Ivan winds as measured by HIRT

YouTube · #1 Postby **hurricanetrack** » Sun Sep 19, 2004 11:58 pm

Hello all:

Just a quick note to let you know I was going over my data log from Ivan and I finally found the maximum gust on Gulf Shores. Our vehicle mounted anemometer- 4 meters above the ground- and solid as a rock, measured 114 mph gust at 2:02am EDT. The maximum sustained wind at that time was 89mph. The lowest pressure recorded on the vehicle's barometer was 947.6 MB at ~2:47am EDT.

I also know the water level was 8 feet above the ground where we found the vehicle- some 500 feet north of where we left it. It was near the ocean on the SOUTH side of Hwy 182 at 4:27pm EDT, 9/15. Then, when we found it Thursday afternoon, it was on the other side of Hwy 182 where the amusement park USED to be. That's about 500 feet north- or inland. The water reached our camera housings and breached one of them. That housing was 8 feet 3 inches above the ground. So 500 feet north of the Gulf, the water level was at least 8 feet high during the maximum envelope of water. Yikes. Too bad it was DARK. Otherwise I would be sitting on some serious footage. The cameras recorded well in to the night- but it was simply too dark to see anything. Oh well, I guess there are some things that God is not going to allow us to see on video. Notice how no one got Camille's surge on movie film either. Some things must remain a mystery- that's my take on it.

More to come...

Mark
HIRT/HLP

Matthew5 · #2 Postby **Matthew5** » Mon Sep 20, 2004 12:08 am

Only 89 mph with a gust of 114 mph? Which on top of that the 947 millibars had to be close to the center. So there is no way that this storm was a cat4...It may not have been a cat3! Maybe if that data was on the western eyewall...That this storm could still be a cat3...I'm sorry but if this data was on the Eastern Quad/Northeastern Quad...There is no way that this was stronger then 110 mph cat2.

tallywx · #3 Postby **tallywx** » Mon Sep 20, 2004 12:20 am

Not so fast. Check out the preliminary landfall wind analysis map from the hurricane hunters.

http://www.aoml.noaa.gov/hrd/Storm_page ... th_mph.pdf

If you know where Gulf Shores is on this map, it's right where that "80" mph number is. In other words, that means that the strongest winds of hurricane were east of Gulf Shores, and significantly stronger at that.

Aerial damage surveys show that typical upper-end category 3 wind damage occurred in Orange Beach, Perdido Key, and W. Pensacola Beach, but not Gulf Shores.

Guest · #4 Postby **Guest** » Mon Sep 20, 2004 12:33 am

So your gonna tell me that all the damage pics i seen of that area was caused by this? Something just doesnt fit right. I cannot see how all that damage was caused by what you or saying. Sorry but i disagree. Perhaps your equipment malfunctioned or something. But that seems a bit on the low side IMHO.

tallywx · #5 Postby **tallywx** » Mon Sep 20, 2004 12:37 am

The damage in Gulf Shores appears much less (mostly surge damage) than areas just to their east (both surge and wind damage). Therefore, the HRT's wind readings might be accurate for that location, but are certainly not reflective of where the strongest part of the storm came ashore.

ColdFront77 · #6 Postby **ColdFront77** » Mon Sep 20, 2004 12:51 am

The NOAA Hurricane Hunter Aircraft measured a minimal central pressure of 943 millibars for the 2:00 AM Central Time Advisory (#55B) on Thursday, September 16th.

Mark observed 947 millibars at 2:02 AM Central Time with a maximum sustained wind of 89 mph, gust to 114 mph. So the chances of a higher sustained wind and
higher wind gusts is possible in eyewall as tallywx alluded to.

Matthew5 · #7 Postby **Matthew5** » Mon Sep 20, 2004 12:58 am

Recon did not support the 115 knots up to almost the coast. The storm only was reporting around 115 knots flight level. On the last few recons.. The the depth of the ocean under the cyclone was much cooler in not that deep. The eddy that the storm run into earlier on was around 85 degrees. That is warm enough to support a cat4 hurricane. But as it got closer tot he coast the water cooled to around 81 degrees. That is hardly warm enough for a maj hurricane moving slowly. That is why it was weaking as it moved in for landfall. They most likely where not over 110 to 115 mph. With gust upwards to 130 mph. Another think is the storm was sucking in dry air which holds the highest of the winds above the surface. It was the surge that done a good amount of the damage. Why because this cyclone was a cat5 for a few days while over the southern Gulf of Mexico. What that doe's is form a large storm surge just like hurricane isabel last year that had one of the highest storm surges in history for the northeast.

SwampDawg · #8 Postby **SwampDawg** » Mon Sep 20, 2004 1:06 am

hmmmmm....ok....we still have the same amount of deaths reported and the same amount of damage reported. My point is that it doesn't matter what category it was. I'll put it into a category of death and destruction

Lindaloo · #9 Postby **Lindaloo** » Mon Sep 20, 2004 1:13 am

SwampDawg wrote:hmmmmm....ok....we still have the same amount of deaths reported and the same amount of damage reported. My point is that it doesn't matter what category it was. I'll put it into a category of death and destruction

Matthew5 · #10 Postby **Matthew5** » Mon Sep 20, 2004 1:14 am

I'm sorry for acting like that...But this hurricane was weaking upto the coast which means that the stronger down dives that come with a storm getting stronger was not there. I will say even with the dry air wraping in the mid part of the tropical cyclone that the winds where around 115 to 120 mph...With maybe a peak gust to 135 mph...If you think I'm wrong then give me the data to prove it??? I feel sorry for all the people that lost there houses.

https://www.youtube.com/user/senorpepr · #11 Postby **senorpepr** » Mon Sep 20, 2004 1:16 am

Matthew5 wrote:Recon did not support the 115 knots up to almost the coast. The storm only was reporting around 115 knots flight level. On the last few recons.. The the depth of the ocean under the cyclone was much cooler in not that deep. The eddy that the storm run into earlier on was around 85 degrees. That is warm enough to support a cat4 hurricane. But as it got closer tot he coast the water cooled to around 81 degrees. That is hardly warm enough for a maj hurricane moving slowly. That is why it was weaking as it moved in for landfall. They most likely where not over 110 to 115 mph. With gust upwards to 130 mph. Another think is the storm was sucking in dry air which holds the highest of the winds above the surface. It was the surge that done a good amount of the damage. Why because this cyclone was a cat5 for a few days while over the southern Gulf of Mexico. What that doe's is form a large storm surge just like hurricane isabel last year that had one of the highest storm surges in history for the northeast.

Recon found a flight level wind of 125-127kt near landfall. That would relate to 115KT on the surface.

HurricaneJim · #12 Postby **HurricaneJim** » Mon Sep 20, 2004 3:46 am

I'm with Swamp dog....thing was surge like I have never seen. It tore things up like you wouldn't believe.

To heck with wind on this one, it was the fifty foot breakers dumping metric tons of water that did it. The surve line was like a blender full of knives and boards.

Wind wasn't the monster here, it was the sea.

Jim
ukweatherworld.co.uk

SouthernWx · #13 Postby **SouthernWx** » Mon Sep 20, 2004 8:52 am

Matthew....I've surveyed tornado damage for many years, and have seen wind damage to homes in the Pensacola and Pensacola Beach areas consistent with F3 tornado damage....so that tells me gusts reached at least 160
mph....possibly 175-180 mph.

I saw a hi-rise condo with large pieces of the exterior walls missing...on the upper floors. That wasn't caused by storm surge.....not 75-100' in the air. It was caused by wind...gusts IMO between 160-180 mph. The airport at Pensacola was severely damaged....by wind. Even the AFOS anemometer and weather equipment was BLOWN away.

Remember....the strongest winds in a powerful hurricane moving NNE occur in the eastern eyewall. During Hugo, downtown Charleston (in the eye) didn't measure wind gusts over 125 mph....yet 20-40 miles to the NE (in the eyewall), wind gusts were estimated at 135-140 mph sustained with gusts of 160-175 mph.

Clearly the maximum winds in Ivan didn't occur at Gulf Shores....they occurred to the east....between Orange Beach and Navarre (including the city of Pensacola and Pensacola Beach). In this area, I estimate those peak 10 m winds at 135 mph sustained with gusts of 160-170 mph (and 175-180 mph gusts likely occurred 75-150' feet above the ground, based upon damage to high rise structures along the beachfront).

#14 Postby **mascpa** » Mon Sep 20, 2004 9:05 am

Whether Ivan was a cat 2, 3 or 4 is academic. The death and destruction he brought is reality.

therock1811 · #15 Postby **therock1811** » Mon Sep 20, 2004 9:10 am

KingOfWeather wrote:So your gonna tell me that all the damage pics i seen of that area was caused by this? Something just doesnt fit right. I cannot see how all that damage was caused by what you or saying. Sorry but i disagree. Perhaps your equipment malfunctioned or something. But that seems a bit on the low side IMHO.

Some of it is storm surge remember. Still I do have to respectfully disagree with that measurement Mark. It doesn't make a lot of sense to me either.

wxwatcher2 · #16 Postby **wxwatcher2** » Mon Sep 20, 2004 9:10 am

The fact is this was a strong and DEADLY hurricane.

It's easy to Monday morning quarterback this storm but the fact is it was a bad one.

#17 Postby **vbhoutex** » Mon Sep 20, 2004 9:11 am

Not that the wind matters at all, but I must agree with Perry here. My Mom lives in Niceville, 50 miles East of Pensacola and before the instruments went out there they were recording 90 mph gusts with sustained at hurricane force. That is a minimum of 75 miles East of the landfall!! Considering that winds in a hurricane do not cover an entire area but come in individual rainbands/storms within the system I find it entirely possible that winds in the Eastern eyewall did reach Perry's estimates in some areas.

That being said, I could care less about the final determination of the Category of Hurricane Ivan at landfall. We need to be concentrating on what we can do to help others in need and leave it to the scientists to make a final determination, which you can be sure they will, using every bit of data avavilable to them from every source availble to them including Mark's readings.

karenfromheaven · #18 Postby **karenfromheaven** » Mon Sep 20, 2004 9:46 am

I find this discussion useful and informative. I evacuated Panama City to Gainseville and returned to find our house intact and my sailboat peacefully at anchor where I left her. I'm sure my story would have been much worse had Ivan recurved more to the east. This discussion of wind strength helps me understand the relationship between damage on the ground and windfield predictions like the excellent GFDL animation on the PSU Met site. Karen

Website · #19 Postby **Brent** » Mon Sep 20, 2004 10:37 am

The surge with this storm was worse than I expected, as was the wind damage. If this was a Category 3, it was a strong 3(125-130 mph) with higher gusts as Perry stated. The surge with it was defintely Cat 4 surge though.

birdwomn · #20 Postby **birdwomn** » Mon Sep 20, 2004 7:47 pm

I am waiting for the overall analysis of this one, because it doesn't seem to be consistent from the data vs the damage overall. We shall see what the experts decide

Ivan winds as measured by HIRT

Ivan winds as measured by HIRT

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