Eric Berger

In brief: Invest 97L continues to hold its own in the Gulf, with increasing potential that it may develop into a depression or named storm before coming ashore in Texas or Louisiana on Tuesday. We are sharing this update below, published Sunday evening on The Eyewall, due to heightened interest from our readers.

First off, Invest 97L looks mostly the same this evening as it did earlier today, which is a bit of a small feat in and of itself, as typically these nascent systems strengthen more overnight and weaken during the day. That it has held its own indicates it’s probably in shape to organize a bit further.

What has changed as a result of the storm’s development today, and recent model guidance, is two-fold. First, a bigger risk of locally heavy rain in Texas and Louisiana. Second, a higher chance that 97L will actually develop into a depression or storm. The NHC has raised odds to 70 percent this evening, but I would think the odds are closer to 90 percent for a depression and 60 to 70 percent for a named storm. Either way, they are now higher.

Modeling is in good agreement on both track and timing of the system, giving it about 36 or so more hours over water before making landfall near Port Arthur or High Island, TX sometime during the second half of the day Tuesday. Models have become a bit more scattered in terms of intensity of 97L today, with a few more pulsing up into tropical storm status.

At this point, if you live on the Upper Texas Coast east of Baytown through about Cameron Parish, LA, it makes sense to prepare for a tropical storm. This means the potential for heavy rain, gusty winds, some minor to moderate coastal flooding, and rough seas.

The problem with these smaller systems like 97L is that they don’t give you a whole lot of warning and then all of a sudden they ramp up. Think of Hurricane Humberto in 2007 as a prime example of this. It wound up from a disturbance to a small hurricane in about 24 hours. The initial forecast from the NHC for Humberto had max winds of 45 mph. I’m not saying Invest 97L will do that; our modeling has improved quite a lot in 20 years. But I am saying that model guidance still doesn’t always capture these smaller storms properly, and it’s better to err on the side of caution in these areas, especially to the east side of where the storm may come ashore.

I am growing a little more interested and potentially concerned about the potential for flash flooding in parts of Texas from 97L, especially north of Houston and east of I-35. Rain total forecasts have trended up a good bit since earlier today, and I think the potential exists for rain totals to increase more over the next couple days. I’d watch the triangle between Beaumont, College Station, and Lufkin closest right now, but let’s see how things play out over the next couple days before pinpointing areas highest at risk.

We’ll have a full update in the morning.

In brief: A tropical low has developed in the northern Gulf, and it will move generally west toward Texas over the next couple of days. We assess what this means for the greater Houston region this week, which hopefully means some beneficial rains.

Over the last day or so we have seen a low pressure system in the northern Gulf slowly develop. Thunderstorms associated with the low, designated Invest 97L, have become better organized overnight, but so far surface pressures (another indication of organization) have yet to drop significantly. So we have, essentially, a tropical blob sitting out there 100 miles or so south of the mouth of the Mississippi River.

With high pressure over the southern United States we can expect this tropical low to to generally move to the west or west-northwest over the next couple of days. This is likely to bring the system toward the upper Texas coast by midweek, which is to say somewhere probably between Galveston Bay and the Texas-Louisiana border. Of course, in the absence of a well-formed center, there remains some uncertainty in the track.

So something is coming toward the upper Texas coast, and it will likely reach land on Tuesday or Wednesday. Our baseline expectation is that this remains a tropical low pressure system or a depression, but there is a chance for development into a tropical storm. Surface waters are more than warm enough (sizzling actually) to support intensification, and wind shear is relatively low. So if the current system can develop some spin, it will have a chance to organize.

Should you be concerned? Not at this time. The system would be beneficial should it bring some much needed rainfall into the region on Tuesday or Wednesday, but these rains could just as easily fall to our east, over Beaumont or southwestern Louisiana. As for amounts, maybe 1 to 3 inches? It’s difficult to say with any confidence yet. Regarding winds and storm surge, we will keep an eye on things for you, especially with the tropical low so close to Texas.

More tomorrow.

In brief: We actually have some dynamic weather to talk about in today’s forecast! Due to a boundary moving in, the region will see some shower and thunderstorm chances. The most likely time frame for this is Thursday afternoon north of the city, and the evening hours in Houston and closer to the coast.

Rain, actually

It has been a long, hot, and mostly dry August but some real change is on the way. It’s still going to be sizzling today, with temperatures in the upper 90s. But after today most of the region will fall back into the mid-90s for awhile. And thanks to a stalling boundary, we are going to see a healthy chance of rain showers today in the greater Houston area. Not everyone is going to see showers or thunderstorms, but overall chances are probably on the order of 50 percent, which represents our highest likelihood of rain in weeks.

Thursday

With a check of the radar just before sunrise, we can see shower activity developing north of the Houston region, in areas such as College Station and Livingston. These showers should progress into Montgomery County over the next hour or two before stalling out. I don’t think they will get all the way to Harris County, at least for the most part.

We will see sunny skies during the middle of the day, and very hot conditions like we’ve experienced so far this week. However we should see another round of showers and thunderstorms this afternoon, possibly initiating north of Interstate 10 and then moving down toward the coast through the evening hours. This time frame represents when most of the region should see its best chance of rainfall. Accumulations will vary widely, from no rain to some bullseyes of 1 or more inches. Showers should subside by or before midnight.

Friday

We should see a few more clouds on Friday, limiting highs to the low- to mid-90s. Rain chances will be lower, possibly in the 20 to 30 percent range.

Saturday and Sunday

The weekend should bring mostly sunny and (for late August) temperate conditions. Expect highs in the low- to mid-90s. The likelihood of rain showers is not zero, but it’s close. Overall this should be a pretty nice weekend for outdoor activities involving water.

Next week

At this point we should see a summer-like pattern next week, with high temperatures mostly in the mid-90s and a low-end potential for daily showers along the sea breeze. These are typical conditions for early September here.

In brief: After one more very hot and sunny day, a modest pattern change arrives in Houston. This will bring improved rain chances into the area on Thursday and Friday, along with slightly cooler daytime temperatures over the weekend.

Rain, actually?

Most of Houston has not recorded measurable rainfall in more than two weeks. Officially, the city has received just 0.21 inches this month. Thanks to earlier rains in June and July, the greater Houston region still remains out of drought conditions. However we are starting to see rapidly drying vegetation, and background conditions that support wildfires are increasing. All of this is to say, we could use some rain.

Over the next couple of days a weak and dying front will move into the greater Houston region. It is not going to bring any meaningful change in our humidity, but it will perturb the atmosphere enough to bring some decent rain chances on Thursday and Friday. Most of the region is unlikely to see too much rainfall, but a few locations could pick up 0.5 to 1 inch of rain, or even higher isolated totals. Next week should also see slightly better rain chances as well, so with some luck our region’s very dry pattern in August should break, at least a little.

Wednesday

All of that talk about rain is going to have to wait one more day, however, as we experience another hot and sunny day with high temperatures in the vicinity of 100 degrees. Winds will be light from the southwest, picking up a little bit during the afternoon and evening hours. Lows on Wednesday night will drop only to around 80 degrees.

Thursday

This will be another hot day, with highs in the upper 90s to 100 degrees. We may see a few clouds in the sky, however, along with increasing rain chances that may take some sting out of afternoon highs. These rain chances will persist into the overnight hours.

Friday

Another day with a healthy chance of scattered showers. Additionally, partly cloudy skies may hold highs in the low- to mid-90s, which is more typical for late August. Rain chances should diminish by Friday evening, with overnight lows dropping into the upper 70s.

Saturday and Sunday

The weekend should bring mostly sunny skies with highs in the mid-90s for most locations (possibly upper 90s for far inland areas). Rain chances will fall back to about 10 percent daily.

Next week

This period should bring typical late summer weather to Houston, which is to say highs in the low- to mid-90s and daily rain chances roughly in the range of 30 percent. While this is still pretty hot, it is notably more moderate than the last 10 days or so of ‘peak’ summer we have experienced in Houston.