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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He is officially on Pensacola Beach...he posted on twitter maybe 2 hrs ago.
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Quoting Patrap:
Need more HH data as were kinda lacking info at the moment.


I agree..... Just wondering how much longer before HH get into her again....

Taco :0)
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1139. 789
when do we get doppler
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OMG! Been glued all day, but just looked at someones post and can't believe how far Ida has traveled since shooting the gap...wasn't that only this morning. Days are starting to run together on this blog. This thing is gonna be here before we know it!
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Quoting taco2me61:
Hey Patrap I think Ida will win out from whats going on out there.... I also think she is moving faster than what they are saying.....

taco :0)


no he means the two steering influences; one from the east (Ridge) and one from the west (Trough)
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1135. Patrap
Need more HH data as were kinda lacking info at the moment.
Member Since: July 3, 2005 Posts: 421 Comments: 127673
Where is Jim Cantore?

Has there been any Cantore sightings in Miss or Alabama?
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Quoting DestinJeff:


is that a cold cloudtop or center clearing there? i suspect just a cold top

that is the eye
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Hey Patrap I think Ida will win out from whats going on out there.... I also think she is moving faster than what they are saying.....

taco :0)
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1131. Patrap
Somethings going on, as two influences.. one east,one west of Ida try to win out .

Member Since: July 3, 2005 Posts: 421 Comments: 127673
Quoting DestinJeff:


is that a cold cloudtop or center clearing there? i suspect just a cold top


It apears to be an eye opening from what I'm seeing anyway...

Taco :0)
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Hurricane Warning issued in Mississippi all the way from Pascagoula to Ocean Springs. and Hurricane watch from Biloxi to portions of Louisiana
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StormW,
Do you foresee any severe weather tornado threat for Central FL should I keep my weather radio on tomorrow night and Tuesday? Or ids everything too far away for such a threat?
Member Since: July 7, 2005 Posts: 0 Comments: 5194
1124. 789
tampa spin is worth his weight in gold for all he does and were is 456
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Quoting constantine:


Living in Florida, I have been visiting these boards for years. I have rarely posted but have enough common sense to know that TampaSpin and a few others try very hard to offer solid information based on what they see.

Some of the most recent posts in response to TampaSpin's message are imbecilic at best.

Apologies for perhaps drawing a bit more attention to this than was necessary but I am sure most will agree that TampaSpin's posts are always well-written and welcomed by most.

Thank you for your time.



I agree with this too..... Keep up with the great work TampaSpin....

Taco :0)
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Member Since: Posts: Comments:
Quoting constantine:


Living in Florida, I have been visiting these boards for years. I have rarely posted but have enough common sense to know that TampaSpin and a few others try very hard to offer solid information based on what they see.

Some of the most recent posts in response to TampaSpin's message are imbecilic at best.

Apologies for perhaps drawing a bit more attention to this than was necessary but I am sure most will agree that TampaSpin's posts are always well-written and welcomed by most.

Thank you for your time.



Very well said, I agree TampaSpin does a great job
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Thanks to all that answered my post...looks like we might take a little water again. All puckered up and soon to be hunkered down...

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Quoting TampaSpin:


I don't want this dam thing......already been through this stuff before.....when i say a faster turn....did i say to TAMPA..geeesh...

Tell me is there a hook in the NHC forecast..Yes..if it hooks even 50miles faster than what NHC has down the middle the way the shape of Florida is would take it near the Tallahassee area......thats my only point....and i think a quicker turn is coming based on the progression of the front.....thats not wishcasting at all.

Quoting TampaSpin:


I don't want this dam thing......already been through this stuff before.....when i say a faster turn....did i say to TAMPA..geeesh...

Tell me is there a hook in the NHC forecast..Yes..if it hooks even 50miles faster than what NHC has down the middle the way the shape of Florida is would take it near the Tallahassee area......thats my only point....and i think a quicker turn is coming based on the progression of the front.....thats not wishcasting at all.



Living in Florida, I have been visiting these boards for years. I have rarely posted but have enough common sense to know that TampaSpin and a few others try very hard to offer solid information based on what they see.

Some of the most recent posts in response to TampaSpin's message are imbecilic at best.

Apologies for perhaps drawing a bit more attention to this than was necessary but I am sure most will agree that TampaSpin's posts are always well-written and welcomed by most.

Thank you for your time.

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Quoting sarahjola:


actually looking at the loop, I am seeing a jog due north in the last few frames; have to see if that is temporary or the beginnings of that turn north
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Right now its looking @ just east of Pensacola.. but I have no clue on what will evolve after going inland. My best call is for the LLC to move east then southeast around florida (eighther coast) while the midlevel low and moisture gets pulled ENE thru Georgia-S Carolina and form a Bara Low out in the Atlantic...

Landfall I expect this to be around 85mph still.
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Quoting BurnedAfterPosting:


She is not quite halfway, looks to be about on track; noticed a wobble due north though at the end

Looks 1/2 way to these eyes .. looks to be accelerating.
Member Since: August 27, 2008 Posts: 0 Comments: 1497
Quoting rareaire:
Nope Tampa its coming to your house. I called it 5 months ago and by golly im gonna be right at some point, lol



I remember that.....not this time....i don't like the camping outside with no Electricity or water for 5 days stuff....its not im my plans......LOL
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Quoting PcolaDan:
Santa Rosa schools, Okaloosa schools, UWF, PJC all open tomorrow according to WEAR TV.


Yeah, I just saw that on their website. Baldwin and Escambia (FL) are closed, Santa Rosa and Okaloosa are open. Crazy. By the time school lets out, the winds could be too high for buses to be out on the road.

I'm guessing they're just waiting the night and will decide early in the morning. Hopefully they'll think of families trying to keep their kids safe, rather than trying to squeeze another day of school in.
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Quoting DestinJeff:


got it, but man the near-term modeling is in very good agreement. and NHC has even backed off the severe hoof to some degree (keeps it over panhandle in 5 day track). i understand the cone supports your argument, but that consistent modeling is very hard to ignore since it is near-term


The models can be and have been wrong before (not saying they will be here though)... believe they were for Hurricane Charley and other storms. We are talking about a storm that will be making an extratropical transition as the time of the curve as well.

I actually like the Panhandle landfall but a curve east is definitely possible.
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Quoting sarahjola:

if the eye is where i think it is, it looks like it went west a little. am i wrong?
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Quoting BurnedAfterPosting:


She is not quite halfway, looks to be about on track; noticed a wobble due north though at the end


Yep saw that, now we need to see if a trend follows.
Member Since: September 6, 2009 Posts: 2 Comments: 3710
1106. Patrap
Ida's Northern Outer band can now be seen on Mobile Doppler Long Range..lower right

Member Since: July 3, 2005 Posts: 421 Comments: 127673
Quoting Patrap:


Well..looking at the NOAA Loops carefully the Last 10 minutes. I think maybe Ida is Bumping up against the FLow on her west side in the last frames.

But Shes still making headway nnw,..so either were gonna see a N trend soon,or Ida may tack west a tad more.

Hard to say,hard to forecast..But,
I would pay close attention if in the Watch and Warned Areas.

Floater - Rainbow Color Infrared Loop

Rainbow Still





Crucial to when she does go north though.
Member Since: September 6, 2009 Posts: 2 Comments: 3710
Quoting TampaSpin:
It would not surprise me if it came ashore near the Suwannee River area......JMO.....wow what some edgeeee peeps tonite....LOL

Nope Tampa its coming to your house. I called it 5 months ago and by golly im gonna be right at some point, lol

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Quoting 850Realtor:
Within 10 minutes local news showed storm surge of 5 ft...then in full forecast says 5-7 ft...
I know there is nothing we can do about it regardless, but it would be nice to have the accurate info for those of us in low lying areas.
Is high tide added on top of storm surge amount or is it already factored in? Storm surge= 5 ft total or 5 ft Storm Surge plus an additional 2-3 ft from high tide= 7-8 ft total?

The tide is added to or subtracted from the surge. ex. High tide +1 ft. surge +5 ft. total 6 ft.
Jesse
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Quoting SouthALWX:
Ida looks to be halfway between 00z TP and 12Z TP .. don't think it's 6z yet ..


She is not quite halfway, looks to be about on track; noticed a wobble due north though at the end
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Quoting TampaSpin:
It would not surprise me if it came ashore near the Suwannee River area......JMO.....wow what some edgeeee peeps tonite....LOL


Hey, I've been rooting for you all day. :)
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Ida looks to be halfway between 00z TP and 12Z TP .. don't think it's 6z yet ..
Member Since: August 27, 2008 Posts: 0 Comments: 1497
Quoting Patrap:


Well..looking at the NOAA Loops carefully the Last 10 minutes. I think maybe Ida is Bumping up against the FLow on her west side in the last frames.

But Shes still making headway nnw,..so either were gonna see a N trend soon,or Ida may tack west a tad more.

Hard to say,hard to forecast..But,
I would pay close attention if in the Watch and Warned Areas.

Floater - Rainbow Color Infrared Loop

Rainbow Still




if the eye is where i think it is, it looks like it went west a little. am i wrong?
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Weather Channel has a crew in Pascagoula Mississippi already. I wanted to stop my car and advise them to move several miles to the east maybe Pensacola or Gulf Shores Alabama, but would they listen to me? Oh well all I hope is that they do not know something we don't. This ane took me completely by surprise. I am staying home though.
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Quoting 850Realtor:
Within 10 minutes local news showed storm surge of 5 ft...then in full forecast says 5-7 ft...
I know there is nothing we can do about it regardless, but it would be nice to have the accurate info for those of us in low lying areas.
Is high tide added on top of storm surge amount or is it already factored in? Storm surge= 5 ft total or 5 ft Storm Surge plus an additional 2-3 ft from high tide= 7-8 ft total?


from Wikipedia:
"Two different measures are used for storm tide and storm surge measurements. Storm tide is measured using a geodetic vertical datum (NGVD 29 or NAVD 88). Since storm surge is defined as the rise of water beyond what would be expected by the normal movement due to tides, storm surge is measured using tidal predictions, with the assumption that the tide prediction is well-known and only slowly varying in the region subject to the surge. Since tides are a localized phenomenon, storm surge can only be measured in relationship to a nearby tidal station. Tidal bench mark information at a station provides a translation from the geodetic vertical datum to mean sea level (MSL) at that location, then subtracting the tidal prediction yields a surge height above the normal water height."
I think this means on top of the tide.
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Quoting reedzone:


I was in school, my teacher told me to come up and track it for the class (11th grade). I mentioned to them that if the front is stronger, Charley could make a run for Orlando instead of Tampa. The next day, Charley made a run for Tampa. I also predicted Rita in 2005 to become a monster in the GOM and hit the borderline of LA/TX, a few days later, it did. Then I was called a noob on flhurricane for predicting Humberto in 2007 to at least be a 65 mph. Storm at landfall when it was a 40 mph. at that time, a few hours later, it was surpassing 65 mph. before landfall.


Weather is unpredictable and the forecasted turn right early is within the cone, so it is entirely possible

I think some just like to ruffle feathers on here lol
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1095. Patrap
Quoting sarahjola:
patrap-can you elaborate a little? give an opinion. what do you think?


Well..looking at the NOAA Loops carefully the Last 10 minutes. I think maybe Ida is Bumping up against the FLow on her west side in the last frames.

But Shes still making headway nnw,..so either were gonna see a N trend soon,or Ida may tack west a tad more.

Hard to say,hard to forecast..But,
I would pay close attention if in the Watch and Warned Areas.

Floater - Rainbow Color Infrared Loop

Rainbow Still



Member Since: July 3, 2005 Posts: 421 Comments: 127673
It would not surprise me if it came ashore near the Suwannee River area......JMO.....wow what some edgeeee peeps tonite....LOL

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TampaSpin..where do you feel landfall will be and what will happen?
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Tampa I know everybody going to think the good stuff must have arrived in Miami but looking at the satellite I think a chunk of energy has spun off and looks to be heading your way. I don't know if it will last but you may see a little weather later.
Member Since: August 18, 2008 Posts: 0 Comments: 3112
Thanks StormW for the update
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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.