Thursday evening.

Wary of offshore rains

As the Houston region has fallen into a very wet pattern over the last two days, the heaviest rains have fallen north of the city. Some locations in The Woodlands, for example, have received in excess of 9 inches of rainfall, and areas near Kingwood have received 4 to 6 inches. These heaviest rains have been fairly isolated, however, as most of the Houston region has picked up 1 to 2 inches so far.

We have a couple of more days during which the threat of heavy rainfall is high, so what will happen next? The majority of our modeling guidance suggests the threat will shift southward, particularly from southern Brazoria County up the coast through Galveston Island and all the way to Beaumont-Port Arthur. For this reason, we are elevating our flood alert for coastal counties to Stage 2 on our flood scale.

This means that for coastal counties—Brazoria, Galveston, Chambers, Jefferson, and Orange—there is the threat of flash flooding today, tonight, and on Thursday. Under Stage 2 conditions we generally expect widespread street flooding, and the potential for some localized flooding of homes and businesses. For the rest of the Houston metro area, and particularly areas along and inland of Interstate 10, lesser impacts are expected. We are maintaining a Stage 1 flood alert there.

Houston radar at 5:38 am CT on Wednesday showing a band of strong storms just offshore. (RadarScope)

Wednesday

Just before sunrise this morning we are seeing moderate showers across much of the Houston area, and for now these are totally manageable. But there is a line of showers and thunderstorms just off the coast that is more menacing. There is a fairly good chance this line will slowly lift northward into the coast, including Galveston Island, this morning. This will pose a distinct threat to flood streets.

These showers will gradually spread inland today, but based on our latest modeling they should gradually have a reduced impact and weaken some as they do so. Due to widespread showers and mostly cloudy skies, we can expect highs today to top out in the the low- to mid-80s for most locations.

Wednesday night and Thursday

The most likely scenario is that we see a similar pattern tonight. Some time after midnight another line of showers and thunderstorms appears likely to congeal offshore and then push into Galveston, Chambers, and Jefferson counties during the wee hours. This may spark another round of flooding for areas along and near the coast through Thursday morning. These showers should move inland during the daytime, albeit with likely reduced intensity.

Area in red shows where the threat of excessive rainfall is highest. (NOAA)

All told, most locations south of Interstate 10 should receive at least 2 to 6 inches of rainfall on Wednesday and Thursday. My concern, and the reason for a heightened flood scale alert, is the possibility for some of these storms to dump 10+ inches of rainfall right along the coast. The models are increasingly highlighting this threat for places such as Galveston Island and the Beaumont-Port Arthur area.

Friday, Saturday, and Sunday

The threat of very heavy rainfall should end by Thursday evening or so, but that does not mean our wet pattern will end. Rather, we’ll continue to see a healthy chance of showers through the weekend. We don’t expect to see the kinds of storms that will produce significant flooding, but there look to be fairly widespread showers. If you have outdoor activities planned, especially for Saturday, I would not feel great about them.

Highs for this period will range from the upper 80s to lower 90s, with partly to mostly cloudy skies. There is a chance of some sunshine by Sunday afternoon, however.

Next week

As high pressure starts to build into the area, next week should be hotter. Starting Monday, I expect we’ll reach at least the low-90s, and by midweek I expect Houston to be solidly in the mid-90s with lots of sunshine. We cannot rule out a stray shower here or there along the sea breeze, but these should not result in any serious accumulations.

We will have an addtional update later this afternoon or early evening to keep tabs on the situation.

Storm coverage and intensity peaks the next couple of days, with lessening impacts by the weekend

In brief: Houston faces three days of widespread showers, with the potential for heavy rainfall and street flooding, before conditions start to ease heading into the weekend. The entire metro area lies under a Stage 1 flood alert through Thursday, although the potential for heavy rain this week is highest near the coast. That’s where we expect the greatest accumulations, with 6 or more inches possible in some locations.

NOAA rain accumulation forecast for now through Thursday night. (Weather Bell)

Tuesday

Showers have developed near the coast this morning, at sunrise, and are making their way inland. Coverage of these storms may widen for areas south of Interstate 10 this morning, and this may prove impactful during the morning commute. Some street flooding is possible. Later today we can expect widespread showers for much of the area, with embedded heavy rainfall through the daylight hours. Please be weather aware as you get out and about today.

The coverage and intensity of showers today should wane as we get toward sunset, but some light to moderate rain will still be possible overnight. Highs today will get into the mid-80s for most locations, although far inland area (with lesser rain) may reach 90 degrees. Winds will generally be light, from the east, at 5 to 10 mph. Lows tonight will drop into the mid-70s.

Wednesday and Thursday

These days will both see widespread coverage of moderate to heavy rainfall, with the highest totals likely along and south of Interstate 10. Most of our modeling continues to paint coastal areas, from southern Brazoria County to Galveston Island, and up the Texas coast to Port Arthur with the greatest accumulations. Heavy rainfall is certainly possible for areas further inland, such as Katy, Tomball, The Woodlands, or Kingwood, it’s just that widespread coverage is less likely. In any case, be prepared for travel delays during the heaviest storms; but also understand that not everywhere is going to see heavy rainfall nor serious impacts.

The entire Houston metro area will be at risk of excessive rainfall on Wednesday. (NOAA)

Rain totals through Thursday night should be on the order of 2 to 4 inches for areas north of Interstate 10, with higher end totals of 6 inches or greater possible south of Interstate 10 and especially along the coast. We should also continue to see quieter nights in terms of storm coverage.

Heavy rainfall remains the big threat this week, with the possibility of damaging winds and other severe impacts much lower. Highs both days should be in the low- to mid-80s for most locations. Evening temperatures will be, dare I say, almost pleasant?

Friday, Saturday, and Sunday

Rain chances remain high for the weekend, albeit with less coverage and storm intensity with each passing day. By Sunday or so, only about half of Houston is likely to see rain, and accumulations should be modest. Daily highs will correspondingly rise from the mid-80s on Friday into the low-90s by Sunday.

Mild high temperatures this week will increase heading into next week. (Weather Bell)

Next week

By Sunday or Monday, we’ll start to feel the encroaching high pressure from the eastern United States. This will lead to sunnier days—we can probably expect mostly sunny skies most of the time next week—and warmer temperatures. Highs will likely start out in the low-90s next week, but I suspect we’ll be in the mid-90s by the second half of the week as we enter August. Rain chances are not going to go away entirely, but they’ll be greatly diminished, and likely to only occur during the afternoon along the sea breeze. Summer is going to summer in Houston, as it does in August.