ATL: LAURA - Post-Tropical - Discussion

[tolakram]

saved loop

[Shell Mound]

Personally, even if Laura manages to deepen substantially in the Gulf of Mexico, I think storm surge will be a greater threat than wind. It is clear that land interaction and strong wind shear, along with some mid-level dry air, has resulted in a tilted structure with a broad pressure gradient. In fact, Laura rather closely resembles hurricanes Ike (2008) and Isaac (2012) in this respect, and is not situated too far from the onetime positions of those storms. While several models do show substantial pressure drops in the GoM, soundings seem to indicate rather dry mid-level air will persist, and given the lack of a well-defined inner core, the environment suggests that Laura’s winds should struggle to “catch up” with any future decrease in central pressure, despite relatively lower wind shear and decent SSTs in the GoM. Therefore, I would suggest that the greatest threat to SE TX/SW LA is not wind or even rainfall, but a potentially devastating storm surge due to Laura’s sprawling fetch, angle of approach, and low pressure. Think Ike, Katrina, Sandy, et al. At this point I’m becoming quite skeptical of Cat-5 or even Cat-4 peak winds in the GoM, even if the pressure manages to dip into the 940s or even 930s. So I do believe that the threat of high winds is being greatly overestimated and that people are overlooking the threat of storm surge. As far as wind is concerned, I’m thinking high-end Cat-2 or low-end Cat-3, but with a pressure much lower than the winds would normally imply.

[SoupBone]

Personally, even if Laura manages to deepen substantially in the Gulf of Mexico, I think storm surge will be a greater threat than wind. It is clear that land interaction and strong wind shear, along with some mid-level dry air, has resulted in a tilted structure with a broad pressure gradient. In fact, Laura rather closely resembles hurricanes Ike (2008) and Isaac (2012) in this respect, and is not situated too far from the onetime positions of those storms. While several models do show substantial pressure drops in the GoM, soundings seem to indicate rather dry mid-level air will persist, and given the lack of a well-defined inner core, the environment suggests that Laura’s winds should struggle to “catch up” with any future decrease in central pressure, despite relatively lower wind shear and decent SSTs in the GoM. Therefore, I would suggest that the greatest threat to SE TX/SW LA is not wind or even rainfall, but a potentially devastating storm surge due to Laura’s sprawling fetch, angle of approach, and low pressure. Think Ike, Katrina, Sandy, et al. At this point I’m becoming quite skeptical of Cat-5 or even Cat-4 peak winds in the GoM, even if the pressure manages to dip into the 940s or even 930s.

Great summary and thoughts. But for the record, Ike put over 3 million in Houston without power, some for over a month. There were widespread power outages.

[tiger_deF]

I really think this is a wait and see situation. I've seen developed storms and invests that have looked better than Laura get shredded over the same areas of land she has managed to survive over, while there is some residual dry air, OHC content from now until landfall are some of the highest in the world

[Shell Mound]

Personally, even if Laura manages to deepen substantially in the Gulf of Mexico, I think storm surge will be a greater threat than wind. It is clear that land interaction and strong wind shear, along with some mid-level dry air, has resulted in a tilted structure with a broad pressure gradient. In fact, Laura rather closely resembles hurricanes Ike (2008) and Isaac (2012) in this respect, and is not situated too far from the onetime positions of those storms. While several models do show substantial pressure drops in the GoM, soundings seem to indicate rather dry mid-level air will persist, and given the lack of a well-defined inner core, the environment suggests that Laura’s winds should struggle to “catch up” with any future decrease in central pressure, despite relatively lower wind shear and decent SSTs in the GoM. Therefore, I would suggest that the greatest threat to SE TX/SW LA is not wind or even rainfall, but a potentially devastating storm surge due to Laura’s sprawling fetch, angle of approach, and low pressure. Think Ike, Katrina, Sandy, et al. At this point I’m becoming quite skeptical of Cat-5 or even Cat-4 peak winds in the GoM, even if the pressure manages to dip into the 940s or even 930s.

Great summary and thoughts. But for the record, Ike put over 3 million in Houston without power, some for over a month. There were widespread power outages.

https://i.imgur.com/65EkLuz.png

Yes, I’m certainly not downplaying either Ike or Laura. But a repeat of Ike is far better than a repeat of Carla. Similar size, stronger winds → much higher surge.

If this comes in as a large Cat-2 or low-end Cat-3, storm surge will be devastating, owing to the large size of the wind field, but nothing compared to HWRF runs.

[eastcoastFL]

[aspen]

Laura is approaching her final major challenge before entering the Gulf: the western tip of Cuba. The mountains there aren’t as tall as the ones she passed over last night, so odds are the core won’t be as damaged.

[tolakram]

In my opinion I don't see very many similarities to Ike. Ike was a large strong hurricane going through an eyewall replacement cycle when it struck Cuba and never recovered. Stuck in the ERC was a term thrown about a lot. Laura doesn't have a distinct core to get disrupted.

I think the main question is just how good conditions will be in the gulf. I know we've been told this season has excellent background conditions, and it does, but there's always areas of marginal conditions the models sometimes fail to pick up on, which drives a lot of people here crazy. Right place right time ... or maybe better described as wrong place wrong time for intensification.

Prepare for the worst, hope for the best.

[USTropics]

Pressure continuing to fall, down to 999mb on last pass:

[HoustonFrog]

My wife and two kids are ditching town first thing in the morning unless something changes in the next 20 hours. We live in Houston proper

[sponger]

My wife and two kids are ditching town first thing in the morning unless something changes in the next 20 hours. We live in Houston proper

Could be an absolute zoo. I know many people are uncomfortable leaving at night but it is often better than sitting in stopped traffic for the day.

[MississippiWx]

Laura has the look of a developing typhoon in the Western Pacific. Large storm that just won’t weaken. Once it’s over the Gulf, it’s game on. The west shifts in the models are not good. More west = more water time.

Since Laura has consistently been south of forecast track, I feel a landfall near Houston is more likely. Just my opinion. It doesn’t look pretty regardless.

[Shell Mound]

 https://twitter.com/pppapin/status/1297892484366950401



 https://twitter.com/yconsor/status/1297842405736091649



 https://twitter.com/webberweather/status/1297816408852762624

[TheStormExpert]

 https://twitter.com/derekortt/status/1297891450932396033

[HurryKane]

My wife and two kids are ditching town first thing in the morning unless something changes in the next 20 hours. We live in Houston proper

Could be an absolute zoo. I know many people are uncomfortable leaving at night but it is often better than sitting in stopped traffic for the day.

Almost every time I have evacuated it’s been in the dead of night and it was much easier than daytime evacuations. Then again I don’t have kids, etc. to wrangle.

[HoustonFrog]

My wife and two kids are ditching town first thing in the morning unless something changes in the next 20 hours. We live in Houston proper

Could be an absolute zoo. I know many people are uncomfortable leaving at night but it is often better than sitting in stopped traffic for the day.

Think tomorrow morning is too late?

[ThunderSleetDreams]

City of Houston has called a 1 pm PC with the mayor and judge.

[Kazmit]

Laura looks like a comma this morning. I don’t think it will intensify too much until it gets into the GOM as it looks like Cuba is keeping it in check. The structure looks favorable for strengthening at that point as it has a well defined LLC.

[Crackbone]

My wife and two kids are ditching town first thing in the morning unless something changes in the next 20 hours. We live in Houston proper

Could be an absolute zoo. I know many people are uncomfortable leaving at night but it is often better than sitting in stopped traffic for the day.

Think tomorrow morning is too late?

Long time lurker, seldom a poster. I've been through evacs. The earlier you pull the trigger the better. At worst you have a nice little vacation away from home. At best you avoid the mayhem and inability to move. Ofc, we all have to make the best decisions for our given situations, but usually I have found the earlier you make a decision on what you're going to do, the better (whether that's staying and riding it out or going)

[plasticup]

More west = more water time.

And bigger population centers with longer evacuation times. Bad combo.