For Houston and Texas, the rains cometh. But where?

As of 2:30pm CT, Harvey remains a depression in the southwestern Gulf of Mexico. We remain most concerned about the potential of this tropical system to drop a prodigious amount of rain from Friday through Tuesday or Wednesday of next week, primarily due to the fact that it will likely stall, or nearly so, once it moves into Texas this weekend. Let’s jump into the forecast.

Harvey track and intensity

The depression remains fairly poorly organized this afternoon, and that’s a good thing, because once it begins to develop a tightly organized circulation, there will be little to inhibit from strengthening further. The official forecast calls for a 75-mph hurricane to make landfall along the Texas coast Friday afternoon. It’s worth noting that the models (including the European forecast system) have shifted a bit to the left, meaning that a landfall between Brownsville and Corpus Christi now seems most probable. That may be good for the Houston region in terms of storm surge, but as we’ll see, it may matter little in terms of rainfall.

The GFS model ensembles are clustered between Brownsville and Corpus Christi. (Weather Bell)

Rainfall, and timing

Please note that the following is speculative, but we’re attempting to affix a time frame to this storm and its effects because we’ve had a lot of travel questions. The following forecast assumes a Friday landfall along the south Texas coast, and therefore the forecast is subject to change. You have been warned.

A south Texas landfall means that, initially, the heaviest rainfall will come over that region, between Brownsville and Corpus Christi, and in the Valley region. For example, through Saturday, it seems likely that while 5 to 10 inches of rain may have fallen over south Texas, the upper Texas coast, including Houston, may only see 1 to 3 inches of rain.

Unfortunately, this is not a conventional tropical cyclone that will move inland and slowly die. Because the steering currents will weaken after Harvey runs into high pressure over west Texas, it’s likely to eventually get pushed east, perhaps toward Corpus Christi, or even southeast. At that point it may move back over the Gulf of Mexico, or ride up the Highway 59 corridor into the Houston area. The European forecast track, shown below, highlights this erratic movement. The bottom line is that the low pressure system will likely remain near the water, and have access to warmth and moisture needed to fuel heavy rain showers over several days.

European model operational track suggests Harvey will ramble. (Space City Weather)

Accordingly, for now, we don’t anticipate any really heavy, flood-causing rain showers occurring in Houston until Sunday, and they may not arrive until Monday. This all remains dependent upon the track that Harvey follows once inland (this weekend) and then as it moves back toward the east. This will determine the placement of the heaviest showers. Unfortunately the track forecast is likely to change over the next few days, and so will our forecast.

One thing is crystal clear, however. Harvey is going to pack a really potent punch of moisture. It is going to bring widespread areas of 10 to 15 inches over several days to Texas, and within those areas some locations are likely to see 20 inches or more. Most of the current model guidance shows 15 to 20 inches of rain over Houston from this storm, and even spread over several days this would cause significant flooding. I am hesitant to fully buy into that, because the track of Harvey is so uncertain.

Therefore I would be personally skeptical of any rainfall total forecasts at this time for your location. If you live near the coast in Texas, simply know that it’s either going to bad, or really, really bad between Friday and Wednesday.

Later today we’ll have an update with all you need to know about inland flooding caused by these kinds of storms, along with tips for preparation, and evacuation questions.

Posted at 2:40pm CT on Wednesday by Eric

79 thoughts on “For Houston and Texas, the rains cometh. But where?”

  1. Thank you again for no theatrics and just telling it to us straight.

    That being said, I have to drive up to San Antonio this Friday morning, then Austin Friday night, and won’t be back till Monday evening.

    Should I skip this or just wait until Thursday night to make a judgement?

    • Phew. Tough call. I’d try to wait until Thursday to make a judgment call. Drive up should be OK, but not sure about coming back.

  2. Is this the sort of thing that might delay air travel coming back into Houston over the weekend? Flight in on Sunday morning. Obviously not looking for a firm answer- just if these sort of storms make the planes run slow 😊

      • What about flying out of IAH Monday afternoon? And getting to IAH from heights?
        Would it be best to stay Sunday night near airport?

        • Weather conditions for Monday are going to be difficult to forecast, sorry. I don’t think staying near the airport would help. If it’s bad enough to not be able to drive, your flight will probably be canceled.

        • What about if way more people try this than can be accomidatet. What if the weather is so bad they ground all flights.
          Just an old pilot with over ten thousand hours in command thought.

          Just get out a day or two of procrastination could kill you.

  3. Your weather report is the first one I check. Thanks so much for your dedication!

  4. Hoo boy. Eclipse on Monday, TS/Hurricane Friday, cicadas are close enough to locusts… Anyone have an infestation of frogs or see water turned to blood?

      • What about if way more people try this than can be accomidatet. What if the weather is so bad they ground all flights.
        Just an old pilot with over ten thousand hours in command thought.

        Just get out a day or two of procrastination could kill you.

      • Come here. At night you can hear hundreds of frongs all night. Turn on a light and look at the windows at night. Usually a few tree frogs on them. Oh be careful at night and don’t step on the little critters.

  5. If system does make landfall between Brownsville & Corpus what if any impact on rainfall totals in central Texas may occur? Specifically Marble Falls

  6. Thanks Eric
    What in your opinion can be the very best scenario for Houston?, since we already got an idea about the bad one….
    Thanks again

  7. supposed to be flying out of Hobby airport Sunday morning, should we try to get an earlier flight? Live on the NW side of Houston

  8. Thank you for straight information. I can make my own choices with your information, Montgomery, TX

  9. Thank you for keeping us updated without drama and hype, just the correct information.

  10. Being in SE Houston (Clear Lake) I’m concerned that by the time the severity of the potential flooding is determined, it’ll be too late to do much but tread water, literally. Is there any sort of metric we have to guessimate how long the floodwaters might stay, if indeed we are flooded? How fast does the area tend to drain? I realize that if we have rains to our north, that our water could drain off only to be immediately replaced by southward traveling floodwaters. The maps I’ve seen seem more oriented toward hurricane rather than a purely (or nearly so) heavy rain event (even if it’s of a tropical nature) over several days.

    • Flood waters drain quickly after the storm passes. So within 12-24 hours most roads should be clear. The problem is, the storm may not pass for a few days 🙁

  11. How does it look for flying out Houston Saturday morning ? Thanks for the hype free reporting !

  12. Do you think flights out of IAH will be okay Friday evening? Or should we fly out of Dallas instead?

  13. So what affect if any do you think the approaching cold front for Houston will have on the storm

  14. Based on the current forecasts (which I understand are subject to change), can you compare the potential flooding impact on Houston to Ike? Does this have the potential for longterm widespread power outages? I’m concerned about my parents, who are getting older, enduring days on end without electricity in this heat.

  15. If I’m supposed to fly out of Hobby Friday noon and come back Sunday at 9pm, I run a pretty fair risk of being stuck out of town for some days, don’t I? My petsitters are already hedging their bets (aka they may not show up). I’m thinking I should call my game on account o’ rain.

    • Hmmm. Sunday flight probably gets through, but it may be delayed. But if you’re worried about your pets being left in the lurch that may decide it for you.

  16. I have a flight out of Hobby on Friday evening – would it be worth trying to change it to earlier?

  17. Your forecasts are the best, Eric. I’m trying to decide what to do: I have a flight back into Hobby on Sunday around 1pm. Think the heaviest rain stays away long enough? Or should I move that to 9am Sunday morning?

  18. We have a trip planned to NOLA, leaving Friday morning and heading back to Houston on Sunday. Any forecast on the impact of Harvey on NOLA for the weekend? Also, concern about making it back into Houston on 1-10?

    • I’d still tentatively plan on going. I think the Sunday drive back will be manageable, but I’d want to check the forecast Friday before I left.

  19. We live in West Pearland. Should we consider evacuating or would that be a little drastic?
    I don’t trust the news and all their hyperbole.

  20. We are flying into Houston tomorrow morning and driving to Alvin and then have a wedding in Pearland Friday evening. We fly out Sunday morning. Should we be concerned? Flooding in the area? Airport shutting down? Etc?

  21. Eric – flying to Monterrey, México on Friday at around 5pm from IAH. do you think I will be ok? Do you think there is any chance Monterrey could get hit? Thank you so much for your coverage of the storm

  22. I’m flying out of IAH on Tuesday. Any thoughts on whether we’ll be ok, or is it too early to tell? I’m new to this site and very impressed. Thanks for the diligent and well-communicated info.

    • No promises about Tuesday. If the heavy rains come to Houston, that will probably be the worst day.

  23. We are flying to Italy out of IAH on Friday at 4:40 on a big plane. Should we reschedule?

  24. Hi Eric,

    In the scenario where the heavy stuff doesnt hit Hou until late sun / early Mon, what would you expect in Galveston on Saturday? Steady rain or will the system not reach that far?

  25. Thanks Eric for the straight-forward and level-headed information! So glad you are continuing to provide Houston with your expertise!

  26. We have plans to drive to New Braunfels early Friday afternoon and head back Monday afternoon. With all the flooding concerns, we are considering postponing our road trip. How will the tropical depression effect the New Braunfels area and roads heading there from the Houston area? Should we postpone at this point? Thanks!

  27. I have a flight out of Hobby on Sunday night. I would really rather not have to move it but if I do, would you recommend Sunday morning or Saturday or even Friday?

  28. Thanks for all your helpful info. I have family members who just moved to the Corpus Christi area and are very new to this weather. I’m feeling pretty prepared up here in Houston but worry about them. With your knowledge and research can you give me some outlook on that area? Is their biggest problem flooding too? Or hurricane issues? Thanks!

    • Flooding, winds, and surge will all probably be a problem in Corpus. I’ll have an update later this morning that addresses these issues.

  29. Thanks for your insight!

    We’re supposed to be leaving on a cruise Sunday from Galveston. We live in Austin and are trying to determine travel plans. Our dogs will be staying with friends in NW Houston so we must go through there before Galveston. Originally planned to leave Saturday for Houston and drive to the port in Galveston on Sunday. Now, we’re rethinking—drive into Houston Friday night and Galveston Saturday. We’re trying to minimize bad road conditions and traffic. Which makes the most sense?

  30. Eric, I hope you’ll update in the morning! We’re scheduled to fly back to IAH from Montrose CO on Monday (small regional jet) and wondering if we should come home early. And if so, how much earlier.

  31. We’re supposed to drive to Dallas Friday night and come back to Houston Saturday night. Does it look like the Saturday drive back could be a problem?

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