Ida takes aim at the U.S. Gulf Coast

By: Dr. Jeff Masters , 11:17 PM GMT on November 08, 2009

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Hurricane Ida burst into the Gulf of Mexico as a Category 2 hurricane with 100 mph winds this afternoon, and is poised to deliver a solid blow to the U.S. Gulf Coast between Southeast Louisiana and the Florida Panhandle on Tuesday morning. Radar imagery out of Cancun reveals that Ida has retained its tight inner core this afternoon, with only limited rain bands affecting Mexico and western Cuba. Top winds at Cancun, Mexico today were only 15 mph, despite the fact that Ida passed just 60 miles east of the city. Infrared and visible satellite loops show little change in the intensity of Ida's heavy thunderstorms this afternoon, but the cloud pattern is beginning to become distorted due to strong upper-level winds from the southwest that are creating 20 - 25 knots of wind shear over the hurricane. Water vapor satellite imagery reveals a large area of dry air to the southwest of Ida, but this dry air has not yet intruded into Ida's core. The latest 5:30 pm EST vortex report from the Hurricane Hunters showed that the central pressure had risen 1 mb, to 977 mb, but that the surface winds were still near 100 mph. They noted that the eyewall was open to the east, a sign that Ida's inner core may be in trouble.


Figure 1. MODIS satellite image from NASA's Terra spacecraft, taken at 1:35 pm EST 11/08/09. Image credit: NASA.

The intensity forecast for Ida
The high wind shear of 20 - 25 knots currently affecting Ida is forecast to persist at that level until Monday night. With the storm now beginning to show a distortion of the cloud pattern due to this shear, it would not be a surprise of the shear managed to inject some dry air into Ida's core Monday morning, significantly weakening the storm. Aiding this process will be cooler waters. Early Monday morning, Ida will be crossing over waters of 26°C, which is barely enough to support a hurricane. By Monday night, wind shear is expected to increase to 40 knots, which ordinarily would begin to tear the storm apart. This wind shear is due to an extratropical low pressure system over the western Gulf of Mexico, and this low will begin dumping cold, stable air into Ida Monday night through Tuesday. This will cause Ida to begin transitioning to an extratropical storm, and it is possible that during the transition Ida's winds will die down relatively slowly, despite the wind shear. The intensity forecast has a high amount of uncertainty, and I wouldn't be surprised at a landfall strength anywhere in the range of 45 mph - 80 mph. My personal best guess is a 50 - 60 mph tropical storm at landfall. Regardless of Ida's strength at landfall, the storm will be able to dump 4 - 8 inches of rain along the Gulf Coast, from New Orleans to Panama City. Isolated tornadoes will also be possible, primarily to the right side of Ida's track.


Figure 2. Maximum storm surge (depth of water above ground) for a Category 1 hurricane with 85 mph winds moving north-northeast at 15 mph. Ida is expected to be moving at this speed and direction at landfall, but will probably be weaker, so surges will not be this high. Image credit: NOAA SLOSH model run for Mobile Bay, 2008 version. Heights are given relative to the NAVD88 datum.

The storm surge forecast for Ida
Storm surge is the other major concern for Ida. With a strong high pressure system anchored over the U.S. today, the pressure difference between this high and Ida is creating a strong pressure gradient that will drive tides 3 - 5 feet above normal from New Orleans to the Florida Panhandle tonight. As Ida approaches on Monday, an additional rise in water will occur, and a large stretch of coast will be subject to very high water levels for an extended period of time. With battering waves building Monday afternoon into Tuesday morning, a significant coastal erosion event is shaping up. A particular concern is the western end of Alabama's Dauphin Island, where storm surges from four hurricanes over the past fifteen years have caused heavy damage to the low-lying heavily developed island. If Ida makes a direct hit on Mobile Bay as a Category 1 hurricane with 85 mph winds, a storm surge of up to six feet is possible there, assuming the storm hits at mean tide. The tidal range along the Gulf Coast varies by about 1.5 feet between low and high tide (Figure 3). High tide is near 2 am EST on Tuesday, but the official NHC forecast currently has the storm hitting between 6 am - 9 am, when the tide will be going out, so the storm may indeed be hitting at about mean tide.


Figure 3. The tide forecast for the Gulf Coast calls for high tide to occur around 2 am EST Tuesday morning. Ida is expected to hit later that morning, while the tide is going out.

I'll have an update Monday morning.

Links to follow:

U.S. Severe Weather Page
Cancun radar

Jeff Masters

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hey guys - before you get so upset -- check 456 blog - he isn't banned, he doesn't feel well so he signed off.

Atmo made a joke - and unfortunately it got spread as the truth.
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1238. ...and the shear
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Quoting xcool:




so la. coast is now under hurricane warning?
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See how Ida has flattened out on the WNW side the Cirucalation...she is felling the trough now......
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Rules are rules fellas we must stay between the lines. I call them Green Lizard awards now in honor of Storm W. By the way storm is Ida leaving a little something behind s. of Cuba. Some of the models spin something up down there even before were done with this mess I guess I shouldn't include me.
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Ida looks like a strong TS then a hurricane too me



this is one pathetic 105mph hurricane i have evere seen in my life
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Anybody looking at these HH findings?

991.3 is the lowest they could find on the first pass..
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In my local weather news it said it was pretty imenant that Ida was coming into Pensacola, has that changed?
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well now they say it is moving North at 14 mph....

Taco :0)
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Ida is coming apart

Now

997.1 mb (~ 29.44 inHg)
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Looks like the gradual weakening is finally underway. Climatological southwesterly 200 mb winds win yet again.
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Quoting Stormchaser2007:
The convection seems displaced from the center.

Should be around 70 knots or so.


if it was displaced that would put the center east of 87W, which it is not
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1228. xcool



Member Since: September 26, 2009 Posts: 2 Comments: 15684
1227. 786
Just want to say good luck to anyone here that will be effected by Ida's path, hope you are prepared and that she will weaken before landfall, prayers are with you.
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Quoting Patrap:


Yes,,repeatedly with the repeating Same Ol..again

DH taking care of it...no weapons involved, of course!
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Quoting BurnedAfterPosting:


I find it pretty pathetic that admin would ban one of the best posters on this site because he posted 1 off-topic image. His expertise would have really been appreciated tonight.

Way to go admin, you really have a clue


That is F'n BS.....one of the best this blog offers gets banned.....unreal.....The Admins. that run Dr. Masters site is pathetic to do such a thing. He's a feature blogger on top of it.......How funny.
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The convection seems displaced from the center.

Should be around 70 knots or so.
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Quoting theFatherofNature:
schools are closed in baldwin, escambia and santa rosa anyway


First I heard of Santa Rosa. All night they saying open.
edit:
WEARTV still says open
"Escambia County, Florida Schools Will Be Closed Monday And Tuesday. All Escambia County Administrative, Professional & Maintenance Personnel Report. Escambia County Food Service, Custodians And Teachers Do Not Have To Report.

Santa Rosa County Schools Will Be Open Monday

Okaloosa County Schools Will Be Open Monday

Baldwin County Schools Will Be Closed Monday

UWF will be open Monday, night classes and Tuesday classes to be determined Monday"
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Sorry lilith should have erased that.
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1205. MisipiGrl 11:19 PM CST on November 08, 2009
Agreed, I lived on West Beach Blvd...Wish I was back there...Sure miss Mississippi...Night all
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Quoting reedzone:
I'm serious, I think Ida is splitting due to high wind shear, anyone else seeing this?


satellite presentation is pretty lame for a 90-kt cyclone.
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1217. Patrap
Quoting NOLA2005:
Patrap, thanks for the link. Is your weather alert going of as often as mine?


Yes,,repeatedly with the repeating Same Ol..again
Member Since: July 3, 2005 Posts: 426 Comments: 128663
Quoting NOLA2005:
Patrap, thanks for the link. Is your weather alert going of as often as mine?


I know mine is.... I had to turn it off because my wife told me too....

Taco :0)
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Quoting PcolaDan:


Sounds smart to me.
schools are closed in baldwin, escambia and santa rosa anyway
warnings are getting closer. pearl river ms. just got a high wind warning. mandeville schools said they will close early. i bet in the morning they will close completely.
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1213. Patrap
Rain and T-storms Nwest of Ida,not associated with her.
But embedded wind gust to 35 Have been reported in them.
Member Since: July 3, 2005 Posts: 426 Comments: 128663
1212. lilith
Quoting gordydunnot:
Ida don't know,Ida don't know, Ida don't where the hurricane going to go until the hurricane blows.

Oh great - now I'm going to have that tune stuck in my head for the next week! :-)
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1211. xcool
start rain here in slidell .
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Ida dying a slow and painful death due to shear. Should see her winds get knocked down a bit.

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Quoting CosmicEvents:
I just got a tweet that weather456 was banned!
What's up?


I find it pretty pathetic that admin would ban one of the best posters on this site because he posted 1 off-topic image. His expertise would have really been appreciated tonight.

Way to go admin, you really have a clue
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Patrap, thanks for the link. Is your weather alert going of as often as mine?
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1207. emguy
I'm going with Tampa Spin's Map. he may even be a little too far north. I am looking at the CONUS water vapor and there's a hitch in the gitty up with the westerlies across the US, Mexico and the Central/Western Gulf. Advancing quickly and Ida is not far away from seeing these impacts time frame wise.
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I just got a tweet that weather456 was banned!
What's up?
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ajcamsmom...We lost all to Kat as well. I will definitely run if she takes a more northerly track. We already have everything prepared and a place to go, if need be. Because I live south of the tracks, I evac for anything above tropical storm strength. Some call it overkill, I call it safety :)
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Well I just don't like the fact that she is still moving NNW at a faster clip than what she was.... and if she stays on this track the cone of uncertainty will move back towards the west....

Taco :0)
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Quoting WeatherCaneFF1331:


i live in santa rosa county and ill be dang if my kids are going to school tomarrow in all this.


Sounds smart to me.
Member Since: August 22, 2008 Posts: 12 Comments: 6010
Quoting StormW:


Not yet.


OK thanks.
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Twins in the GOM.....nice convergence with the Xtratropical Low.....you can see how the trough has it on the move....
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Quoting TexasGulf:
Where is Jim Cantore?

Has there been any Cantore sightings in Miss or Alabama?

He was buying everybody shots at New York Nicks in Pensacola about a hour ago
Member Since: November 6, 2009 Posts: 0 Comments: 41
Here's one you can add, Dan......

Schooners (PCB)

http://www.schooners.com/multimedia/beachcam.htm
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Quoting TampaSpin:



The red is my forecast track...its not that much different really from NHC in miles from the turn to the right when it begins.....but look at the impact difference.
what did i do to you?????,lol.
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this think if this storm came in JULY or AUG this storm could have been march stronger
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1182. MisipiGrl 11:08 PM CST on November 08, 2009
If you are right about the wildlife being gone, you had better run...That's what I did when there were no birds on my pier the Saturday before Katrina hit, the ants, squirrels, opossums, raccoons, even the mosquitos were long gone...I got in my truck and followed them...glad I did...my house was gone when I finally got to go home...This doesn't look to be that bad a storm to me, but, I am no expert...
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The red is my forecast track...its not that much different really from NHC in miles from the turn to the right when it begins.....but look at the impact difference.
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List of cams along AL and FL, think most work. Should be interesting (I may not be able to watch) during the course of the day tomorrow and Tuesday. Of course provided there is power.

http://www.brett-robinson.com/webcams.html
http://www.bamabeachcams.com/
http://www.gulfcondos.com/webcam/
http://flhurricane.com/jjohnston/
http://www.lulusathomeport.com/webcam.php
http://www.alohasurf.net/
http://www.destinpasslive.com/navarre-beach.html
http://www.islandempress.com/webcam/
http://destincam.com/
http://innerlightsurf.com/pages/crosscam.html
http://piercam.net/
http://204.215.38.82/view/index.shtml
http://remaxsouthern.com/cam.htm
http://www.destinpasslive.com/sandestin-beach.html
http://sowal.com/beachcam.html
Member Since: August 22, 2008 Posts: 12 Comments: 6010
JSL Loop of Ida. The darker spot in the middle of the CDO is basically the center. I don't believe it's an eye, but really it sort of gives us a fair assessment of where the center is located. Still moving NW-NNW at a fast clip.

JSL
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1191. Patrap
Member Since: July 3, 2005 Posts: 426 Comments: 128663

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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.