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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378. IKE
Quoting atmoaggie:
360:
When using Dr. Masters' blog, please refrain from posting material not relevant to the discussion of tropical weather, or the topic of the blog entry itself. Please do not engage in personal attacks or bickering. Material not conforming to these standards should be flagged with the "!" button and ignored.

That is the only remotely useful post I have ever seen from you. Can't you come up with anything at all to say related to tropical weather or are you really limited to self-appointed blog policeman?


+1.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Parts of Ft Pickens Road have water, but that would be in the park - Ive not seen any reports in the condo area yet as to water on the road.
Member Since: Posts: Comments:
Quoting DrNo:
There are shenanigans here...

When using Dr. Masters' blog, please refrain from posting material not relevant to the discussion of tropical weather, or the topic of the blog entry itself. Please do not engage in personal attacks or bickering. Material not conforming to these standards should be flagged with the "!" button and ignored.


shenanigans...hold me back rare
Member Since: October 1, 2007 Posts: 0 Comments: 551
Well this was the last chance for all the insurance adjusters and roofers to make some money this year. My brother is an insurance adjuster and has one of those jobs that needs mother nature to make money. I told him his job was like the guy who bets the dont pass line on the craps table. Going against everyone else. lol
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372. IKE
Quoting MsBlanch:


Ike are you talking about before landfall or after?


Before.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Thank you Skyepony and 850Realtor. I'm hunkered down in Pensacola proper but was curious.

I know parts of the road inside the park gates floods pretty easily. Do you know if Ft. Pickens Road outside the gates does likewise?

I thought about staying on the beach tonight (condo is on 3rd floor) but I like my car too much! :-)
Or to make it easier here's a knots to mile per hour converter.

Knots to mile per hour converter
Member Since: August 11, 2008 Posts: 0 Comments: 2315
SST's decline as the system gets closer to the coast. Center decoupling and the pumping of cold dry air into the system will help with extratropical transition.


Nowcoast Real-time Observations of SSTs with visible satellite imagery
Member Since: October 28, 2006 Posts: 57 Comments: 30841
ooooooops... should have been "most people can't run that in their head"
Member Since: July 15, 2006 Posts: 0 Comments: 142
360:
When using Dr. Masters' blog, please refrain from posting material not relevant to the discussion of tropical weather, or the topic of the blog entry itself. Please do not engage in personal attacks or bickering. Material not conforming to these standards should be flagged with the "!" button and ignored.

That is the only remotely useful post I have ever seen from you. Can't you come up with anything at all to say related to tropical weather or are you really limited to self-appointed blog policeman?
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Conch Storms a flyer he doesn't guess!! in flying close is relevant!!
Member Since: August 19, 2007 Posts: 0 Comments: 1601
Storm W.: Do you see Ida eventually moving back to the South East after making landfall as the GFS, GFDL and HWRF models suggest or do you see it heading out to the Atlantic and then Northeast as the UKMET suggests (it seems as if the NHC is going with the latter rather than the consensus)? Thank You.
Member Since: Posts: Comments:

it's a giant comma. My guess is it will be declared extratropical at next advisory. Yes, Ida is still there but it's basically imbedded in a front and a large developing ULL.
Member Since: July 29, 2006 Posts: 28 Comments: 1802
Quoting TheCaneWhisperer:



I was joking with BAP on a comment he made earlier.


Oh i see
Member Since: August 11, 2008 Posts: 0 Comments: 2315
How about just multiplying by 1.1516
Hey Storm, most people can run that in their head... but most folks can do 10%, then 1/2 of it (which works out to X 1.15 and the error is inconsequential...) :-)
Member Since: July 15, 2006 Posts: 0 Comments: 142
Quoting StormW:


How about just multiplying by 1.1516.


Or as JFV does it, behind the curtain... mult by 1.17...Sir
Member Since: October 1, 2007 Posts: 0 Comments: 551
Quoting rareaire:
pressure is still falling, correct?


It fell by 5mb since last advisory, yes. No change in winds, though, so far. HH still out there.
Member Since: Posts: Comments:
Quoting Ossqss:
Lot's of dry air chasing Ida.


And SSTs not going to get any better than they are now:


I think this is why we will see a further weakening Ida and no Hurricane warnings out of NHC.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting StormChaser81:


HUH, its was a cat 2 earlier in its life.



I was joking with BAP on a comment he made earlier.
Quoting IKE:
56 knots
(~ 64.4 mph)


That would be something if it made a cane again and the NHC had to put hurricane warnings back up again after they lowered them.


Ike are you talking about before landfall or after?
Member Since: Posts: Comments:
Normally when the winds get 45mph Escambia County will close bridges to barrier islands, i.e., P'cola Beach, Perdido Key. I've not looked at the recent local news - still waiting on P'cola base closure...
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Quoting Skyepony:
SLOSH has been activated for IDA..

LINK


highest tides roll in on thursday
Member Since: August 11, 2008 Posts: 3 Comments: 1750
351. BobinTampa
6:21 PM GMT on November 09, 2009
Quoting dearmas:


OMG


I quit. If you need insurance, send me an email. You can get insurance in Tampa today. No worries.

Member Since: August 14, 2008 Posts: 0 Comments: 553
350. ConchHondros
6:21 PM GMT on November 09, 2009
Rare...I had duck jerkey and beans for breakfast...Mrs Conch has issued a tropical storm warning for all of Moore, Ok
Member Since: October 1, 2007 Posts: 0 Comments: 551
349. StormChaser81
6:21 PM GMT on November 09, 2009
Quoting TheCaneWhisperer:
I can't believe the NHC named this one. Stretching for numbers I see, sheesh.


HUH, its was a cat 2 earlier in its life.
Member Since: August 11, 2008 Posts: 0 Comments: 2315
348. NRAamy
6:21 PM GMT on November 09, 2009
any My Little Pony shower curtain sightings off the coast of Florida?
Member Since: January 24, 2007 Posts: 317 Comments: 31946
347. TheCaneWhisperer
6:21 PM GMT on November 09, 2009
I wasn't surprised to see her flirt with Cat 3 in the NW Caribbean. I was surprised however to see the NHC didn't agree much with that earlier on.
346. rareaire
6:20 PM GMT on November 09, 2009
pressure is still falling, correct?
Member Since: August 19, 2007 Posts: 0 Comments: 1601
345. Ossqss
6:20 PM GMT on November 09, 2009
Quoting presslord:
my secretary just gave me a dirty look and closed my office door...s'pose she doesn't like my taste in music...or the volume of it...


I cannot bring myself to make a comment about the view that poor woman has to deal with.... :) LoL

Lot's of dry air chasing Ida.


Member Since: June 12, 2005 Posts: 6 Comments: 8188
344. Drakoen
6:19 PM GMT on November 09, 2009
Max winds only 65mph
Member Since: October 28, 2006 Posts: 57 Comments: 30841
343. IKE
6:18 PM GMT on November 09, 2009
Quoting Drakoen:
Her center is on the southern most portion of the radar Ike posted. It is not that clear spot.


Okay.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
342. nrtiwlnvragn
6:18 PM GMT on November 09, 2009
Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 9th day of the month at 18:13Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 303)
Storm Number & Year: 11L in 2009
Storm Name: Ida (flight in the North Atlantic basin)
Mission Number: 7
Observation Number: 05
A. Time of Center Fix: 9th day of the month at 17:39:00Z
B. Center Fix Coordinates: 27°27'N 88°25'W (27.45N 88.4167W)
B. Center Fix Location: 201 miles (323 km) to the SSE (150°) from New Orleans, LA, USA.
C. Minimum Height at Standard Level: 1,357m (4,452ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 57kts (~ 65.6mph)
E. Location of the Estimated Maximum Surface Wind: 34 nautical miles (39 statute miles) to the WNW (295°) of center fix
F. Maximum Flight Level Wind Inbound: From 35° at 72kts (From the NE at ~ 82.9mph)
G. Location of Maximum Flight Level Wind Inbound: 20 nautical miles (23 statute miles) to the WNW (293°) of center fix
H. Minimum Sea Level Pressure: 991mb (29.26 inHg)
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 13°C (55°F) at a pressure alt. of 1,520m (4,987ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 22°C (72°F) at a pressure alt. of 1,523m (4,997ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 16°C (61°F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Poorly Defined
M. Eye Shape: Elliptical (oval shaped)
M. Orientation of Major Axis in Elliptical Eye: 70° to 250° (ENE to WSW)
M. Length of Major Axis in Elliptical Eye: 32 nautical miles (37 statute miles)
M. Length of Minor Axis in Elliptical Eye: 16 nautical miles (18 statute miles)
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 850mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1 nautical mile
Remarks Section:
Maximum Flight Level Wind: 73kts (~ 84.0mph) in the northwest quadrant at 17:32:00Z
Maximum Flight Level Temp: 23°C (73°F) which was observed 18 nautical miles (21 statute miles) to the SE (129°) from the flight level center

Member Since: September 23, 2005 Posts: 15 Comments: 11347
341. dearmas
6:18 PM GMT on November 09, 2009
Quoting 850Realtor:


Check with your Realtor, Closing Agent or Attorney. Most times, regardless of landfall...if there is a storm in the "box", no insurance binders, no exceptions. If it hits here, Tampa is still within the box. The box is all of GOM, east to the Bahamas and south near South America. If you already have your insurance, then you should be able to close, I think. The problem is with those that have not secured insurance already.


OMG
Member Since: August 23, 2006 Posts: 0 Comments: 121
340. atmoaggie
6:18 PM GMT on November 09, 2009
Quoting nrtiwlnvragn:
312. atmoaggie

Also after thinking about it I believe the averaging time is 8 minutes, not the 1 minute given for cyclone winds, so a net-net neutral?

I know the NDBC method is 8-minutes, but cannot say about these other platforms. It could be less than that.

Got a retired NDBC marine met right here (really sitting 20 feet from me) and he says there is no easy way to tell...NDBC may not even have that info.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
339. winter123
6:17 PM GMT on November 09, 2009
in other news, this is unbelievable. it's not even peak heat of the day and in upstate NY, in mid november, it is 71. The record yesterday was 63, which was broken, so I'm sure todays will be broken too. Then we will get dumbed on with all this moisture, not ida itself, just the moisture plus the hybrid low to its west.
Member Since: July 29, 2006 Posts: 28 Comments: 1802
338. IKE
6:17 PM GMT on November 09, 2009
Quoting rareaire:
Hey Ike does this thing and I say that as I am beyond confused as to what it really is now at hurricane strength?


According to the NHC...no. Close, but no.

I'm surprised they haven't at least put back up hurricane watches, but they expect it to weaken as she approaches.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
337. TheCaneWhisperer
6:17 PM GMT on November 09, 2009
Quoting BurnedAfterPosting:


LMAO I was waiting for someone to say that



I know :-b
336. Skyepony (Mod)
6:16 PM GMT on November 09, 2009
SLOSH has been activated for IDA..

LINK
Member Since: August 10, 2005 Posts: 227 Comments: 39467
335. BurnedAfterPosting
6:16 PM GMT on November 09, 2009
Quoting TheCaneWhisperer:
I can't believe the NHC named this one. Stretching for numbers I see, sheesh.


LMAO I was waiting for someone to say that
334. Selu
6:16 PM GMT on November 09, 2009
Hey everyone...haven't seen many of you since last year. Pretty quiet gulf season this year.

We're getting rain and wind off of Ida right now...I'll take this over Gustav and Katrina any day.

Hope everyone fares well.
Member Since: February 5, 2004 Posts: 7 Comments: 312
333. heavyweatherwatcher
6:16 PM GMT on November 09, 2009
The quickest knots to mph is to take the speed in knots, add 10%, then add 1/2 of the 10%; e.g. 80kts = 80 + 8 + 5 = 93mph
Member Since: July 15, 2006 Posts: 0 Comments: 142
332. kmanislander
6:16 PM GMT on November 09, 2009
Quoting TheCaneWhisperer:
I can't believe the NHC named this one. Stretching for numbers I see, sheesh.


LOL
Member Since: August 19, 2006 Posts: 0 Comments: 15948
331. Drakoen
6:16 PM GMT on November 09, 2009
Her center is on the southern most portion of the radar Ike posted. It is not that clear spot.
Member Since: October 28, 2006 Posts: 57 Comments: 30841
330. WaterWitch11
6:15 PM GMT on November 09, 2009
Quoting PalmBeachWeather:
I'm just thankful IKE ..Isn't playing Cashmir
Link
Member Since: August 11, 2008 Posts: 3 Comments: 1750
329. BobinTampa
6:15 PM GMT on November 09, 2009
Quoting Detrina:


This does bring to mind though the special issues that the hurricane season bring when you are trying to Buy or Sell a home. I am talking about home owners insurance. The problem is that all insurance companies that write policies in the sunshine state suspend writing of any NEW business when a storm threatens Florida.There are two ways insurance companies determine when to temporarily suspend issuing new coverage:

1. When the National Hurricane Center issues a tropical storm or hurricane watch or warning.
2. When a tropical storm or hurricane enters a company’s “storm box.”


Hubby used to work for an unnamed insurance company...



As I said earlier, most carriers will suspend binding in affected counties only. Citizens will suspend statewide. Most other carriers have suspended in panhandle counties only.

I still work for an unnamed insurance company.
Member Since: August 14, 2008 Posts: 0 Comments: 553
328. treehuggingsister
6:15 PM GMT on November 09, 2009
Between Bowden Way and Fort Pickens Road ~ ALWAYS just completed/open and then BLAMMO ~ you wonder if they were ever meant to be there. The Rangers at the Fort have to be gnashing their teeth.
Member Since: August 18, 2006 Posts: 0 Comments: 188

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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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