Hurricane Katrina

Tropical Storm Katrina has just made it into a Hurricane...minimal, but a hurricane non the less

Hurricane KATRINA Update

000
WTNT62 KNHC 251940
TCUAT2
HURRICANE KATRINA TROPICAL CYCLONE UPDATE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
335 PM EDT THU AUG 25 2005

...RECONNAISSANCE AIRCRAFT REPORTS AND DOPPLER RADAR DATA INDICATES
THAT TROPICAL STORM KATRINA HAS STRENGTHENED INTO A HURRICANE...

SHORTLY BEFORE 330 PM EDT...REPORTS FROM A NOAA RECONNAISSANCE
AIRCRAFT AND NOAA DOPPLER RADAR DATA FROM MIAMI INDICATE MAXIMUM
SUSTAINED SURFACE WINDS INCREASED TO A CATEGORY ONE HURRICANE.

DATA FROM THE STEPPED-FREQUENCY MICROWAVE RADIOMETER ONBOARD THE
NOAA AIRCRAFT MEASURED HURRICANE-FORCE SURFACE WINDS...WHICH IS
SUPPORTED BY NOAA DOPPLER RADAR VELOCITY DATA FROM WFO MIAMI.

FORECASTER STEWART

sorry I'm not video capable quite yet

[edit on 8-25-2005 by worldwatcher]

Not a surprise. The last couple hours you can really see it developing.
It's going to be interesting to see what happens when it reaches the Gulf...

I'd worry more about the second landfall too if I wasn't in the path of the first one. I'm more scared of random tornadoes that actual hurricane force winds.

I think Katrina will probably become a hurricane again before making the second landfall somewhere on the gulf coast of Florida again...

About time to edit the title to "Hurricane Katrina", ....

Wow, originally, I was going to guess this status by the 5pm update, but figured that'd be pushing it, so went with 8. I certainly wasn't expecting it around 3.... Let's hope it doesn't have time to get to a cat 2, but even those are fairly mild (as hurricanes go)....

I'm more scared of random tornadoes that actual hurricane force winds.

Yep, the last mild hurricane spawned a micro-tornado that had me spending the day cleaning up quite a bit (more than any hurricanes last year even).....

[edit on 25-8-2005 by Gazrok]

Originally posted by Gazrok
About time to edit the title to "Hurricane Katrina", ....

Wow, originally, I was going to guess this status by the 5pm update, but figured that'd be pushing it, so went with 8. I certainly wasn't expecting it around 3.... Let's hope it doesn't have time to get to a cat 2, but even those are fairly mild (as hurricanes go)....

It's making landfall now, so it won't have time to strengthen further...

It's pretty nasty outside right now, constant rain and winds I would say sustained about 48-55mph with stronger gusts. I've already had a brief power outage and internet outage, not sure how long i'll keep power though.

definitely seems to be getting a bit stronger right before the landfall.

There is a live chat session going on right now until 9pm with a senior meteorologist here in Tom Rector here in Ft. Myers if anyone is interested in asking questions.

www.nbc-2.com...

Unfortunately but expected you cannot find a single surface observation anywhere close to what the NHC reports as maximum sustained winds.

This observation station is closest to the center of the storm. It recorded a low central pressure of 29.06 but no wind over 45mph

www.wunderground.com...

Here is a list of observation stations near Boca Raton...

www.wunderground.com...

Higest reported wind speeds at 5pm central time was 37mph

Highest from Hollywood, FL was 39mph. Here is their link...

www.wunderground.com...

This observation which is monitored by the NDBC shows something a little better which is still only 42kts or about 46 or 47mph

www.ndbc.noaa.gov...

Here is another link to the NDBC dedicated to the hurricane. Highest observation from any of the points is 52kts or about 57mph.

www.ndbc.noaa.gov...

Thats about normal for the NHC. They overstate some 15 to 20mph. I challenge anyone to find an observation where the sustained wind (not gusts) is 65mph let alone 75mph.

Here is an image of a storm that the NHC likes to call a hurricane. As of the latest update they have increased the winds to 80mph even though there hasn't been a 60mph sustained wind anywhere.



This storm in reality is poorly organized. The deep convention is mostly to the east and south of the center. There looks to be alot of dry air mixing in with the storm. There is no eye visible on this image either. Reason? This isn't a hurricane but a tropical storm that they are calling a hurricane. I know you'll think there is an eye based on radar but alot of tropical storms show this signature provided the center isn't fully exposed to dry air. Maximum sustained winds should be listed at 60mph. Maybe 65mph if you were lucky. That would be more consistent with the satellite signature and more consistent with the surface observations.

Here is the wind and pressure history from Hollywood, FL which is on the north side of the center. The reports were collected here...

link
7:11pm 29.29" 54.1mph sustained Wind Easterly
7:02pm 29.25" 46.0mph sustained Wind Easterly
6:53pm 29.23" 43.7mph sustained Wind Easterly

6:45pm 29.20" 36.8mph sustained Wind ENE
6:38pm 29.21" 39.1mph sustained Wind NE
6:28pm 29.21" 40.3mph sustained Wind NE
5:53pm 29.21" 50.6mph sustained Wind NNE

After this point the wind is Northerly and the pressure is rising. This point is pre landfall. There are a couple reports where the wind was 52.9mph but thats as high as the sustained winds ever reach.



(mod edit to reduce large url to shorter link)

[edit on 26-8-2005 by pantha]

It was the recon flights that confirmed it was a hurricane Indy.

Plus, when they say the sustained winds are 80mph, they are talking about in a very small section of the storm. Also, these storms are constantly fluctuating. At the time the measurements were taken, they found sustained winds that strong, by no means does that mean that it will stay like that for long.


Edit: Just to add....Port Everglades saw a wind gust up to 92. Fort Lauderdale to 91. It really doesn't matter what they say the sustained winds are, if you're in the way, just know you there's a chance you can see winds that strong.

[edit on 25-8-2005 by ThatsJustWeird]

The sustained winds do matter. That is what you base the storm classification on. And I'm telling you the NHC is fudging on the numbers. They definately fudge when they take the recon data to come up with surface winds. And again there wasn't a surface sustained wind report anywhere close to 80. I think someone almost hit 60 but that was it. Still 20mph below what the NHC reports. Show me a hurricane sustained wind. Show me something over 60 sustained. I'd bet you can't. Wind gusts don't matter in the classification. It has been the same problem all year long and it was the same problem all last year as well. Not a single surface observation that matched what the NHC said.

The NHC fudging continues. Here is a statement from the 5am discusstion.

www.nhc.noaa.gov...

"WHILE THE LATEST DOPPLER RADAR VELOCITIES ONLY SUPPORT 60 KT AT THE SURFACE... THESE VALUES ARE STEADILY CLIMBING... AND THE FIRST DVORAK ESTIMATES OVER THE GULF ARE A UNANIMOUS T4.0/65 KT. THEREFORE... KATRINA IS REASSIGNED HURRICANE STATUS WITH INTENSITY OF 65 KT."

They are taking the higher estimate from a storm model over a real time dopler reading. Nice. Here is a more detailed description of Dvorak.

"The Dvorak technique is a method using enhanced Infrared and/or visible satellite imagery to quantitatively estimate the intensity of a tropical system. Cloud patterns in satellite imagery normally show an indication of cyclogenesis before the storm reaches tropical storm intensity. Indications of continued development and/or weakening can also be found in the cloud features. Using these features, the pattern formed by the clouds of a tropical cyclone, expected systematic development, and a series of rules, an intensity analysis and forecast can be made. This information is then standardized into an intensity code."

Source: www.ssd.noaa.gov...

So basically they think it looks like a 65 even though a real reading says its only 60. And even that 60 may be high depending on how much the NHC decides to trim off the higher altitude readings. Remember the dopler readings happen above the surface. You then take off a percentage to come up with the surface estimate. Its the same technique used by the hunters. This is where the problem comes in. Pre Andrew the percentage was higher. Post Andrew the percentage was lower. Before Andrew a 100kt wind observed by the hunters would equate to something like 75 or 80kts at the surface. Post Andrew they report it at around 90kts.

The only TRUE measure you have is a surface observation. Surface observations aren't subject to flight level to surface level adjustments. They are real time. And they don't support what the NHC says. Haven't in quite some time.

I guess this one was bigger than they anticipated? Several websites are reporting different figures of damage and destruction:

www.foxnews.com... (see headline)

4 Dead As Hurricane Katrina Lands in Fla


news.bbc.co.uk...


(mod edit to reduce long link)


[edit on 26-8-2005 by pantha]

It seems the damage is consistant with a Cat 1 hurricane.

But....how can that be when it was only a mid sized tropical storm as Indy is suggesting?



Again Indy, think very small area (especially with a cat 1), think fluctuations (constantly), and think surface observation station's distance from that very small area.

Do Semantics really matter though? I'm sure Worldwatcher doesn't much care WHAT one calls it, hurricane or tropical storm.... She's probably without power right now.... Good luck WW, and stay battened down...

Whatever the case, it looks pretty damn organized as of the latest sat image at 9:30am, with a well-defined eye and moving over 90 degree water. By ANYONE's definition, its a hurricane now. But I'll agree with Indy on the NHC fudging, they always do... Still, if it helps people take it seriously, then that may not be such a bad thing....

That dive to the south was strange, it it almost like the storm near the path it had to take to quickly get back on the water.


The pressures they are reporting are consistant with a minimal hurricane. There are only a limited number of weather stations that take surface obsrvations and especially with a small system like Katrina they likely missed the worst of it. Also this storm seemed to be stronger on the south side, unlike most storms going the same direction having the worst in the NE quadrant. Somewhere in the Miami/ Ft Lauderdale had hurricane conditions, I dont think there is any doubt and the NHC did a great job of forecasting this one IMO.

This storm is fall from over, when it makes landfall again it will likely be a major hurricane.

If it stayed on the original path, I would have agreed it'd never go above one. With the south jog though, it's likely to be a cat 3 when it hits the panhandle.... I hope those folks are keeping an eye out, and taking precautions, because they could be quite surprised by this one...

Katrina has already turned into a category 2 hurricane after just leaving south Florida...looks like she'll be a major hurricane when she hits land again.

Hope you're OK worldwatcher....lots of people without power and several deaths in south Florida...