In brief: In today’s post we take a broader look at rains expected to move into Texas from the remains of a Pacific hurricane, and look ahead to cooler and wetter weather across the Houston region toward the end of this week.

Polo’s remains bring Texas rains

Hurricane Polo, a powerful storm in the Pacific Ocean, is about to make landfall over Baja Peninsula and then will move toward Texas over the next couple of days. There it will bring the potential for heavy rainfall. Houston, under less of a threat, will see rains later this week, which we’ll discuss below. But to start I wanted to highlight the threat from Polo to central Texas. The following is a snippet from our companion site, The Eyewall.

Copious amounts of moisture will surge into the Desert Southwest and eventually the Southern Plains and Texas from Hurricane Polo. The moisture from Polo and a slow or stalling cold front will probably focus repeating rounds of rain from Hill Country into North Texas. Those areas are already under a moderate risk (level 3/4) for flash flooding on Wednesday, and that will likely extend into Thursday as well.

Rain totals are likely to end up in the 4 to 8 inch range from south of San Antonio through Dallas and perhaps up toward Durant, OK through Friday. There is a chance that some areas see as much as 10 to 12 inches though, as we know Texas flood history is littered with these types of remnant Pacific hurricane events.

For now the more serious flooding concerns are likely to stay north and west of the Houston region. Texas folks in Hill Country and the Metroplex should monitor the next couple days of forecasts very closely and be prepared for disruptions on Wednesday and Thursday.

Monday, Tuesday, and Wednesday

Locally, we don’t expect too much rainfall over the next few days. Rain chances through Wednesday will be on the lower end, probably 20 to 30 percent each day. Yes, there could be a few more clouds, and we certainly cannot rule out some thunderstorms, but any moisture related to Polo should remain well to our west. Highs each day will be in the low- to mid-90s with plenty of humidity. Nights will be muggy, in the upper 70s for the most part.

Thursday, Friday, Saturday, and Sunday

This is the period when we expect improved rain chances across the Houston region as available moisture in the atmosphere surges upward. Unfortunately, I cannot give you a precisely detailed forecast for each day. However, rain chances should be 50 percent or above, with with partly to mostly cloudy skies. At this point Friday appears likely to have the best overall chance for rain, but this could shift over the next couple of days. In terms of overall accumulations, they will vary widely, but I expect most of the Houston region to pick up 1 to 4 inches of rainfall through Sunday. Again we’ll need to fine tune this forecast as we get closer.

In terms of daily temperatures, the cloud cover, rain, and a weak front should help pull highs down into the 80s on most days, with overnight lows in the mid-70s. So basically we’ll be at pretty seasonable levels for early October.

Next week

The rains should subside by Monday or Tuesday of next week, after which point something of a stronger front may arrive to possibly push nights into the 60s during the second half of the week. More on that in the coming days as we get more clarity on the situation.

In brief: A humidity front pushed through overnight, which will allow today to be significantly less humid and a couple degrees cooler. Humidity does return heading toward next week. While we are continuing to track a possible cold front later next week, confidence remains quite low in what it will actually do for the Houston area, other than lowering high temperatures a bit.

Just as a reminder, in case you missed it, we did make an important comment about hurricane season in Texas yesterday. We also have big app update news!

On to the forecast.

Today

Do you feel less humidity today? You should. A weak little boundary pushed in out of the north and east overnight, and with perhaps the exception of the extreme south and west parts of the area, it should be noticeably less humid today. Dewpoints are running about 5 to 10 degrees lower than this same time yesterday, meaning it feels that much more comfortable.

It will remain hot for sure, so look for highs in the low-90s. Thankfully not as hot as yesterday’s 97 degrees. But that humidity will make it feel far less painful regardless.

Weekend

The humidity will slowly return this weekend, especially on Sunday. But otherwise, it’ll be more of the same: low 90s, maybe a few mid 90s, and sun and clouds. Rain chances, while not zero look to remain fairly low.

Early to mid next week

The late summer party continues early next week, with heat and a slight chance of a storm on Monday. By Tuesday, a cold front is going to work across part of the state. Our modeling confidence drops off beyond that.

Mid to late next week

Either the front is going to stall west of Houston keeping us warm and humid (80s) with thunderstorm chances. Or the front is going to slowly push through the Houston area bringing in less humid and pleasant weather with thunderstorm chances.

Let’s diagnose this a little further.

If you look at the European ensemble’s probability of highs near 90 degrees, you’d see Houston generally running at 70 to 90 percent odds most days through Tuesday. By Wednesday, those odds drop to 50 to 70 percent, Thursday’s odds are 20 to 50 percent, and Friday’s odds (shown here) drop to about 10 to 30 percent.

This is the under the hood element of the models we will look at to say, “Alright, you’re forecasting a certain value, but what does it actually mean the probability of X, Y, or Z is?” In this case, we have a decent signal that the odds of 90 degree heat are dropping through later next week. So, we at least can say that with some confidence. Will we get the full-frontal experience (rated G for Great)? That remains TBD. At this time, models want to keep our precipitable water levels pretty elevated into next weekend, which I would say is a proxy for higher humidity.

So sitting here today, I would expect declining temps but maybe not necessarily declining humidity, at least not substantially so later next week. That said, eventually one of these things is going to break through and allow lows in the 60s or 50s. It’s a matter of when, not if, and there’s still at least some chance next week’s front is the one. I’m just not terribly confident in that today.

At the least, we should all see a bit of rain next week, although the highest totals will probably stay toward Hill Country and North Texas.

We will have more on all this Monday!

In brief: In today’s post we discuss the end of the Texas hurricane season, which is at hand. Fall now appears to be firmly on horizon, with a weak front today and then chances for more fronts in the coming weeks. Can I get an amen?

September 24th is here

Most years, around this date, we proclaim that the Texas hurricane season—that is, the period of the year when a hurricane could strike Texas—is over. We don’t do so every year. If it has been an especially busy hurricane season, or if there is a storm that could reasonably threaten the state within the next 10 days, or if we just don’t have any cold fronts on the horizon, we have been known to hold off. But not this year.

For starters, due in large part to El Niño, we still have not seen a single hurricane develop in the Atlantic basin this season. That has never happened in the modern era. Additionally, the Gulf looks quiet at least through the end of the month, and probably longer. And finally, we do have some fronts on the horizon: a weak one today, and potentially a another one next week. Add it all up, and we are confident that Texans can breathe easy when it comes to hurricane season this year.

Yes, more than two months remain in the official season (which ends on November 30). But by this time of year, in Texas, we start to see more influence from the mid-latitude westerlies, which tend to push tropical activity away from the state. The chance is not zero: historically there is about a 2 percent likelihood that a hurricane will strike Texas after this date. We also could see a weaker tropical storm make landfall. But our concern level is not high.

Albeit in fits and starts, fall is coming, and we encourage you to enjoy it without worrying too much about the tropics.

Thursday

Houston tied its record high (99 degrees) on Wednesday, but after a very hot mid-September stretch we should hopefully be done with the extreme heat here. A weak front will back in from the northeast later today, bringing some drier air with it (slowly). The front may spark a few isolated showers, but mostly I anticipate mostly sunny skies. Highs today will be in the low- to mid-90s, with northeast winds at about 10 mph. For lower humidity we are going to have to wait for tonight, or Friday morning.

Friday

By or before sunrise a slightly stronger push of drier air should arrive from the northeast, and this now looks set to knock dewpoints down into the 50s during much of the daytime. This will be fairly noticeable. Lows on Friday morning will likely be in the lower 70s for most of the region (so pleasant-ish with the drier air), with daytime highs warming efficiently into the lower 90s. Friday evening should still see lower humidity before dewpoints begin rising late Friday night into Saturday.

Saturday and Sunday

Along with a return of humidity, the weekend should bring partly to mostly sunny skies, with highs generally in the lower 90s. There is a slight chance of showers with daytime heating on both days, but I think rain is unlikely. Lows should be in the upper 70s.

Next week

Monday should bring more of the same, but with an approaching upper-level system rain chances and cloud cover should start to increase on Tuesday, with widespread showers likely on Wednesday and possibly Thursday. Whether this helps drag a stronger fall front through remains to be determined. But we probably will be in the upper 80s, for highs, regardless with the increased cloud cover. As noted above, our flirtations with triple digit temperatures should finally be over.