Harvey late night: Some final Thursday thoughts

As of 8:00pm CT tonight, a well-organized Hurricane Harvey is moving northwest, toward the Texas coast. It packed 85-mph winds, but forecasters at the National Hurricane Center still expect it to come ashore late Friday night, or Saturday morning as a major hurricane. The most likely landfall location is between Corpus Christi and Port O’Connor. The storm’s strong winds and storm surge, likely at least 10 to 12 feet above normal tide levels, will pack a punch along the central Texas coast. For people in low-lying areas from Corpus to Freeport, these are potentially life-threatening conditions, and I urge you to heed the warnings of the Corpus Christi National Weather Service office and local officials.

For tonight’s post I wanted to discuss the most likely scenario for immediate effects in Houston, and then reconsider the uncertainty about what comes next. The National Hurricane Center anticipates that sustained winds on Friday night and Saturday morning in Houston and Galveston have about an 80 percent chance of reaching 39 mph, or greater. I think that’s possible, and certainly chances are higher southwest of Houston, in places like Sugar Land. However, at this point the available model data indicates that winds will be manageable in the Houston region during Harvey’s landfall. This is important for a number of reasons, not the least of which is that minimal tropical storm force-winds are something the region’s power grid should be able withstand. Mostly.

Harvey’s satellite appearance at 8pm CT Thursday. (NOAA)

In terms of rainfall, the picture is more grim. It still appears as though the Houston region will see manageable rainfall totals through most of Saturday. That is not to say it won’t rain hard at times, and streets may briefly flood. But for the most part I don’t expect mobility to be greatly impaired. If this forecast changes, we will of course be all over it.

Now, looking ahead to the period of Sunday through Wednesday, uncertainty in the track forecast reigns. We’ve hammered this point for a couple of days, but the point remains that we can’t be sure where the storm is going to go after it reaches the coast. It’s like putting a bowling ball down in the middle of an alley—where will it roll? Harvey is going to be something like that. And unfortunately, for us to really get a good, solid handle on rainfall, we ultimately need to know where the center is going to go. Perhaps the best way to handle this is to spitball some probabilities. So let’s discuss three different scenarios.

The Euro special

Odds: 40 percent. Earlier today we discussed the European model solution for Harvey, which brings the storm into the Texas coast, stalls it, then pulls it back over the Gulf of Mexico and eventually into southwestern Louisiana. Under such a scenario, depending upon the track, much of the Houston area would likely get 5 to 25 inches of rainfall, with the greater totals closer to the coast.

The wandering 59 special

Odds: 35 percent. This solution is favored by many members of the GFS model ensemble, in which Harvey comes inland, and wanders around Corpus Christi, and the rest of the Valley until Sunday or Monday. Then it moves up the Highway 59 corridor, into Houston, over Beaumont, and off into Louisiana. Such a scenario would likely bring 10 to 25 inches of rain to much of the Houston metro area, but totals might not necessarily be greatest along the coast.

Dying in the Rio special

Odds: 25 percent. Not all of the GFS ensembles pull Harvey back to the north. Some stay in south Texas and peter out. NOAA’s new hurricane model, the HMON, has depicted such a scenario over the last few runs, too. The HMON forecasts that Harvey’s remnants burn themselves out in northern Mexico and southern Texas. Under this scenario Houston might get 5 to 10 inches of rain from Harvey—a lot of rain, but certainly manageable. If this happens, amore than a few people will be mad at meteorologists for having stood in line at grocery stores today, and now what they heck are they going to do with all these Pop Tarts?

Key takeaways

  • A major hurricane is coming to the Central Texas coast. It will have bad consequences for that region. However the best available data as of Thursday night suggests the immediate impacts on Houston won’t be extreme.
  • The unanswered question is what happens to Harvey once it reaches the coast. Where will it go, and will it go fast enough? Houston’s rainfall totals over the next five days depend on this, and we just don’t know.
  • Big-time floods are coming to Texas. Certainly the Corpus Christi area and points immediately north and west of there will get too much rain. Flooding will spread to other parts of Texas too, quite possibly Houston. But right now we can’t say that for certain. As I’ve said, it’s either going to be pretty bad, or really really bad here.

We’ll have a comprehensive update early Friday morning.

Posted by Eric at 8:15pm CT on Thursday by Eric

87 thoughts on “Harvey late night: Some final Thursday thoughts

  1. Hal D

    You got any insight into San Antonio rainfall from this? Or someone who does work as good as yours for that area?

    1. Eric Berger

      I can’t speak about and specific site, although one day I’d like to expand to central Texas, including San Antonio.

      Right now we can’t rule out 5-15 inches of rain in San Antonio, but again this is highly dependent upon the track forecast. Which remains very iffy.

      1. Jaynie Leija

        Thank you so much for the update on Harvey , I have a lot of family in Corpus Christi and my 2 daughters in San Antonio. They don’t like to worry me so its always nice to know what is going on .

  2. Dana

    Are you expecting serious delays for Sunday morning flights out of Hobby? Or serious flooding in that vicinity?

  3. DF

    Great info as always. Your efforts to keep us informed with data-driven conclusions and a minimum of drama are much appreciated.

        1. Eric Berger

          It was pushing 9pm. I’d been up a long time. And was halfway into a glass of Cabernet. Couldn’t be helped!

          1. Josh

            I’m so used to Reddit – wanted to upvote each of the comments on this thread!

            On a serious note, thank you, Eric, for your hard work!! Much appreciated and I try to share this page with anyone who’ll listen!

  4. Emily

    Eric –
    Thank you for having such a sane presentation of the information regarding our area’s weather.

    We used to go to the NOAA site and look at Doppler radar locations around the US. Do you happen to know if those still exist in the NOAA site someplace? We looked and haven’t been able to find them.

  5. Oscar Ram

    Eric, just curious, how much rain per day is manageable by Houston’s bayous system? Is it 6 inches per day? 10 inches? How much does it take to saturate the system?

    1. Eric Berger

      I’ll go with 5 inches per day, and 15 inches over four days, as a threshold for widespread flooding. That is a guess, however.

  6. G.M.

    Thank you for this. I guess essentially what you’re saying is that at this point, there is a great deal of uncertainty about Harvey’s track once it makes landfall, and it would be pointless for you to estimate rainfall totals in specific neighborhoods until the track becomes more clear. So, readers of your blog should check back for updates, listen to their local emergency management officials and prepare for significant rain, wind and storm surge with the hope that nothing unmanageable presents itself?

    1. Eric Berger

      Brilliantly put. I mean, Harvey is absolutely going to flood a major part of Texas. It is not 100 percent clear to me that that includes Houston at this time.

  7. Janette Larson

    If the Rio special occurs, people should just keep those Pop Tarts ( and other less perishable stuff) for next time. The season still has a ways to go.

  8. Penny

    What is the likelihood of the storm spawning tornadic activity in the Houston area? Information I’m seeing other places online is contradictory on the topic.

  9. Scott

    Thanks for the great work, as usual. What needs to happen to offer greater certainty in the forecast, and is there a time when you expect that information will become available?

  10. Eric Wilson

    Great information. All we can do is hope. Meanwhile, have you ever seen a storm as unpredictable as this one? It seems to just be wandering aimlessly.

  11. Armando D.

    Thank you Eric for your words today. My dear Fulgencio and I will have our peaceful night tonight and eagerly await seeing what comes next. We are prepared with water and food and other necessities we need and have you to thank. Ciao!

  12. Kris Volk

    As always we appreciate all you guys do for us in Houston to make sure we get the best weather forecast any where. You guys stay safe and do what you do to keep us informed.

  13. Juan Septien

    Thanks again for all the good guidance on this kind of events. My question is relative to the rain totals and how the effects of Harvey could be compared, for instance, to those of the Labor Day 2015 flood?

  14. Jake

    Not the new we want, but it’s what we need. Keep us posted, we all appreciate the work you’re doing.

  15. Christa

    Thank you so much for your service. It is helping stay inordinately calm. I truly appreciate it. You’re a great writer.

  16. Terrie

    Thank you for your consistent information without all the hype and fear. I will always appreciate the straight forward information you provide.

  17. Lisa Paffel

    Eric, the work you’re doing is unbelievable. I can’t tell you how many other news and weather sites I’ve seen today calling this “the most devastating hurricane Houston has seen in a decade” or “more devastating than Allison.”

    I like the facts, and the likely scenarios. What you give is truly hype-free. I love that you spend so much time and effort making sure your fellow Houstonians know the truth, and are prepared for what’s going to come.

      1. Brigitte Dauwalder

        I agree!! As a scientist myself I so appreciate that you provide information and discuss scenarios based on the available data!! And present them in a clear and coherent way!

  18. Lindsey

    Could you be more specific of what you expect in the Ft. Bend county area? We are not used to flooding as much, even with a lot of rain, but we are much closer to the action than say downtown