Matt Lanza

Good evening, and we hope folks are doing well and are safe after the passage of Nicholas. After nearly half a million customers lost power in the Houston area this morning, Centerpoint has restored all but about 150,000 as of 4:45 PM. Meanwhile, Nicholas is just barely a tropical storm, centered in far eastern Chambers County.

Maximum sustained winds are 40 mph, but in the Houston area, most sites are no longer reporting wind gusts, and those that are report fairly benign gusts. Nicholas is done with us, and it’s a reminder that wind and surge are issues here too. The next act will be rainfall and flooding along the central Gulf Coast. About 6 to 10 more inches of rain is possible in eastern Louisiana, southern Mississippi, southern Alabama, and parts of the Florida Panhandle from Nicholas as it very, very slowly creeps east across Louisiana tomorrow and Thursday before dissipating.

Hopefully the flooding will not be too serious in those areas, particularly those still very much recovering from Ida.

Back here in Houston, we get to look forward to 2 or 3 days in a row of calmer weather.

Wednesday through Friday

Look for a mix of clouds and sun all three days, with perhaps more sun than clouds on Thursday and/or Friday. Highs will be in the mid-80s tomorrow, upper-80s on Thursday and 90 or so on Friday. Morning lows will be tolerably in the low-70s tomorrow to perhaps mid-70s by Friday in spots. Rain chances are not zero, and it’s possible we could get a few showers or storms here or there, but those should be fleeting and isolated.

Rest of the tropics

A lot of folks are beginning to ask questions about Invest 95L, a tropical disturbance wayyyyy out in the Atlantic. The National Hurricane Center gives it a 90 percent chance of developing by the weekend.

First, let’s just breathe after Nicholas for a moment.

Second, it appears that the models are split into two camps with respect to 95L. Those that strengthen it quickly over the next few days turn it north into the open Atlantic quickly. Those that don’t, keep it coming west or west-northwest into the islands or just north of there by the weekend. So far as I can tell, there is not one single ensemble member of 85 on either the GFS or Euro that delivers 95L into the Gulf of Mexico. Most turn it out to sea before getting to the islands. Still, it’s probably something to check in on again in a few days. But at this point, we don’t view this as a serious concern for the Houston area. Rest easy tonight if you’re able.

A final word

Thanks to all of you for your kind words of support and encouragement through yet another storm. We are grateful to those of you that choose us and share us with your friends and family. This certainly was not an easy forecast, but we tried our best to manage expectations throughout. We always put a lot of thought into our word choices and the messages we want to send, and it’s a responsibility we don’t take lightly. Certainly a few lessons learned from the ramp up in intensity last night that we’ll carry forward with us for the future too. But, whether you’re a new reader or a longtime reader, thanks for sticking with us, and we hope to be your choice during the next storm, whenever it may occur.

Eric will have our usual daily update in the morning.

Good morning. A rollicking night across a healthy chunk of the Houston metro area continues this morning, as now-Tropical Storm Nicholas slowly, but steadily, passes through. As of 4:45 AM, Centerpoint’s website reports over 380,000 customers without power. Wind gusts of 45 to 55 mph are still occurring across southern and some eastern parts of the metro area, with gusts generally in the 30s to the north. The maps here shows the maximum wind gusts we’ve seen at various sites across the area since midnight.

You can see a list of highest reported wind gusts for the entirety of the storm (as of 5 A.M.) here. Judging by radar at 4:55 AM, Nicholas’s center was just getting ready to exit Brazoria County, just north of Rosharon. The center should pass very near or right over Houston a little later this morning. Maximum sustained winds were still reported to be 70 mph at the 4 A.M. National Hurricane Center advisory, though it’s likely to have weakened a bit further by now.

Wind impacts

As Nicholas continues to move north, you can expect gusty winds to travel north and east with the storm. Continued wind gusts of 45 to 55 mph are likely in the city of Houston and points south and east for another couple hours, with a general trend toward lessening wind overall. Areas north of Houston will likely see 35 to 45 mph gusts continue as well through the morning. This could continue to sporadically knock out power to folks across the area. If you have power, it would be a good idea to keep your phone charged, just in case you lose power. As winds subside a bit this afternoon, power crews should be able to get out to begin to repair damage. Power restoration may take somewhat longer where damage is more significant, namely along the coast and southeast of Houston. It would be a good idea to check in on anyone vulnerable, especially the elderly today, just to make sure they have what they need in case they’ve lost power.

Rainfall/Flooding

The good news in Houston is that serious flooding has not materialized in the city. The story is a bit different south and east of the city, however. The Harris County Flood Control maps of gauge status as of 5 A.M. shows several locations that are either flooding or close to flooding in far eastern Harris County and along Clear Creek or into Galveston and Brazoria Counties.

Some of the flooding south and east of Houston is coming as a result of surge on Galveston Bay. With the center of the storm over inland Brazoria County, winds have piled up water on the west side of the bay, leading to a generally 2 to 5 foot surge in many areas, highest along the bayshore in Harris or Galveston Counties.

Clear Lake even is close to a 6 foot surge. Expect these values to peak soon, with gradual improvement through the morning and into the afternoon.

Rainfall continues heavy at times, mainly in Houston and points east now. The circled area below is seeing rates at times over 1 inch per hour. This will be enough to cause some flash flooding, especially as you get into southeast Harris County, Chambers County, and Jefferson County.

While these rates are a little less than we feared, we will still see travel issues in spots east of the city, as well as south of the city as water continues to flow through the system. These conditions should improve a good bit by later this morning and especially this afternoon. The lopsided nature of this storm means that although the center may only just be on the east side of Houston by midday, the main impacts should be mostly out of our area by then.

Heavy rain and flooding risk will continue through the morning across Beaumont, Port Arthur, and into western Louisiana.

Later today and tonight

Though we expect the overall picture to greatly improve this afternoon, at least a few areas may see daytime heating lead to additional showers and storms popping up. Any of those would be capable of producing heavy rainfall, but they will be scattered and likely not widespread. We should see dry conditions tonight. High temperatures today will peak in the 70s, but if we do see any breaks in the clouds west of Houston, we could sneak into the 80s in a few spots. Certainly not terrible, but something to keep in mind if you are still without power this afternoon.

Eric will have our next update around 10 A.M.

Sorry for the delay: Groceries and kids and life get in the way sometimes! Eric and I spoke earlier this evening and agreed that we have enough evidence right now to upgrade to Stage 3 on the SCW Flood Scale.

As we note on the SCW Flood Scale page, a stage 3 event:

Our third stage is probably the most difficult stage to define. These are storms that may be quite memorable for parts of the Houston area but not for the entire area. These are basically larger, more damaging versions of Stage 2 events. You could expect perhaps hundreds of homes flooding in multiple neighborhoods during Stage 3 events.

In this situation, we believe we have enough evidence in model data to support a decent risk for a stage 3 event somewhere in our area or region. We currently believe the highest odds of this type of level being achieved is to the south and east of Houston proper, but the frustrating reality is that flash flooding could occur virtually anywhere in the Houston area. We aren’t much closer this evening than we were earlier today to defining exactly where the highest totals will occur. But we do have some other clarity perhaps.

Tonight & Monday

The rain we see tonight and Monday will be the appetizer to the main event, which should occur on Monday night into Tuesday and possibly Wednesday in our area. Expect scattered to numerous thunderstorms developing overnight and Monday morning along coastal sections, spreading inland tomorrow. Rain amounts by Monday evening will generally be on the order of 1 to 3 inches in Houston proper, lower amounts north of I-10 perhaps and higher amounts possible south of I-10 to the coast. Matagorda County may get into the core of the storm later tomorrow, which could bring additional rain totals in excess of 6 inches there. But for the most part, the rains tomorrow, though locally heavy and with localized flash flooding possible should be manageable.

Tuesday and beyond

I won’t dwell too much on Nicholas’s forecast in terms of tropical impacts, as we discussed that a bit in earlier posts and the flooding threat is of more concern for us. But the track and intensity forecast for Nicholas have remained fairly consistent, though with some risk that it could briefly attain hurricane status before landfall.

Onto the rain forecast. Many of you may have seen the European model today which printed a *lot* of rain for parts of the area. And while that certainly was a bit scary to see, it’s important to note that this model is an outlier, both in terms of track of Nicholas and in terms of the physical amount of rain it’s showing. While we aren’t discounting that model, I think it’s important to focus on the official forecast. Once you get up north of 15 inches of rain possible, it’s a serious flooding event potentially; we don’t need to make it scarier with outliers that show that. I have more issues with where the European model places the heavy rain (in and west of Houston) than how much it shows. With a track likely east of that specific model, I do believe the odds of the highest rain totals are highest east and south of Houston proper, similar to the official NWS rainfall forecast, which also increased today.

As of this evening, the outlook shows basically 5 to 10 inches of rain in the Houston metro area, with 10 to 15 inches in Galveston and Brazoria Counties. That seems reasonable right now, with the one caveat that higher amounts are likely depending on the exact track and speed of Nicholas as it comes through our area. A slow moving but steady outcome like most tropical models and the GFS model show would spread the rain out a bit more, keeping those higher totals somewhat in check. But a very slow, meandering outcome as the European model shows would potentially increase the max totals in spots. We want to see how the Euro goes overnight to see if it trends back to the consensus of tropical models and the GFS, which would further boost our confidence in worrying most about areas south and east of Houston. Regardless, rain will fall at the rate of 2 to 4 inches an hour at times. That can add up quickly.

A personal comment to close with here: This is an extremely difficult forecast because small changes in track outcomes will have big changes in impacts felt across a major metro area. If you live anywhere in the Houston metro area, north, south, east, or west, you should be preparing as if travel will be difficult to perhaps impossible on Monday night, Tuesday, and possibly Wednesday. We will hope for the best possible outcome here, but because of the uncertainty, you need to be ready. Folks east of Houston, particularly in Beaumont, Port Arthur, and Lake Charles: This bullseye could easily shift your way as well, so you need to be paying attention and prepared too.

Eric will have the latest in the morning on the flood threat, as well as tropical impacts from Nicholas, which will be minor in Galveston to moderate in Matagorda.

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.