Ida weakens to a tropical storm; tropical disturbance 96E kills 124 in El Salvador

By: Dr. Jeff Masters , 3:20 PM GMT on November 09, 2009

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Tropical Storm Ida is steadily weakening as it hurtles northwards towards the Gulf of Mexico coast. Rains from Ida have already pushed into south-central Louisiana, where radar estimates indicate up to an inch of rain has fallen. Winds along the Gulf Coast of Mississippi, Alabama, and the Florida Panhandle were 20 - 25 mph this morning, and will steadily increase today as Ida draws near. Winds at the Mississippi Canyon buoy 150 miles south of Gulfport, MS were sustained at 45 mph at 8 am EST this morning, with 19 foot waves.


Figure 1. Microwave "radar in space" image of Ida taken at 7:15 am EST on Monday, 11/9/09. The eye is visible as a dark spot, but the eyewall has partially collapsed. The strongest echoes are on the north side of the storm, and Ida's heaviest rains and highest winds will hit the coast tonight, well in advance of the arrival of the center. Image credit: Navy Research Lab, Monterey.

Infrared and visible satellite loops show that wind shear has substantially degraded the appearance of Ida, and there is very little heavy thunderstorm activity in the storm's eyewall. Most of Ida's heavy thunderstorms have been displaced to the north of the storm, due to strong upper-level winds out of the southwest creating 30 knots of wind shear. Water vapor satellite imagery reveals a large area of dry air to the southwest of Ida, and the shear has now driven this dry air deep into the core of the storm, significantly disrupting it. The latest 6:30am EST vortex report from the Hurricane Hunters reported that the eyewall was ragged, and the pressure had risen to 997 mb. A recent microwave satellite image of Ida (Figure 1) shows that the eyewall is weak and has partially collapsed. Ida's most intense thunderstorms are on the north side of the storm, and the heaviest rains and highest winds will hit the coast tonight, well in advance of the arrival of the center.

The intensity forecast for Ida
The intensity forecast models predict that Ida's winds will range between 50 - 65 knots (58 - 74 mph) at landfall. The high wind shear of 30 knots currently affecting Ida is forecast to increase to 40 knots by late afternoon, and 55 knots by midnight. With Ida now over waters near 26°C, which is barely enough to support a hurricane, and with water temperatures decreasing to 23°C near the coast, the combination of high wind shear and cold waters will act to significantly weaken Ida. However, Ida is beginning to transition to an extratropical storm, and it is often the case that during such a transition the winds will gain energy from the process, though that's looking unlikely in this case. I expect Ida's top winds will be in the 50 - 60 mph range along the coast tonight and Tuesday morning. Regardless of Ida's strength at landfall, the storm will be able to dump 4 - 8 inches of rain along the Gulf Coast and well inland. We can't rule out the possibility of an isolated tornado when Ida makes landfall, but the Storm Prediction Center Discussion maintains that the airmass in place over the Gulf Coast is relatively stable, and prospects for an appreciable severe weather threat appear low.


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 be much weaker, so surges will not be this high. Furthermore, the storm will not create this level of surge along the entire coast--the image above is a composite worst-case scenario for all the storms shown by the black tracks with arrows. 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 was driving tides 2.5 feet above normal at Shell Beach, LA (on the east side of New Orleans) this morning, one foot above normal at Dauphin Island, AL, and one foot at Pensacola, FL (Figure 3). NHC is now calling for a storm surge of 3 - 5 feet above ground level, which is a reasonable forecast even if Ida weakens further. A large stretch of coast will be subject to very high water levels for an extended period of time today and tomorrow, with battering waves on top of the surge likely to cause a significant coastal erosion event. A particular concern is the western end of Alabama's Dauphin Island, when even a strong tropical storm can cause significant damage to the low-lying, heavily developed barrier island. The tidal range along the Gulf Coast varies by about 1.5 feet between low and high tide, and high tide is near 2 am EST on Tuesday.




Figure 3. Observed vs. predicted water levels at three coastal stations. Top: Shell Beach, LA (just east of New Orleans); middle: Dauphin Island, Alabama; bottom: Pensacola, FL. The green line shows how high above normal the water is. For Shell Beach, it was 2.5 feet above normal at 9am CST, while it was just over 1.0 feet above normal at the other two locations. Image credit: NOAA Tides and Currents.

Comparing to Hurricane Kate
The last November hurricane in the Gulf of Mexico was Hurricane Kate. Kate struck the Florida Panhandle near Mexico Beach on November 21, 1985 as a Category 2 storm with 105 mph winds. According to Wikipedia, Kate killed five people in Florida and did $300 million (1985 dollars) in damage. Ida will cause relatively minor damage compared to Kate.

Links to follow:
U.S. Severe Weather Page
Wundermap for the Gulf Coast of Alabama.
Long-range radar out of New Orleans, LA.
Navarre Beach, FL webcam.
Coastal observations from the University of South Alabama.
Coastal observations from LSU.

El Salvador floods kill 124
Heavy rains that began on Thursday due to tropical disturbance 96E have killed at least 124 people in El Salvador, with 60 people still missing. The flooding hit the capital of San Salvador and rural areas to the east. The heavy rains were due to tropical disturbance 96E (Figure 4), which formed off the coast of El Salvador on Wednesday, November 4. The counter-clockwise flow of air around the disturbance pulled large quantities of moist, Pacific air over the coastal mountains in El Salvador, dumping heavy rains of up to five inches, according to satellite estimates. The rains must have been much heavier over a small area that the satellite could not resolve. The terrible devastation I'm seeing in news photos indicates much higher rains of perhaps 10 - 15 inches must have fallen in a concentrated area in the mountains.


Figure 4. Satellite image of tropical disturbance 96E, which moved over El Salvador Thursday through Saturday, bringing heavy rains. Also pictured is Tropical Depression Eleven, which intensified into Tropical Storm Ida later that day. Ida was not responsible for the flooding in El Salvador, though it may have helped pull 96E into El Salvador. NASA has a nice zoom image> of 96E from November 5.

I'll have an update on Ida this afternoon.

Jeff Masters

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Latest model 12Z outputs:

Member Since: August 14, 2008 Posts: 4 Comments: 5038
WOW :O!!!!

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Small burst of convection on visible. I expect it to either stay as a ts or loose just a bit of strenght before landfall.
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123. Tim, how do you get those hamweather images to post properly?
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I'm in Gulf Breeze, Florida...so I'll get a birdseye view of whatever happens. May try to squeeze out to the beach before they close the bridge.
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1195. TampaSpin 12:14 AM EST on November 09, 2009

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.



I posted the above late last night! I might have been off some!

Current MODELS




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My Local Weather:

John Wayne-Orange County, California

59 °F
Haze
Member Since: January 24, 2007 Posts: 317 Comments: 31946
Quoting gordydunnot:
Where they flying from shouldn't be long to get there.

Unless they nap or examine their schedules on their laptops in the cockpit...
Member Since: August 16, 2007 Posts: 6 Comments: 12463

Just starting to see the center or eye on Radar out of Mobile, AL.
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Quoting AwakeInMaryland:
Greetings, all. and Grothar! where you been, glad to see you. Been traveling? I've noticed you and NRAAmy have been MIA from the Blog at the same time...hmmmmm

In Greenland (Kalaallit Nunaat)watching the glaciers melt. Hey, my wife reads this blog!! Did you see Ike's animated image of Ida in post #95? Looks like a little bit more convection trying to ramp up. Hope everyone stays safe.
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Over all I have the NHC a A+ with the track of Ida, they did an excellent job in the face of a very complex system with other enities involved, I have to give credit where credit is due & they deserve a great deal on this one,jmo.
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Where they flying from shouldn't be long to get there.
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Quoting nrtiwlnvragn:
103. atmoaggie

The anemometer on that site is at 122 meters, so there is some reduction.... but it does seem Ida is stronger than may have been expected.

Dangit! I knew there was something about those platform obs. Thanks, nrt. (in sing-song voice)
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Center just starting to appear on Mibile Radar.
Hello everybody!,what will be the effect of this system on South Florida??? rain,wind etc.Some of the models like the GFDL,shows the system or some remanants of the system moving all the way down the Florida peninsula? after stalling,looking at the Satellite presentation there is a lot of thunderstorms and rain activity closing on the south east coast of FLorida,any comments about this please.Thank you.
Member Since: August 28, 2006 Posts: 0 Comments: 638
Quoting stormsurge39:
Reed Does Ida have some more surprises for us with that burst of convection? I live about 30 miles Inland in N Mobile County, close to AL/MS. line


Winds should start to spread more out and I think Ida is hybrid now, moisture from the BOC low has merged with the storm and Ida is absorbing it, interesting system.
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convection appears to be firing up again near or over the coc of Ida, what a fighter shes been.
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103. atmoaggie

The anemometer on that site is at 122 meters, so there is some reduction.... but it does seem Ida is stronger than may have been expected.
Member Since: September 23, 2005 Posts: 14 Comments: 11305
Isn't it kind of funny that home depot and lowes seasonal department went straight from hurricane (a couple of weeks ago) to christmas season, and now there's a tropical storm in the gulf.
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I think Ida has become a large Hybrid low, this was a potential possibility. Warm core, small burst of convection, cold core around..
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Quoting reedzone:


It looks like Ida has merged with the BOC lows moisture.. Very interesting phenomenon!
Reed Does Ida have some more surprises for us with that burst of convection? I live about 30 miles Inland in N Mobile County, close to AL/MS. line
107. Skyepony (Mod)
Recon AF303 just took off.
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the wind is starting to gust a little here with a few showers...This has been one weird year for weather...canes in November, that's just wrong.
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Greetings, all. and Grothar! where you been, glad to see you. Been traveling? I've noticed you and NRAAmy have been MIA from the Blog at the same time...hmmmmm

TWC is finally mentioning heavy rain on Veteran's Day for us, from Carolinas(whoopsie, N. & S.C. to Mid-Atlantic.

Today's National Situation Report has all the folks playing nicely together (call it "Lessons Learned...The Hard Way"). Code: PDAs are preliminary damage assessments, IA is Individual Assistance, PA is Public Assistance, meaning public facilities.

In part (deleted some outdated stuff):

Total storm accumulations of 3 to 6 inches with isolated maximum storm totals of 8 inches will be possible through Tuesday from the eastern Gulf Coast northward into the eastern portions of the Tennessee Valley and the Southern Appalachians.

Federal HQ Coordination
FEMA NRCC
• Level III activation effective Monday, Nov. 9 at 09:00 a.m. EST with select activation team members supporting 24-hour operations
• MERS support detachments are on alert
• FEMA Regions I, III, V, and VII IMATs and ERT-As are on alert to serve as back up to any affected regions
FEMA Logistics Management Directorate (LMD)
• FEMA Logistics Management Center activated
• Stock levels verified
• Staff and distribution centers are on alert
• No shortfalls reported

FEMA Regional Coordination
Region IV
• RRCC will go to Level III at 07:00 a.m. EST on Nov 9, 2009
• Region IV IMAT deploying to Mississippi
• FEMA Liaison enroute to the Florida state EOC
• PDA teams (IA & PA) on standby
• No shortfalls

Region VI
• RRCC at Watch/Steady State and monitoring. Region VI will activate to Level III at 07:00 a.m. CST on Monday, Nov 9
• Region VI IMAT deploying to Louisiana EOC
• Some ESFs have been put on alert
• PDA teams (IA & PA) on standby
• No shortfalls

State Coordination:
Louisiana
• State activated its Crisis Action Team at noon on Sunday, Nov 8
• The state EOC is activated for 24/7 operations
• Select state agencies are present in the EOC
• Governor Jindal declared a State of Emergency for parishes in southeastern Louisiana with the impact potential
Mississippi
• Mississippi state EOC activated
• Reviewing evacuation plans and orders
Alabama
• Alabama EOC activated
• EOC is preparing for potential evacuations
Florida
• State EOC is activated
• 5 SERT Liaisons are prepositioned to support affected counties in Florida
• High water vehicles have been identified for deployment
• Working in coordination with the states of Alabama and Mississippi
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104. IKE
Quoting tkeith:
Get your raincoat out Ike...


Yo bud.

No rain here yet...30 miles inland...Florida panhandle.

Now 66.7 degrees outside my window.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Hmmm, I think the H*Wind analysis might be a bit conservative.



Shell's MARS platform getting 45 knot sustained...with more to come. Doesn't really jive with H*Wind.


That is here:

(Click for full size)


Not supposed to be 45 knots sustained that far from Ida...well looking again it might be close, at least.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Get your raincoat out Ike...
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Quoting IKE:
Ida making a comeback...south of the Alabama/Mississippi line...



Thanks Ike


From the Alabama Mississippi line...where I live 4 miles inland :-)
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That is just a huge mess.
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Quoting IKE:


Thanks, Ike. You were posting the image as I was requesting. Must have read my mind!
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Good brunch... and/or lunch,

If you would like to make a contribution to NHC then go to this link and propose updates to their "Public Advisories":

http://www.nhc.noaa.gov/feedback_tcp.shtml


Member Since: August 14, 2008 Posts: 4 Comments: 5038
Quoting IKE:
Ida making a comeback...south of the Alabama/Mississippi line...



Hey, Ike, looks like something is happening, hoped it is short lived. Convection is getting stronger near the center. Can anyone post an amimated color image. I can't!!!

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If I get banned for this so be it because I am no weather man. But run the visible loop at the nhc and tell me what you see. I see a new set of warning going up again.IMO Also I did promise not to issue forecast on systems close to land so after this no more for me and please dont take it to heart, it is only for discussion.
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95. IKE
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting IKE:
Ida making a comeback...south of the Alabama/Mississippi line...



It looks like Ida has merged with the BOC lows moisture.. Very interesting phenomenon!
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Is Ida pulling another quick change?
Aggie's link shows central rebuilding of thunderstorm activity.
All the condition estimates in the blog above say there isn't enough energy there to support much.
Comments?
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Quoting 850Realtor:


Have been congested/sinuses for a few days. It's not like fall on the floor dizzy, just a little off. Thanks for the tip!

Hope you feel better soon! Storms like this seem to clear out the air behind it, so it should bring some good, cool fresh air to our area! :)
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91. IKE
Ida making a comeback...south of the Alabama/Mississippi line...

Member Since: June 9, 2005 Posts: 23 Comments: 37860
im glad no hurricane hopefully ill be able to goto work tommorow im in destin
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Quoting seflagamma:
Hi everyone, good morning and
Thank you Dr Master's for the good news.

Looks like all those "worse case" situations we were talking about 2-3 days ago are not pulling together..

however, even a strong TS like Ida will bring some damage and flooding to the affected areas.

Please friends in the line of fire, be prepared and stay safe.


Well, I have a personal reason to be glad it is not making landfall as a hurricane! because it keeps my spring prediction at 100% correct...

so next year when you all want to know the "figures" for number of storms just ask me!

(I am just kidding everyone! LOL)

I predicted no landfalling hurricanes to hit the CONUS this season and so far so good.

I did say we could have a few Tropical Storms and we have had 2 almost in same area.

I will check back later.

Good luck everyone!

Season aint done yet!
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low to the west is making ida look more symetrical
Member Since: August 22, 2008 Posts: 0 Comments: 755
We have a Lake Wind Advisory, a High Surf Advisory, and the potential for severe t-storms and tornadoes according to the Hazardous Weather Statement. I guess I can't say Ida didn't do something here in Tampa. If we could get a little rain from this I'd be happy.
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Quoting gordydunnot:
Ever since she developed that feeder band to the east she looks like she has been on a mission plus the system behind her doesn't seem to be fighting her, more in unison so to speak.
That "feeder band" is going to continue to develop before moving ashore in w fl. It will resemble for of a squall line than a tropical feeder band by that point.
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Quoting beell:
Good work, Storm! The Met coulda just left it at this:

...INSTEAD A FUNCTION OF THE INTENSE LATENT HEATING FROM SIMULATED DEEP CONVECTION (CONVECTIVE FEEDBACK).


Maybe so,...but we could really use a good 3-5 inches here in NC.

Plus, when does one get to say'SUTCLIFFE-PETTERSSEN "SELF-DEVELOPMENT"...AND
LEAD TO THE INTENSE "PHASE-LOCKED"/OCCLUDED LOW' in their discussion! :)
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Good morning storm if you are still there. Read your updates all the time.
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Ever since she developed that feeder band to the east she looks like she has been on a mission plus the system behind her doesn't seem to be fighting her, more in unison so to speak.
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Quoting CaptnDan142:


Sure it can. Not drastic, but certainly could cause the slight 'off' feeling you described. If the pressure is falling faster than the air cavities in the sinuses can equalize due to some upper respiratory inflammation or congestion, you could feel it.

If it becomes bothersome, grab a piece of gum and chew it. The motion of the jaw will likely allow the pressures to equalize more easily.


That's exactly what it is then. Have been congested/sinuses for a few days. It's not like fall on the floor dizzy, just a little off. Thanks for the tip!
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Hi everyone, good morning and
Thank you Dr Master's for the good news.

Looks like all those "worse case" situations we were talking about 2-3 days ago are not pulling together..

however, even a strong TS like Ida will bring some damage and flooding to the affected areas.

Please friends in the line of fire, be prepared and stay safe.


Well, I have a personal reason to be glad it is not making landfall as a hurricane! because it keeps my spring prediction at 100% correct...

so next year when you all want to know the "figures" for number of storms just ask me!

(I am just kidding everyone! LOL)

I predicted no landfalling hurricanes to hit the CONUS this season and so far so good.

I did say we could have a few Tropical Storms and we have had 2 almost in same area.

I will check back later.

Good luck everyone!
Member Since: Posts: Comments:
Quoting atmoaggie:

Virga. Howdy, StormW.

Hope these folks are aware, but few will prolly perish from this one regardless.



Can you imagine for a moment if this were to make landfall as a cat 2? 3 days, or less, after leaving Honduras?
With most folks not paying any attention at all to the tropics?
Could have been a lot uglier than it is going to be, thankfully.


Mobile county never declared a state of emergency and the kids are in school.
Quoting TampaBayfisher:
Much ado about nothing, imagine that.


Isn't that how it normally is the majority of the time. :)
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Question: Some models bring the remnant low back south along the Florida coast. But wouldn't the moisture field keep going north? The models are a little confusing. Come on someone can answer this.
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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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