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WxWatcher007

Major Hurricane Michael

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On 10/21/2018 at 5:57 PM, Amped said:

gjjrPa9.png   i5fAji3.png

 

Pressure wise, Micheal is the 3rd lowest

Wind wise and excluding Typhoon Karen and the other Guam storm, the list would read:

1.Labor Day

2.Camille

3.Andrew

4.Okeechobee

5.Micheal-Maria tied

Also the pressure tumbled from 933mb to 919mb in the 4 hrs before landfall.   A 933mb 145mph storm wouldn't have made the top 10, so that final push did a lot.

https://www.wunderground.com/hurricane/atlantic/2018/tropical-storm-michael

 

 

 

Lol, now Yutu on the list, and if it hit on the same day as The Labor Day hurricane it wouldn't be, because it wasn't part of America yet.  Pacific Island storms deserve their own Category.

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Here's the RMS Hwind estimated 3-second wind gust map for Hurricane Michael; following their extensive ground surveys of the hardest hit areas in Florida and SW Georgia.  

As expected, their highest estimated winds were centered on Mexico Beach; at 170-180 mph!

I can certainly believe it based on what I observed, there, first-hand.  Not sure what the peak values really were, but I'm confident they were no less than 155 mph.  Likely, much higher.  With velocities of such extreme intensity, it was virtually impossible to see much of anything. 

The ear-piercing screams of the wind will be something I'll never be able to forget!  

Oct-2018-Peter-Datin-HU-Michael-Fig-1-720px.jpg

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15 hours ago, Roger Smith said:

Glad you survived. 

Thanks for the kind words, Roger!  I was most fortunate and am exceedingly grateful that the condo I sought for refuge didn’t suffer the same fate as so many others on the beach.  Like, for instance, the two houses that were lifted completely off their foundations and carried across hwy 98 to be slammed against the condo where I was filming the onslought.  Or the beach-front home that was lifted up by the surge and blown apart by the extreme winds, whose owner was found two days later hidden underneath the large mounds of wreckage in front of our condo.   

When those, like myself and other chasers, willingly put ourselves in the direct path of such violent storms, and survive the experience without personal injury, it’s easy to forget just how fortunate we truly were.  No matter how much experience we have or the various precautions we may take, it’s not a given that the structure we choose to endure the core of such ferocity will not collapse upon us.  Going through such an event is a stark reminder of how easily ones life can be snuffed out by a tempest of such magnitude!

Here’s the way I described the experience to a local news reporter less than 24 hours after the horrific calamity had befallen Mexico Beach (please keep in mind, had only slept 4.5 hours over the preceeding 3 days)

https://m.facebook.com/story.php?story_fbid=2263377383885830&id=121026441243349

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A 19' storm surge verified in Mexico Beach, FL by USGS!  

Yet more incredible images and data being obtained, exemplifing the severity of hurricane Michael's impact along the NE Florida panhandle (especially, Mexico Beach)!

DqzqqrGUUAAV5ML.jpeg

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5 hours ago, ncforecaster89 said:

A 19' storm surge verified in Mexico Beach, FL by USGS!  

Yet more incredible images and data being obtained, exemplifing the severity of hurricane Michael's impact along the NE Florida panhandle (especially, Mexico Beach)!

DqzqqrGUUAAV5ML.jpeg

I saw this posted in a tweet this morning. It was accompanied by this:

NEW: USGS confirms a 19 foot storm surge in Mexico Beach from Hurricane Michael. This sets a new record for the state of Florida.

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14 hours ago, NavarreDon said:

I saw this posted in a tweet this morning. It was accompanied by this:

NEW: USGS confirms a 19 foot storm surge in Mexico Beach from Hurricane Michael. This sets a new record for the state of Florida.

Hard to imagine 155mph winds and 19ft of water at the same time. Like a lot of other storms, it could have been a lot worse if it were 30 miles west,   most of Panama City Beach would have been under water.

 

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Civil Air Patrol media flight photography:

The Civil Air Patrol, a civilian auxiliary component of the U.S. Air Force, has conducted over 100 air and ground missions in the Florida Handle beginning days before the hurricane made landfall on Wednesday, Oct. 10, 2018. They have uploaded over 6,000 photos and surveyed Tyndall Air Force Base, Mexico Beach and other hard-hit Northwest Florida counties. [Herald-Tribune staff photo/Carlos R. Munoz]

https://www.heraldtribune.com/photogallery/LK/20181031/NEWS/103109978/PH/1

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This facebook pic caught me off guard! Life after a monster I guess. People set up at the end of their driveways in parts of PC so kids could trick or treat. Talked to family in St Joe Beach and there was none.
1a86593c049101b2660043068dc184ae.jpg


.

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Really good post on Reddit I felt is worth sharing here explaining why Michael may be upgraded to a Category 5 at landfall in post analysis by NHC/NCEP:
 

Quote
Points that support a higher intensity (>135kt)

1. Damage to trees was comparable to Andrew, with entire Pinus elliottii strands flattened, debarking observed in hardwoods and softwoods, and denuding.

2. As previously mentioned, the MSLP was likely about 918mb based on 920mb observed several miles from the center at Tyndall. Using the process outlined in Knaff and Zehr 2007 taking into account other factors, this works out to a low end category 5 hurricane.

3. Doppler radar velocities were consistently 155kt, with some readings exceeding 165kt. Accounting for beam height, the highest velocities translate to a low end category 5 hurricane.

4. The highest 10-second flight level wind was 152kt. Using the ratio between SFMR readings and FL winds that previously fit best for the storm (~92%), this translates 139.8kt, a category 5 hurricane. There was likely some undersampling, and this was not right at landfall, so winds could have been higher.

5. High water marks in areas impacted by the eastern half of the storm reached up to 21.16ft above NAVD88. The difference between MHHW (used for surge calculations) and NAVD88 is just over a foot in the region, meaning this should translate to 20 foot surge including waves. Not sure what the wave height was, but the gently sloping ocean floor in the region means they were likely not that high. I'm going to estimate surge was about 18 feet, which is 4 feet higher than the estimate for surge using the SLOSH model provided by the NHC. This could be a result of a larger windfield (did not occur), vastly different track (did not occur), or the most likely situation - the storm was more intense than the operation 135kt, possibly 140kt or higher.

6. SFMR peaked at 138kt unflagged, which is a category 5. This was discarded initially by the NHC because of the potential impacts of shoaling (waves breaking as coastline elevation ramps up dramatically). However, as previously stated, the coast in the area does not ramp up in the area where this was observed. This makes this reading more reliable than it may seem, so I'm taking it into account. There also may have been undersampling and further strengthening, so it may have reached a higher intensity.

7. Damage to manmade structures from wind was extensive. From downtown Panama City to the area between Mexico Beach and Port St. Joe, there was intense damage ranging from very widespread EF0-1 level, most areas with EF2 damage, and localized areas of EF3 level damage. Examples of severe wind damage observed include a collapsed water tower, collapsed metal truss/transmission towers, nearly all wooden homes with collapsed sidings and roofs torn off, and industrial buildings made of brick or concrete with destroyed walls. For a hurricane's straight line winds to produce this level of damage it takes an intense storm - certainly cat 5, with the possibility of mesovorticies having a role. The best hurricane analog to this damage is Andrew.

8. At Tyndall peak gusts were said to be 172mph. This was not observed by the WeatherFlow observing site in the area, which collapsed after a cat-4 gust in the leading eyewall. I'm not exactly sure of the method used to measure the 172mph gust, perhaps pitot tubes on aircraft, perhaps observational estimates, or perhaps they had another anemometer with data not publicly available. But what I do know is that, if the gust can be verified, it would probably support a higher intensity - Tyndall is far enough inland for land friction to start playing a role in reducing observed winds, and the area did not get the strongest portion of the eyewall. However, if survey teams find that damage was more associated with mesovorticies, than this gust will probably have less weight as mesovorticies can enhance gusts without ramping up sustained winds. But since mesovorticital damage has not been confirmed yet, I'm going to say this supports a category 5 intensity.

9. For what it's worth, Dvorak satellite intensity estimates were at or above T7.0 (category 5) for the time leading up to and of landfall. Now this shouldn't really be that significant since there are direct measurements from recon that are much more solid evidence for an upgrade, but it's still meaningful to note that the satellite appearance supported a higher intensity.

TLDR: Tree damage, pressure ratio, doppler velocities, flight level winds, surge levels, SFMR measurements, structural damage, peak measured gusts, and satellite presentation all support a higher intensity of low-end category 5 in Hurricane Michael.


Discussion Link

I agree there is an excellent chance of upgrade.

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That was an excellent listing of data, outlined above, arguing for an upgrade to category-five intensity.

There was also alot of debate and discussion about this topic on Twitter...for which I participated...and included former NHC forecaster Todd Kimberlain.  As shown in the link below, It was mainly a debate where chasers Simon Brewer and Justin Drake were arguing for the upgrade while Todd suggested that the NHC will be very reluctant to modifying their operational landfall intensity; baring any other significant data becoming available. 

https://mobile.twitter.com/tbrite89/status/1052748706670399490

Considering that some subjectivity will be involved in the final landfall intensity estimate produced by the NHC (in the TCR), it's essentially a 50/50 proposition as to whether hurricane Michael will be upgraded to a category-five.

All things being equal, the 152 kt flight-level-wind (FLW) measured in the SE quadrant of the eyewall is the strongest data point in support of category-five classification.  The standard 90% ratio of FLW to surface wind estimate (for an intensifying hurricane) equates to 137 kts.  Even though it's rounded to the nearest 5 kt interval (135 kt), one must take into account that it's highly unlikely Recon was able to measure the absolute peak wind velocity contained anywhere else within the eyewall.  This alone argues for an intensity of no less than 140 kts.  It is also the most objective data available; the 138 kt SFMR reading, notwithstanding.       

Given that the central pressure dropped at least another 3 mb after the aforementioned FLW was obtained, one could even make a plausible argument for 145 kt...but 140 kts. would be my choice.

All the rest of the data and factors, listed in the Reddit post, provides further substantiation of the in-situ data measured by Recon just prior to landfall.      

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That twitter thread is a bit disheartening.  There's no reason why the operational intensity should be given the benefit of the doubt (i.e. that there should be a higher burden to 'overturn' the original analysis).  Reanalysis should be clean slate.

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On 11/6/2018 at 7:12 PM, Windspeed said:

Really good post on Reddit I felt is worth sharing here explaining why Michael may be upgraded to a Category 5 at landfall in post analysis by NHC/NCEP:
 

6. SFMR peaked at 138kt unflagged, which is a category 5. This was discarded initially by the NHC because of the potential impacts of shoaling (waves breaking as coastline elevation ramps up dramatically). However, as previously stated, the coast in the area does not ramp up in the area where this was observed. This makes this reading more reliable than it may seem, so I'm taking it into account. There also may have been undersampling and further strengthening, so it may have reached a higher intensity.
Discussion Link

I agree there is an excellent chance of upgrade.

 

SFMR is the best chance of getting an upgrade.  All the others assumptions are approximations which would neither support nor reject it being a CAT 5 and the ruling on the field would stand in the NFL.

 

Even if Micheal is upgraded, it will probably keeps it's rank, just below Andrew and Okeechobee.

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I agree that though Michael may be upgraded, it will likely be strict reanalysis of that SFMR data and the realization that shoaling should not have discredited it. 140kts/160 mph seems logical; and yes, it would still rank behind Andrew and Okeechobee. Rank is not as important versus just getting as close as possible to correct landfall intensity from a scientific standpoint however. We may still have unreleased data from TAB/military as well that may find its way into post analysis. As has been stated previously, their gust data is very high if shown accurate, based on its inland location and all things considered. Some have also suggested that they may have had closed network instrumentation/obs we have not yet been privy to online that could find its way into reanalysis. The report will be an interesting one for sure.

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20 hours ago, Amped said:

 

SFMR is the best chance of getting an upgrade.  All the others assumptions are approximations which would neither support nor reject it being a CAT 5 and the ruling on the field would stand in the NFL.

 

Even if Micheal is upgraded, it will probably keeps it's rank, just below Andrew and Okeechobee.

I agree that technically the SFMR is the only data that specifically correlates to category-five intensity.  That said, I worry the NHC will continue to fall back on their operational decision to discount it due to the “assumption” that shoaling inflated that figure...as Todd Kimberlain suggested is most probable. 

Baring any other data not yet publicly released, the 152 kt FLW is the next best piece of emperical data supporting a 140 kt cat 5 reclassification.  Although, it does round down to 135 kt when converting to a 1-min surface wind estimate without taking into account the exceedingly high likelihood that there were slightly higher winds Recon didn’t measure, and/or the fact Michael was still offshore and intensifying when it was taken.  

It’s also conceivable that IF the much higher storm surge estimates (provided by the USGS post-storm surveys) are determined to be legit, the NHC might perform another hind-cast SLOSH model run containing the adjusted surge data to estimate Michael’s MSW, as they’ve often done in the reanalysis of past hurricanes.  Albeit, it would carry much less weight in any present day reanalysis considering all the in-situ data they do have for Michael, obviously.  Since it’s likely they’ll determine the central pressure continued to drop below their operational 919 mb estimate, that too further argues for the upgrade.  

In short, and to your point, if the NHC continues to discount the validity of the 138 kt SFMR measurement, a little well-reasoned subjectivity will be required in order for the current operational assessment to be modified.  Of course, and as the Reddit poster so well articulated, I’d argue that the entirety of all the data makes low-end category five the most reasonable intensity estimate.   

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