Matt Lanza

Hurricane Laura’s track continues to slip a little farther east of Houston

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.

The ECMWF operational forecast model (blue lines) had consistently been too far north of the actual position of Laura (red Xs) until today. This led to lingering doubt as to how far northeast Laura could go. (University of Albany/Brian Tang)

 

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.

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.

The Tuesday evening National Hurricane Center forecast takes Laura ashore at the Texas/Louisiana border as a major hurricane. (NOAA)

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.

Laura’s satellite appearance has improved significantly this afternoon and evening, likely indicating intensification will be notable tonight. (Weathernerds.org)

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.

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.

Laura will enter the Gulf tonight, as the storm’s track possibilities narrow slightly

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.

The National Hurricane Center forecast continues to focus toward Louisiana, but we continue to see some risks this could be a very close call for Houston. (NOAA)

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’s center is about to emerge off Cuba into the Gulf this evening. (Weathernerds.org)

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.

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.

Marco on track to our east, but Laura’s forecast is inching farther west

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 continues to lift NNW across the Gulf and is flirting with hurricane strength this morning. (Weathernerds.org)

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.

Marco is expected to come into eastern Louisiana, and it should then meander westward while significantly weakening. (NOAA)

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.

Marco’s heaviest rainfall continues to look to stay well off to our east. Coastal areas may stand the chance for some locally heavy rain, but nothing serious expected right now. (Weather Bell)

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.

Laura is not terribly strong this morning, but that has helped it begin to exit Hispaniola with an impressive area of thunderstorms. (Weathernerds.org)

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.

Laura’s track is now shifting slowly to the west, and further shifts are possible if not likely today and tomorrow. (NOAA)

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.

Marco enters the Gulf as Laura lumbers across Hispaniola

Good evening. Eric’s update from this afternoon has most of the situation covered. I’m here to just refresh what’s going on, and I also want to talk a little bit about Laura.

Marco

As of this evening, Marco has moved past the Yucatan channel and into the southern Gulf of Mexico.

Marco has moved into the Gulf this evening as a 65 mph tropical storm, although most of its storms and winds are north and east of the center. (Weathernerds.org)

Marco still has maximum sustained winds of 65 mph and is still moving just slightly west of due north around 10 to 15 mph. I put a tropical storm icon on the satellite image above to indicate where Marco was located. It’s worth noting how lopsided Marco’s thunderstorms are, with basically everything north and east of the center. This has implications on the rainfall forecast for Marco after landfall.

There has been little to no change in terms of expected track with Marco relative to what we thought most of the day.

Marco should roughly track toward eastern Louisiana, possibly becoming a hurricane and maintaining low-end hurricane intensity up to landfall. (NOAA)

The National Hurricane Center’s forecast track takes Marco broadly toward eastern Louisiana. The storm is expected to become a hurricane, and it could maintain hurricane intensity up to landfall. Marco is compact, so any hurricane-force winds will only extend out a few miles from the center, mainly to the east of where it tracks.

As far as rainfall goes, we feel the bulk of it will end up well into Louisiana, Mississippi, and Alabama. The map of rainfall below (through Tuesday evening) will look a little odd because it’s a composite of various National Weather Service offices putting together their own forecasts, so some may be older or newer and not smoothed out. But it shows that the heaviest rain is expected to be closer to New Orleans than Houston.

Rainfall from Marco is expected to be heaviest well to the east of Houston, deep into Louisiana. (Weather Bell)

If for some reason Marco starts to weaken tonight and ends up falling into disarray tomorrow, there is some chance it could drift back west of the forecast cone. We feel that possibility is highly unlikely however, and we are not going to worry about significant rainfall from Marco in our area. Marco should fall apart after coming onshore, drifting into northwest Louisiana, Arkansas, or northeast Texas as a remnant low with isolated pockets of heavy rainfall. We should be able to close the books on Marco by Tuesday night or Wednesday morning.

Laura

Let’s talk about Tropical Storm Laura. I’m going to be really honest about this one: We do not know who is most likely to see landfall from Laura when it gets to the Gulf. There is a plausible risk that it could go toward the Florida Panhandle, the central Gulf, Louisiana, southeast Texas, or even Matagorda, Corpus Christi, or Brownsville. So quite literally no one (save maybe the Florida Peninsula) can let their guard down with respect to Laura. We really want folks in Southeast Texas to be prepared in case this does come this way. There will likely be some element of “Well, y’all were fired up about Marco and look what it’s gonna do” from some people out there. With Marco, we laid out scenarios because we knew there was no answer key (til today). With Laura, we’re in that same scenario phase right now, and there is no clear model or forecast that is able to see Laura’s future clearly at this point.

We have laid out some of the factors involved with Laura’s interaction with Hispaniola through the day today. As of this evening, it appears Laura may be choosing to set itself up on the south side of Hispaniola.

A satellite loop of Laura this evening shows a lot of storms but weak organization with a loose center on the south side of Hispaniola. (Weathernerds.org)

This and other such interactions with Hispaniola and Cuba are critical to Laura’s future. They are also unpredictable. The current NHC forecast takes Laura generally off to the west or west-northwest.

Laura’s NHC forecast takes it into the Gulf as a hurricane, with a turn north somewhere in the western Gulf, with areas from Texas through the Florida Panhandle still in the cone. (NOAA)

But each shift like this, with a center possibly forming farther south keeps the storm disorganized and following the bottom or left side of the cone.

The rule of thumb: As with Marco, the weaker the storm is, the more likely it will come farther west before turning northward. So if Laura continues to struggle in the islands and remains weak, there’s a pretty good chance it will follow the bottom of the cone more than the top of it, which puts it farther south to start in the Gulf and gives it a much easier route to get as far west as Texas. A stronger storm will be more apt to lurch poleward and help limit the impact of high pressure over the Southeast, meaning it would likely turn well before it gets to Texas, either near Louisiana or east of there. As of Saturday evening the weaker option is winning out, which is why it’s important to continue to stay tuned in tomorrow and Monday. We are going to still have questions tomorrow, but I predict that by Monday, we’re going to have a good idea if this is an ominous threat to Texas or another miss to our east. Stay tuned.

Our next update will be posted no later than 9 AM on Sunday.