Katrina officially downgraded to a Category 3

By: Dr. Jeff Masters , 4:08 PM GMT on December 21, 2005

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Today is winter solstice--the darkest day of the year--and an appropriate time to revisit America's other darkest day of the year, August 29. The National Hurricane Center (NHC) issued its official Tropical Cyclone Report for Katrina on Tuesday. Katrina officially made landfall as a Category 3 hurricane, not a Category 4. Ground-based and aircraft measurements only support 110 knot winds (127 mph) at Katrina's first landfall near Buras, Louisiana. Katrina weakened only slightly before her second landfall, and was still a Category 3 hurricane with 105 knot (121 mph) winds on the Mississippi coast. The NHC report also stated that the highest sustained winds over metropolitan New Orleans were only of Category 1 or 2 strength, although buildings over 25 stories high may have seen winds a full category higher.

The reason Katrina was originally classified as a Category 4 at landfall was because winds measured by the Hurricane Hunters at flight level (10,000 feet) were 150-155 mph. The normal rule of thumb used to estimate surface winds is a 10% redution from the winds at 10,000 feet. This rule of thumb was applied for the official NHC advisories issued at the time of Katrina's landfall, and made Katrina a Category 4 hurricane with 135-140 mph surface winds. However, detailed analysis of the wind structure of Katrina in data gathered by Doppler radar and dropsondes showed that at landfall, Katrina had its highest winds in an unusually strong band of winds between 2 and 4 km (the flight level of the Hurricane Hunters was about 3 km). Normally, the highest winds in a hurricane are found much lower, near .5 - 2 km. Surface winds measured by dropsondes, surface towers, and the SFMR microwave radiometer on the aircraft all agreed that the surface winds at landfall were no higher than 100 knots (115 mph). NHC adjusted these upwards by 10% to account for the fact that the strongest winds were likely not sampled. The 10% adjustment left Katrina just 5 mph shy of Category 4 status--but still a very potent and deadly major Category 3 hurricane.

The 10% reduction "rule of thumb" was not valid for Katrina at landfall, probably because the storm's convection was weakening at that time. Because momentum transport from aloft to the surface was impaired by the weakening convention, Katrina was less able to carry the strong winds that were aloft down to the surface. Thus, winds at the surface were about 80% of the winds measured at 10,000 feet. Still, NHC does mention that given the uncertainties and large wind field of Katrina, the very tip of the Mississippi Delta near Buras may have received Category 4 winds for a few minutes, and it is possible Katrina really was a Cat 4 at landfall.

Why Katrina weakened at landfall
At peak intensity, Katrina was a Category 5 hurricane with 150 kt (174 mph) winds, but in the 18 hours before landfall weakened to 110 kt (121 mph). This weakening occured as a result of entrainment of dry air into the storm, slightly cooler sea surface temperatures near the coast, and interaction with the land. NHC notes that the relative importance of these three factors cannot be determined without a lot more study, but all 11 hurricanes with pressures less than 973 mb that have hit the Gulf coast the past 20 years have weakened in the 12 hours prior to landfall. Thus, Katrina's weakening should come as no surprise. Note, however, that Hurricane Camille of 1969 did not weaken when it pounded Mississippi as a Category 5 hurricane; perhaps it's small size protected it from substantial land interaction and entrainment of dry air.

Storm surge
To me, the biggest disappointment in the report came in the treatment of Katrina's storm surge. No storm surge data was presented for New Orleans. No mention was made that Katrina, despite its Category 3 strength at landfall, pushed a Category 5 level storm surge to the coast. The report noted that official storm surge measurements were unavailable, due to failure of most of the tide gauges. However, one unofficial storm surge height of 27 feet at the Hancock County Emergency Management Office in Mississippi was mentioned, which would make Katrina's storm surge the highest on record for an Atlantic hurricane. The previous record was Hurricane Camille's 24.7 feet. Any surge above 18 feet is considered a Category 5 level storm surge. I've seen unofficial estimates that the storm surge affecting the eastern side of New Orleans was 18-25 feet high, which is clearly a Category 5 storm surge. Not surprisingly, the levees protecting the east side of the city were overwhelmed and failed in multiple locations. However, observational data and computer modeling indicate that storm surge entering the canals from Lake Pontchartrain reached 9 to 11 feet in the 17th Street Canal and 11 to 12 feet in the London Avenue Canal. The flood walls were 13.5 feet high or higher along much of the two canals and were designed to withstand water rising to 11.5 feet. A Category 3 storm surge is 9-12 feet, so these flood walls failed in a Category 3 level storm surge, even though they were supposedly designed to withstand that type of storm surge.

Katrina officially made landfall at Buras, LA, with a central pressure of 920 mb. This is the third lowest pressure on record for a U.S. landfalling hurricane, surpassed only by the two Category 5 hurricane to hit the U.S.--the Florida Keys Labor Day Storm of 1935 (892 mb) and Hurricane Camille of 1969 (909 mb). Katrina had the lowest pressure ever measured for a Category 3 hurricane; the previous record was 930 mb for Hurricane Floyd of 1999. Katrina's unusually low winds were primarily due to the fact that Katrina was a huge storm--the change of pressure from outside the storm to inside the storm happened over a large distance. It's the pressure gradient--the change of pressure with distance--that drives winds, not the pressure itself.

Death Toll
The official death toll so far is 1336, with 1090 of those victims in Louisiana and 228 in Mississippi. This makes Katrina at least the fifth deadliest U.S. hurricane of all time. The death toll could go much higher, making Katrina the third deadliest. Over 4,000 people are still listed as missing. Most of these missing people are probably alive and well, according to Kym Pasqualini, CEO of National Center for Missing Adults. However, she indicates that 1,300 of the missing from the most heavily damaged areas of New Orleans are a matter of great concern, and many of these people may have died in the storm.

The report quotes a preliminary figure of $75 billion in damage for Katrina, a number used by the American Insurance Services Group (AISG). This would make Katrina, by a least a factor of two, the costliest hurricane ever. A recent estimate by the world's largest re-insurance company, the Swiss Munich Re Foundation, put Katrina's total damage closer to $125 billion.

Forecast accuracy
NHC gives themselves high marks for forecast accuracy for the 2 1/2 days prior to Katrina's landfall. Indeed, their landfall location forecasts had errors more than a factor of two better than average. These exceptionally accurate forecasts likely saved hundreds of lives. On the other hand, NHC intensity forecasts for Katrina were up to a factor of two worse than average, and perhaps more lives could have been saved had these intensity forecasts been better.

Jeff Masters

katrina surge (cncguy2000)
1st. Baptist Church Gulfport, MS
katrina surge
Katrina Damage at the 17th St Levee Break (JimInGreenfield)
Katrina Damage at the 17th St Levee Break
Hurricane Katrina Search and Rescue (smithfarms)
I work for Louisiana Wildlife and Fisheries. We are in search and rescue mode. Storm damaged and flooded house.
Hurricane Katrina Search and Rescue

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176. TampaSteve
7:20 PM GMT on December 30, 2005
xealot: Yup...it's politics, pure and simple...
175. xealot
2:43 PM GMT on December 27, 2005
This is very simple. There is a huge political pressure to blame someone for the mess in New Orleans. People need a scapegoat, something or someone to blame for a disaster, even one such as this which is simply Mother Nature at work.

Personally I believe the storm was a cat 4 at landfall, it's satellite presentation was more consistent with a 4. However we cannot know for certain... even at Cat 3 speeds winds instruments are destroyed and operational data is sparse and often inaccurate.

But that's not the point. This has nothing to do with data or analysis... this is a purely political move probably motivated by pressure from certain factions within the government. There is a huge drive to blame Bush and the Army Corps of Engineers for this disaster. This drive is especially strong in academic sections of the government... in other words, including the NHC. By downgrading to a Cat 3, regardless of whether or not it is true, the NHC creates ammunition for the media to put pressure on the federal government to pay for the disaster.

This is the real reason, and let's not kid ourselves by saying it has anything to do with the data. The NHC, along with some other organizations within the government, want to put pressure on the Bush administration. By blaming the Army Corps of Engineers for the levee failure and Bush for not spending federal money on them, the NHC along with the LA government and many others want to create a situation where Bush and the federal government must pay massive compensation to the victims.

I've heard a lot of arguing about wind speeds and storm surge, etc... but truth be told, Cat 3 or 4.. it doesn't matter. The storm was massive, powerful, carried a huge surge and destroyed New Orleans along with whole sections of Mississippi. We already know this, and political stupidity aside it doesn't much matter what us mere mortals rate a disaster. It is what is.
174. Jedkins
5:24 PM GMT on December 26, 2005
By the way that is false,the surge from katrine was measured over 30 ft which is almost double of what the minimum is required to be category 5 surge of 18 ft.It was widespread more than 15 to 20 ft not just a very small area.I don't know where you got that info from bvut it is not accurate..
173. Jedkins
5:21 PM GMT on December 26, 2005
That is because hurricanes are destructive and debis can blow onto them,that is why we need reporters to be ther,to me as long as they are there in a safe place it is fine,me myself like doing it.Aso mant times the reportys reporting in the hurricane wanted to be there,radars and observations alone,bassically lie to you when it comes to hurricanes.Sattelites and live on the scene reporters are the most accurate tools of teling how bad a hurricane really is.Now I do think it is silly when they are way out in the open without a sturdy structure to take shelter in when it gets real bad,but as long as they are in a safe place it is in some ways needed,and absolutely fine they are there.So for y'all that are against it totally,I will not fight with y'all on this issue,but think about it a little better before you speak.
172. BahaHurican
12:25 AM GMT on December 25, 2005
This whole set of posts make very interesting reading.

I have only a couple comments. First, I read the NHC report before coming here, and I found it interesting that at least a couple of the unofficial reports of wind speeds, especially in FL, were taken from wunderground.com. I guess it is fair to say that NHC knows we are out here and have at least some respect for what members are doing .

The other thing that struck me is that consistently NHC is unable to report accurately regarding wind speed, wave / surge heights, etc. because THE MEASURING EQUIPMENT FAILED!!!!! If anybody is writing to the NHC, someone should be querying that little fact, with a view to finding out what is to be done about it. I think it is ridiculous that more than 100 years after Galveston there are still no accurate, DURABLE measuring tools on the ground.

Rather than disputing over the accuracy of landfall intensities, we all should be encouraging the "powers that be" to actively seek avenues whereby the quality of reporting in future storm events can be improved.
Member Since: October 25, 2005 Posts: 19 Comments: 21156
171. hurricanechaser
12:04 PM GMT on December 23, 2005
I'm sorry about that. I had lost the link to my blog. I want to take this opportunity to wish everyone and their families a safe and very Merry Christmas.:)


Your friend,

170. hurricanechaser
12:01 PM GMT on December 23, 2005
Hey everyone,

I have just created a new blog relating to global warming and whose responsible for it. I believe everyone will at least find it interesting reading whether they like the contents of it or not.

Here is the link to my blog.:)

169. KatrinaRitaWilmaZeta
5:05 AM GMT on December 23, 2005
my new blog is up so when ever some one come on the blog stop by my blog to see if you like if you post and i am not there that mean i am in bed or not aroud to get back to you so this post what ever you like then i will get back to you on your post as soon as i can

so good night all
168. squeak
3:12 AM GMT on December 23, 2005
You can use mapquest to aid in locating streets or cities.

I didn't write those last paragraphs very clearly. Here is a rewrite to sum up the areas with Cat 4 and 5 level surge:

We can conclude that one very small area of the MS coastline, the immediate coast of Waveland and southern BSL, was subjected to a surge that just barely edged over the Cat 5 level. This area was so small compared to the total area of land inundated by surge, that it is almost negligible, statistically speaking. The elevation of this area was already so low that it was well underwater, the difference in the height of the surge was probably not a significant factor in incurring the total property devastation, but, if it can be quantified, will be useful for denoting the record height of the surge.

The areas that received Cat 4 surge were Waveland and the part of BSL that curves into the bay and GOM, and a small portion of coastline along eastern Pass Christian, to the Long Beach / Gulfport border, and Diamondhead area south of I-10.
167. tornadoty
1:41 AM GMT on December 23, 2005
I have the petition thus far updated on my blog.
166. AySz88
1:19 AM GMT on December 23, 2005
Awesome post, squeak! Thanks for the research and explaination. It was a little hard to follow - I made some images to try to keep track, using screenshots of maps and such, but I wasn't completely sure of the locations you were talking about. If you want them as a starting point to illustrate your post, I can email them to you or something. :)
Member Since: August 25, 2005 Posts: 0 Comments: 8
165. KatrinaRitaWilmaZeta
1:01 AM GMT on December 23, 2005
hey tornadoty what up
164. tornadoty
12:55 AM GMT on December 23, 2005
Hellooooooooooooooooooooooooo! Is anyone home?
163. squeak
8:36 PM GMT on December 22, 2005
SLOSH - Sea, Lake and Overland Surges from Hurricanes

MEOW - maximum envelope of wind

MOM - maximum of MEOWs
162. squeak
8:10 PM GMT on December 22, 2005
If you want to know more about SLOSH modeling, MEOWs and MOMs, search GOOGLE online, or go to the HES home page at USACE. A mathematical grid is used to represent a particular coastal basin, and modeling is done for a number of hurricanes at different tracks and intensities. The worst case flooding scenario (basically, the MOM, or a group of MEOWs) is identified for any location, from the sum of these modeling runs.
161. squeak
8:05 PM GMT on December 22, 2005
Here is some information I hope will clarify a lot of the questions about Katrina's surge. In order to visualize it, you'll have to go to those links and at least give them a cursory glance. On the HES tool, disable evac zones and enable flood zones, to see the five levels of surge.

Notes on Katrina's surge levels

Not all of the information on Katrina's surge along the MS Gulf Coast has been made available. The initial NHC Katrina report did not go into extensive detail about the surge.

High water marks do not by themselves denote surge levels. High water marks, especially outdoor ones, also include height from waves. Waves right at the shoreline can be quite high. Allegedly a DVD with amateur video which was distributed locally in limited quantities in MS, showed approximately 30 foot waves at the shore in Gulfport. Wave estimates at the shore there were already in that range; waves on top of the 20+ foot surge there were large enough to wash all the dolphins out of their 30 foot high tank at the marina. However wave action, even as small as half a foot, can travel very far inland. Tides are also a factor in computing the actual surge. Tides along the MS Gulf Coast are not a significant factor; the different between high and low tides is only a couple of feet at most. This factor is easy to take into account as the times and heights of high and low tide are known. These factors must be subtracted to obtain the water height generated from the hurricane surge.

Just as with sustained wind values, identifying the highest level of surge is not the same thing as saying that level of surge occurred everywhere. It is important to quantify the extent of the area flooded by each category of surge.

We can make an unofficial but informed guess as to what areas of the MS coast received what categories of surge, based on information currently available, with the caveat that it may be changed later, and we are not 100% certain of its accuracy.

What tools are currently available on the internet to determine this information?

First, FEMA has published maps of the surge on the MS coastline. These maps show an extremely limited number of high water marks, mostly outside, and that information is too sparse right now to give an overall picture of the surge. Along with these selected high-water marks (which the NHC Katrina report may possibly have implied are not valid because the wave and tide levels have not been subtracted yet), the FEMA maps show all areas which were flooded, by some level of water, by the surge. This may mean only one foot of water from surge (as in the parking lot of the Jackson County sub station in Ocean Springs), to 25 feet of water from surge (as along the southern coast of the Waveland / Bay St. Louis area).


Second, we can use detailed online elevation maps such as Topozone, to identify the elevation at any location along the coast.


Third, we can use the Hurricane Evacuation Study (HES) maps for Mississippi, from the USACE web site. These maps were generated from SLOSH runs (the parameters for the runs are documented as well), and seem to be extraordinarily accurate. These maps show what areas of each county, down to individual addresses, would be flooded for each of the five hurricane category classifications. The HES maps do not show a range of heights associated with each hurricane category, and there is a good reason for that: the height differs with each location based on surrounding topography.


By comparing the elevation maps to the HES maps, we can determine at what level each category of surge begins, based on the location. Thus, Category 4 surge begins at 21 feet for BSL, Pass Christian, and Ocean Springs, but at only 15 feet for Pascagoula. This last may have been an error on the part of the model, underestimating the vulnerability of this location, because these Cat 4 levels on the map were flooded, or there may have been certain characteristics of the surge that resulted in an anomaly with higher surge here, because the flooding of the Pascagoula River Basin in general was extreme (
http://www.nasa.gov/vision/earth/lookingatearth/h2005_katrina.html ).

Fourth, FEMA has also provided an overview map with their estimates on the height of the surge across the MS coastal region.


Finally, to back up the FEMA flood maps, we can go directly to the aerial images from NOAA taken shortly after the event (but of course this would be after most of the floodwater had receeded). It cannot always be seen from these maps which areas were flooded. Some places, such as in a large part of Hancock County, everything is covered with mud, but other places will have not discernable sign, and you cannot always go by the debris line as an indicator either.


Based on this information, and assuming it to be accurate, we can answer the following questions:

What areas of the MS coast experienced Cat 3 level surge from Katrina? What areas, if any, had Cat 4 level surge? Cat 5? Where did this occur, and how large were these areas?

This is not completely straightforward. It is clear that the highest level of surge did not go very far inland. All of the areas that experienced the highest levels of surge were right on the shore, and most are so low they already flood at Cat 1 level. For those we would want to rely on accurate high-water marks to determine what level surge occurred. But that information is not available right now. Luckily we can go by the FEMA overview map to determine where these areas are. Secondly we can look at the areas along the coastline that were at an elevation of Cat 4 or Cat 5, and see if any of these areas flooded. The problem with this method is that there is very little actual real estate along the entire coastline that is that high, as the MS coast is one of many areas in the US that is a flood plain. Also, these areas may not all be right on the coast.

In addition, the FEMA overview map only lists the surge in terms of feet. How can we determine what level of surge that corresponds to? Considering it can be different depending on location, we have to first use the elevation maps in conjunction with the HES maps to find out where Cat 3, Cat 4, and Cat 5 surges begin.

Before we get into this level of detail, we find that at a high level, comparing the FEMA overview map to the HES map, solid Cat 3 surge occurred along the entire MS coastline. This Cat 3 surge finally ended, inland, just NE of Pascagoula City limits, at around 611 and Old Mobile Hwy. The extensive amount of land to the south of that location, all the way into AL and to Mobile Bay, was at Cat 1 and 2 level, and was all flooded. So the Cat 3 surge ended inland, just miles short of the AL border. Cat 1 and 2 surge extended eastward into Alabama. On the western edge of the MS coast, in Hancock County, the surge ended just south of the NASA Stennis facility on the MS / LA border, and just north of Kiln and the Diamondhead areas. The most extensive area of inland surge was on the eastern edge of the MS coastline, along the Pascagoula River Basin, and this is predicted on the MS HES maps.

This, just by itself, is really the most remarkable thing about Katrina's surge: the extent of the Cat 3 surge, not the small area that may have been affected by higher Cat 4 or 5 surge.

Did any of these areas at higher surge levels exist?

We know from the overview map that the highest levels of surge, in feet, were along the southern shore of the Waveland / Bay St Louis area, the Diamondhead bay shore area south of I-10, and an area of the coast from about Menge Ave in the Pass, east to the Long Beach / Gulfport border, so we can decide that the coast on either side of Saint Louis Bay is a good place to start identifying the highest level of surge.

Also, we can use the MS HES maps to locate any land that is at Cat 4 or Cat 5 surge level in Hancock and western Harrison Counties. We find that there are very few areas and that they are very small. Just south of the BSL bridge we find the eastern end of four small city blocks that are at Cat 4 level right along the shoreline. Another area of land that will not flood until Cat 4 or Cat 5 level is SW of there, and runs inland, parallel to the southern shoreline, cutting across the man-made lake for the water treatment plant (an easily-found location on a map). The remainder of the Hancock County shoreline, and quite a ways inland, will flood with a Cat 3. In western Harrison County, along the shoreline, we find only one narrow area, starting just west of Menge Ave in Pass Christian, that runs east along the shoreline into Long Beach, Gulfport, and Biloxi, that will only flood at Cat 4 or Cat 5 level.

Locating these areas on topozone.com, and following the brown elevation lines (which are given every five feet, for instance 15, 20, and 25 foot elevations), and comparing with the MS HES maps, we can make a general assessment at what elevation Cat 4 and 5 start for these particular locations. We find that it looks like Cat 4 starts at around 21 feet in elevation in both places, and Cat 5 at 24 feet for BSL, and 25 feet for the Harrison County area previously mentioned. This is a guess, but is probably not off by more than a foot.

Now, we can use the FEMA flood maps to see how much of each of these areas did actually flood.

In BSL, we find that everything was under water except for most (but not all) of the areas that only flood with a Cat 5 surge. We find that the 25 foot surge identified on the FEMA overview map did not reach far enough inland to affect any areas that were not already flooded. We find that all the tiny areas of land at Cat 4 did flood, and the edges of the Cat 5 area around the water treatment plant flooded. So we know that the highest surge in this area was approximately 24 to 25 feet. Perhaps the area on the Waveland / BSL coastline received higher surge, even though they were already well under water, but we will have to wait for accurate high water marks to assess that.

In eastern Pass Christian, we find that the areas that are at Cat 4 level flooded, but the strip of land at Cat 5 level (beginning at 25 feet of elevation) did not. Since this area is right on the shoreline, we can conclude the surge there reached 25 feet but did not go much over that, if any, and most likely did not reach Cat 5 level.

We can conclude that very small areas of the MS coastline, most likely less than one percent of the land on the MS coast that was flooded directly from surge, were subjected to a surge that just barely edged over the Cat 5 level, although the total area receiving surge at the Cat 5 level was so small compared to the total area of land inundated by surge, that it is almost negligible, statistically speaking. Most of the area receiving a Cat 5 level surge was already so low that it was well underwater, the difference in the height of the surge was probably not a significant factor in incurring the total property devastation, but, if it can be quantified, will be useful for denoting the record height of the surge. Another small area, bordering that, perhaps a couple percent of the total area, received Cat 4 surge. The areas that were on the shore were also devastated by waves on top of the surge.

The majority of the coastline received Cat 3 surge, and the area receiving this level of surge covered a wide range that was unprecedented, spanning the entire MS coastline, and reaching inland a considerable distance along all but a few miles close to the AL border. The area receiving Cat 1 and 2 level of surge was even more extensive, reaching completely to the northern Jackson County border, in eastern MS, and into AL, crossing Mobile Bay.

160. cozumeldude
7:20 PM GMT on December 22, 2005
Looking at Katrinas amount of damage and destruction to me is amazing. I live in Cozumel and we were here on the island for Wilma. Wilma stayed here for close to 50 hours at CAT4+ and we did have a lot of damage but nothing compared to New Orleans. I am thinking it must be because everything in mexico is concrete and we dont have many tall buildings.

159. CrazyC83
6:50 PM GMT on December 22, 2005
You're partly right about Charley, although it was also a very small storm in size, which didn't get the wave action going. That was basically the opposite of what happened with Katrina. It was more like a 20-mile-wide tornado than anything...
Member Since: September 19, 2005 Posts: 0 Comments: 142
158. WeatherWeasel
5:46 PM GMT on December 22, 2005
Wow...looks like NHC stirred up a hornet's nest. I think that what this all shows is that the current classification system is need of an overhaul. Hurricanes are very dynamic events. Wind speed, wave heights, storm surge are all variables that the current system does not address as a whole. Downgrading (or upgrading) a storm does not change the effects of the storm. It did what it did, and what government officals (and blog commentors) think don't change that. What really needs attention to prevent this in the future is the tools we use to monitor weather. What all the instruments that failed show us is that we have a system that is not designed to withstand the actual weather it may encounter. I lost a house and half my possessions to Frances and Jeanne, and it's irrelevant how they were classified. Changing a number does not change what happened. The classification is NOT the storm. The storm is the totallity of all the things that everyone here has mentioned, and then some. As a final example, there has not been much mention of rainfall totals, yet that is sometimes more damaging than the winds for people inland. (I lived through Agnes as a kid well inland from the Chesapeake Bay, yet lost some friends to flash floods from rainfall. My guess is this debate will go on for years. It won't change anything for those that lost everything.
Member Since: October 18, 2005 Posts: 1 Comments: 50
5:12 PM GMT on December 22, 2005
AMEN, brutha! My in-laws live in PGI...I agree 100%

Tampa Steve
I live in PGI too. All of PGI would be gone if Charley had the "normal" Cat 4 surge. I might not be here today. We rode out the storm in the closet with life jackets, pool floats and an ax to take to the attic if needed. God, what a day I will never forget. I will definitely not stick around for anaother and risk it ever again. I have had motel reservations made for every storm after Charley and will do the same next year.Where do your in laws live? We are renting a place over here and moved in two monthes before Charley roared through. Oh by the way I am a sista LOL
156. Pensacola21
5:11 PM GMT on December 22, 2005
Hey Code1, Merry Christmas! Email me sometime :-)
Member Since: September 16, 2005 Posts: 30 Comments: 3912
155. lightning10
4:18 PM GMT on December 22, 2005
Good morning everyone,

Hope everyone is haveing a good day. For Southern California a large high sits over the area like a huge brick. In Southern California my christmas tempture will be in the 80's. Thats not holiday like :-(. I remember last year winter kicked into high gear the day after christmas where we had on and off rain from the 26 of December tell January 10th if my memory is correct. I also beleave that the city of LA got the second most amount of rain ever in a 24 hour period someing like 5.30 inces. For LA that is something I would probally never see again if I lived around the area for the rest of my life.

This year however I have already wrote off this winter as below normal and am looking toward next year.
Member Since: November 24, 2005 Posts: 41 Comments: 630
154. TampaSteve
3:49 PM GMT on December 22, 2005
SWFLKR wrote:

" think after seeing these devestating hurricanes the past two years all of us have to realize there isn't an "exact" to what each catagroy a storm can do. In Punta Gorda wheere I live on the water a "normal high end Cat 4" storm we would all be under water from the surge. The highest elevation home is at 10 feet. But as you know with Charley due to its size, fast moving and strengthening ect.. we didn't get the deadly surge just the wind damage. But now only what 18 short months later the majority of the clueless in town say oh well we lived through Charley and look we are still here. I always voice my opinion saying yes but remember if it had been a "normal Cat 4 the whole county would have been washed away. And they still don't get it.... Hello???"

AMEN, brutha! My in-laws live in PGI...I agree 100%!
153. TampaSteve
3:46 PM GMT on December 22, 2005
Dear NHC,

We require an explanation, given in a sound, scientific manner, and supported by verifiable, objective evidence, regarding the following two things:

1. How you arrived at your final landfall wind speeds at Buras, LA and the MS Gulf Coast, when numerous measurements from inland stations at different points along the storms path clearly indicate much higher wind speeds at landfall.

2. How a supposed "Category 3" hurricane, with a landfall strength and windfield size comparable to Hurricane Ivan of last year, carried a surge almost twice the height of Ivan's into the Gulf Coast.


2:57 PM GMT on December 22, 2005
I think after seeing these devestating hurricanes the past two years all of us have to realize there isn't an "exact" to what each catagroy a storm can do. In Punta Gorda wheere I live on the water a "normal high end Cat 4" storm we would all be under water from the surge. The highest elevation home is at 10 feet. But as you know with Charley due to its size, fast moving and strengthening ect.. we didn't get the deadly surge just the wind damage. But now only what 18 short months later the majority of the clueless in town say oh well we lived through Charley and look we are still here. I always voice my opinion saying yes but remember if it had been a "normal Cat 4 the whole county would have been washed away. And they still don't get it.... Hello???
151. code1
2:32 PM GMT on December 22, 2005
Merry Christmas Atmos! Good to have you back. Be safe on your travels this season.
Member Since: September 18, 2005 Posts: 66 Comments: 13872
150. atmosweather
2:23 PM GMT on December 22, 2005
Good morning everyone,

Since I will be away until the 30th and won't be able to post I would like to wish all of you a very merry Christmas. As soon as I get back I will continue with my blog entry on Hurricane Katrina.

Thank you everybody and enjoy the holiday period

Rich (Atmos)
Member Since: September 24, 2005 Posts: 33 Comments: 9265
149. KatrinaRitaWilmaZeta
5:00 AM GMT on December 22, 2005
well good night tornadoty and oh ever is on her
148. tornadoty
4:59 AM GMT on December 22, 2005
Good night KWRZ. And to all of you also. I'm hitting the hay.
147. KatrinaRitaWilmaZeta
4:56 AM GMT on December 22, 2005
tornadoty wow i hop the nhc get back to you did you see my last post

osted By: KatrinaRitaWilmaZeta at 4:48 AM GMT on December 22, 2005.
tornadoty well i think i am going to call it a night and get some ZZZZ so go fix up where ever you need to fix up on my post send me a e mail of whe you fix up i will look at it and i will get back to you has soon as i can

did you see this part yet?
146. tornadoty
4:52 AM GMT on December 22, 2005
Wednesday, December 21, 2005

To whom it may concern:

I have read the National Hurricane Center report on Hurricane Katrina, issued Tuesday, December 20th, 2005. I have a couple nagging questions that I feel must be answered concerning Hurricane Katrina.

1. In section b, paragraph nine, sentences ten and eleven, it is mentioned that sustained Category 4 winds of 135 MPH (115 kt) may have reached the southeastern coast of Louisiana . If this did occur, would Katrina not count as a Category 4 strike on Louisiana?

2. I understand how the expansion of the pressure field could lower the winds in the hurricane. However, I was looking at the advisories and report on Katrina and comparing them to Hurricane Ivan of last year and I noticed a few things that puzzled me:

a. When Ivan made landfall on the Alabama Gulf Coast last year, it had winds of 120 MPH, a pressure of 946 mb, and a maximum hurricane-force wind radius of 105 miles. According to the Katrina report, the winds at landfall were 125 MPH, the pressure was an incredible 920 mb, and the wind field was 120 miles at the Buras, LA, landfall. Was the fifteen-mile difference in the radius of the wind field really enough to counteract the huge 26 mb difference in pressure between the two hurricanes and bring the sustained landfall winds so close together? I understand the effect that pressures in the surrounding environment of a hurricane affect the wind speeds in a hurricane, but were the environments surrounding each hurricane different enough to cause this large difference in pressure and wind relationships in the absence of a large difference in the wind fields?

b. The authors of the report explain on page 9 of the report that the huge surge of Katrina’s was caused by a large Category 3’s storm surge and the large wave action of up to 50 feet prior to landfall. The surge of Katrina, according to the report, is at least 28 feet. Hurricane Ivan produced an unofficial wave height of 131 feet over the Gulf, with numerous reports of 50-60 foot-tall waves. I know that the topography near the Mouth of the Mississippi River is a more surge-vulnerable and surge-enhancing area, but why is there a 12 feet+ difference in surge if Katrina’s was enhanced by wave action? Wouldn’t Ivan’s be higher if the wave action played a large role?

Thank you for taking time to answer these questions.

Anthony Lyza
145. KatrinaRitaWilmaZeta
4:49 AM GMT on December 22, 2005
tornadoty no i did not can i see it be for i go to bed
144. KatrinaRitaWilmaZeta
4:48 AM GMT on December 22, 2005
tornadoty well i think i am going to call it a night and get some ZZZZ so go fix up where ever you need to fix up on my post send me a e mail of whe you fix up i will look at it and i will get back to you has soon as i can
143. tornadoty
4:45 AM GMT on December 22, 2005
Did you get to read the letter I sent the NHC earlier today?
142. tornadoty
4:44 AM GMT on December 22, 2005
I think (hope) that we are at the very least spurring deep thought.
141. KatrinaRitaWilmaZeta
4:43 AM GMT on December 22, 2005
tornadoty do you think that the nhc would look at all of are e mail and get back to us
140. tornadoty
4:36 AM GMT on December 22, 2005
Also, Camille was beginning its weakening at landfall. The pressure had risen from 905 mb to 909 mb, leading me to believe that it was on the cusp of beginning an eyewall replacement cycle.
139. KatrinaRitaWilmaZeta
4:36 AM GMT on December 22, 2005
tornadoty you may fix it up has march as you like what did you like at it
138. tornadoty
4:35 AM GMT on December 22, 2005
Frederic was also strengthening upon landfall.
137. tornadoty
4:34 AM GMT on December 22, 2005
KWRZ, I love what you said, but I am just going to clean it up for the old geezers at the NHC. I hope you don't mind! I will check with you to make sure you approve of any changes before the petition is sent.
136. atmosweather
4:33 AM GMT on December 22, 2005
YES COLBY!!! And what about Camille??? NHC have so much to answer for
Member Since: September 24, 2005 Posts: 33 Comments: 9265
135. KatrinaRitaWilmaZeta
4:29 AM GMT on December 22, 2005
tornadoty was my ok and did i do it right
134. tornadoty
4:27 AM GMT on December 22, 2005
It was good guys. I'm just going to clean them up a bit. They are old men, we have to remember.
133. KatrinaRitaWilmaZeta
4:26 AM GMT on December 22, 2005
tornadoty you can fix it up a little bit uif they need it
132. KatrinaRitaWilmaZeta
4:24 AM GMT on December 22, 2005
tornadoty how was my?
131. tornadoty
4:21 AM GMT on December 22, 2005
Guys, hope I don't offend you great guys, but do you mind if I do a spelling and grammar check before I send the petition to the NHC?
130. KatrinaRitaWilmaZeta
4:19 AM GMT on December 22, 2005
yes we will get rian but i want some low snow
129. theboldman
4:15 AM GMT on December 22, 2005
i dont know david more rain i think were supposed to get more rain 2morrow
Member Since: September 8, 2005 Posts: 25 Comments: 2
128. KatrinaRitaWilmaZeta
4:13 AM GMT on December 22, 2005
yes it is what more can yo have for the last few days of 2005
127. theboldman
4:11 AM GMT on December 22, 2005
but it was amazing to have it on the first day of winter

Member Since: September 8, 2005 Posts: 25 Comments: 2
126. KatrinaRitaWilmaZeta
4:11 AM GMT on December 22, 2005
this t-storm dos not want to ene

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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