In brief: The Sun has reached its highest point in the sky, so why is this not the warmest time of summer? We explain. Also, we take a look at a forecast that includes rising temperatures and reduced rain chances. Beginning Sunday or so, it looks like we’ll be in the mid-90s for awhile.

Summer solstice

Thursday was the longest day of the year in the Northern Hemisphere—but only just. The Sun reached its highest point in the sky over Houston, a peak altitude above 84 degrees, at 1:23 pm CT. The time from sunrise to sunset was 14 hours, 3 minutes, and 31 seconds. Today will be one whole whopping second shorter. But for the next six months our days will progressively get shorter, until the winter solstice on December 21, when the day length will be just 10 hours, 14 minutes, and 2 seconds.

On of the quirks of Texas’ weather is that, while the Sun reaches the highest point of the sky in June, our hottest weather does not come until nearly two months later, in early- to mid-August. This is not true for all of the northern hemisphere, but there is a decided lag in Texas peak heating due to a number of factors. These include weather patterns (pervasive high pressure systems are more common in August than June), and a lag in ocean heating that brings the warmest onshore flows from the Gulf of Mexico later in the summer. Essentially, it takes longer for the ocean to heat up than it does the land.

The bottom line is that, even as our days get shorter over the next two months, on average our temperatures will continue to go up. Summer has not peaked in Houston, my friends. Fortify yourselves, because it has only just begun.

Friday

With Tropical Storm Alberto dissipating over Mexico, our seas are beginning to recede and winds have died down. Any lingering coastal flooding concerns should completely subside by this evening. Winds today will be generally from the east, at 5 to 10 mph. What about rain chances? I expect to see the development of some spotty showers later this afternoon. These will be more likely south of I-10, but even then overall chances are low, perhaps 20 or 30 percent. Skies, otherwise, should be partly to mostly sunny with highs of around 90 degrees. Lows tonight will be in the upper 70s.

Saturday

Expect sunny skies, with highs in the low- to mid-90s. Winds will be light, from the east. This will be a great day for outdoor activities, especially those that involve water of some sort. With the Sun high in the sky, please be sure and protect your skin.

Sunday

Skies should again be sunny, with highs generally in the mid-90s. There will be a smattering of rain chances, perhaps on the order of 20 percent. But most of us should remain dry.

Next week

You may have noticed that the National Hurricane Center has highlighted an area in the southern Gulf of Mexico where yet another tropical depression or storm may form during the next several days. This is almost exactly where Alberto formed, but we are not overly concerned this time. Why? Because this system is likely to be smaller than Alberto, so the upper Texas coast will probably see considerably less wind and less coastal flooding. Moreover, with high pressure building over the southern United States, it’s not clear how much, if any, precipitation we’ll see from this second tropical system.

What all of this means is that, for most of next week, Houston is likely to see mostly sunny skies and daytime temperatures in the mid-90s. There will be some daily rain chances, perhaps on the order of 30 percent with the afternoon seabreeze, but I’m not expecting anything too organized. Rain chances may inch up a bit next weekend, but we’ll have to see about that.

Have a great weekend, everyone. After a busy spell, I’m looking forward to not writing about the weather for a couple of days!

In brief: Tropical Storm Alberto is about to move inland into Mexico, ending the threat of tropical rainfall across the Houston metro area. However, we are still likely to see at least some scattered showers and thunderstorms for several days—mostly passing downpours. After a few days with highs around 90 degrees, we’ll start to warm up this weekend into the low- to mid-90s.

How did the new AI models do?

Recently, I mentioned that Matt and I were assessing the value of relatively new weather forecast models, which are based in machine learning. These AI-based models have been ‘trained’ on historical datasets and have shown some promise in limited testing. They’re now starting to become publicly available in real-time, and we’ll be using them for the Atlantic hurricane season. (You can find some of them here).

Anyway, the evolution of Alberto offered the season’s first test. Last Friday, the models offered a distinct difference in forecasts. The majority of traditional, physics based models that crunch through complex physical equations to reproduce the atmosphere, produced a system that remained largely in the Southern Gulf of Mexico. I saved the output from the U.S.-based Global Forecast System model that was initialized on Friday morning. Here is its five-day forecast for the morning of Wednesday, June 19:

At the same time, the AI-based version of the European model, or AIFS, had for several runs been bringing Alberto much further north, toward the central Texas coast. This is what the output from the model, initialized at the same time as the GFS model shown above, looked like for Wednesday, June 19:

That is a lot different, and certainly would have been more eye-popping for the Houston area. I frequently appear on the Houston Matters radio program with Craig Cohen, and we discussed this difference in output at the time. I told him it would be a good test. Five days later, on Wednesday morning, here’s where the tropical system, which had just formed as Tropical Storm Alberto, was:

As you can see, the physics-based GFS model was spot on, whereas the AI-based model misfired. This was not universally true, but the majority of physics-based models were much closer on track accuracy, whereas the AI-based models tended to have a more northerly track for Alberto (Huawei’s Pangu model was a notable exception, nailing the position). In our forecasts at Space City Weather, we relied on the physics-based models since they seemed more in-line with the overall atmospheric setup.

That’s track. None of the models did a great job with precipitation. There were several runs where the GFS model splashed 25 inches of rainfall over Houston, and the AI models that have rainfall outputs were also considerably more bullish than what Houston ultimately experienced. In any case, it’s going to be a long hurricane season. One test case proves nothing, but nevertheless I thought it was interesting to share.

Thursday

After coastal waters rose fairly high on Wednesday, due to the winds and surge of Alberto, they’re starting to recede some this morning. They’ll become less and less of a problem today and tonight now that the tropical system is inland. We’ll still see some gusty winds from the east today, perhaps up to 25 mph, but they’ll also be less than those of Wednesday.

In terms of precipitation, showers will be considerably more scattered today after much of Houston picked up 1 to 2 inches of rainfall on Wednesday. The most likely time for showers will be this afternoon, but they could come at any time, especially for coastal areas. Skies will turn partly sunny this afternoon, with highs of about 90 degrees. Lows tonight will drop into the mid-70s.

Friday

Another partly sunny day, with perhaps a 30 to 50 percent chance of showers and thunderstorms. Most of this activity will be fleeting. Highs will be around 90 degrees, with lows again in the mid-70s.

Saturday

Skies should be mostly sunny, with highs in the low- to mid-90s. Rain chances will be much lower, perhaps on the order of 10 percent.

Sunday and beyond

Our weather for next week is a bit uncertain due to the development of another tropical disturbance in the Southern Gulf of Mexico. However, this system is likely to be smaller, with lesser impacts. As a result I don’t think we’ll see nearly the winds and high seas we experienced from Alberto. Rather, for Sunday and most of next week, I expect we’ll see partly to mostly sunny skies, highs in the low- to mid-90s, and a decent daily chance of showers as tropical moisture pushes in from the Gulf. At this time there is no clear threat of heavy rainfall. So the weather looks pretty typical for late June.

In brief: A tropical system is bringing heavy rains and lashing winds to the Texas coast this morning, but most of this activity is south of Houston. We’ll see the potential for widespread showers on Wednesday before lesser rain chances through the weekend. Houston’s skies will turn partly sunny starting Thursday, with lots of sunshine on Saturday and Sunday.

Potential Tropical Cyclone One

A tropical system in the southern Gulf of Mexico is close to becoming a tropical depression, but it is running of time as it turns toward the east coast of Mexico. It should move inland by Thursday. Regardless of whether it develops further, the effects for Texas are baked in: elevated winds and seas, with the potential for heavy rainfall along much of the coast—but critically not the Houston region.

The light-to-moderate rainfall the city is experiencing this morning is basically the main thrust of the tropical moisture. Yes, this is it. In preceding days, we have been careful to balance expectations for this storm by suggesting there was a possibility that the heavy rainfall could go south of Houston, which it ultimately did. But there is no question our modeling whiffed badly on the risk of flooding in the Houston metro area. (Speaking of modeling, I’ll have a short analysis of the performance by AI models tomorrow on this tropical system).

The bottom line is that there is no longer any serious risk of flooding in the greater Houston metro area. To the south of the city, including areas such as southern Brazoria County, Bay City, and down into Matagorda Bay, there are notably higher rainfall totals and some risk of additional flooding today. These southern areas are also at risk of higher tides and coastal flooding, as well as wind gusts up to 40 mph.

Wednesday

The Houston region should see continued scattered light to moderate showers through the morning hours of the Juneteenth holiday. It’s possible that an additional, broken “band” of showers could develop over Houston this afternoon or evening. However, I don’t anticipate any of this rain leading to serious flooding issues. For the most part, these should be nuisance showers.

Winds associated with the tropical system in the southern Gulf should peak this afternoon over the Houston metro area, with gusts of 25 to 30 mph possible inland, and up to 40 mph along the coast, including Galveston Island. With elevated tides, some coastal flooding of low-lying areas is likely today, and again Thursday morning. Skies should be mostly cloudy today, limiting high temperatures to the 80s.

Thursday

As the tropical system moves into Mexico, it will cease to be a threat in terms of rainfall. As a result we are likely to see only scattered showers on Thursday with lesser accumulations. Skies will be partly sunny with highs of around 90 degrees.

Friday

Skies will be mostly sunny on Friday, with highs near 90 degrees. There will be a chance of showers and thunderstorms during the afternoon hours, but it likely is only about 30 percent.

Saturday and Sunday

The weekend should bring sunny weather with highs in the low 90s. Several readers have asked about a second tropical system, expected to develop in the southern Gulf of Mexico this weekend (see image at the top of this post). At this time I don’t expect it to have a significant impact on Houston’s weather, although it could drive some scattered showers and thunderstorms for coastal areas—that is, along and south of Interstate 10—this weekend. We’ll keep an eye on it, but for now it’s not something to be too concerned about.

Next week

Most of next week looks partly to mostly sunny, with highs in the low- to mid-90s. We may also see some afternoon, seabreeze-driven showers. All in all, the pattern looks fairly typical for late June as we march toward the heart of summer.

In brief: We’re starting to see a few bands of showers move into the Houston region from a ‘potential’ tropical storm in the Southern Gulf of Mexico. However, as we have observed over the last day or two, the threat of sustained heavy rainfall and flooding in the Houston area continues to decrease. We’re still watching things closely over the next 24 hours, but we don’t anticipate major problems in the metro area.

Airports and severe weather

Let us begin this post with question: My wife is flying into Bush Intercontinental Airport on Wednesday shortly after noon. Do you think her flight will be canceled with the storms?

It turns out this is a trick question! The wife in question is actually my wife. She really is flying into Houston tomorrow. Matt and I frequently receive questions regarding air travel and inclement weather, and I totally get the anxiety. However, neither of us are aviation meteorologists nor pilots. Unfortunately, we don’t have any special expertise or insight into the decision-making at airports that lead to flight stoppages, nor the cancellation of flights. We try to be helpful, but we’re never going to be able to give you the certainty on this issue that readers want. So I’ll give you the same answer I gave my wife: Probably not. Maybe. But probably not.

Before jumping into the post, I want to take care of a couple of housekeeping notes. If you’re wondering how to find us via email, our free app, or social media channels, please find all of those details here. Secondly, while this tropical system is increasingly unlikely to have serious weather consequences for the Houston area, that is not necessarily the case for southern Texas and Mexico. For more information about those sites, please check out The Eyewall. And finally, please find a brief message from our sponsor, Reliant, at the end of this post. Their support helps keep us online, and free for all.

Tuesday evening and Tuesday night

I anticipate that we’ll continue to see on-and-off showers and thunderstorms across the Houston metro area through this evening and during the overnight hours. Based on current model trends and radar activity, some of these showers may be briefly heavy, but we’re not seeing the kind of training storms that will lead to significant or widespread flooding. Some coastal areas may pick up 1 to 3 inches this afternoon and tonight, but most of us will see less than this.

Wednesday

Some time on Wednesday morning, possibly during the pre-dawn hours, more organized storms should move into the Houston area from the coast. Traveling from east to west, some of these showers may bring bursts of intense rainfall, and there could be some street flooding. This is a potential issue for the morning commute, especially for locations along and south of Interstate 10. Due to this potential for street flooding, we are maintaining a Stage 1 flood alert for the Houston region.

By Wednesday afternoon I think shower activity will start to become a bit more sporadic, but the potential for tropical rainfall will remain in place through the evening hours.

Rest of the week

We’ll transition to a pattern of more scattered showers on Thursday and Friday. Rain chances aren’t going to go away, but I also don’t think we’re going to be at any great risk of flooding. The gusty winds we’re experiencing today should persist into Thursday morning, by which time the “potential tropical cyclone” should move into Mexico.

Needless to say, we’re watching the evolution of these storms closely, and if there’s a change in our thinking we’ll post promptly.

A message from Reliant

Thanks to Eric and Matt for keeping us informed during this week’s tropical system and potential impact. We want to remind readers that Reliant stands ready to support Texans and help prepare. Here are a few things to keep in mind as we move through storm season:

1. Reliant’s Storm Preparedness Checklist is a good place to start when thinking through what you need in place, like an emergency kit, go bag and communications plan with loved ones.
2. Be prepared in case of an electricity outage. Your utility company (like CenterPoint in the Houston area or AEP for Corpus Christi) maintains the power lines, utility poles and electricity infrastructure necessary to deliver the power you purchase from Reliant to your home. Contact your utility company to report an outage or check the status of the repair.
3. Check out more preparedness tips and recovery resources at ReliantStormCenter.com. The site provides resources for before, during and after a storm, including preparedness checklists and evacuation routes, weather and power outage updates, flood maps, safety tips and more.

Just like the summer heat, storms are a part of life in Texas, so being prepared is critical. Reliant is proud to power Space City Weather and help bring this important resource to Houstonians and our neighbors.