Matt Lanza

We continue to monitor Invest 94L Potential Tropical Cyclone 14 Tropical Storm Nicholas in the Bay of Campeche, which is likely to become a tropical storm before the day (or possibly the morning) is out. As I write this, hurricane hunters are investigating the storm and they have found tropical storm force winds, and subsequently they have tagged this as a PTC, as it lacks a defined low level center. In other words, it quacks like a duck but it doesn’t yet look like a duck, so we can’t technically call it a duck. But from your perspective, it’s basically a duck. Sorry, Ohio State fans.

Nothing better than writing a bunch of stuff only to have it get blown up. Anyway, we now have Tropical Storm Nicholas. Here’s the forecast track from the National Hurricane Center.

With the formation of Nicholas, we now have Tropical Storm Watches along the coast and in Galveston Bay. The initial read on Nicholas from the NHC is to strengthen it to a moderate to strong tropical storm before making landfall somewhere between Rockport and Sabine Pass. The Matagorda area is favored at this time, but that could always change.

From our vantage point: First, we will be holding this at a Stage 2 flood event. Given the higher end risks and uncertainties involved in this forecast, it’s important to note that this is pretty low confidence. We would continue to skew this as lower risk for a Stage 2 event north and west of Houston and higher risk south and east. In other words, the farther south and east you are in the metro area, the more likely you are to receive heavy rainfall that could produce flash flooding. Or at least that’s our going assumption sitting here today.

Sunday/Monday

Next, let’s talk briefly about today and tomorrow. We are expecting thunderstorms at times, especially along the coast. And those could easily produce 2 to 3 inch per hour rainfall rates which could cause flash flooding eventually. It’s important to note that this rain today and tomorrow is indirectly related to Nicholas, and what we see on Tuesday into perhaps Wednesday would be directly related. In other words, we are expecting multiple rounds of rain and storms between now and Wednesday. If you don’t get rain today or tomorrow, that doesn’t mean you won’t on Tuesday or Wednesday and vice versa.

The Weather Prediction Center arm of NOAA has placed the southeast metro in a slight risk (level 2 of 4) of excessive rainfall today and the bulk of the metro area in that slight risk tomorrow.

This means that there is at least some chance that we get enough rain to produce flash flooding in spots today or tomorrow. Rain will likely fall at the rate of 1 to 3 inches per hour in the heaviest storms, and any storms that linger awhile or “train” repeatedly over the same areas could begin to produce some street flooding. This would be most likely at the coast or just inland today and tomorrow, but some risk exists farther inland as well tomorrow.

How much rain do we expect today and tomorrow? Well, here’s the official NWS outlook for rainfall through Tuesday morning.

We would expect to see about 3 to 5 inches of rain along the immediate coast with 1 to 3 inches inland. There will likely be isolated higher amounts in here — through late Monday night or Tuesday morning.

Beyond Monday night

Here’s where forecast confidence drops a good bit. When we have tropical storms we often tell you not to focus on the center line because impacts will extend far from the center. That’s as true as always with this storm, but the reality is that: Because of the angle at which this is coming up the Texas coast, that track actually really matters in terms of what we experience in the Houston area and coast on Tuesday into Wednesday. Why is this? We can look at two goal posts here to get a sense of why this is important.

Last night’s GFS model took the storm into Cameron Parish, Louisiana and because it spent a lot of time over water, it basically intensified it into a hurricane. But! Because it tracked offshore, the bulk of the tropical storm and hurricane force winds stayed offshore, and Galveston saw just moderate tropical storm conditions. The Euro brings the system inland over Matagorda and because that’s far enough south Galveston again just saw moderate tropical storm conditions on that run. But from a rainfall perspective, the farther east GFS directs most of it into Louisiana, while the west tracking Euro brings it more into the Houston metro area.

The final track of Nicholas will be dictated by where exactly the low level center forms. So in terms of Houston rainfall, a solution like the GFS provides minimal impacts Tuesday and Wednesday, whereas the Euro implies significant risk of flash flooding. It’s important to note that both solutions imply heavy rainfall risk is likely along the immediate coast, so for places like Galveston, you should expect at least another period or two of heavy rain Tuesday into Wednesday regardless of the exact track.

The good news is that with a defined tropical storm now and hurricane hunters continuously investigating, and better data going into our models, we should have some clarity on this by tonight, or so that’s the hope!

In terms of tropical impacts: Based on the track above. Winds will likely approach 30 to 40 mph at times beginning late Monday night or early Tuesday along the coast. Winds will likely be sustained at 30 to 45 mph on the coast Tuesday, with gusts of 45 to 55 mph possible. Higher winds are possible with a stronger storm or one that splits the model difference right now and comes ashore near Galveston. A storm tracking farther east would likely result in slightly less wind at Galveston and more impacts to Port Arthur or Cameron, LA. Inland winds should remain below tropical storm force, but it would likely be a breezy day at times on Tuesday, especially south and east of Houston. This doesn’t appear to be a major power outage risk event for the majority of the Houston area, but coastal areas could have a few issues.

Tides are going to approach levels of about 3 to 5 feet above mean low lower water (MLLW). This may lead to impacts close to what you may have experienced during Tropical Storm Beta almost exactly one year ago. This is mostly minor coastal flooding. If Nicholas does intensify beyond current expectations or come ashore closer to Galveston, tides could be a bit higher and flooding would become more of a concern along the bay communities as well as in Galveston, Surfside, and Bolivar.

So just to summarize:

• Periods of heavy rain, indirectly associated with Nicholas are likely today and tomorrow, with the highest amounts likely closer to the coast. Flash flooding is possible with those storms.
• An additional period of heavy rain is likely on Tuesday into Wednesday, contingent on the exact track of Nicholas. That is where we have significant forecast uncertainty still. Additional, possibly more significant flash flooding is possible then.
• Tropical storm conditions are becoming more likely along the immediate coast, with Galveston likely to experience tropical storm conditions on Tuesday. At this time, we don’t expect inland locations, including the city of Houston to see significant wind, though it will be a bit breezy Tuesday.
• Minor coastal flooding is likely, with impacts possibly similar to what was seen during 2020’s TS Beta. A stronger storm or a storm closer to Galveston would likely yield slightly worse impacts, but a storm passing east of our area may reduce impacts some.
• We expect better model data this afternoon and evening to hopefully help boost some forecast confidence.

Eric will have the latest based on morning model data around 2 P.M. today, and we’ll have another post this evening as well.

For some folks, today is the coolest morning in months! Crockett, for instance, is down into the 50s. IAH, at least as of 6 A.M. has not gotten under 70 just yet.

We will see if we can match our cool day of the week (69° on Wednesday) or even sneak just below it before the sun gets up. Either way, it’s comfortable out there today, and we’ll be closing the week on a very high note. Enjoy it, because things will begin to change in earnest later this weekend. We detail the situation below. Look for a post later today that will set our initial Flood Scale expectations for next week.

Today

No issues whatsoever. It’s beautiful. Enjoy it if you can. We will see highs peak in the 90s with abundant sunshine and rather comfortable humidity.

Saturday

While Saturday morning won’t start off quite as cool as we are this morning, it should still be a pleasant start to the day, with morning lows ranging from the 60s inland to 70s near the coast. There is even a chance that Galveston checks in cooler tomorrow than it did today. Look for more sunshine, highs in the 90s, and perhaps just a tinge higher humidity.

Sunday

The end of the weekend will bring the beginning of our transition into the wet period we’re expecting. I would expect at least a chance of thunderstorms in Houston and south of I-10 with increasing clouds elsewhere. Morning lows in the 70s will warm into the upper-80s or low-90s depending on how much sun you see. No serious problems are currently anticipated Sunday, but if you have outdoor plans, keep the rain chances in mind.

Next week

So let’s talk about next week. There are a number of factors that will go into exactly how next week plays out, some of which are rather low confidence still today. But in general, expect increasing rain chances Sunday through Wednesday, with locally heavy rainfall and potential for at least some flash flooding concerns, especially south and east of Houston and along the coast. Let’s walk through some of the players and how they will influence what happens next week.

First, the primary reason next week looks wet: High pressure over us today will leave us to the east over the weekend, steering Gulf moisture back into the area. The remains of our cold front offshore transition to what we call a surface trough. And then you may add a tropical system to the mix in northern Mexico or far south Texas. You can see this all reflected on a forecast surface map below.

Confidence is relatively high that the high pressure area will move to our east and open the door to Gulf moisture. So that much we know. Where confidence drops is in relation to possible tropical development off the Mexico or Texas coast.

Odds have been increasing that whatever moves into the Bay of Campeche this weekend will develop into a tropical depression or weak tropical storm. That’s one thing we have moderate to high confidence in: That this system has a rather low ceiling in terms of intensity. It should track along the coast and north, probably making landfall in northern Mexico or far south Texas on Monday sometime.

This will matter some, however because the exact location of the track and how well organized this disturbance is will help dictate where the highest rain chances are located and how high the totals will be. These situations are not straightforward. Sometimes you’ll see the heaviest rain hug the coast or just inland and cause flash flooding problems. Other times the heaviest rain will fall offshore and end up mostly harmless for coastal communities. We just don’t know at this point exactly what it will look like.

Here’s what I think we can say right now, with some level of confidence:

• We will have periods of thunderstorms beginning later Sunday and continuing into Tuesday or Wednesday of next week.
• It won’t rain the entire time, and there may be some substantial breaks in the rain, especially north of I-10.
• Rain will likely be heavy at times however, especially along the coast and possibly south or east of Houston.
• Localized street or flash flooding is possible, especially south and east of Houston, but it is too soon to tell you exactly where and when that may occur.
• Rain totals of 2 to 6 inches on average for most of the area between Sunday and Wednesday, with the highest totals in smaller pockets south and east of Houston, perhaps up to 8 to 10 inches or even more.
• While tropical development is becoming increasingly likely, we do not expect this to be a wind or surge issue for us. Some rough seas, rip currents, and elevated tides will be possible, but development should remain weak enough and far enough to our south to avoid the wind & surge problem. This will be almost exclusively a heavy rain situation for us.

Here is the current NWS rainfall outlook into next week.

While some areas will probably see less rain than forecast above, their placement of the bullseye totals south and east of Houston is logical right now, and higher amounts are possible in those areas.

Drier air and lower rain chances should begin to build in after Wednesday.

After we digest the morning weather model data, look for a post from Eric later this afternoon that will initiate our Flood Scale outlook for this event. And we’ll keep you posted over the weekend.

Happy Sunday everyone! We hope your weekend has been going well so far. The weather has certainly cooperated for the most part. The rest of today should behave similarly. We just wanted to post about a couple things since we sort of left the weather situation for the upcoming week on an open-ended note on Friday. We’ve gotten a good bit of clarity over the last couple days, which, as it turns out is good news for us.

This evening & Labor Day

As noted on Friday, we do expect conditions to become a little more unsettled heading toward tomorrow. If we look at a quick surface weather map of the region, we can see the main players. First, we have a weak little trough (orange dashed line) dropping southeast across Texas today. That could focus a few showers and storms tonight, and this would primarily be north of Houston.

The second item to note on that map is an actual cold front. Sadly, this isn’t going to be a classic autumn cold front, but this may be just enough to help lower humidity a little for the week ahead, particularly during the afternoon. Instead of nighttime lows in the mid to upper-70s, perhaps we’ll have a few mornings in the low to mid-70s this week. For those seeking that true pumpkin spice latte weather, this won’t be it, but it will be a start.

More importantly, this front will serve as a focal point for scattered thunderstorms on Monday. I would not be shocked if we have some activity in the morning and then a break with more in the late afternoon. Storms tomorrow afternoon could be on the strong side with locally heavy downpours. Just keep that in mind if you’ll be traveling to or from somewhere or hosting an outdoor BBQ. Probably good to have a backup plan for the BBQ, just in case. Outside of rain, it should again be in the 90s tomorrow.

Tuesday through Thursday

Back on Friday we told you about how models had gotten a little more excited about the potential of a tropical system in the Gulf. For us, some good news: Whatever “that” is should not develop much, and it will almost certainly miss well to our east.

The National Hurricane Center is continuing to assign about 30 percent development odds over the next 5 days from Invest 91L, now emerging in the Bay of Campeche. But the upper level pattern will feature a strong ridge in the upper atmosphere that builds from about Las Vegas on Monday to the Four Corners on Thursday. That eastward expansion of high pressure in the upper atmosphere, combined with a pretty strong trough in the eastern U.S. will likely help deflect the tropical noise into the central or eastern Gulf. This leads our rain chances to drop in the Houston area Tuesday, Wednesday, and Thursday. Obviously we don’t want to see Louisiana face yet another tropical threat, but thankfully whatever does develop here (if anything does at all) should be weak. That said, some heavier rain is possible in the eastern Gulf from this system. As of right now, official forecasts are only about 1 to 4 inches, aimed mainly at Alabama and the Florida Panhandle.

Some locally heavy rain is possible in Louisiana from this, but the primary focus is likely to stay east of there as well. We’ll keep watching, just in case, but we feel fairly good about the upcoming week overall for the Houston area.

Beyond next week: Other tropical threats?

There have been some posts circulating on social media regarding various deterministic (singular) model runs showing a hurricane in the Gulf around mid-month. I’ll be honest, the operational GFS has been quite consistently showing a system (of varying intensity) in the Gulf around mid-month (sometimes in Mexico, sometimes in Texas, sometimes elsewhere). While the GFS ensemble has been, in this forecaster’s opinion, one of the best tools to use in the tropics to identify possible threats the last two hurricane seasons, the GFS operational model still has many flaws. This is especially true on a day 10+ forecast. I don’t care how consistent it has been showing a certain outcome: It is still a day 10+ operational forecast model, and it is *not* meant to be used with any specificity whatsoever. While it’s nauseating to deal with this stuff multiple times per hurricane season, it is the world we presently live in, and so let me be the one to tell you: At this time, you do not need to be worried about the threats shown on operational models that various, mostly anonymous Facebook pages are sharing.

Ensemble support for this system is not zero, but it’s not at a high enough volume yet where I begin getting concerned. And there is absolutely no dominant signal within the ensembles as to where such a system may or may not track even if it develops. Some show Mexico, some show Texas, some show east of here, some (roughly half) show no development at all! We see scenarios like this show up multiple times per hurricane season. Sometimes they lead to development. Often times, they do not. So, could this change? Absolutely, but sitting here today it would irresponsible to pump up the operational GFS model on day 11 without showing the ensembles at the same time which paint a less ominous picture. Let’s talk when it’s inside 7 days and see where we stand. It is the peak of hurricane season, so you should be checking in regularly anyway. But we see nothing exceptional at this very early stage.

Alright, that’s enough for now. Enjoy Labor Day if you’re able, and we’ll come back at you on Tuesday with the latest.

Good evening! One of the things we’re trying hard to do this year is meet more readers in ways that are comfortable for them or they find to be the most useful for getting weather information. We’ve developed an app and started a Spanish language site, spearheaded by Houston meteorologist Maria Sotolongo. With Maria’s background in television, we’re also going to try to provide some more video content when possible. As we head into Labor Day weekend, we wanted to provide you with a quick video update on the outlook for the weekend, the latest on the Gulf tropical mischief next week, and musings about our first fall front.

We certainly aren’t going to pivot away from what we do each day on both the English and Spanish language sites, which is post our morning updates and more frequent updates when it counts. That’s our bread and butter and we know it. And we definitely won’t constantly bombard you with notifications. But we are efforting to reach Houston-area folks in more ways and meet you where you are, so we will experiment with some videos like this from time to time. Please feel free to share your feedback with us in the comments or the feedback link above. I will say that it is great to have Maria here with us, and she’s been full of great ideas to continue serving you!

Just as a quick note: There was nothing earth-shattering about today’s model guidance regarding next week’s potential tropical system in the Gulf. We’re still in wait and see mode, and there is nothing too alarming at this point. But it’s September, so we’ll be watching. Look for a post probably Sunday with the latest. Meanwhile, enjoy the holiday weekend if you are able!