ATL: HARVEY - Post-Tropical - Discussion

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Re: ATL: HARVEY - Tropical Storm - Discussion

#6101 Postby NDG » Sun Aug 27, 2017 3:54 pm

Meteorcane wrote:
NDG wrote:
Sanibel wrote:


Is that confirmed? Maps were showing 25 inches for that area just a few hours ago...


Both Lake Charles Radar and Houston radar show nearly 50" of rain since Thursday.



Single-pol storm totals are probably inflated because they are purely using a tropical Z-R when some of the more intense precip yesterday was more convective in nature (e.g. containing large drops from melting hail and graupel) rather than the warm-rain process precip usually associated with tropical cyclones. I would trust the Dual-pol storm total (e.g. the digital storm total product on radar scope) more in this situation since it can use ZDR, KDP estimators.


I always thought that if anything radars do no justice to tropical rains, which are much heavier than what radar show a lot of times.
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6102 Postby tolakram » Sun Aug 27, 2017 3:55 pm

 https://twitter.com/DavidBernardTV/status/901909588806651912




David Bernard ✔ @DavidBernardTV
Before & After: Flooding on Buffalo Bayou in Houston https://youtu.be/7Saq_ZYPS40 via @YouTube @ericblake12 @spann @fox8nola
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6103 Postby wxman57 » Sun Aug 27, 2017 3:56 pm

I'm still dry. Measured 20" so far, 12" since midnight. Below is the view from my driveway, taken at 11am. Water went down some since then. Nowhere close to getting into the house. Lots of friends around the city have flooded. Just talked to my friend and former co-worker Larry Gregory, president of the Lone Star Flight Museum (grand opening at Ellington this weekend) and his home flooded, along with his 80 year-old mother's home. Museum is dry. Rain may focus on the east side of Houston tonight then quickly shift east of Galveston Bay and move into Beaumont to Lake Charles overnight.

http://wxman57.com/images/Street.JPG
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6104 Postby ScottNAtlanta » Sun Aug 27, 2017 3:57 pm

tolakram wrote: https://twitter.com/DavidBernardTV/status/901909588806651912




David Bernard ✔ @DavidBernardTV
Before & After: Flooding on Buffalo Bayou in Houston https://youtu.be/7Saq_ZYPS40 via @YouTube @ericblake12 @spann @fox8nola

That is a tremendous amount of water
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6105 Postby GCANE » Sun Aug 27, 2017 3:57 pm

Image

Mesoscale Discussion 1587
NWS Storm Prediction Center Norman OK
0307 PM CDT Sun Aug 27 2017

Areas affected...portions of southeastern Texas...southwestern
Louisiana...and adjacent coastal waters

Concerning...Tornado Watch 471...

Valid 272007Z - 272200Z

The severe weather threat for Tornado Watch 471 continues.

SUMMARY...The tornado threat continues across WW 471.

DISCUSSION...The general regime supporting occasional tornado
activity remains in place. Although stronger buoyancy remains
mostly offshore and along immediate coastal areas, scattered bands
and cells within the Watch area are continuing to exhibit occasional
rotation and result in a threat of brief tornadoes. Harvey remains
nearly stationary, and this regime should continue well into the
evening hours and through the remainder of the Watch (07Z).

A brief lull has been noted in convection across a large part of
southwestern Louisiana. Previous convective overturning has
resulted in slightly cooler surface temperatures (around 73-75F) and
stratiform precipitation/cloudiness is currently limiting
destabilization. However, additional rotating convection off the
coast just south of this region will approach within the next hour
or so, and southeasterly low-level flow may lead to advection of
more buoyant air into this region and potentially result in an
increasing tornado threat returning to that region over the next 1-2
hours.

..Cook.. 08/27/2017
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6106 Postby ScottNAtlanta » Sun Aug 27, 2017 3:58 pm

wxman57 wrote:I'm still dry. Measured 20" so far, 12" since midnight. Below is the view from my driveway, taken at 11am. Water went down some since then. Nowhere close to getting into the house. Lots of friends around the city have flooded. Just talked to my friend and former co-worker Larry Gregory, president of the Lone Star Flight Museum (grand opening at Ellington this weekend) and his home flooded, along with his 80 year-old mother's home. Museum is dry. Rain may focus on the east side of Houston tonight then quickly shift east of Galveston Bay and move into Beaumont to Lake Charles overnight.

http://wxman57.com/images/Street.JPG

Is that because the water simply cant drain fast enough or are you close to one of the creeks or bayous?
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6107 Postby WeatherGuesser » Sun Aug 27, 2017 3:59 pm

Based on radar motion only, CoC looks to be between Victoria and Edna
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6108 Postby artist » Sun Aug 27, 2017 4:00 pm

From galvnews.com

Update, 3:41 p.m.

Friendswood had imposed a curfew starting tonight at 10 p.m. until 6 a.m., the city said in a Twitter post. There was no immediate word about how long the curfew will continue.

The city also reassured residents that the city's drinking water was safe and plentiful.

Update, 1:34 p.m.

Texas City ISD will be closed through next weekend. Schools will reopen Tuesday Sept. 5, Director of Communications Melissa Tortorici reported in an email.

Update, 1:29 p.m.

Galveston Sheriff Henry Trochesset is helping what he calls the "Texas Navy" at FM 517 and Interstate 45 in Dickinson.

Emergency responders and volunteers are using a fleet boats to go east into Dickinson and retrieve people from flooded homes, Trochesset said.

Trochesset said between six and eight school buses had been filled. Evacuees were sent to shelters in Hitchcock and Santa Fe, Trochesset said.

"Right now, pretty much the whole city is under water," Trochesset said of Dickinson.

Operations on the highway have been going since 9 a.m., he said. They will go as long as people are requesting evacuations.

Update, 12:24 p.m.

Clear Creek ISD will be closed through Friday. Schools will reopen Sept. 5, district staff said.
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6109 Postby Tarahh1 » Sun Aug 27, 2017 4:00 pm

Hello all. First time poster - but I've been glued to this forum since Friday. You have been my source of real understanding of the storm. I learned a lot from y'all and also got introduced to Jeff and his time in Rockport Friday night.

I am a resident of Katy TX and I am trying to find out what the next few days hold and the news is more focused on what has happened - which is certainly epic- but not so much of what's to come. We are now getting intense bands of rain again and tornado warnings again. I know this will be the case today and certainly tomorrow. Is The storm really going to head back into the GOM and restrengthen and come back and dump more? Maybe even CAT1 strength? I just can't believe that to be true. We are NW of the city but got close to 18 inches already and I can't even think what more would do to Houston. Can you all give me your thoughts on what you think will happen starting tomorrow?

I can't thank you all enough for your amazing insight. You've helped me help a tremendous amount of people who count on me to make the right decisions that impact their safety.
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6110 Postby wxman57 » Sun Aug 27, 2017 4:02 pm

ScottNAtlanta wrote:
wxman57 wrote:I'm still dry. Measured 20" so far, 12" since midnight. Below is the view from my driveway, taken at 11am. Water went down some since then. Nowhere close to getting into the house. Lots of friends around the city have flooded. Just talked to my friend and former co-worker Larry Gregory, president of the Lone Star Flight Museum (grand opening at Ellington this weekend) and his home flooded, along with his 80 year-old mother's home. Museum is dry. Rain may focus on the east side of Houston tonight then quickly shift east of Galveston Bay and move into Beaumont to Lake Charles overnight.

http://wxman57.com/images/Street.JPG

Is that because the water simply cant drain fast enough or are you close to one of the creeks or bayous?


I'm 1 mile south of Brays Bayou off Hillcroft. Nothing can flow into Brays Bayou.
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6111 Postby Meteorcane » Sun Aug 27, 2017 4:04 pm

NDG wrote:
Meteorcane wrote:
NDG wrote:
Both Lake Charles Radar and Houston radar show nearly 50" of rain since Thursday.



Single-pol storm totals are probably inflated because they are purely using a tropical Z-R when some of the more intense precip yesterday was more convective in nature (e.g. containing large drops from melting hail and graupel) rather than the warm-rain process precip usually associated with tropical cyclones. I would trust the Dual-pol storm total (e.g. the digital storm total product on radar scope) more in this situation since it can use ZDR, KDP estimators.


I always thought that if anything radars do no justice to tropical rains, which are much heavier than what radar show a lot of times.


Yep you are right usually the high concentrations of small drops cause radars using a Z-r relationship trained on continental convection (which is characterized by smaller concentrations but larger median drop sizes) to underestimate precipitaiton. In this case though the Houston/Lake Charles radars are using the tropical Z-R which is more aggressive, and the convective precip last night was overestimated by this relationship. You can see from this table (https://www.weather.gov/lmrfc/experimental_ZR_relationships what Z-R different radars are using in the region (Houston is HGX and Lake Charles is LCH) you can see they are overestimating a bit.

Thankfully in the dual-pol era we don't have to use set Z-Rs we can use relationships that incorporate ZDR (which is highly correlated to median drop size) and KDP (which is more linearly related to rain rate than reflectivity (Z)).
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6112 Postby ScottNAtlanta » Sun Aug 27, 2017 4:05 pm

wxman57 wrote:
ScottNAtlanta wrote:
wxman57 wrote:I'm still dry. Measured 20" so far, 12" since midnight. Below is the view from my driveway, taken at 11am. Water went down some since then. Nowhere close to getting into the house. Lots of friends around the city have flooded. Just talked to my friend and former co-worker Larry Gregory, president of the Lone Star Flight Museum (grand opening at Ellington this weekend) and his home flooded, along with his 80 year-old mother's home. Museum is dry. Rain may focus on the east side of Houston tonight then quickly shift east of Galveston Bay and move into Beaumont to Lake Charles overnight.

http://wxman57.com/images/Street.JPG

Is that because the water simply cant drain fast enough or are you close to one of the creeks or bayous?


I'm 1 mile south of Brays Bayou off Hillcroft. Nothing can flow into Brays Bayou.


Thats one of the ones pushing at record territory I noticed earlier
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6113 Postby NDG » Sun Aug 27, 2017 4:14 pm

Meteorcane wrote:
NDG wrote:
Meteorcane wrote:
Single-pol storm totals are probably inflated because they are purely using a tropical Z-R when some of the more intense precip yesterday was more convective in nature (e.g. containing large drops from melting hail and graupel) rather than the warm-rain process precip usually associated with tropical cyclones. I would trust the Dual-pol storm total (e.g. the digital storm total product on radar scope) more in this situation since it can use ZDR, KDP estimators.


I always thought that if anything radars do no justice to tropical rains, which are much heavier than what radar show a lot of times.


Yep you are right usually the high concentrations of small drops cause radars using a Z-r relationship trained on continental convection (which is characterized by smaller concentrations but larger median drop sizes) to underestimate precipitaiton. In this case though the Houston/Lake Charles radars are using the tropical Z-R which is more aggressive, and the convective precip last night was overestimated by this relationship. You can see from this table (https://www.weather.gov/lmrfc/experimental_ZR_relationships what Z-R different radars are using in the region (Houston is HGX and Lake Charles is LCH) you can see they are overestimating a bit.

Thankfully in the dual-pol era we don't have to use set Z-Rs we can use relationships that incorporate ZDR (which is highly correlated to median drop size) and KDP (which is more linearly related to rain rate than reflectivity (Z)).


Very nice explanation, thank you.
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6114 Postby 1900hurricane » Sun Aug 27, 2017 4:22 pm

18Z soundings from Corpus Christi and Lake Charles are still supportive of extremely heavy rains.

Image

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Re: ATL: HARVEY - Tropical Storm - Discussion

#6115 Postby Steve » Sun Aug 27, 2017 4:26 pm

Tarrah - hard to say. As you can see from the last couple of days, it depends on where the bands set up. You should follow the radar frequently. It's a given near the center it will rain. Short range models seem to indicate the worst rain in the near term to points north and northeast of the circulation will get the worst the next day or so. If I had to bet, i would think Beaumont and Port Arthur get the worst through noon tomorrow. I'd think Harvey will be back offshore and we will have to take a look at how Day 4 into 5 is going to unfold. Hang in there on the west side.
Last edited by Steve on Sun Aug 27, 2017 4:28 pm, edited 2 times in total.
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6116 Postby SunnyThoughts » Sun Aug 27, 2017 4:27 pm

Barker Reservoir, the flood control reservoir for Buffalo Bayou that flows through downtown Houston is now close to Westminster parkway Hope it doesn't fail. Also saw where an official says every freeway in Houston is under water, yet they are opening the Big arena As a shelter. Sure hope it doesn't end up like the dome in Katrina considering no way to get in or out if all the freeways are under water. Thoughts and prayers to everyone affected. Wish there was something I could do to help, just breaks my heart.
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6117 Postby ronjon » Sun Aug 27, 2017 4:31 pm

Tarahh1 wrote:Hello all. First time poster - but I've been glued to this forum since Friday. You have been my source of real understanding of the storm. I learned a lot from y'all and also got introduced to Jeff and his time in Rockport Friday night.

I am a resident of Katy TX and I am trying to find out what the next few days hold and the news is more focused on what has happened - which is certainly epic- but not so much of what's to come. We are now getting intense bands of rain again and tornado warnings again. I know this will be the case today and certainly tomorrow. Is The storm really going to head back into the GOM and restrengthen and come back and dump more? Maybe even CAT1 strength? I just can't believe that to be true. We are NW of the city but got close to 18 inches already and I can't even think what more would do to Houston. Can you all give me your thoughts on what you think will happen starting tomorrow?

I can't thank you all enough for your amazing insight. You've helped me help a tremendous amount of people who count on me to make the right decisions that impact their safety.


Welcome to Storm 2K! The HRRR high resolution model did well with last nights rainfall in Houston area. Tonight it redevelops heavy bands again over the Houston metro area. I linked the total rainfall the next 18 hours below. I wouldn't concern myself with CAT 1 redevelopment as thats highly unlikely. The system over water will just continue to pump tons of rainfall to the east of it.

https://www.tropicaltidbits.com/analysis/models/?model=hrrr&region=scus&pkg=apcpn&runtime=2017082719&fh=17&xpos=0&ypos=420
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6118 Postby gigabite » Sun Aug 27, 2017 4:31 pm

ScottNAtlanta wrote:
wxman57 wrote:I'm still dry. Measured 20" so far, 12" since midnight. Below is the view from my driveway, taken at 11am. Water went down some since then. Nowhere close to getting into the house. Lots of friends around the city have flooded. Just talked to my friend and former co-worker Larry Gregory, president of the Lone Star Flight Museum (grand opening at Ellington this weekend) and his home flooded, along with his 80 year-old mother's home. Museum is dry. Rain may focus on the east side of Houston tonight then quickly shift east of Galveston Bay and move into Beaumont to Lake Charles overnight.

http://wxman57.com/images/Street.JPG

Is that because the water simply cant drain fast enough or are you close to one of the creeks or bayous?

He is just upstream of Willow Waterhole Greenway Park. It looks like it is designed to handle a 100 year storm. The outflow is looks like it almost a straight shot to Braeswood blvd canal.
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6119 Postby bamajammer4eva » Sun Aug 27, 2017 4:32 pm

Rain is approaching the Biloxi area from this over 400 miles away from the center with very little rain south of the center. Could this transition to subtropical?
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Re: ATL: HARVEY - Tropical Storm - Discussion

#6120 Postby GCANE » Sun Aug 27, 2017 4:34 pm

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