Matt Lanza

POSTED AT 2 PM CT WEDNESDAY: Good afternoon. Hurricane Laura has continued strengthening in the Gulf of Mexico all day so far, showing no signs of slowing. It is now up to category 4 intensity, with maximum sustained winds of 140 mph.

Could Laura achieve category 5 status before landfall? It’s possible, as there are no signs of strengthening slowing down as of this writing (pressures keep falling). Laura is expected to come ashore below its peak intensity. It may feel the effects of some wind shear, shown in red on this map below.

That shear is moving with Laura to the north, so it may not help as much as you’d otherwise hope. More likely, Laura could experience what is known as an “eyewall replacement cycle” before landfall; basically a way for the storm to reorganize itself. When that happens, a drop in intensity usually occurs, sometimes substantial. We hope this happens right before landfall, which would allow Laura to come in on the decline, rather than at maximum intensity. Unfortunately, this aspect of the forecast is difficult to predict and we are really only relying on hope at this point. It’s possible Laura could just continue strengthening right up to landfall, similar to what Hurricane Michael did 2 years ago near Panama City, FL, though as a colleague of mine pointed out in a conversation earlier, the coastal topography of the Gulf here is much more shallow than off Florida. Shallow water can be more easily churned up and help to reduce the fuel available for hurricanes to feed off of. Whatever it is at landfall doesn’t much matter at this point, as it will still likely be bad.

Laura is moving northwest at 16 mph, which is blazing fast for this part of the Gulf. For folks in Houston, it’s important to know that Laura is doing what is expected, and “the turn” is underway. It’s not “if” or “when.” It “is” happening, and thankfully in the world of 21st century meteorology we can say that with authority. We will not be hit too hard here by this storm. Laura is expected to make landfall on the Cameron Parish side of the Texas/Louisiana border as a category 4 hurricane tonight perhaps around or just before midnight.

 

Let’s walk you through the expected wind and surge impacts at this time.

Houston area: West of I-45 (The Woodlands, Katy, Cypress, Sugar Land, etc.)

Periods of showers and thunderstorms possible to likely tonight. Impacts peak between 9 PM and 3 AM with winds of 15 to 25 mph and gusts as high as 30 mph or so.

Houston area: East of I-45, north of I-10 (Kingwood, Humble, Crosby, etc.)
Impacts peak between 9 PM and 4 AM with winds of 15 to 25 mph. Gusts will peak around 35 mph or so.

Areas around or just inland from Galveston & Trinity Bays (Bay Area communities, Texas City, League City, Baytown, etc.)
Impacts peak between 8 PM and 4 AM with sustained winds of 25 to 35 mph and gusts of 40 to 50 mph, highest south, lowest north. Surge of 1 to 3 feet, though northerly/northwesterly winds may push water to the south toward Galveston

Galveston & Bolivar
Impacts peak between 8 PM and 4 AM with sustained winds of 30 to 40 mph and gusts of 50 to 60 mph, or a bit higher possible. Storm surge on Galveston Island is expected to be on the order of 1 to 4 feet, with the bay side experiencing surge as well. Storm surge on the Bolivar Peninsula may be as high as 4 to 5 feet.

Beaumont-Port Arthur-Orange area
Impacts peak between Midnight and 5 AM with sustained winds of 75 to 90 mph and gusts of 95 to 110 mph. Surge of 10 to 15 feet into Sabine Lake.

Lake Charles area
Impacts peak between midnight and 6 AM with sustained winds of 75 to 100 mph and gusts of 95 to 120 mph. Storm surge of 15 to 20 feet into Calcasieu Lake.

Rainfall
Just to further put you at ease, the total rainfall through tomorrow in the Houston area is expected to be 1 to 2 inches total. Many places will likely see less than this. A few to the south and east may see a bit more.

But in this case, flooding, other than some nuisance street flooding is not expected. On Friday, we may see a slightly better chance of some heavier rain as modeling has been in agreement on a better signal for storm chances from a trailing band feeding into Laura’s remnants over the Mississippi Valley then. Something we’ll check into more closely tomorrow.

So again, just to summarize, Laura is moving northwest and will turn more north-northwest this evening, likely making landfall on the Louisiana coast, well east of Houston, as a major hurricane. Eric will have our next post no later than 5:30 PM CT.

POSTED AT 8:30 PM CT TUESDAY: Good evening, and we come to you with some positive news for once, at least as it relates to Houston.

In a nutshell, we have a growing consensus for Laura to make landfall far enough east of Houston to likely spare us really bad impacts. Just to be clear, you should still be heeding the advice of local officials, and you should remain vigilant in case something changes at the last minute. But from all we’ve seen today, we feel good about our position here in Houston.

The biggest challenge for us in forecasting Laura’s potential impact in Houston has been dealing with the European model and, in particular its ensembles. The overnight run of the Euro (ECMWF) and its ensembles continued stubbornly pushing Laura’s track west to the point that I’ll be honest: I woke up by chance at 3 AM, decided like a good meteorologist and foolish human being to look at my phone to see how the model finished, and basically woke my wife up by belching out an expletive. It had precedent. The Euro had been consistently on the left side of guidance (farther south), and every updated forecast point was coming in south of even that guidance.

 

And since the Euro is generally considered our best performing model, you have to at least grant that some credibility. All along, the models we use specifically for tropical storms and hurricanes have been consistently focused on the Texas/Louisiana border or into southwest Louisiana. Well, wouldn’t you know it but now those verification points above are coming in north of forecast.

Getting questions about track trends/wobbles re: #Laura and #HOUwx implications.

Hurricanes wobble all the time, as you can see by plotting the estimated center each hour from 1-7 PM CDT.

That said, the center is consistently a hair N of EPS forecasts. pic.twitter.com/kzuwTaU11I

— Jack Sillin (@JackSillin) August 26, 2020

In fact, the 18z European operational model takes Laura just over the Louisiana side of the border, in line with tropical models

What does this mean? It means the folks at the National Hurricane Center are pretty <redacted> good at what they do. The latest forecast track for Laura takes the center ashore near the Texas/Louisiana border tomorrow night as a major hurricane.

For us in Houston this explicitly would mean primarily tropical storm impacts instead of hurricane impacts, as tropical storm force winds do extend out over 175 miles east of the center (it will be less to the west). At the coast, that could be different, with slightly stronger wind (perhaps close to hurricane force) and a storm surge of 3 to 5 feet in Galveston to upwards of 6 to 9 feet across the Bolivar Peninsula to High Island.

The caveat to all this? Hurricanes do tend to wobble sometimes. In most cases, the wobbles average themselves out and cancel out. But at times some more distinctive wobbles could yield a track farther southwest or northeast. We will monitor that tonight and tomorrow to see if there are any trends that stand out. This is why it’s important to remain vigilant. We look fortunate now in Houston, but things can sometimes change quickly.

In case you wanted a look at Laura on satellite this evening, here you go.

This is a much healthier looking storm than even 6 hours ago, so we’re likely heading for some impressive strengthening tonight.

While we’re very positive on Houston at the moment, I personally can’t help but feel some sense of despair for folks in the Golden Triangle and southwest Louisiana who have been through the ringer over the last 15 years between Rita, Ike, Harvey, Imelda, and now Laura. Unfortunately, Laura’s storm surge impact into extreme east Texas and southwest Louisiana looks very serious.

Here's the latest ADCIRC estimate of water inundation depth as of 5PM ET (Aug 25). Shows 10+ feet near the landfall spot & feet of water nearing Lake Charles. This could be one of the worst U.S. surge events in recent memory. FYI: 90% of hurricane deaths are due to water. #Laura pic.twitter.com/15wgIOTP4x

— Steve Bowen (@SteveBowenWx) August 26, 2020

While the Houston area gets a lot of air time because we’re the 4th largest city in the country, the folks in Beaumont, Port Arthur, and Lake Charles are sometimes overlooked. So if Laura does indeed spare Houston, we hope we can pay it forward in some way to our neighbors to the east.

Eric will have our next post up no later than 7:30 AM CT Wednesday.

Good evening. We don’t have any real good news or bad news tonight on the Laura front relative to Eric’s post earlier today. I would not change any of the scenario percentages he put down either. I was hoping we might have some good news, but alas, we are not there yet. This is explained below.

The 7 PM National Hurricane Center Advisory maintains Laura on a course for somewhere between Houston and central Louisiana as a borderline major hurricane Wednesday night.

Since our post this afternoon, a Hurricane Watch was issued for Galveston Bay and Port Bolivar into central Louisiana. A Tropical Storm Watch is posted from San Luis Pass through Port Bolivar. And a Storm Surge Watch is posted for all areas north of San Luis Pass.

Laura is about to emerge in the Gulf of Mexico this evening off Cuba, entering the healthiest environment it has yet had for strengthening.

Laura looks a bit ragged overall, but it is putting together a bit of a core tonight, if not something mimicking an eye-like feature. Once this enters the Gulf with high water temperatures and low shear, there is little to hold it back from organizing steadily. That’s our going thought at least. We will see if some slightly “cooler” water that has been present in the eastern Gulf acts to keep the intensification slow and steady rather than explosive over the next day or so. At some point, as long as Laura is able to develop a firm inner-core, we would expect intensification to perhaps become more rapid. Either way, the odds of seeing a major hurricane in the northwest Gulf of Mexico remain pretty substantial.

So what about track?

The million dollar question. We will be honest here. We don’t yet feel comfortable. Here is the problem we have been facing. The tropical models, ones that are tuned to handle tropical storms and hurricanes, have been incredibly consistent the last couple days in indicating that the landfall point would be somewhere in southwest Louisiana or close to Port Arthur. This explains why the National Hurricane Center forecast has frankly not moved much either. The thing myself, Eric, and a lot of other meteorologists have been squirming in our chairs over despite this is the European ensemble. The Euro is generally considered the “gold standard” for most things weather forecasting. It runs an ensemble, where the model has the initial conditions tweaked just a little and is run 51 different times. In most years, this model has been really tough to beat. By no means is it perfect; it, too, has its moments.

Well, for the last couple days it has continued to show risks of the storm tracking farther south and west of the tropical models, coming in anywhere from Corpus Christi to Galveston. Today has been no different. The very latest run (pushed out in the last 90 minutes or so) has shifted a little to the north, narrowing some but not as much as either of us would have liked to see for Houston’s sake.

Tracks of the 12z EPS vs 18z EPS lows, tracks in general shift a bit up the coast #Laura images from https://t.co/b4vzQrTBpF pic.twitter.com/XvTF4zunzK

— Allan Huffman (@RaleighWx) August 25, 2020

So how should you be interpreting this information?

The reality is that despite the NHC track focused in Louisiana, despite very consistent behavior from the GFS model and from tropical models, the model we tend to consider the best in the business still shows a distinct risk that Houston and Galveston could end up much too close to the center of Laura and could still take a direct hit. Those are just the facts. That trend we saw in this evening run of the ensemble may continue to shift northeast overnight. We don’t know. But at this specific point in time, you should by no means let your guard down with respect to this system. You will need to be ready to act quickly tomorrow in case something changes. Fortunately, we should get our answers tomorrow morning or early afternoon on how real a risk this is for Houston or if it will be another in a litany of close calls for our region. Eric will have the very latest in the morning, no later than 8:00 AM.

Good morning. We’ll run down both storms this morning, though at a high level our concern and interest is primarily focused on Laura at this time.

Marco

Tropical Storm Marco continues to try and become a hurricane this morning in the Gulf.

Marco is expected to continue lifting just west of due north today, and it is aiming for a landfall somewhere in eastern Louisiana before making a fairly hard left turn and basically falling apart over southern Louisiana.

We have seen a model or two bring the remnants more west along the coast, which would increase some storm chances for us and deliver some localized heavy rain on Tuesday, but right now those issues aren’t expected to be too serious.

Rainfall through Tuesday evening is expected to be mostly minor, with the best chance of something heavier along the immediate coast and lesser chances inland. The heaviest rain remains directed into eastern Louisiana.

The brief summary on Marco: Perhaps a small hurricane into southeast Louisiana before it dissipates while shuffling west across southern Louisiana, keeping most heavy rainfall well off to our east.

Laura

Tropical Storm Laura looks impressive this morning, mainly because it’s coming out of the typical nighttime peak in thunderstorms, and because it is doing this while interacting with Hispaniola, which often rips these things apart. Laura is the unfortunate one that actually gets by Hispaniola without a lot of trouble because it was disorganized to begin with.

If you want to provide some criticism of Laura, it’s that the storm is somewhat lopsided. But short of that it has a healthy core of storms, some developing outflow, and it is now exiting the highest hurdle it needed to survive, Hispaniola. Cuba comes next, but the bottom line here is that Laura has the skeleton it needs to become a healthy tropical system when it eventually finds a more hospitable environment for strengthening, likely Tuesday and Wednesday over the Gulf.

Laura’s track has shifted a little to the west since yesterday, but if you read between the lines in the National Hurricane Center’s discussion, there are likely to be more westward shifts to come.

The battle lines right now are between some of the typical global models we use for day to day forecasting, which take Laura farther west, more into Texas and the tropical models we use for situations like this, which have skewed a little farther east, more into western Louisiana. Laura is going to basically work around the periphery of high pressure off to our north and east. Typically, we would expect the global models to have a better handle on the steering situation, so there is a reason to put some trust in them over the hurricane ones for track right now. Once Laura works across Cuba and emerges into the Gulf tomorrow, we will have a better idea of whether Corpus, Houston/Galveston, Port Arthur, or central/eastern Louisiana are most at risk. Right now, all we can tell you is that trends since yesterday have only served to give us more pause about how close Laura may come to southeast Texas. We continue to urge you to pay close attention to this storm and make your preparations today in case they need to be implemented quickly tomorrow and Tuesday.

How strong will Laura be when it gets where it’s going? That’s a great question, and right now, the reliable model intensity guidance ranges from a low-end category 1 storm to a high-end category 3 storm. Given the history of the Gulf, the fact that it’s going to be in a fairly favorable environment for strengthening, and frankly how it has performed so far, we would likely lean toward the higher end of things with respect to intensity right now. The NHC forecast is calling for a category 2 hurricane at max, which is right in the middle of reliable guidance at this time. Hurricane intensity remains a very, very difficult thing to predict and though we are bullish on this storm’s strength right now, there are still risks equally spread that we may be too aggressive or not aggressive enough. More clarity on this should come tomorrow.

As far as rainfall goes? That is always a concern, but Laura is expected to keep moving and no models indicate a slowing or stalling. For all intents and purposes, we are viewing this a tropical threat (storm surge, wind) first and foremost and a rainfall flooding threat secondarily. Again, please stay aware and ready to act.

Eric will have our next update posted no later than 3 PM today.