ATL: LAURA - Post-Tropical - Discussion

[Nuno]

I am a broken record but we watched Michael go from a forecast Cat 2 at landfall to a Cat 5 at landfall.

My plan is for a high Cat 4 and will be glad if wrong.

Chuck

Wise decision but is the difference between cat and cat 4 preps?

With Cat 4 storms you should take pictures of your house to prove there was a habitat there and leave.
We adjusted claims for mobile home owners after hurricane Andrew and there were often just concrete slabs.

Hell, forget mobile homes, there were regular homes in Country Walk or Homestead that were pretty much just concrete slabs as well.

[aspen]

If this rate of deepening continues, with a pressure of ~981 mbar, Laura would bottom out at 940 mbar in 24 hours.
https://mobile.twitter.com/TropicalTidb ... 0914611200

[Highteeld]

The broad wind field is both good and bad. On one hand, getting anything over 115 knots by landfall is a very tall order at this point. However, the larger wind field means more people get the hurricane-force winds and storm surge.

[BYG Jacob]

Laura's probably on track for Cat 5 landfall at this point. Intensification will only get quicker once a closed-off eye is formed

Cam down there. That is an extremely rare event and it's unlikely for any given storm to achieve that. 2 in 3 years would be insane.

We've had 3 straight year of category 5 hurricanes, all of them except for Lorenzo made landfall at some point as a category 5

[Nuno]

Ike managed to get down to 944mb in the middle of GOM with sustained winds only at 85kts. Isaac in 2012 was another classic example of how winds can significantly lag behind pressure drop under loose structure — It was 965mb/70kt.

...but Laura doesn't have "loose structure," at least not anymore.

Still relatively loose compared to other intense Gulf storms. It likely won’t stay like this for long but the current lag in wind speeds reported by recon is understandable.

I know large systems often cause a lag between pressure and wind speeds, but why is this seemingly common in the Gulf? Is it because Gulf systems tend to already be developed and undergoing EWRC?

[NDG]

Dropsonde confirms pressure is down to 981mb.
Fairly good pressure drop in just an hour and a half.

981mb (Surface) 70° (from the ENE) 16 knots (18 mph)

[Kingarabian]

While it is still deepening it looks like it gulped some dry air and is pushing it out, as you can tell with the crack of warm convection near the CDO.



Also some >-80C cloud tops starting to go off again.

[Highteeld]

Pressure is approximately 979.4 mb right now

[eastcoastFL]

[abajan]

Still not sure why this isn’t popping out a visible Eye yet

it’s not quite going thru RI, as many are expecting, yet. It is also possible that it never quite rapidly intensifies per the technical definition. It could just strengthen normally and/or level off. I’ve seen that happen quite a bit despite it looking like all systems go. I’m not saying it won’t commence RI. -Just saying it’s not a given.

You are about one of the few people that doesn't think it won't happen. Some of us even expect SEVERE RAPID INTENSIFICATION.

That's called explosive intensification, and it's pretty rare (I think). It's what happened to Hurricane Maria when it was just hours away from Dominica on September 18, 2017.

[Rail Dawg]

I am a broken record but we watched Michael go from a forecast Cat 2 at landfall to a Cat 5 at landfall.

My plan is for a high Cat 4 and will be glad if wrong.

Chuck

Wise decision but is the difference between cat and cat 4 preps?

Good question. A Cat 2 doesn't have the surge and an exit plan is not as important.

Cat 4 or 5 you are making absolutely sure you can get to an accessible parking garage that isn't so packed with cars you can't climb up 30 ft or more. You also with Cat 4-5 must have an exit plan. If you get to the town where you thought you could make a stand and you can't make that stand you must be able to get out before the surge blocks your escape path.

Plus with Cat 4-5 gas is more critical as you may have to sleep for a week in the truck. Those are just a few examples I could name more. It's definitely something you have to go into with both eyes open.

Chuck

[Highteeld]

it’s not quite going thru RI, as many are expecting, yet. It is also possible that it never quite rapidly intensifies per the technical definition. It could just strengthen normally and/or level off. I’ve seen that happen quite a bit despite it looking like all systems go. I’m not saying it won’t commence RI. -Just saying it’s not a given.

You are about one of the few people that doesn't think it won't happen. Some of us even expect SEVERE RAPID INTENSIFICATION.

That's called explosive intensification, and it's pretty rare (I think). It's what happened to Hurricane Maria when it was just hours away from Dominica on September 18, 2017.

maria had similar conditions for growth as Laura, but its eye was 10 nm wide

[BYG Jacob]

it’s not quite going thru RI, as many are expecting, yet. It is also possible that it never quite rapidly intensifies per the technical definition. It could just strengthen normally and/or level off. I’ve seen that happen quite a bit despite it looking like all systems go. I’m not saying it won’t commence RI. -Just saying it’s not a given.

You are about one of the few people that doesn't think it won't happen. Some of us even expect SEVERE RAPID INTENSIFICATION.

That's called explosive intensification, and it's pretty rare (I think). It's what happened to Hurricane Maria when it was just hours away from Dominica on September 18, 2017.

Watching -80C convection wrap completely around Maria's eye just as she was about to flatten Dominica was jaw-dropping

[aspen]

Dropsonde confirms pressure is down to 981mb.
Fairly good pressure drop in just an hour and a half.

981mb (Surface) 70° (from the ENE) 16 knots (18 mph)

That’s a pressure drop of 3mbar in 1hr 28min, or roughly ~2.05 mbar/hr. If Laura continues to deepen around this rate, it’ll break 940 mbar and possibly get down to 930 mbar 24 hours from now.

[Buck]

You are about one of the few people that doesn't think it won't happen. Some of us even expect SEVERE RAPID INTENSIFICATION.

That's called explosive intensification, and it's pretty rare (I think). It's what happened to Hurricane Maria when it was just hours away from Dominica on September 18, 2017.

maria had similar conditions for growth as Laura, but its eye was 10 nm wide

Maria was an incredible storm... seemingly immune to EWRCs.

[Kingarabian]

[url]https://cdn.star.nesdis.noaa.gov/FLOATER/data/AL132020/AirMass/GOES16-AL132020-AirMass-1000x1000.gif?hash=23684[url]

Clearly outflow to the N/NE is becoming established. Look at the area of cold convection SE of LA.

[Highteeld]

 https://twitter.com/burgwx/status/1298424553945923590

[abajan]

How can y'all remember what storm had what kts with how many mbs at any given time during their formation? I have trouble remembering what I cooked for supper last night! I am so impressed and in awe!

For obvious reasons, the only one whose pressure I can remember is Hurricane Gilbert in '88 which bottomed out at 888 mb.

[Hammy]

Laura's probably on track for Cat 5 landfall at this point. Intensification will only get quicker once a closed-off eye is formed

Cam down there. That is an extremely rare event and it's unlikely for any given storm to achieve that. 2 in 3 years would be insane.

We've had 3 straight year of category 5 hurricanes, all of them except for Lorenzo made landfall at some point as a category 5

Matthew was Cat 4 in Haiti if I remember.

[Highteeld]

How can y'all remember what storm had what kts with how many mbs at any given time during their formation? I have trouble remembering what I cooked for supper last night! I am so impressed and in awe!

For obvious reasons, the only one who's pressure I can remember is Hurricane Gilbert in '88 which bottomed out at 888 mb.

Gilbert and Wilma both had some of the coldest CDO's in the satellite era of the Atlantic.