Will Laura be upgraded to a cat 5 landfall?

[HurricaneEnzo]

Doubtful IMO

Sent from my SM-N986U1 using Tapatalk

[Ubuntwo]

"both of these anemometers failed soon after" The anemometers at Lake Charles worked as it approached, as it passed, and after it passed to the west slightly. The Buoy never failed in its wind readings all the way through, so I think the comparison to Michael fails on that aspect. Bottom line is we'll never really know, because unlike Michael, no major populated areas or structures around landfall, hence those who want to believe it was 150 or more will believe it, and those who don't won't... regardless of what they are presented with. And I believe that applies to both sides.

 https://twitter.com/jgodwinWX/status/1298888238959132673



^ easily verifiable there

The coastal Calcasieu Pass station did survive and record both sides of the storm supporting nothing more than a cat 2, but since it didn't receive the RFQ winds were likely higher elsewhere. You're right though - you'd expect higher winds recorded for a 150mph landfall even outside of the RMW. Needs further analysis by the pros there.

Helicopter footage over Cameron looks like high-end cat 3 tree damage? If anyone more knowledgeable wants to pitch in.

Only populated area that might have received the max winds/surge is Creole, LA though I've yet to see any footage out of there.

Think your last sentences hit the money and that's probably why the NHC will leave landfall intensity as-is.

[Fancy1001]

I really want it to be so that I don't lose a bet, but I think it might have peaked at 155. If it had slowed down earlier so that it had another few hours over water, I think it might have reached 160.

[Nuno]

The damage seems more similar to what was seen after Charley rather than a Michael. Though since so much of the impacts were over rural locations we may not be seeing where the worst of it passed through.

[Chris90]

I go with no. I think the only evidence that can possibly support it is that radar capture that was posted that measured 223mph with 6 bins surrounding it greater than 200mph, and even then, that was attributed to a mesovort.

Michael got his upgrade because there was A LOT of evidence. SFMR, Flight level, and radar analysis all supported Michael getting 140kts, and there's a possibility he was actually a touch higher at 145kts, the evidence just wasn't quite strong enough to go there. Laura doesn't have nearly enough going for her. I can see a bump to 135kts being justified due to 145kts flight level and a few 133kt SFMR readings, but that's her ceiling in my opinion.

[TheStormExpert]

No. Now if it was a 155mph storm at landfall that would make more of an argument. Not to mention pressure was only 937 millibars at landfall which is not indicative of a Cat.5.

[Shell Mound]

I think no, strongest gusts were not anywhere close to Category 5 force, and the highest flight level and SFMR winds do not support Category 5 intensity.

Practically no surface observations along the coast where the highest winds would have occurred. Regardless, I don’t think cat5 winds existed there and 150mph is probably justified.

Personally, I don't believe any 150 mph winds hit anywhere at landfall. I know about recon and doppler measurements but every surface based instrument where the storm came in, and all readings from Lake Charles Airport, and from University of Florida in the areas around there, both before, and those after the storm, none of them that I saw showed anything sustained over 109 mph. Now I'm sure there were embedded winds much higher--but not enough to say it was 150 sustained. I'll say definitely not. Pressure isn't quite low enough either although I think it maxed intensity at 938 hPa which I suppose would make it "possible", I say nope.

Do you have any theories as to why the winds derived from reconnaissance and radar data seemingly were not mixing down to the surface?

[Ubuntwo]

Practically no surface observations along the coast where the highest winds would have occurred. Regardless, I don’t think cat5 winds existed there and 150mph is probably justified.

Personally, I don't believe any 150 mph winds hit anywhere at landfall. I know about recon and doppler measurements but every surface based instrument where the storm came in, and all readings from Lake Charles Airport, and from University of Florida in the areas around there, both before, and those after the storm, none of them that I saw showed anything sustained over 109 mph. Now I'm sure there were embedded winds much higher--but not enough to say it was 150 sustained. I'll say definitely not. Pressure isn't quite low enough either although I think it maxed intensity at 938 hPa which I suppose would make it "possible", I say nope.

Do you have any theories as to why the winds derived from reconnaissance and radar data seemingly were not mixing down to the surface?

Not OP but here's a take: dropsondes right before landfall indicated good mixing all the way down, so I'm guessing the frictional effects from land + a well-forecasted rapid weakening around and after landfall have a lot to do with it. It had also leveled off leading up to LF, and usually that means poorer translation of winds overland.

[Hurricane Mike]

Nah, I think 125-135 kt was the intensity. I'd stay with 130 kt.

[Shell Mound]

Personally, I don't believe any 150 mph winds hit anywhere at landfall. I know about recon and doppler measurements but every surface based instrument where the storm came in, and all readings from Lake Charles Airport, and from University of Florida in the areas around there, both before, and those after the storm, none of them that I saw showed anything sustained over 109 mph. Now I'm sure there were embedded winds much higher--but not enough to say it was 150 sustained. I'll say definitely not. Pressure isn't quite low enough either although I think it maxed intensity at 938 hPa which I suppose would make it "possible", I say nope.

Do you have any theories as to why the winds derived from reconnaissance and radar data seemingly were not mixing down to the surface?

Not OP but here's a take: dropsondes right before landfall indicated good mixing all the way down, so I'm guessing the frictional effects from land + a well-forecasted rapid weakening around and after landfall have a lot to do with it. It had also leveled off leading up to LF, and usually that means poorer translation of winds overland.

What would be your estimate as to Laura’s maximum sustained winds at the time of landfall? Personally, I would side with a peak of 135 knots several hours prior to landfall, followed by weakening to 105–115 knots by the time of landfall. Even though the MSLP may have been lower at landfall, the winds were also lower, so Laura likely peaked offshore, when its wind field was more compact and its ambient (environmental) pressure higher. As Laura neared the coastline, increasing vertical wind shear, combined with cooler shelf waters and a broadening of the pressure gradient, induced less efficient mixing of higher winds to the surface, so the TC weakened just before and as it made landfall, with high-end Cat-3 or low-end Cat-4 winds affecting a very small region of unpopulated coastline between Creole and Grand Chenier, LA.

[gfsperpendicular]

No. Now if it was a 155mph storm at landfall that would make more of an argument. Not to mention pressure was only 937 millibars at landfall which is not indicative of a Cat.5.

If Laura doesn't get upgraded (and I don't think she will), it won't be because of the pressure. Laura was pressed against a very strong ridge and the pressure gradient made very strong winds. That's why the strongest winds were in the NE quad and not the NW quad. And Matthew, who was in a somewhat similar situation, was a cat 5 at 934 mb.

[NotoSans]

Matthew’s assessment was based on SFMR winds alone, but from 2017 onwards NHC has become skeptical of SFMR’s performance under very high winds. Once research into SFMR is completed, Matthew’s downgrade to category 4 in re-analysis cannot be ruled out.

That said, for Laura, there aren’t even SFMR winds supporting category 5.

[CrazyC83]

I don't think so. The data, for the most part, does not support such.

[CrazyC83]

The damage seems more similar to what was seen after Charley rather than a Michael. Though since so much of the impacts were over rural locations we may not be seeing where the worst of it passed through.

I agree. The wind damage from the trees look like something you'd expect from a cat 4 - also comparable to, say, Harvey in Rockport. The maximum winds were over places swamped by storm surge and very remote areas that it will be hard to analyze. However, Lake Charles had damage indicative of cat 3 and it is 30 miles "inland" (although the swamps would slow weakening compared to solid land).

[CrazyC83]

Regarding the Lake Charles ASOS station, it did spend at least 1 1/2 hours in the eyewall but not the eye. The pressure bottomed out there at 956 mb, but remained in the high 950s for an extended period as the barometer remained on throughout. Note that Sulphur, where Josh Morgerman measured 948 mb in the eye, is about 12 miles farther inland. The maximum winds should have been in the eyewall as the eye was passing almost due west of LCH (based on the exposure of the site which aligned well with the direction of motion). Based on its forward motion, that would have been about 2:15 am CDT - about 20 minutes after the last wind reading came back.

It is likely that LCH could have recorded winds sustained of category 3 level had it remained on throughout the storm, but certainly not 150 mph. Those winds would have been on the open Gulf just southwest of Creole with the maximum exposure over water. Few houses are there - there are a small number at the end of Rutherford Beach Road (29.760N, 93.129W) that might have caught the absolute maximum. As the eye likely went right over Calcasieu Lake, it is unlikely any sites on the lake would have been aligned perfectly to capture the maximum winds.

 https://twitter.com/CC_StormWatch/status/1299467513101774853

[supercane4867]

Michael was a clear cut case for T7.0 140kts
Laura was a clear cut case for T6.5 plus ADT would yield 130kts
Harvey was a clear cut case for T6.0 115kts

Dvorak and satellite estimates had been spot on with them. Well in-line with actual intensities.

 https://twitter.com/weatherdak/status/1299196156057063424

[Ubuntwo]

Regarding the Lake Charles ASOS station, it did spend at least 1 1/2 hours in the eyewall but not the eye. The pressure bottomed out there at 956 mb, but remained in the high 950s for an extended period as the barometer remained on throughout. Note that Sulphur, where Josh Morgerman measured 948 mb in the eye, is about 12 miles farther inland. The maximum winds should have been in the eyewall as the eye was passing almost due west of LCH (based on the exposure of the site which aligned well with the direction of motion). Based on its forward motion, that would have been about 2:15 am CDT - about 20 minutes after the last wind reading came back.

It is likely that LCH could have recorded winds sustained of category 3 level had it remained on throughout the storm, but certainly not 150 mph. Those winds would have been on the open Gulf just southwest of Creole with the maximum exposure over water. Few houses are there - there are a small number at the end of Rutherford Beach Road (29.760N, 93.129W) that might have caught the absolute maximum. As the eye likely went right over Calcasieu Lake, it is unlikely any sites on the lake would have been aligned perfectly to capture the maximum winds.

https://twitter.com/CC_StormWatch/status/1299467513101774853

This is all that's left of that area. From the aerial damage survey.

[CrazyC83]

This is all that's left of that area. From the aerial damage survey.

That is truly unsurvivable. I hope everyone there evacuated.

In terms of the intensity analysis, what is the KZC wind estimate for a pressure of 936 mb at landfall? I don't have it on me.

[Ivanhater]

Poll closes today at 3:01 PM EDT

[1900hurricane]

This is all that's left of that area. From the aerial damage survey.

That is truly unsurvivable. I hope everyone there evacuated.

In terms of the intensity analysis, what is the KZC wind estimate for a pressure of 936 mb at landfall? I don't have it on me.

Backtracking through KZC for Vmax using 936 mb and the rest of the 06Z best track data yields about 120 kt. It should be noted that Laura was running a little above the KZC expectations on its entire passage through the Gulf of Mexico.