Hurricane Harvey: 2017 Central Texas Coast

[Steve Miller]

Thunderstorms are beginning to redevelop near the estimated center. Rather rapid development into a tropical storm is expected during the next 36 hours. A continued northwest track toward the central Texas coast is forecast through Friday. More rapid intensification is expected on Thursday and Friday as Harvey approaches Texas. Current indications are that Harvey will pose a major threat for excessive rainfall and significant inland flooding over portions of Texas Friday through Monday. It is worth noting that Harvey will move slowly over Texas this weekend and may end up moving back over the northwest Gulf early next week resulting in a threat for re-development.

 

[Joerg Kachelmann]

This would be landfall according to the new ECMWF 12z - other parameters via menu, to zoom out use (-), click to zoom in, for pan click into edges. Time zone and units via gear icon top right

https://weather.us/model-charts/euro/951-w-261-n/sea-level-pressure/20170825-2100z.html

Accumulated ECMWF rain until Monday noonish

https://weather.us/model-charts/euro/953-w-320-n/acc-total-precipitation/20170828-1500z.html

 

[MClarkson]

Some of these potential rain totals are massive. Stalled or slow-moving remnants look like the overriding concern from this one. Shades of Allison?

 

[Steve Miller]

The latest from our meteorologists here at WDT:
Tropical Depression Harvey has redeveloped within the northern Bay of Campeche and is forecast to track to the north-northwest towards the southeastern coast of Texas. Over the next 48 to 60 hours, Harvey is forecast to make landfall as a tropical storm with a chance to become a hurricane prior to landfall. Beyond 60 hours, a complex steering environment will be in place leading to Harvey becoming somewhat stationary. The long term forecast track remains uncertain. What does remain certain is the potential for excessive rainfall along the coast of Texas leading to flash flooding and flooding.
http://www.weatherops.com

 

[Steve Miller]

Looks like things are beginning to get underway along the coast, preparation-wise.

Now we wait and watch for the model solution that makes the most sense. Nearly all agree on a stall when it reaches the coast.

 

[Warren Faidley]

Likely not chasing this one due to several factors: There will not be a lot of time for the storm to pile up a decent storm surge. The right front quad will likely (if the current forecast verifies) come inland between Corpis and Galveston, in an area that is not favorable for chasing. Timing is difficult but it appears to be a night falling storm. Agree with others that flooding could be a life threatening event.

 

[Steve Miller]

Rainfall totals in the Houston area across models and then given a weighted average:


Interesting fact. The ### you see for the 12z GFS is 11.84 inches. Our table didn't have the capacity... The 24" rainfall estimates are a thing.

 

[Randy Jennings]

Shades of Allison?

I was thinking the same thing. Despite "just" being a tropical storm and not a hurricane, Allison is the 14th most costly Atlantic storm and ranks right up there with all the major Cat 4 and 5 storms. My grandmother lived in NW Houston at the time, and the damage in her area was far worse from Allison than any hurricane during the time she lived there. I went back and did some reading on Allison, and several of the models have Harvey taking a similar track (a loop) and the slow moving aspect is certainly similar. However, from what I read it sounds like there was a high pressure system closer to the north of Allison that what the models are projecting for Harvey. I also read that with Allison a "subtropical ridge off Florida weakened, while the ridge west of Texas intensified." I haven't seen a strong indication of that with models for Harvey. I wish the WPC surface analysis archive went back that far. I'd be curious to see if anyone else say any strong (or not strong) correlations to Allison.

 

[cstrunk]

Harvey is now a 986 mb, 60 mph Tropical Storm. Rapid intensification overnight. It will be interesting to see if this kind of strengthening can keep up, and for how long...

 

[Bart_Comstock]

Very impressive sat image to wake up to this morning. As mentioned above Harvey 's pressure fell to 986 mb per the Hurricane Hunter's findings (EDIT: DOWN TO 982 mb AS OF 10AM!). Very warm SST and little in the way of shear ahead of Harvey should allow the rapid intensification to continue. Sat scans this morning show that an eyewall is rapidly forming as the CDO gets better organized. It also shows that Harvey is a pretty large storm and the forming eye is in relation small, I imagine that the NHC will account for this in later outlooks and get very bullish in their late day advisories. To add to this, the SHIPS Rapid Intensification indices are incredibly high. It shows a 70% chance the winds in the storm will increase 45kts in the next 36 hours.

I would not be surprised to see it make landfall as a major Cat 3. I also imagine the NHC will be getting more bullish with its advisories today. It's not been since 2008 that Texas has had a landfalling cane, and even longer for the area to be impacted. Let's hope they heed the warnings. When you combine the fact that Harvey will be a major hurricane AND will stall with noah's flood like rainfall rates I imagine this storm can surpass the damage done by Allison and Ike.

Interesting and slightly related note, today is Andrew's 25th anniversary of his landfall.

 

[Warren Faidley]

Wow. I won't re-post the latest NHC discussion regarding Tropical Storm Harvey (10AM 8-24-17) but they are predicting a major hurricane by landfall.

 

[MClarkson]

In addition to the stronger satellite presentation, every model's overnight runs are much stronger. New 12z guidance in shortly though. Good agreement on a stalled or slow moving system after landfall...

 

[MClarkson]

12Z GFS continues to show rapid strengthening up to landfall... as do the NAMs. I trust the NAM flavors a bit less for tropical systems, but some of that might be my old bias from the old eta core.

 

[Steve Miller]

A beautiful satellite image:

See it for yourself as Harvey evolves: http://bit.ly/2vjk8l8
Also, here is something interesting. Check out the loop after landfall. Our mets here are beginning to lean toward a solution that takes Harvey back offshore and potentially seeing him make a secondary landfall in LA.

 

[Bart_Comstock]

I have been looking at that too Steve. One interesting thing will be to see how much the upwelling from the storm affects the SST and how much Harvey re-strengthens when he moves back out to sea. Another thing to consider is how slow the storm will grind over the Corpus area with its eyewall winds as it stalls and turns back around. If it doesn't make it as far inland as forecast you could see really powerful winds grind down on the area it hits, especially if the more bullish runs are to be believed and this storm makes it to Cat 4. The Yucatan couldn't kill it, Texas likely won't kill it, is there anything that can stop the dreaded "ZOMBIE STORM?!?!?!?!" (I just got an idea to pitch to Scifi Channel. Maybe even a Sharknado/Zombiecane cross over? Hmmmm.... October is almost here!)