Eric Berger

In brief: This post describes the distinct pattern change we’ve seen from a wet end of July into a warmer August. Yes, sunshine is back on the menu. Additionally, we take stock of where we are with summer in Houston now that we’re about half way through it.

Where we are so far

By most measures we are about half way through summer in Houston, having gotten through June and nearly all of July. Moreover, as of today, we have reached the historically “hottest” time of year, when daytime and nighttime temperatures peak. This period runs through July 29 through August 12, typically the warmest two weeks of the year. So congratulations, we had to come through a Category 1 hurricane and some pretty nasty power outages to get here, but we are making progress toward fall.

What I didn’t say above is anything about extreme temperatures. That’s because, so far, temperatures this summer have been near normal for the last 30 years. The monthly average temperature in June was 1.6 degrees above normal, and for July we are likely to end up at around 1 degree below normal. Thus far this summer, we have hit 100 degrees just a single time, on July 1. Last month we actually had one day with a high of 78 degrees, thanks to the persistent rainfall during the last 10 days of July.

So where does that leave us staring into the abyss of August? Well, there is no drought for as far as the eye can see, and indeed well beyond that. With our saturated soils, we are well positioned for the rest of summer. The wet soils should also help moderate daytime high temperatures, at least a bit, for a few weeks. And, of course, all the rain during the last week will continue to produce a bumper crop of mosquitoes for awhile longer.

August is my least favorite month of the year, by far. It is prone to the hottest weather, and it is when the threat of large and powerful hurricanes starts to peak. (While the Atlantic tropics are starting to wake up from their slumber during the second half of July, there are as yet no threats to Texas). Honestly, if we can get through the next eight weeks, then fall is distinctly on the horizon, and we’ll be near the end of hurricane season for Texas.

Most of our modeling guidance (CFS, European, GFS temperature 30-day temperature forecasts) suggests that temperatures in August will be near normal. In terms of precipitation, we are also likely looking at near-normal levels of precipitation. We shall see. One tropical system can scramble all of that.

Monday

The long-awaited pattern change has arrived. For the first time in awhile, as I checked the radar, there wasn’t much happening in the Houston area this morning. This is because we’re beginning to feel the influence of high pressure, which will help suppress rain showers. That is not to say rain chances will be zero, but they will be much lower, on the order of 10 to 20 percent daily, with a few showers possibly popping up along the sea breeze.

High temperatures for much of Houston will likely rise into the low- to mid-90s for much of the region today. Skies will be partly sunny, with south winds at 5 to 10 mph. Overnight lows should drop into the upper 70s for most areas except the coast.

Tuesday

Conditions will be similar to Monday, although skies may appear to be a bit more hazy. This will be due to the influx of Saharan dust. This same dust has helped keep a lid on hurricane activity over the last week or two across the Atlantic basin. The spread of this dust typically peaks during July, and its decrease in August is one of the reason we typically see more hurricane activity in August and September.

Wednesday and Thursday

Both of these should be sunny days, with high temperatures in the mid-90s. We’ll continue to see some haze on Wednesday, although it may start to wane on Thursday.

Friday, Saturday, and Sunday

Our mostly sunny pattern should continue into the weekend, when we see high temperatures in the mid- to possibly upper-90s by Saturday and Sunday. Atmospheric moisture levels could rise a bit, and this may introduce rain chances in the 20 percent range daily, but for the most part I expect these to be sunny days. If you have outdoor plans for this weekend they look, tentatively, pretty good expect for the heat. But what else would you expect in August, in terms of temperatures?

In brief: Tropical rains brought flash flooding to a belt of the region south and east of the city of Houston overnight, but the worst of these storms is ending. We still have some rainfall concerns this weekend, but we are getting through it. Next week looks sunny and warmer.

As anticipated, we saw a another round of heavy rainfall develop near the coast after midnight, and these storms have dropped a significant amount of rainfall for some areas south and east of Houston. During the last 12 hours, for example, locations such as Dickinson and Baytown have recorded 5 to 7 inches of rainfall, and parts of Pearland and League City have recorded 4 to 6 inches. These heavy rains produced flash flooding consistent with our Stage 2 flood alert for these locations.

The strongest impulse of these storms has now cleared the area, but we are continuing to see some high water locations on streets and feeder roads in parts of Galveston and eastern Harris County. Please take a little extra care heading into work this morning from impacted locations. For the majority of the Houston metro area, overnight impacts were far less significant and there are no issues.

It appears that this was the last mass of truly organized storms for the region, however that does not mean we are done with the rain. We can probably expect fairly widespread showers and thunderstorms to develop near the coast early on Saturday morning and propagate inland. Due to the potential for these storms to hit already water-logged areas, I am going to maintain a Stage 1 flood alert through Saturday noon.

Friday

In the wake of the overnight storms, we’re seeing a fair number of showers and thunderstorms across the Houston metro area. Generally, we should see these storms move toward the northeast later this morning, with things quieting down later this afternoon or evening.

However, we could see an additional impulse of heavy rain right along the coast today, pinpointing locations such as Galveston Island and Bolivar Peninsula. I’m hopeful that these rains will develop to the south of Dickinson, Baytown, and other areas hard hit overnight. But radar trends will be something we should watch today for coastal areas.

For the majority of Houston, however, Friday should be mostly business as usual, with totally manageable accumulations and few impacts. With mostly cloudy skies, we can expect highs to top out in the low-80s. Winds will be generally light, from the southeast. Overnight low temperatures will drop into the 70s.

Saturday and Sunday

We are likely to remain in a pattern whereby we see storms develop during the overnight hours offshore and move inland. However, coverage and intensity should be lower on Saturday morning, and again on Sunday. Still, some isolated locations could see heavy rainfall, and both weekends could see a rainy start—especially south of Interstate 10. If any of this changes, I’ll pop in with a forecast update this afternoon, or over the weekend.

Highs on Saturday should be in the low-80s, with mid- or upper-80s possible on Sunday. As we’ve been saying, this weekend is fairly difficult for outdoor activities, especially anything involving the beach.

Next week

Our pattern shifts in a big way by early next week, with mostly sunny skies likely in place by Monday, and rain chances falling way back. Most of next week should see sunshine, highs in the low- to mid-90s, and give our area a chance to dry out. Pretty soon we’re going to realize that Houston’s highs at this time of year are not usually in the 80s, as we’ve experienced this week.

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.

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.

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?

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.

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.

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.