ATL: HARVEY - Post-Tropical - Discussion

[smithtim]

100% this is getting retired. First hurricane to make landfall as a major since Wilma? The sheer amount of flooding this is about to cause? God I can't bear to think about the devastation.

I think the last major landfall in the Atlantic was either Dean or Felix.

Matthew, many times last year

Yes the eyewall brushed the coast just south of New Smyrna Beach and it was 3 at the time (just before made that saving turn). Not a direct landfall but defintley hurricane force winds... I remember since live local and had a rental property at the time in southern New Smyrna Beach right across the street from the ocean = fun clean up, blue tarps on roofs

But I really feel for the people of Texas right now as this one seems to be playing out with direct hit as there is no saving turn for it to make, and regardless of if cat 2/3 the predicted rainfall is crazy scary. I was just watching the local Houston TV meteorologist (https://www.click2houston.com/) and he broke it down with an old school method to show how 25-30 inches of rain is a reality!!!

[ScottNAtlanta]

I am confused on this last vortex. In the loop they did there were readings everywhere from 965.9 to 971...I never saw a 972 in the center vicinity yet thats what recon has in the vortex. Can someone explain this to me? I dont see a dropsonde in the area either.
In the loop were 968.5, 969.8, 969.5, 966.6 (dont even go there on that on), 965.9
How do those numbers give you 971?

[Michele B]

From NASA Space!

Taken from where?!?!

ISS???

If so, how can they be IN the pic???

[Hurrilurker]

Track nudged to the left. Things are looking dire for Corpus Christi. Around half a million people, a lot of low-lying shoreline, and not a lot of roads out.

[WxGuy1]

If they find 85kt, could the forecast possibly be upped to a Cat 4 landfall? Weird things happen in the Gulf and while it'd be a longshot I wouldn't at all rule out a Cat 5 either, stranger things have happened.

This official forecast is for Harvey to be at 95 kts by 12z tomorrow morning. In other words, the NHC expects Harvey's max sustained winds to increase 20 kts in the next 9 hrs. We'll see what the max winds are in the NE quad in the coming few minutes as that quad is sampled, but, make no mistake, rapid intensification is needed (and expected) to bring Harvey to Cat 3 intensity by landfall. If the forecast is going to be wrong, I find it slightly more likely that it'll be wrong by overforecasting the intensity of Harvey than by underforecasting it. Of course, anything is possible, but it's the current forecast seems to be very fair (hey, who am I to judge how a forecast looks when that forecast is made by some of the best tropical cyclone forecasters in the world?)...

That band of intense convection may be a little parasitic, though it may be removed enough from the central core of the hurricane to not affect the overall intensity much. We're heading into the diurnal max in terms of convective intensity, and the cold cloud tops surrounding the eye are in line with the NHC forecast for continuation / resumption of rapid intensification.

This is the one part of your answer I have an issue with. Matthew fully well bombed to our first Cat 5 since 2007 with that HUGE convective blob of a vestigial twin that everyone thought would hinder it, why couldn't Harvey?

I don't remember Matthew in detail (other than the whole Cat 5 and mega destruction to parts of the Caribbean). However, in my experience, the "parasitic convective band" tends to be more detrimental to tropical cyclone than helpful (or trivial). As with most tendencies/things, I can find exceptions, but that's been more observation.

[Bizzles]

From NASA Space!

Taken from where?!?!

ISS???

If so, how can they be IN the pic???

You know the ISS is the size of a football field right?

[AubreyStorm]

From NASA Space!

Ñ


Taken from where?!?!

ISS???

If so, how can they be IN the pic???

Obviously, Astronauts aboard International Space Station captures #Harvey image! C’mmoon!

[CryHavoc]

From NASA Space!

Taken from where?!?!

ISS???

If so, how can they be IN the pic???

https://www.nasa.gov/sites/default/file ... of_iss.jpg

It's a big station.

[psyclone]

I hate to be a wet blanket on discussion but I really don't think we should be giving stay/go advice on evacuation for individual parties. Individuals should be paying attention to local and state government evacuation orders. The orders are very clear. I'd rather see people pointed to sources of local info than be told to do x or z.

This. You should know what your evac zone is and be ready if your county EOC pulls the trigger. around here that's easy to figure out but I don't know how other parts of the country do it. investigating that is a part of pre season preparedness

[Michele B]

I hate to be a wet blanket on discussion but I really don't think we should be giving stay/go advice on evacuation for individual parties. Individuals should be paying attention to local and state government evacuation orders. The orders are very clear. I'd rather see people pointed to sources of local info than be told to do x or z.

I would tend to agree with you, however, I basically always tell people to GO. Unless they are in a building that has been "hurricane tested" in the past....then they have a chance to survive in it...if it's still in relatively stout condition.

But each person must make their own decision....IF it's based on knowledge and not emotion ("I don't want to come home to nothing," or "If I leave, they'll loot my house...").

A person's life is MORE VALUABLE than any valuables you have, folks!

I think if someone's on a forum like this asking "should I go or stay?" they've probably already decided something and just want someone to agree with them, or talk them into (through) something. Again, I would always err on the side of caution and say [b]GO[/b].

[tolakram]

The only saving grace is this may reach peak intensity before landfall and an EWRC might begin.. The bad news is the EWRC would likely expand the size of the wind field and rain too.. but it would limit the winds somewhat. I think this will be peaking in the next 12-18 hours, by early tomorrow afternoon it should be near peak strength IMO, possibly a 160mph 915mb cat 5.

I think at this point talking about the storm as if it's "got a bright side" could lead people in the wrong direction.

This is going to be a monster and there aren't really any "best case" scenarios for a major hurricane landfalling near populated areas.

By the same token, if you're going to talk about Cat 5s, it would help to know where you're extrapolating that data from. Not saying it's impossible -- just want to know why you're thinking in that direction.

I know it's my first post here, but this seems to be a more scientific forum so I'm wondering where sub 930mb forecasts suddenly came from when none of the models show that.

Models aren't very great at predicting rapid intensification. Hunches are also a thing. Patricia's extreme intensification nor Matthew's were really expected as models were very slow at readjusting and adapting to the rates of intensification. The conditions in the Gulf are good enough to harbor a Cat 5, the main factor in if it gets there is time.

I think we've all had a say here. I personally don't think conditions are good enough for a cat 5, they are good but not perfect and cat 5 requires near perfect conditions. It's perfectly fine to provide a hunch here, as long as you say so.

[Aric Dunn]

That NW/N eyewall on radar is getting very intense on radar. Noaa plane arriving right on time..

[MaineWeatherNut]

Kermit is approaching, hopefully will get a good ne quadrant sample.

We JUST got a NE Quad Sample from the AF Recon plane... Nothing really of note except pressure continues to drop and the eye is only 10nm wide down from it's 15 to 20 nm width on past passes. No increase in winds.

[txwatcher91]

The only saving grace is this may reach peak intensity before landfall and an EWRC might begin.. The bad news is the EWRC would likely expand the size of the wind field and rain too.. but it would limit the winds somewhat. I think this will be peaking in the next 12-18 hours, by early tomorrow afternoon it should be near peak strength IMO, possibly a 160mph 915mb cat 5.

I think at this point talking about the storm as if it's "got a bright side" could lead people in the wrong direction.

This is going to be a monster and there aren't really any "best case" scenarios for a major hurricane landfalling near populated areas.

By the same token, if you're going to talk about Cat 5s, it would help to know where you're extrapolating that data from. Not saying it's impossible -- just want to know why you're thinking in that direction.

I know it's my first post here, but this seems to be a more scientific forum so I'm wondering where sub 930mb forecasts suddenly came from when none of the models show that.

My reasoning for a cat 5 has been explained a few times on here but I don't mind summarizing You have the system entering the highest TCHP waters, excellent outflow, a nearly symmetrical CDO, contracting eye (from 16nm to 10nm) and steadily dropping pressure. The structural changes from a banding TS/Cane to a powerful cane are pretty much complete as the CDO is now expanding quite nicely in all quadrants. The next step is a rapid pressure drop and winds bumping up quickly. My experience with storms like Rita, Wilma, Katrina, etc over the years has led me to be able to pick up the features that typically precede a period of intense RI and this one has all the hallmarks. The only thing that would stop it would be an eyewall replacement cycle.

In addition, the GFS has been predicting a pressure around 930-945 at landfall for quite awhile now and the 3km NAM has been in the 880-920 range. It's fairly reasonable to conclude that this could deepen quicker than the GFS suggests, but not as extreme as the 3km NAM, given the above mentioned observations.

[KC7NEC]

Track nudged to the left. Things are looking dire for Corpus Christi. Around half a million people, a lot of low-lying shoreline, and not a lot of roads out.

Though it's night there now I honestly wonder if the Mayor will issues a mandatory evac now instead of voluntary. Easily could be 100-200k in the most dangerous zone that only have about 12 hours to get clear now.

Second question for others, since its been awhile can anyone refresh my memory. In this case, the "east" side would be the higher storm surge right?

[GeneratorPower]

Unnecessary evacuations are in themselves dangerous. This is partly why both voluntary and mandatory evacuation orders exist. If you're not under either one, you may be in the way of others who actually need to get out. This is again why I don't think we should be telling people yes or no. Let them go to the safe sources of info and make their own decision.

[Chris_in_Tampa]

I am confused on this last vortex. In the loop they did there were readings everywhere from 965.9 to 971...I never saw a 972 in the center vicinity yet thats what recon has in the vortex. Can someone explain this to me? I dont see a dropsonde in the area either.
In the loop were 968.5, 969.8, 969.5, 966.6 (dont even go there on that on), 965.9
How do those numbers give you 971?

My site checks a file every minute, at most, for data of a certain type and agency. When some obs come in fast, a new ob overwrites the old ob. Sondes came in at 11:22pm, 11:24pm and 11:25pm EDT. My system couldn't get the data before the 11:25pm ob overwrote the 11:24pm ob. As a backup, my site checks the NHC archive and downloads all the data, getting missed data. So missed data takes time to appear so I don't put too much stress on my site or the NHC archive.

I manually added that sonde so you don't have to wait:
http://tropicalatlantic.com/recon/recon ... -972-17-17

Information about when the system is updating:
http://tropicalatlantic.com/recon/recon ... tem_status

[verbs]

I hate to be a wet blanket on discussion but I really don't think we should be giving stay/go advice on evacuation for individual parties. Individuals should be paying attention to local and state government evacuation orders. The orders are very clear. I'd rather see people pointed to sources of local info than be told to do x or z.

There's a mandatory evactuation for Victoria where he/she's at. https://www.victoriaadvocate.com/news/2 ... tory-evac/

Was just "strongly" suggesting he follow the orders you reference. Surprised there's opposition to this.

[AubreyStorm]

From NASA Space!


Taken from where?!?!

ISS???

If so, how can they be IN the pic???

[ForeverFlorida90s]

This official forecast is for Harvey to be at 95 kts by 12z tomorrow morning. In other words, the NHC expects Harvey's max sustained winds to increase 20 kts in the next 9 hrs. We'll see what the max winds are in the NE quad in the coming few minutes as that quad is sampled, but, make no mistake, rapid intensification is needed (and expected) to bring Harvey to Cat 3 intensity by landfall. If the forecast is going to be wrong, I find it slightly more likely that it'll be wrong by overforecasting the intensity of Harvey than by underforecasting it. Of course, anything is possible, but it's the current forecast seems to be very fair (hey, who am I to judge how a forecast looks when that forecast is made by some of the best tropical cyclone forecasters in the world?)...

That band of intense convection may be a little parasitic, though it may be removed enough from the central core of the hurricane to not affect the overall intensity much. We're heading into the diurnal max in terms of convective intensity, and the cold cloud tops surrounding the eye are in line with the NHC forecast for continuation / resumption of rapid intensification.

This is the one part of your answer I have an issue with. Matthew fully well bombed to our first Cat 5 since 2007 with that HUGE convective blob of a vestigial twin that everyone thought would hinder it, why couldn't Harvey?

I don't remember Matthew in detail (other than the whole Cat 5 and mega destruction to parts of the Caribbean). However, in my experience, the "parasitic convective band" tends to be more detrimental to tropical cyclone than helpful (or trivial). As with most tendencies/things, I can find exceptions, but that's been more observation.

Tropical wave to the east of Harvey is helping him I say nothing is stoping Harvey from becoming a category 5