Katrina H-Wind Analysis, marginal 3 at landfall

[wxmann_91]

the lesson of this season is that it does NOT take a category 4 or 5 to cause severe damage. Before this year, cat 3 has often been thought of as the transition category between nuisance and destructive. The last 2 years have shown that the transition category in reality is category 2. Cat 1 hurricanes tend to be more nuisance, except in mountain regions, cat 2 is the bridge from this to total devastation, which starts at cat 3 (that is, regions experiencing true cat 3 conditions, not people thinking they went through a cat 3, like many said they did with Jeanne, but really only receive cat 1 winds)

Actually Derek, I'm starting to think that Cat 1 is the transition point - look at what Katrina did to S. Florida.

[Anonymous]

Bottom Line

KATRINA WAS A CAT 4
RITA WAS A CAT 3

[jazzfan1247]

Bottom Line

KATRINA WAS A CAT 4
RITA WAS A CAT 3

Based on what?

"People won't want to hear this was a Category 3"...how true

[Anonymous]

Oh jeez.

Why dont we just call it an Open wave? Or a subtropical Category 4 Hurricane? I just highly doubt that the NHC will downgrade it.

[Derek Ortt]

I fully expect Katrina will be downgraded to a 3

In the grand scheme of things, Katrina was a mere nuisance here. The high damage figures were just due to the fact that there was a lot to damage, and rainfall flooding. The high rises fared fine

[Weatherfreak000]

Where did those wind observations in the first post come from anyway? The Houston Observer?


Bottom Line, The New Orleans International Airport recorded 130 Sustained. That would be in the wind swath where according to those links it should have had 100 sustained.


And that's FAR INLAND. Are you telling me that in the WEST QUAD this thing registering 130 isn't significant? What wind should have been recoridng in the Eastern Quadrant?

145 Sustained in Buras, Lousiana.




Now please show me where i'm wrong.

[jazzfan1247]

Oh jeez.

Why dont we just call it an Open wave? Or a subtropical Category 4 Hurricane? I just highly doubt that the NHC will downgrade it.

I sense a lot of desperation in this post. We'll see in the end when NHC posts its final report, but such definitive statements like "bottom line: CAPS LETTERS" suggest YOU are the one who's done the research to justify your conclusions, which you have not. At the very least, be open to the idea that she could've been a Cat 3 at both landfalls.

One question I do have for Derek or other profs, I was browsing through the past couple year's wind analysis on that site, and something I noticed was that the max surface winds were usually consistently lower than the listed NHC advisory. Is there a reason for this?

[Derek Ortt]

the advisory winds are subject to a 20% error. They try to smooth out the rapid intensifictaion and weakening, and often do not weaken systems as quick for a very good reason, because the public tends to think the storm is falling apart, or if it goes down a category, say to a 3, they think the storm wont be that bad

It also depends upon who does the final report. Some forecasters perfer the higher readings, while others perfer the lower ones

[jazzfan1247]

the advisory winds are subject to a 20% error. They try to smooth out the rapid intensifictaion and weakening, and often do not weaken systems as quick for a very good reason, because the public tends to think the storm is falling apart, or if it goes down a category, say to a 3, they think the storm wont be that bad

It also depends upon who does the final report. Some forecasters perfer the higher readings, while others perfer the lower ones

Yeah that is something I noticed, the wind analysis max winds fluctuate dramatically even every few hours. But the max winds for a storm's path from these wind analyses don't quite measure up to the max advisory intensity, usually from what I've seen. For example (and pardon me if I'm wrong as I haven't checked every single graphic) but Katrina's max wind from HRD was 133 kts, so does this mean Katrina could've NOT been a Cat 5 at any point in its lifetime? I believe for Rita it shows the same thing, the max winds maxing out at around 135 kts. And there are other examples, I'm just wondering why this is the case.

[Anonymous]

I may just be an amateur student...however I do not expect Katrina to be downgraded to a Category 3. The damage from storm surge was that of a Category 5...up towards 30 feet. That's 10-15 feet higher than with Rita. To say that Katrina's winds were 15-20 mph less than advisory is bogus to me.

I highly doubt Katrina went from 165 mph to 125 mph in 8 hours.

[timNms]

POST TROPICAL CYCLONE REPORT...HURRICANE KATRINA NATIONAL WEATHER SERVICE JACKSON MS 500 PM CDT MON OCT 3 2005

http://kamala.cod.edu/offs/KJAN/0510061900.acus74.html

For those who still argue cat 3/2, look at this!

JONES..........ELLISVILLE/WDAM-TV......114 MPH..1830 (EST)
SUSTAINED TWO-MINUTE WINDS...OTHER REPORTS WDAM-TV...ELLISVILLE...JONES COUNTY...70 KT (that's 80.5 mph)
This occured about 18 mile due east of me. If you'll read the entire report, you'll find that instrument failure prevented officials from getting the readings during the peak of the storm.


458 ACUS74 KJAN 061900 AAB PSHJAN POST TROPICAL CYCLONE REPORT...HURRICANE KATRINA NATIONAL WEATHER SERVICE JACKSON MS 500 PM CDT MON OCT 3 2005 DESTRUCTION IN THE PATH OF HURRICANE KATRINA HAS BEEN WIDESPREAD AND OVERWHELMING. CATASTROPHIC DESTRUCTION WAS LEFT ACROSS THE GULF COAST AND PARTS OF SOUTHEAST MISSISSIPPI. SEVERAL VISUAL SURVEYS WERE MADE BY NWS PERSONNEL ACROSS PORTIONS OF CENTRAL...EAST-CENTRAL AND SOUTHEAST MISSISSIPPI. THESE SURVEYS INDICATED WIDESPREAD DAMAGE COMPARABLE TO F1 TO F2 TORNADOES...WITH AREAS BORDERING ON F3 TYPE DAMAGE. THE MOST EXTENSIVE DAMAGE...FROM THE SURVEYED AREAS...IS ROUGHLY LOCATED SOUTH AND EAST OF A PURVIS TO COLLINS TO NEWTON TO MERIDIAN LINE. AREAS NORTH OF I-20 DUE HAVE CONSIDERABLE TREE DAMAGE...COMPARABLE TO AN F1 TORNADO...BUT THE DAMAGE IS NOT AS WIDESPREAD LIKE ACROSS SOUTHEAST MISSISSIPPI. THE SWATH OF DAMAGE EXTENDED ACROSS CENTRAL AND NORTHERN SECTIONS OF MISSISSIPPI. DOWNED TREES AND POWER LINES HAVE BEEN REPORTED AS FAR WEST AS BOLIVAR COUNTY WITH WIND GUSTS OVER 50 MPH OBSERVED AT MANY LOCATIONS ALONG THE MISSISSIPPI RIVER. HURRICANE KATRINA HAS PROVEN TO BE A NATIONAL DISASTER, LEAVING UNTOLD NUMBERS DEAD, THOUSANDS OF HOMES DESTROYED AND HUNDREDS OF THOUSANDS OF HOUSEHOLDS DAMAGED OR WITHOUT POWER. PLEASE TAKE NOTE THAT METEOROLOGICAL OBSERVATIONS WERE INCOMPLETE FROM MANY AREA WEATHER STATIONS DURING THE STORM DUE TO WIDESPREAD WIND-RELATED POWER AND COMMUNICATION OUTAGES. SOME OF THE DATA HAD TO BE ESTIMATED OR JUST SIMPLY MARKED AS "MISSING" BECAUSE OF THIS ISSUE. ANY ESTIMATED DATA IS NOTED IN THE TABLES BELOW. ADDITIONALLY...MOST OF THE WIND AND PRESSURE OBSERVATIONS OCCURRED 8/29 AND WERE ONLY DATED IF THEY OCCURRED DURING A DIFFERENT CALENDAR DATE (UTC TIME).

[Anonymous]

Derek...why do you use the same info when it failed you last year?

I've seen nearly all of the best tracks, I am surprised that Gaston weakened, but it did; thus, thats what I will accept. A moderate 50KT TS at landfall

The SFMR data from NOAA recon also indicated 95KT at the time of landfall, just below the thresshold of a cat 3. The surface obs were consistent with the recon findings (well, at least the one at Pensacola)

Both those were wrong.

Gaston was 75 mph...not 60 mph
Ivan was 120 mph....not 110 mph

The SFMR data has a rocky past...I don't buy it.

[Derek Ortt]

Many wanted 100KT for Ivan

there was a brief SFMR problem during Rita, which was fixed and all flights after are fine

SFMR does not have problems detecting high winds, it had 112 for Jeanne

again, no hard evidence to refute the claims of a category 3 hurricane, just conjecture and avoidance of the question

[Anonymous]

Look...student to student, Why would a Category 3 at landfall in LA...cause a 137 mph wind gust in Mississippi?

[jazzfan1247]

Look...student to student, Why would a Category 3 at landfall in LA...cause a 137 mph wind gust in Mississippi?

Is that a serious question?

[Anonymous]

In the eyewall of Hurricane Charley (150 mph), a gust to 132 mph was recorded. If we have a 140 mph hurricane...and have a 137 mph gust...isn't that just as much proof as Charley?

[Derek Ortt]

re-read the Charley report, there was a 150KT gust recorded at Charlotte hospital

[Anonymous]

re-read the Charley report, there was a 150KT gust recorded at Charlotte hospital

I understand...and thats why Charley was not a CAT 5...because 150 mph hurricanes DO create 180 mph gusts. But...if somebody recieved a 132 mph gust in a 150 mph hurricane...then why wouldnt you state the claim that Katrina's 137 mph gust was recorded in a 140 mph hurricane..since it had weakened by the time of second landfall?

[Derek Ortt]

that was the maximum gust, like the readings I had at RSMAS were the most intense in S Fla

One thing though, the gusts vary greatly in just a 1000 foot distance. My building had a 94 m.p.h. gust, but another one only had 88. The sustained winds were the same

[Derek Ortt]

the 119KT gust equates to a sustained wind of about 90-100KT

remember at Cameron before the anamometer failed, a gust to 113 was recorded, but the sustained wind was barely of hurricane force