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

Share this Blog
2
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 178 - 128

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14Blog Index

Quoting stormsurge39:
Where do you put landfall now Tampa?
lol that dudes got alot of crow to eat.first tampa,than the appalacha area and now where?nhc has done well with track.they got it nailed down now.
Member Since: Posts: Comments:
I live in Perdido Bay area. Waiting for NAS Pensacola to give the word about base closure then I'm headed for home. Had a little bit of rain here on the base about an hour ago.
Member Since: Posts: Comments:
12Z GFDL tracks along the coast eastward


HOUR: .0 LONG: -88.36 LAT: 25.77 MIN PRESS (hPa): 988.96 MAX SURF WIND (KNOTS): 66.08
HOUR: 6.0 LONG: -88.70 LAT: 27.35 MIN PRESS (hPa): 982.29 MAX SURF WIND (KNOTS): 71.03
HOUR: 12.0 LONG: -88.61 LAT: 28.32 MIN PRESS (hPa): 985.42 MAX SURF WIND (KNOTS): 66.15
HOUR: 18.0 LONG: -88.03 LAT: 29.07 MIN PRESS (hPa): 990.57 MAX SURF WIND (KNOTS): 55.55
HOUR: 24.0 LONG: -87.36 LAT: 30.36 MIN PRESS (hPa): 993.83 MAX SURF WIND (KNOTS): 71.52
HOUR: 30.0 LONG: -86.70 LAT: 30.90 MIN PRESS (hPa): 995.74 MAX SURF WIND (KNOTS): 60.44
HOUR: 36.0 LONG: -85.92 LAT: 30.92 MIN PRESS (hPa): 997.51 MAX SURF WIND (KNOTS): 57.32
HOUR: 42.0 LONG: -85.58 LAT: 30.73 MIN PRESS (hPa): 997.25 MAX SURF WIND (KNOTS): 52.91
HOUR: 48.0 LONG: -85.07 LAT: 30.52 MIN PRESS (hPa): 998.37 MAX SURF WIND (KNOTS): 48.12
HOUR: 54.0 LONG: -84.54 LAT: 30.02 MIN PRESS (hPa): 998.20 MAX SURF WIND (KNOTS): 40.01
HOUR: 60.0 LONG: -83.87 LAT: 29.53 MIN PRESS (hPa): 998.49 MAX SURF WIND (KNOTS): 41.30
HOUR: 66.0 LONG: -83.36 LAT: 29.00 MIN PRESS (hPa): 997.03 MAX SURF WIND (KNOTS): 37.72
HOUR: 72.0 LONG: -82.76 LAT: 28.55 MIN PRESS (hPa): 997.69 MAX SURF WIND (KNOTS): 30.46
HOUR: 78.0 LONG: -81.73 LAT: 28.57 MIN PRESS (hPa): 997.00 MAX SURF WIND (KNOTS): 26.68
HOUR: 84.0 LONG: -80.80 LAT: 28.90 MIN PRESS (hPa): 996.47 MAX SURF WIND (KNOTS): 24.21
HOUR: 90.0 LONG: -80.05 LAT: 29.57 MIN PRESS (hPa): 994.79 MAX SURF WIND (KNOTS): 27.57
HOUR: 96.0 LONG: -79.93 LAT: 30.08 MIN PRESS (hPa): 995.54 MAX SURF WIND (KNOTS): 25.42
HOUR:102.0 LONG: -79.54 LAT: 30.11 MIN PRESS (hPa): 995.40 MAX SURF WIND (KNOTS): 25.93
HOUR:108.0 LONG: -79.27 LAT: 30.38 MIN PRESS (hPa): 997.27 MAX SURF WIND (KNOTS): 22.65
HOUR:114.0 LONG: -79.52 LAT: 30.32 MIN PRESS (hPa): 998.40 MAX SURF WIND (KNOTS): 21.30
HOUR:120.0 LONG: -79.67 LAT: 29.86 MIN PRESS (hPa): 1001.58 MAX SURF WIND (KNOTS): 22.05
HOUR:126.0 LONG: -79.64 LAT: 28.99 MIN PRESS (hPa): 1002.87 MAX SURF WIND (KNOTS): 22.72

Member Since: September 23, 2005 Posts: 14 Comments: 10875
Quoting Thundercloud01221991:
Recon is finding winds around 45 knts not even near the center
How close?
174. IKE
Buoy at 28.8N and 86W....

Wind Direction (WDIR): E ( 90 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 35.0 kts
5-day plot - Wind Gust Wind Gust (GST): 42.7 kts
5-day plot - Wave Height Wave Height (WVHT): 16.1 ft
5-day plot - Dominant Wave Period Dominant Wave Period (DPD): 10 sec
5-day plot - Average Period Average Period (APD): 7.0 sec
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 29.93 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): -0.08 in ( Falling )
5-day plot - Air Temperature Air Temperature (ATMP): 73.9 °F
5-day plot - Water Temperature Water Temperature (WTMP): 77.7 °F
5-day plot - Dew Point Dew Point (DEWP): 70.5 °F
5-day plot - Wind Speed, Wind Gust and Atmospheric Pressure Combined plot of Wind Speed, Gust, and Air Pressure
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting NRAamy:
Awake....no weather here really to speak of...I'm still praying for a ton of rain....crash a few more homes into the ocean....at some point, my ocean view home will be an ocean front property....just in time for 2012....

The whole 2012 thing I'm kinda hopeing.. NOT since that is my birthday BUT I did start a blog called
Turning 45 is soooo the end of the world JIK..
Member Since: Posts: Comments:
Conan, that's why I'm investing in rubber ducky innertubes...
Member Since: Posts: Comments:
Is a HH out there right now?
Recon is finding winds around 45 knts not even near the center
Member Since: August 1, 2006 Posts: 28 Comments: 3716
Quoting StormChaser81:


Probably not strengthing, but holding its current strength.
Thanks
Quoting stormsurge39:
Is Ida stengthing with that burst of convection around the coc?


Probably not strengthing, but holding its current strength.
Member Since: Posts: Comments:
Quoting StormChaser81:


HUH, Say what...
LOL I was ignoreing the weather during "the season" this year LOL
Member Since: Posts: Comments:
Quoting NRAamy:
Awake....no weather here really to speak of...I'm still praying for a ton of rain....crash a few more homes into the ocean....at some point, my ocean view home will be an ocean front property....just in time for 2012....

;)


Then you will have ocean property.
Member Since: September 6, 2009 Posts: 2 Comments: 3710
Is Ida stengthing with that burst of convection around the coc?
Quoting TheMom:
Now see I try a new tactic of "ignore" and it will not come that was working really good and then I watched the weather ONE night and Bam flipping storm!

*Waves around the room* Heyyyy everybody


HUH, Say what...
Member Since: Posts: Comments:
Quoting reedzone:
WOW :O!!!!



lol what?
Member Since: September 6, 2009 Posts: 2 Comments: 3710
Now see I try a new tactic of "ignore" and it will not come that was working really good and then I watched the weather ONE night and Bam flipping storm!

*Waves around the room* Heyyyy everybody
Member Since: Posts: Comments:
it has not made a NNE turn!!!!! NHC is right on track. AL/MS border for landfall
Member Since: Posts: Comments:
seems to be another blow-up of convection around the center.
Member Since: Posts: Comments:
How many miles inland will Ida go N before NE?
Couple of the pilot boats and charter boats just left dauphin island headed up mobile bay. That will be quite a ride. Wow.
156. IKE
Raining at my house now...inland Florida panhandle...66 degrees.

Winds 10-15 mph.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
155. 1965
Looks like our girl gas woken up after a rough night

I was shocked at how ragged she looked when I woke this morning. I'm equally shocked at her comeback as the storm transitions sub/extra tropical.

Member Since: Posts: Comments:
Quoting TampaSpin:


We still might be dam close StormW...Models are starting to bend a little quicker if you look at the major models above....
Where do you put landfall now Tampa?


This is the NAM....it is very good MOdel for a 24-36 hr forecast for Severe Weather.
Member Since: Posts: Comments:
sooo, is the CoC coming into view the last couple of frames?

Member Since: Posts: Comments:
It sure looks like everything is going together as several of us have been saying for the past couple of days. The hybrid and Ida merging together. Also the Center of Ida is starting to look better and the northern portion of Ida is already acting with the hybrid storm
Member Since: March 22, 2006 Posts: 9 Comments: 1570
Quoting reedzone:
WOW :O!!!!

so would you say landfall between AL/MS--- AL/FL?
The Forecast Track Puts Ida in Mobile County
Member Since: Posts: Comments:
Quoting StormW:


Tim, don't feel bad about that call! I was some left of your track, like in between.

But that's OK...it shows just how quick it can change...in a matter of 6 hours.

The 10:00 a.m. NHC track looks good right now. What has happened, the mid layer trof out over the four corners region has amplified, in turn, amplifying the upstream flow to a more northerly to Just west of north motion. You can see it on water vapor imagery:



We still might be dam close StormW...Models are starting to bend a little quicker if you look at the major models above....
Member Since: Posts: Comments:
Quoting NRAamy:
My Local Weather:

John Wayne-Orange County, California

59 °F
Haze


Right Now for
Silver Spring, MD (20901)

Sunny
70°F
Feels Like
70°F
Updated Nov 9 11:45 a.m. ET

UV Index: 3 Moderate
Wind: CALM
Humidity: 40%
Pressure: 30.39 in.
Dew Point: 45°F
Visibility: 10.0 miles

Hi, been traveling to glaciers?
Just kidding. Wow, there was some very nasty weather in north of you. I noticed...though blog has been too busy w/IDA to say anything.
Member Since: Posts: Comments:
OMG, could it be.......could it be that southeast georgia might actually get some rain.........keeping my fingers crossed!!
Member Since: Posts: Comments:
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: Posts: Comments:
Quoting StormW:


Tim, don't feel bad about that call! I was some left of your track, like in between.

But that's OK...it shows just how quick it can change...in a matter of 6 hours.

The 10:00 a.m. NHC track looks good right now. What has happened, the mid layer trof out over the four corners region has amplified, in turn, aplifying the upstream flow to a more northerly to Just west of north motion. You can see it on water vapor imagery:



does that mean MS isn't in the clear and will feel more than anticipated???
Member Since: Posts: Comments:
Current conditions on Schillinger Road in Mobile, Alabama.

Wind at about 20 knot out of the North

No rain, but coming soon.

Clouds aloft moving like Talladega race cars.
Member Since: Posts: Comments:






Could be a huge mountain snow storm coming....
Member Since: Posts: Comments:
Here in Palm Coast,FL its rather breezy and gray out on and off.. Yeah we're on the east coast of FL, so I know we wont get to see much, but any rain we get here or St Augustine to our north I really am looking forward to!!
Member Since: Posts: Comments:
Quoting stormpetrol:
I think Ida might finally be making that NNE turn, personal I think somewhere in the panhandle she'll graze or make landfall before turning E, then ESE, jmo.


A couple models have that possibility...

Interesting to note that 12Z GFS has trended a bit further S on this run... like the 06Z GFDL.
Member Since: Posts: Comments:
omg omg bwaaahaaaaaaaaa my work is closing down at noon and i dont have to come back til Thursdayyyyyy!!!! because the bridge on hwy 331 is supposed to be closed to traffic when wind exceeds 40 mph. Its a miracle a miracle i tell ya!!!!! oh thank you thank you IDAAAA
Member Since: Posts: Comments:
Quoting ElConando:



Yeah but it would have to be quite a pressure drop.
Quoting 850Realtor:
Dumb question, don't laugh...can a pressure drop outside make you dizzy? Not real bad, just feel kind of off?
Conditions feeling tropical around here. Stiff breeze, rain just starting.


well, when the pressure drops my amazon parrot starts singing "oh the weather outside is frightfullll" and i aint even kiddin!
Member Since: Posts: Comments:
Quoting DestinJeff:
just saw a leaf fall off my oak tree ... squirl must have knocked it off, because wind is calm


Yeah, I just came back from the beach in Ocean Springs, MS...just slightly breezy, water fairly calm, actually the Bay of St. Louis (25 miles to the west) is churned up more than the sound.
Member Since: Posts: Comments:
Quoting Grothar:

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.

I just looked at #95. Now my sinuses hurt, too. Thanks, I think, Ike & Grothar.
Watching glaciers melt sounds like my dream of a perfect retirement job except I like warmer climates.
Hello Mrs. Grothar! No worries, obviously we know your Mr. Grothar's SWMBO.
Member Since: Posts: Comments:
I think Ida might finally be making that NNE turn, personal I think somewhere in the panhandle she'll graze or make landfall before turning E, then ESE, jmo.
Member Since: April 29, 2007 Posts: 0 Comments: 7666
I love weather just look at the visible loop floater at he nhc. If you can figure that out you've got to be good for a double Phd. Id stay tropical and severe storm phd kind of a Lyons/Forbes hybrid.
Member Since: Posts: Comments:
Quoting Grothar:

It is above freezing in Greenland in November?!?

Seems like there shouldn't be much melt going on right now: http://www.wunderground.com/global/GL.html

Maybe it isn't water, but a mix with alcohol or some other substance where a hydroxyl group is bound to a carbon atom of an alkyl group.
(Have you been wasting your drink?)
Member Since: August 16, 2007 Posts: 6 Comments: 12461
Latest model 12Z outputs:

Member Since: Posts: Comments:

Viewing: 178 - 128

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14Blog Index

Top of Page

About

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

Local Weather

Scattered Clouds
76 °F
Scattered Clouds