Katrina H-Wind Analysis, marginal 3 at landfall

[timNms]

it just keeps getting more and more entertaining.

[AussieMark]

Could it to do with the pressure background?

Charley was a 150 mph category 4 but had pressure of 941

Andrew was a 165 mph category 5 and had pressure of 922

on the flip side a strorm like Floyd was a 155 mph category 4 and had pressure of 921 mb

[Scorpion]

Could it to do with the pressure background?

Charley was a 150 mph category 4 but had pressure of 941

Andrew was a 165 mph category 5 and had pressure of 922

on the flip side a strorm like Floyd was a 155 mph category 4 and had pressure of 921 mb

Or Rita with 911 mb and a strong 3/weak 4.

[HurricaneBill]

Carla probably was legitimatly a 4. I would have to look at the flight level data, with the vertical velocities

again, had my Rita experience not have happened, I would have thought the idea was downright laughable. What is needed is numericla modeling studies to determine WHEN and WHY some storms like Rita can be 911mb cat 3's, after being 897mb cat 5's

Well, it seems like the ones that weaken right before landfall are moving north towards the Gulf coast.

Storms that don't weaken seem to be the westward moving storms.

[f5]

andrew was a Cat 5 at 922 on the saffir simpson scale anywhere below 920 mb is CAT 5 now that begs the question was Andrew 150 MPH instead of 165MPH.A 922 MB Hurricane is between 150-155 strong CAT 4.Why was Andrew a CAT 5 with Cat 4 pressure i know the skater anology he had his arms tucked in blah blah blah but he had CAt 4 pressure which i'm trying to get at

[jasons2k]

andrew was a Cat 5 at 922 on the saffir simpson scale anywhere below 920 mb is CAT 5 now that begs the question was Andrew 150 MPH instead of 165MPH.A 922 MB Hurricane is between 150-155 strong CAT 4.Why was Andrew a CAT 5 with Cat 4 pressure i know the skater anology he had his arms tucked in blah blah blah but he had CAt 4 pressure which i'm trying to get at

Look @ the wind damage pictures from Andrew I posted a few pages back. That's why.

[Derek Ortt]

no, Andrew was probably closer to 180 based upon the same H-Wind analysis

Winds were much higher because of two things, the small windfield and the very strong ridge to the north

we need to stop using the rediculous Joe Bastardi argument that the pressure itself determines the wind speeds. Joey obviously didnt do too well in dynamics because in the momentum equations, it is the d_phi/dn term that helps to produce the wind (both in geostrophic and gradient balance)

[Aslkahuna]

Some clue would also be available from lightning data (which is unfortunately unavailable for the earlier storms). Both Katrina and Rita had a fair amount of lightning during their intensification phases suggesting very strong convective processes (with Katrina actually extremely electrically active for a TC and Rita siginificantly less so). In fact, the data suggested that strong convection was occuring throughout Katrina but that in Rita it was mostly confined to the outer band and the eyewall. What you saw in Rita was probably characteristic of a mature cyclone with a low pressure but a more stratiform cloud shield with lower topped spirals and less vertical vels in the eyewall and this was probably the case with Katrina as well. Also, we don't know whether or not any Trade air (which is very moist below H6 but dry above in the western boundaries of the oceans) made it into the systems before they got close to land which would have altered their characteristics as well.

Steve

[jes]

That is so interesting --- and professional. I haven't a clue of what you're saying, but loved reading what you wrote. For the first time, I've finally "got it" ---- all storms, no matter their wind speeds or pressures, are different and will cause different damage ---- there is no way to know for sure in advance. So I guess I can't compare all storms to Frederic's intensity or land fall coordinates to make my decision whether to leave or stay. Thanks!!

[Aslkahuna]

A couple of notes about wind sensor failures-it's important to know exactly who has control of the switch for the weather instrumentation at the airports-because if it's the people in the Control Tower or the BASOPS, they are likely to shut everything down when they evacute which is usually when the wind gusts first hit 100mph for Control Towers. I ran across this at Clark AB and when I was on duty for Typhoon Irma I sent the tower operator back up to switch on the wind sensor because I was anticipating very high winds (which I got)-though he wasn't very happy about. But I got a nearly complete wind record of the storm (though we still missed the absolute strongest gust) which I would not have had if I hadn't done what I did. Three years later during TY Kim which was even stronger than Irma, I wasn't on and they didn't do what I did and got no wind record. The older chart recorder wind sensors with scale doublers are better in situations like this because although pen drag will slow the response to gusts, the sensor heads were generally made stronger and the wind speed transmitter actually transmitted an electrical current so the wind speed would always work even without power until the sensor was knocked out. Also, you had a record you could retrieve because the clock drive was mechanical and you had a paper chart whereas newer systems apparently have no data retrieval capability in case of power outages.

Steve

[Stormcenter]

no, Andrew was probably closer to 180 based upon the same H-Wind analysis

Winds were much higher because of two things, the small windfield and the very strong ridge to the north

we need to stop using the rediculous Joe Bastardi argument that the pressure itself determines the wind speeds. Joey obviously didnt do too well in dynamics because in the momentum equations, it is the d_phi/dn term that helps to produce the wind (both in geostrophic and gradient balance)

Sorry Derek but as you call him "Joey" has more credentials to back his theories up then you do so I wouldn't knock the man. Hmmmm who was the one on Fox News doing hurricane analysis you or him? How many years have you been "professionally" forecasting weather? You would an an OKay forum forecaster if you wouldn't spend so much time knocking everyones posts you don't agree with.

[JTD]

I NEVER would have thought it was possible, until my flight into Rita, but I am believing that MAYBE Camielle was also a 3. )

Derek, thanks for posting this as I thought this also. I mean if Katrina was only a cat 3 but did many times the damage of Camille, there's just no way that Camille was a category 5.

Another interesting thing to note is that areas DIRECTLY hit by Katrina and Camille had worse damage for Katrina. That kind of throws the argument that Camille had a small wind field so it wasn't quite as destructive as Katrina due to it's larger wind field out the window.

I mean I know there's a scientific reason I'm sure for what I posted above but Katrina being 2 full categories below Camille but causing x times the damage is something I find baffling.

[tallywx]

no, Andrew was probably closer to 180 based upon the same H-Wind analysis

Winds were much higher because of two things, the small windfield and the very strong ridge to the north

we need to stop using the rediculous Joe Bastardi argument that the pressure itself determines the wind speeds. Joey obviously didnt do too well in dynamics because in the momentum equations, it is the d_phi/dn term that helps to produce the wind (both in geostrophic and gradient balance)

Sorry Derek but as you call him "Joey" has more credentials to back his theories up then you do so I wouldn't knock the man. Hmmmm who was the one on Fox News doing hurricane analysis you or him? How many years have you been "professionally" forecasting weather? You would an an OKay forum forecaster if you wouldn't spend so much time knocking everyones posts you don't agree with.

Notice how Derek did not knock Bastardi but the absurdity of Bastardi's premise...that central pressure alone, no matter the pressure gradient, will determine a hurricane's intensity.

If the best you can come up with is an ad hominem argument that Derek is not on Faux News...pffft. consider this: Derek is fresh out of grad. school and already doing research at one of the foremost atmospheric academic research organizations in the world. Bastardi is employed by some private weather company in the mountains of Pennsylvania that happens to have a contract with Fox News (and thus has contractual obligations to give Bastardi airtime) because of Republican media-mogul Murdoch. with no accountability whatsoever.

Bastardi's central pressure statement is verifiably bunk because it defies the laws of physics. case closed.

[MGC]

Before we know it Andrew will be the strongest hurricane of all time. The atmospheric pressure must be really low down in Miami tonight.....MGC

[Stormcenter]

no, Andrew was probably closer to 180 based upon the same H-Wind analysis

Winds were much higher because of two things, the small windfield and the very strong ridge to the north

we need to stop using the rediculous Joe Bastardi argument that the pressure itself determines the wind speeds. Joey obviously didnt do too well in dynamics because in the momentum equations, it is the d_phi/dn term that helps to produce the wind (both in geostrophic and gradient balance)

Sorry Derek but as you call him "Joey" has more credentials to back his theories up then you do so I wouldn't knock the man. Hmmmm who was the one on Fox News doing hurricane analysis you or him? How many years have you been "professionally" forecasting weather? You would an an OKay forum forecaster if you wouldn't spend so much time knocking everyones posts you don't agree with.

Notice how Derek did not knock Bastardi but the absurdity of Bastardi's premise...that central pressure alone, no matter the pressure gradient, will determine a hurricane's intensity.

If the best you can come up with is an ad hominem argument that Derek is not on Faux News...pffft. consider this: Derek is fresh out of grad. school and already doing research at one of the foremost atmospheric academic research organizations in the world. Bastardi is employed by some private weather company in the mountains of Pennsylvania that happens to have a contract with Fox News (and thus has contractual obligations to give Bastardi airtime) because of Republican media-mogul Murdoch. with no accountability whatsoever.

Bastardi's central pressure statement is verifiably bunk because it defies the laws of physics. case closed.

Please now give me a break the knock was directed toward Bastardi. If you want to play word games then I'm not playing. I'm sorry but just because someone is doing research doesn't give them the right to redicule other mets or posters just because it doesn't agree with "their" scientific thinking.

[Stormcenter]

Before we know it Andrew will be the strongest hurricane of all time. The atmospheric pressure must be really low down in Miami tonight.....MGC

Good post.

[M_0331]

I wish people would respect 'Profession Met' statements. I have a
Mechanical plus Civil Engineer degree which took 4 years plus 2 summer
schools(typical five year degree). So I took courses which are close to what the 'Mets' took.
The 3D fluid action of one storm can not be compared to another storm or A + B =C DOES NOT exist. Storms are like people, no two are the same. I have spent many hours reading posts but attack the 'Mets'
by given certain posters is new and out of line. As a ex-NCO in the Marines, I would never talk to someone who out rank me like what I have read of late.

<Eddie>

[vbhoutex]

Back to the subject or I will be forced to lock the thread.

[Recurve]

Look at long-period NOAA sat animations on Rita and Katrina. These massive storms seem to breathe and cough; central pressure changes might become uncoupled from outflow and inflow; seems to inrease and decrease in spurts. Not just sat image jumps, the storm structure doesn't change uniformly over time. When you watch over days, you see periods of equilibrium and then giant exhalations and inhalations. It looks like if you are in the right place at the right time, a "Cat 5" could have a quieter windfield than "Cat 3" that coughs out an energy burst. These are atmospheric engines running on their own feedback dynamics without governors; they not may have much more divergent windspeed/central pressures than theoretical storms.

[Recurve]

For information about Andrew's intensity and "promotion" to Category 5 at landfall, be sure to read the HURDAT analysis:


http://www.aoml.noaa.gov/hrd/hurdat/andrew.html