Eric Berger

In brief: Summer is not over. In today’s post we explain why the end of September has been very hot, and why that’s not going to change much this week. We’ll also take a look at the weekend forecast, when there are a lot of outdoor events in the metro area. Finally, could we see a real front next week?

Wake me up when September ends

Fifteen of the last sixteen days in September have recorded high temperatures of 90 degrees or higher. (On the single day that did not, the high reached 89 degrees). This has occurred despite a front coming through a couple of days ago.

Why has the daytime heat persisted? Partly because our early fall fronts tend to bring drier air, but not much colder air. So our days remain warm because drier air heats up more efficiently. The primary benefit of the front, however, is that it has taken about 10 degrees out of nighttime temperatures, which has been nice.

October is not going to bring immediate relief, but as our air modifies somewhat this week with higher humidity, we’ll see slightly cooler days by around Wednesday, and correspondingly warmer nights in the mid-70s. Later this month we can almost certainly count on more emphatic fronts to bring cooler daytime weather.

Monday

High temperatures today should, once again, reach the mid-90s for much of the metro area away from the coast (where highs will be a few degrees cooler). Skies will be sunny, with almost nary a cloud in the sky. Winds will be light, generally from the northeast. With dewpoints mostly in the 60s, the air won’t exactly feel dry, but it won’t be Houston-humid either. Lows tonight will drop into the low 70s for most locations.

Tuesday

A similar day to Monday, albeit with possibly a few more clouds in the sky.

Wednesday and Thursday

Expect more sunshine, with daytime highs generally in the low-90s, and nighttime temperatures in the mid-70s. Really, there’s not much more to say.

Friday, Saturday, and Sunday

So there are a lot of fairly big events in Houston this weekend, and a lot of eyes on the weather. On Saturday there’s the Komen Houston Race for the Cure in Sam Houston Park, as well as the Southern Smoke Festival in Discovery Green. What I can tell you right now is a forecast for what will probably happen, but not a forecast for what will absolutely happen.

Our atmospheric pattern will become somewhat more upset by Friday, opening the door to a few passing disturbances. Effectively, this means that we’re likely to see daily rain chances on the order of 20 to 30 percent during the Friday, Saturday, and Sunday period. Chances will be low- to non-existent for areas inland of Interstate 10, and at the higher end along the coast.

Friday and Saturday are likely to see partly sunny skies, whereas Sunday looks to be mostly sunny at this point. High temperatures will probably range from the upper-80s to lower-90s. The risk to the forecast is that the atmospheric disturbances are a little more pronounced than expected, leading to more widespread rain. But at this point the most likely outcome is a fairly warm, mostly rain-free early October weekend that feels more like late summer than early fall.

Next week

There is a fairly decent signal in the global models for a decent front to arrive on Monday or Tuesday of next week, but since I’m not yet certain on its passage I don’t want to give anyone false hopes. Needless to say, next week’s weather in Houston will be determined by whether said front makes it all the way through Houston.

Tropics

We’ve had lots of questions about the tropical blob in forecast maps from the National Hurricane Center. Yes, we’re continuing to keep tabs on it. No, there still is not any indication that an organized tropical system is likely to directly impact the Texas coast over the next week or 10 days. For more information, check out our post from Sunday.

In brief: After more than four months, Houston’s overnight temperature has once again reached 65 degrees, which we consider the threshold for a fall-like night in the city. Accordingly, we’re celebrating Fall Day today! Houston’s temperatures will warm up quickly, but our air will remain dry through the weekend. Rain chances are near zero for at least the next five days.

Yes, it’s Fall Day

The first half of this summer was moderate, temperature-wise. But some of this ‘cooler’ weather was driven by Hurricane Beryl, which uprooted many trees and led to a prolonged, widespread power outages. Then, for much of August (remember that stretch of seven straight 100-degree days?) and September, Houston has experienced warmer than normal conditions. So yes, we’re due for a break.

That came this week, in the form of our region’s second front. Low temperatures at Bush Intercontinental Airport fell to 64 degrees this morning, the first time since May 18 that the city has recorded a low of 65 degrees or below. We therefore decree today to be Fall Day in Houston, and I hope you take a moment to celebrate it outside. No, the weather isn’t going to be particularly cool. But the air will feel much drier than is typical during summer in Houston.

Friday

For a few hours this afternoon it won’t feel much like fall, as much of Houston is likely to climb into the upper 80s or even reach 90 degrees. But with dewpoints dropping into the lower 50s, the air will feel fine. Winds will be from the north-northwest at 5 to 10 mph, and skies will be clear. Low temperatures tonight will likely be a degree or two warmer than Thursday night, dropping into the upper 60s for most locations in Houston, with slightly cooler weather outside the city.

Saturday and Sunday

Expect sunny skies and warm days, with high temperatures in the low- to mid-90s. However, moderately drier air will take some of the sting out of the heat, and with lower humidity mornings and evenings will be pleasant. Expect low temperatures to drop to around 70 degrees. Rain chances are approximately zero percent.

Next week

Sunshine and warmth prevails through the first half of the week, with daytime highs generally in the mid-90s. This is pretty warm for late September and early October, but it’s being fueled partly by slightly drier air than normal. So while it will be hot, I wouldn’t characterize conditions as sweltering. Nighttime lows drop into the low 70s.

During the second half of the week we probably will see the onset of some more clouds, and some modest rain chances return to the forecast. At some point, perhaps over the weekend, another front will make a run at pushing all the way to the coast. I don’t have enough confidence in the forecast to predict when, but at some point within 7 to 10 days from now I’d expect cooler weather to return. We’ll see.

Tropics

After making landfall on Thursday night in northern Florida, Helene has pushed well inland and is now ravaging the southeastern United States with heavy rain and gusty winds. It’s creating an awful mess. As we look deeper into the tropics, the National Hurricane Center is calling attention to an area of low pressure in the southern Caribbean Sea that could eventually develop into a tropical storm. This is something we will, of course, be watching. However, there is no real indication at this point that an organized system is ultimately going to track toward the Texas coast.

In brief: Houston’s second cool front of the season has arrived and it will take our temperatures down a little bit. Long-time residents will know the primary benefit of September fronts is that they knock down humidity levels, rather than temperatures. And we should see drier-than-normal air through the weekend despite warm days. Enjoy!

Is this Fall Day?

Typically, we designate the day after Houston’s first nighttime temperature of 65 degrees, or lower, as Fall Day. The coolest night of the season, so far, came on September 9, when low temperatures reached 67 degrees at Bush Intercontinental Airport. Low temperatures there tonight will get close, so there’s a chance that Friday will be Fall Day.

A few readers have asked whether we are going to have another Fall Day celebration this year. The answer is no, because we’re going to wait a year so that we might have a bigger event in 2025. Why? Because that will be the 10th anniversary of this website. I know, I can’t believe it either. If you have ideas for the celebration, let us know in the comments below. We’re working with our partner Reliant to do something special. Speaking of Reliant, be sure and stay tuned for a message from them at the end of the post.

Thursday

Skies will be sunny today, with a northerly wind at 10 to 15 mph, which may occasionally gust up to 20 mph or a bit higher. Those winds are bringing in drier air that will help dewpoints drop into the 50s later this morning or by the afternoon hours. Drier air warms more quickly, so air temperatures are likely to get into the upper 80s. But it will feel noticeably drier, and temperatures will cool more quickly this evening as the Sun sets. Lows tonight will drop into the upper 60s in Houston, and low 60s for most outlying areas away from the coast. It’s going to be delightful, and I can’t wait.

Friday

Another day with nice, dry air and plenty of sunshine. Expect highs to reach about 90 degrees as a result. Winds will be less, probably about 10 mph. Lows on Friday night will likely be a degree or two warmer than Thursday night. Still pleasant. (Note: Tomorrow’s post may be an hour or so late due primarily to my desire to take a long run with the drier air in the morning. It won’t matter, since the forecast for the next several days is not going to change much. In fact, you can pretty much ignore us tomorrow and that wouldn’t hurt my feelings.)

Saturday and Sunday

Expect plenty of sunshine, with highs in the low 90s. The dry air is going to modify somewhat, but we’re still going to see fairly low humidity levels all things considered. Low temperatures will reach about 70 degrees. There are zero weather concerns this weekend beyond the potential for a sunburn.

Next week

The first half of next week will see continued sunny weather, with high temperatures mainly in the low 90s. Dewpoints will recover into the 60s, so the air will feel more humid, but it’s likely going to be less humid than typical summer conditions in Houston. Nighttime temperatures will probably reach the low 70s. Some chance of a front, with our next real shot of rainfall, arrives by Thursday or Friday, but that part of the forecast remains hazy.

Tropics

Hurricane Helene is on the way to likely become a major hurricane today before striking the northern coast of Florida tonight. It is similar to Hurricane Ike in that, due to its large size, Helene is likely to pack a broad and very damaging storm surge. Another factor with this storm is the potential for heavy rainfall far inland, in such areas as northern Georgia and western North Carolina. We’ll continue tracking the system on The Eyewall.

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In brief: Houston will see another warm and humid day, but there will be a twist this afternoon as a broken line of showers and thunderstorms pushes through the area from northwest to southeast. Drier air will follow overnight, leading to sunny days with lower humidity. It’s a weak front, but in September, who’s complaining?

Wednesday

Most of the area will be warm and humid again today, with high temperatures in the low-90s. Skies will be mostly sunny this morning, but then we should see some clouds building up this afternoon with increasing levels of moisture in the atmosphere. By later this afternoon we should see a broken line of showers, perhaps with a few embedded thunderstorms, moving from northwest to southeast across the area. This line should reach from Sugar Land to downtown Houston to Kingwood by around 4 to 6 pm, and push down to the coast by around 7 to 9 pm.

As it nears the coast, this boundary should gradually run into more moisture, and this could help fill in the gaps. There is a slight threat of some briefly damaging winds in any of the stronger thunderstorms that develop. Unfortunately, I don’t think the frontal passage is going to bring widespread, drenching rains, which the area needs after a fairly dry September. Some locations may pick up 0.5 inch of rain, but most of the region, and especially areas inland of Interstate 10, are likely to see little to no rain. Lows tonight will drop to around 70 degrees.

Thursday and Friday

Drier air starts to filter in overnight, and we’ll see a couple of slightly cooler days. High temperatures on Thursday and Friday will reach the upper-80s, with lots of sunshine. Thursday may be a bit gusty in terms of northerly winds, but these will settle down somewhat by Thursday night. Lows, for the most part, will reach the upper 60s in the Houston area and drop down a little further outside of the city and away from the coast. Mornings and evenings will feel lovely.

Saturday and Sunday

Sunny weather continues, with daytime highs in the low 90s and nighttime lows around 70 degrees. The humidity will recover some, but not get back to really sticky dewpoints. So again, mornings and evenings will be fairly pleasant outside.

Next week

Expect more sunshine and highs in the low-90s. There is some support for a front arriving by Thursday or Friday of next week, but it is far from universal in the weather model ensembles. What does seem clear is that, after today, rain chances are very low for awhile for our area. That’s one reason why I’m hoping for today’s showers to overperform expectations.

Tropics

Now entering the Gulf of Mexico, Tropical Storm Helene is approaching hurricane strength with 70-mph sustained winds. It is expected to become a powerful Category 3 hurricane before striking the northwest Florida coast on Thursday evening. This storm will have widespread, myriad effects. We’ll have continuing coverage today on The Eyewall.