In brief: We are issuing a Stage 1 flood alert for Saturday due to the possibility of slow moving storms capable of producing rainfall rates of 1 to 2 inches per hour. Activity should wane this evening, with less coverage on Sunday.

After a fairly quiet start to the day, we are seeing storms firing up along an area of convergent winds near the coast. At 11 am CT these storms have formed roughly along a line from Bay City to Pearland to Clear lake to Baytown. The heaviest of these storms may briefly produce rainfall rates of 1 to 2 inches per hour.

So what will happen during the rest of today? Our high resolution modeling guidance has not been, to put it politely, great. But given the high levels of precipitable water (well above 2 inches for most of the region) we are now leaning toward a fairly active day today in terms of showers and thunderstorms. Some parts of the metro area will get hit, while others just hear distant thunder. Because some of this activity may be slow-moving, we are going to issue a Stage 1 flood alert through this evening, which indicates the possibility of street flooding.

Creeks and bayous across the Houston region are generally in good condition, so we don’t expect more than nuisance flooding (that is, streets, feeder roads, etc) for today. But this activity could definitely put a damper on outdoor activities. Beyond heavy rainfall there is the threat of thunder and lightning, but no real indication of severe weather such as damaging winds or hail.

Our expectation is that storm activity will begin to wane this evening and then should die off overnight. Rain chances should be lower on Sunday, probably in the vicinity of 20 percent. Rain chances next week will be near zero, with sunny skies and highs in the mid-90s (at least) as high pressure asserts control. So if you’re tired of the rain, its end is at hand. Just not quite yet.

In brief: After yesterday’s ridiculously high humidity in Houston and across southern Texas, we start to think about more rain chances this weekend. We’ll start to dry out a bit more next week, with a return of hotter weather and standard Houston mid-summer.

In the storied history of Texas humidity, yesterday was a first ballot hall of fame day. “But it’s always humid and hot in Texas.” Yes, that is the case from June through September. However, statistically, yesterday was on another level. Let’s start with Houston. I went back and looked at hourly observations from Bush Airport going back to the 1970s. Yesterday ended up being the 12th most humid day on record there. How am I defining “most humid?” It’s the daily average of dewpoints. The higher the dewpoint, the more humid or oppressive it is.

I was surprised to see that one day last summer (August 26th) actually beat it out by a tenth of a degree. The most miserable stretch of humidity on record in Houston had to be June 2019, with dewpoints averaging near 80 degrees.

Now, if you change the location, you get some different results. For instance, at Hobby Airport (where hourly records only go back to 1996), it still ended up being the second most oppressive day on record.

While actual air temperatures weren’t too crazy, the combination of this humidity, in some cases way inland also produced some extreme heat outcomes. Maximum heat index values hit 110° in Galveston and College Station, 112° in Waco, Tomball, and Sugar Land, 113° at Bush and in San Antonio, 114° at Hobby, 118° in Austin and Brownsville, 120° in Bay City, and 122° (not a typo) at Corpus Christi. That Corpus heat index has only been hit on seven prior occasions back to 1948. Their all-time record heat index is 125° on June 17, 2023.

So no, it was not your imagination; yesterday was near maximum tier humidity for the Houston area, and much of Texas for that matter. The cause obviously has something to do with Arthur and the recent surplus of rain we’ve received. But I am assuming it’s pretty nuanced, with some degree of those influences as well as a warm Gulf contributing. I think that the Arthur influence is tenuous, however. Typically, winds behind tropical systems come out of the north or northwest, which actually lowers the humidity a little but allows temperatures to skyrocket (dry air heats up more efficiently than humid air). Yesterday saw winds out of the south or south southeast. I have to think the warm Gulf and recent rains and saturated soil were the primary causes.

Onward.

Today

I wish I could tell you today would be a little less oppressive, but I cannot. At least not for the morning. Dewpoints remain in the upper 70s and low-80s across the area this morning. Thus, heat index values are already in the lower 90s in most spots. As the day goes on, we’ll probably see humidity values drop just a little, which is enough to keep us in Heat Advisory conditions today rather than yesterday’s Extreme Heat Warning. Heat index values will probably peak a couple degrees lower than on Thursday.

Additionally, we could see some rain today, which would help the heat out. Today’s higher rain chances are north of I-10, especially as you get up toward College Station, Conroe, or Lake Livingston. That said, we could see a few storms fire off in the Houston Metro as well. Any storm today could again produce torrential rainfall for a short period of time and localized street flooding.

Saturday

We should cool off a little more on Saturday thanks to some added cloud cover and rain chances. Saturday’s specific rain forecast is a little tricky, but scattered thunderstorms are likely across the entire area. This means not everyone will see rain, but many folks should. Yet again, locally heavy downpours are a possibility. Look for highs around 90 and heat index values probably another 1 to 4 degrees lower at peak than today.

Keep the heat in mind, especially if you’re participating in the Oranje Fanwalk for the World Cup or heading to the events in EaDo (and elsewhere).

Sunday

The end of the weekend should begin to transition us back to more typical summer weather. Look for isolated to scattered thunderstorms, with less coverage than Saturday. High temperatures will be in the low-90s with typical Houston heat index values in the low to mid 100s.

Next week

It would seem that next week will step us up into standard Mid-summer weather here in Houston. High temperatures each day should be in the low to mid-90s.

Morning lows will be generally around 80, give or take a couple degrees. And rain chances will be low but not zero.

In brief: We talk about why, when Arthur’s center was closest to Houston on Wednesday evening, its winds died off. Also, we look ahead to calmer and hotter conditions for the next couple of days, and some rain chances over the weekend.

Looking back at Arthur

Can we agree that it was an odd storm?

Here’s the National Hurricane Center forecast for the position of its center at 4 pm CT on Wednesday, along with a track forecast.

I received a couple of messages yesterday afternoon from readers asking if they should be concerned about this updated track because, as you can see, the center of the storm is forecast to pass directly over Houston on Wednesday evening. And if this were a typical tropical storm or hurricane, the answer would be yes. But I replied no, nothing really had changed with our forecast because the winds and rains associated with Arthur were located hundreds of miles to the east

In the graphic below you can see that the winds in Bay City, where the “center” of Arthur was located at the time, were almost dead calm. And while there were some fairly strong wind gusts at the time associated with Arthur, they were a couple of hundred miles distant from the center of circulation.

This can happen with weak tropical systems that have fairly poor defined centers of circulation. But it made for an odd situation on Wednesday during which Arthur’s strongest winds came several hours before the center of the storm itself arrived. A similar phenomenon happened with its rains, which were even further removed from the center.

Anyway, Arthur has dissipated and we can all hope this is the only named storm that makes “landfall” in Texas this year.

Thursday

We’re going to see a much calmer day. Mostly cloudy skies this morning should give way to mostly sunny skies this afternoon, with high temperatures reaching the low- to mid-90s for most of the Houston metro area. With dewpoints near 80 degrees, the humidity will be something fierce. Winds will be from the south at about 10 mph today, gusting up to 20 mph this afternoon. Low temperatures tonight probably will not fall below 80 for most of the region, so prepare to sweat. Rain chances are basically zero.

Friday

This should be a similar day to Thursday in terms of temperatures and humidity. There may be a few more clouds in the sky. By Friday evening a weak front (it won’t make it to Houston) will be dropping down from north Texas. This could serve as a focus for some isolated showers and thunderstorms from Friday evening into Saturday.

Saturday and Sunday

I expect skies to be partly to mostly sunny this weekend, with high temperatures generally in the lower 90s. Where we have some uncertainty is in the rain department. The aforementioned dying front could generate some additional showers and thunderstorms on Saturday in the Houston region, perhaps most likely north of I-10. I would put overall rain chances at about 40 percent during the morning and daytime hours, but I don’t have supreme confidence in the forecast at this point. There is a higher likelihood of Sunday remaining rain free.

Next week

By the end of the weekend we should see high pressure taking control of our weather, and this will hold sway for much of next week. We are looking at a sustained stretch of sunny skies and high temperatures in the mid-90s. It won’t be peak summer by any means, but it will likely be the warmest period of weather so far this year for Houston. These temperatures will also coincide with some of the longest days of the year, so be sure and use Sun protection.

In brief: Just a short update to note the formation of the Atlantic season’s first named storm, Arthur, and what it means for Houston today. In short: rains ending, but the next several hours will be windy near the coast.

Hello, Arthur

The Atlantic season’s first named storm, Arthur, has formed less than 100 miles from downtown Houston. Although that may sound concerning, we’re here to tell you it’s really not.

Our biggest concern from this system has been the potential for heavy rainfall, but that risk is now rapidly diminishing. The bulk of the precipitation from Arthur is falling well to the northeast of its center, and most of this is offshore. The scattered showers we are seeing across Houston as of 10 am CT on Wednesday will continue to diminish. We are likely to be rain free from the middle of today through Friday evening. For this reason we are ending our Stage 2 flood alert.

The biggest impact from Arthur is being felt right along the coast. Its sustained winds have been measured at 35 mph, or higher, along Galveston Island, with some gusts up to 50 mph. This has, frankly, exceeded our expectations. Even areas as far inland as Hobby Airport have recorded gusts up to about 30 mph. These winds should start to ease by this afternoon as the center of Arthur nears Galveston and starts to move away. After that we expect calm and sunny, albeit hot, conditions on Thursday and Friday.

We’ll have a full forecast for you, per usual, on Thursday morning.