Was Andrew really a Cat 5 at landfall?

[logybogy]

Why did they upgrade him 10 years later? Was there a scientific basis or was it political based on the damage he caused?

[lilbump3000]

When did they upgraded him? I thought his winds were 150 at landfall.

[gkrangers]

150 is not category 5.

[logybogy]

They upgraded him for the 10 year anniversary to 175mph sustained, i think.

[lilbump3000]

I know its not a cat. 5. I thought he was a cat. 4 at landfall but this topic saying he was a cat. 5

[shorrock]

Down here on the news they talked about the upgrade. They said that all the wind insturments failed at 155 i believe it was. After reviewing structural damage, testing, and other fun science stuff, they concluded that it was a 5. I never really detected a political issue for the upgrade.

[Matthew5]

If Andrew was 175 mph winds then Ivan at his peak was just as strong...

[JTD]

Yep, unfortuantely, this was a cat 5 folks.

http://www.disasterrelief.org/Disasters/020821andrew/ and NHC site says so as well

http://www.nhc.noaa.gov/pastcost.shtml

[AussieMark]

he had 165 mph winds at landfall

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

[lilbump3000]

Alright Now.

[x-y-no]

The original estimate was based on the erroneous assumption that surface winds were between 75% and 80% of flight level winds. Later dropsonde investigations have shown that the accurate number is closer to 90%.

I believe there was also some re-evaluation of wind speed based on damage.

[Matthew5]

Ivan had Pressure of 910 millibars...Andrew had pressure of 922 millibars. While a hurricane Mitch(180 mph) in Camille(190) had Pressures both of 905 millibars. I'm going to say Ivan had max winds for a time of upwards of 175 mph maybe 180.

[JTD]

Ivan had Pressure of 910 millibars...Andrew had pressure of 922 millibars. While a hurricane Mitch(180 mph) in Camille(190) had Pressures both of 905 millibars. I'm going to say Ivan had max winds for a time of upwards of 175 mph maybe 180.

Matthew5...totally agree and don't forget Ivan's confirmed winds were up to 165 at one point.

[Guest]

You decide..




Hopefully that one (above) answers the no storm surge thread



If that hurricane was not a CAT 5 I know what is..The real question is Why did it take 10 years to figure it out????

[Matthew5]

Look what Ivan did to the Caribbean!

[SouthernWx]

It's funny...at the time (1992), I estimated hurricane Andrew's intensity at landfall in the 150-160 mph (130-140 kt) range, with gusts of 185-195 mph (160-170 kt); based on damage I observed and the likely pressure gradient in the eyewall. Everyone thought my estimate was too high at the time, because NHC only said it was 140-145 mph.

Now they go and upgrade, and estimate the intensity even higher than my original estimate...go figure

The reason they upgraded Andrew to cat-5 was utilizing something that didn't exist in 1992....eyewall dropsondes. After several years of observing eyewall dropsonde data from other intense hurricanes, NHC and the Hurricane Research Division of AOML realized Andrew's flight level winds were probably on the money...minus the 10%. Thus, the max flight level wind found in Andrew just east of Eleuthera of 170 kt (196 mph)...reduced to 153 kt (175 mph). The last recon flight into Andrew before landfall measured 162 kt winds at 700 mb....which equates to 145 kt (167 mph) at the surface = a 165 mph cat-5.

I can't argue with the upgrade...it was obvious to me at the time that Andrew was an extremely intense hurricane, with wind damage comparable to a strong F3 tornado (180-200 mph). In all honesty, I personally now believe Andrew was even stronger than 165 mph at landfall. The reason? That final recon pass occurred an hour before landfall near Homestead AFB. It's obvious to me that Andrew deepened up to the coast...perhaps even a few miles inland. The same USAF recon crew made a vortex fix almost an hour AFTER landfall, and the eye temp at 700 mb was 2°c degrees warmer than the last fix before landfall -- meaning Andrew was stronger AFTER landfall than an hour before landfall (when the 162 kt flight level wind occured).

It's IMO likely that Andrew's sustained winds in the north eyewall exceeded 170 mph at landfall....with gusts of 200-210 mph (gusts similar to a borderline F3/F4 tornado).

[Matthew5]

Hey southernwx how strong do you think Ivan at his peak could of been?

[Derek Ortt]

matt,

you do need to learn about the gradient wind balance before making wild guesses about wind speed. The pressure itself doesnt have any relation to the wind speed. It is the pressure gradient that determines the wind speed. Since Andrew had a huge high just to its north, the pressure gradient was significantly higher than that for anytime during ivan (except maybe the first time it became a 4, well east of the islands)

[stormcrow]

I have been on Upper Cativa, Pine and sanibel islands, been in Port Charlotte and Punta Gourda, And I went to Homestead after Andrew, There is no comparision! Major damage vs Catastrophic damage.

[DCA]

Read the NHC Re-analysis of Andrew (where every participant unanimously agrees that it was a cat 5 prior to landfall in S. Fla) and it becomes fairly clear that it was either at cat 5 or a smidge below at landfall near Fender Point. One thing is sure, it was definitely not a 125kt (145mph) huricane as NHC declared it after landfall.