Good afternoon! There has not been much change in weather modeling since this morning, which is a good thing for Houston, as that means we expect, with fairly high confidence that Tropical Storm Ida will stay well east of the Houston area, causing only some fringe impacts along the coast. Good news for Houston means bad news for someone else unfortunately, and Louisiana looks to see the core of impacts from Ida. The Gulf has been exceptionally unforgiving in recent years.

Right off the bat I just want to show you how far we have come in terms of track forecast confidence in the last 24 hours. Here is an animation showing yesterday’s ensemble “spread” from the GFS ensemble. Just to quickly recap: The ensemble consists of over 30 individual model runs, each one tweaked just a little at initialization (hour 0) and then run like any other model out over two weeks. The advantage of using an ensemble is that you get a wider range of possible outcomes, which can guide your forecasting, and it can also perhaps highlight areas of higher confidence. In this case, over a 24 hour period, the ensemble went from a wide, unruly range of outcomes to a fairly tightly packed group of outcomes.

That helps boost our confidence. As you can see there, is still a bit of a range of possible outcomes, but instead of ranging from Mexico to Florida, they now primarily range from the Texas/Louisiana border to the Mississippi/Alabama border. And virtually all of these outcomes spare Houston any impacts.

Hurricane models are also in good agreement on this, so we’ve seen our confidence in a miss for Houston grow exponentially in the last 12 to 18 hours or so.

Here is the official National Hurricane Center forecast track for (now) Tropical Storm Ida.

They are explicitly bringing it close to major hurricane status (110 mph is the maximum forecast at this time) as it makes landfall on the Louisiana coast Sunday. There is still some uncertainty around timing and exact intensity, but the takeaway message from the NHC discussion and forecast is that a strengthening hurricane is likely to make landfall in central or eastern Louisiana on Sunday night.

I know some folks are concerned about the Lake Charles area after last year. While they are not out of the woods yet, most model data and this forecast implies that impacts to Lake Charles would be fringe and mostly limited to just some outer bands with a few gusty thunderstorms. The Beaumont and Port Arthur areas should expect similar conditions.

Locally, we will want to keep an eye on tides, rip currents, and rough surf this weekend in the Gulf. If you’re planning a beach weekend, keep the rip current risk in mind, as swells from the storm approach Sunday into Monday. I will have some more on that in the morning.

As far as rainfall, we should not see any direct rainfall from the storm here in Houston. The heaviest rain appears as though it will fall in central and eastern Louisiana and Mississippi.

Some of the storms we get the next few days in Houston, unrelated to Ida, could be a bit heavy, including some tonight. Storms will be moving east to west across the area, which isn’t terribly common, but again, this is not related to the tropical system. Eric’s morning post still looks good for tonight and tomorrow if you need some more details.

Beyond that, we can exhale in Houston for now it seems. There will be other tropical systems to watch over the next 2 to 3 weeks, but none of them looks like a specific threat to our area at this time. Surely that could change, but that is all we can say right now. In the meantime, our thoughts are with our neighbors to the east who will likely be forced to endure yet another considerable tropical system.

Good morning. The tropical system in the Caribbean Sea continues to show better signs of organization this morning, and will likely become a depression or Tropical Storm Ida later today or tonight. We continue to watch this system closely, and over the the last 12 to 24 hours most major models have trended east with their forecast. The most likely possibility now is that a strong hurricane comes ashore somewhere in Louisiana on Sunday or Sunday night. But we definitely cannot rule out impacts to Texas. Please find more information below.

Also, as you may recall, we launched a Spanish-language version of Space City Weather this week. At 11 a.m. CT today please join me, the editor of the new site, Maria Sotolongo, and Rolando Salinas from Reliant Energy to talk about why we’re doing this. The event will take place on our Facebook page.

Thursday

There are some scattered showers offshore this morning, and they should develop inland later this afternoon. This should yield perhaps a 30 to 40 percent chance of rain, but there will still be enough sunshine to drive temperatures into the mid-90s. Winds will be light, generally out of the east. The upper air pattern becomes more favorable for rain this evening, through the overnight hours, into Friday so there is about a 50 percent chance of showers tonight.

Friday

We expect fairly widespread showers on Friday morning, with the potential for some heavy rain to produce a quick accumulation of perhaps 2 inches for some locations. Showers should end from south to north during the late morning or early afternoon hours. Highs will likely reach about 90 degrees under partly sunny skies.

Saturday and Sunday

The overall fairly wet pattern should continue through the weekend, with partly sunny skies, highs in the low 90s, and perhaps 50 to 60 percent rain chances each day. The ultimate track of Invest 99L is going to have a lot to say about our weekend weather so any forecast now is very, very tentative.

Tropics

What we know is that Invest 99L is starting to become better organized, and should move into the Gulf of Mexico on Friday night or Saturday morning. After this time there is not much to hamper its organization—there is little dry air aloft, and wind shear is relatively low—and plenty of warm Gulf water for the system to work with. Our expectation is that the storm will become a hurricane, a possibly a major hurricane by later on Sunday as it approaches the Gulf coast.

So where will the storm go? That will depend on the extent of a high pressure ridge over the southeastern United States. Most of the model guidance now shows enough of a weakness in the ridge to allow the storm to travel more northeasterly, likely bringing it to the coast somewhere between the Texas-Louisiana border and Mississippi. Because 99L is likely to intensify fairly rapidly, this could facilitate a more northerly turn, which probably puts southeastern Louisiana under the biggest threat for now. The bottom line is that if you live in Louisiana, particularly the New Orleans area, there is a significant threat that a powerful hurricane will come to the coast in just a little more than three days from now.

As for Texas, we definitely cannot rule out direct impacts from this system. There are some scenarios in which a weaker storm cannot force its way north by influencing the ridge of high pressure. In this case the storm would turn more westerly, toward the Texas coast. There is enough uncertainty in the forecast to keep a close eye on the system. But at this point I would say we’re cautiously optimistic about the upper Texas coast, including Houston, being spared this weekend and early next week.

Matt or myself will have an update later this afternoon or evening.

We’re continuing to track development of a tropical system in Caribbean Sea that should move into the Gulf of Mexico this weekend. And while we don’t have a lot of additional clarity, we have received a lot of questions today. So although we can’t answer them all, we’re going to do our best.

As of Wednesday afternoon, here’s what we know, and what we don’t, about Invest 99L.

Where is Invest 99L going?

Not much has changed since this morning. We are reasonably confident that the storm will ultimately track toward Texas or Louisiana. Mexico seems less likely because it appears the storm’s center is further north than where forecast models initialized it earlier today. But beyond this there is a wide variance in solutions, and until the system gets more tightly defined, the models are going to struggle with solutions.

When will we know more?

We should know more within 24 hours, and probably have a pretty good sense of things by Friday.

When would we start to see effects the system tracks toward the upper Texas coast?

The earliest would probably be Sunday afternoon or evening, and more likely on Monday.

How strong will Invest 99L get

No idea. Anything from a tropical storm to a major hurricane is possible. However, we’re definitely concerned about intensification. The Gulf of Mexico is near its peak heating for the year, and the atmosphere does not appear particularly hostile to tropical systems this weekend. So yeah, a powerful hurricane is a definite possibility.

Be straight with us, is this going to be another Harvey?

Hurricane Harvey made landfall four years ago today, and then its steering currents collapsed. This lack of movement caused heavy rains to remain in place over the upper Texas coast, including Houston, for days. Right now we don’t expect a repeat of this, but there are some scenarios in which this system goes into the central Texas coast and then does slow down somewhat. In this case, Texas would see heavy rainfall, but probably not anything approaching Harvey’s biblical levels. It’s worth emphasizing that is just one of many possibilities we are watching at this point.

Stop it, y’all are scaring me.

Yeah, we get it. We don’t like hurricanes either. Matt and I own homes here. Hurricanes can be intimidating things. Please understand there are still a wide range of outcomes for this tropical system, and a majority of them right now involve minor impacts to the greater Houston region.

But here’s the deal. We probably aren’t going to have a real good handle on this system until later Thursday or Friday, and by that time we could only be two or three days from seeing significant impacts. So now is the time to review your hurricane plans. For example, under what circumstances would you evacuate? Where would you go? Do you have a plan to take care of pets? Do you have a hurricane kit if you’re staying home? When the time comes to make a decision, we want you to be ready to make it.

We’ll have a full update Thursday morning.

Good morning. This post will address our increasing rain chances toward the end of this week, and then discuss the tropical storm likely to form in the Gulf of Mexico this weekend. The short summary is: The system will bring a lot of moisture with it, and while it may directly impact Texas, it may also make landfall east of the state. Please bear with us, we should have better confidence in a day or two.

Wednesday

The high pressure system that has been responsible for several hot and sunny days will start to retreat slowly to the northeast, and this will allow for more clouds to form today. This will lead to a few scattered showers this afternoon and evening, with perhaps a 30 percent chance of rain at your location. High temperatures should still get into the mid- to upper-90s so this will be something of a transition day to a wetter pattern.

Thursday and Friday

These days will see a mix of sunshine and clouds as upper-level disturbances rotate around the southern edge of the high pressure system. About two-in-three areas will rain each day, and for the most part two-day accumulations should be on the order of 0.5 to 1.0 inch of rain. This should help to moderate temperatures some, and we should look for highs in the low 90s both days.

Saturday and Sunday

If you’ve got outdoor plans for the weekend you’re going to be rolling the dice. Saturday looks like it should have slightly less rain coverage than Sunday, but both days are probably above 50 percent in terms of your odds of seeing at least a passing shower. Sunday’s weather will be determined, in part, by the evolution of a tropical system now in the Caribbean Sea that should move into the Gulf of Mexico this weekend. And because there is so much uncertainty about that, it’s really hard to have much confidence in the weather forecast for Sunday and beyond.

Tropics

The National Hurricane Center now gives the Caribbean system, known as Invest 99L because it has been designated an “area of investigation,” an 80 percent chance of developing into at least a tropical depression or storm within five days. We think it’s highly likely that a tropical storm will form in the southern Gulf of Mexico by Sunday. So what happens after that?

Yesterday the bulk of the model guidance suggested 99L would move toward the Mexico mainland or Texas, but we cautioned there was a high amount of uncertainty. Accordingly, overnight, the models have shifted dramatically. Now the models bring 99L toward Texas and Louisiana. Why the big shift? The upper-air pattern is complicated, and the models are struggling to identify where there will be a weakness in a ridge of high pressure over the southeastern United States, which would allow 99L to turn north. Another challenge is that, right now, the tropical system has no defined center of circulation. The models (shown below) should therefore be treated with skepticism.

So what does this all mean? We probably will see additional shifts in projections of 99L’s track for the next couple of days, and you absolutely should not focus on any single model run. When our confidence increases, believe me, we’ll let you know.

As for impacts, the primary threat from this system is probably heavy rainfall, particularly along the storm’s track and to its east. However the Gulf of Mexico is plenty warm, and if the storm were to track toward Texas or Louisiana (instead of Mexico) it would have time to strengthen into a hurricane. These impacts are possible from later on Sunday through Tuesday.

If we get any clarity on the tropics forecast, we’ll update later today. If not we’ll see you on Thursday morning.