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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1441. Patrap
Ida will be onshore before Midnight CDT.

The NHC Waffles some,and the timing has been terrible the last 24.
But the Bamd and HWRF have done outstanding
Member Since: July 3, 2005 Posts: 428 Comments: 129795
oh good, advisory came out early...thnx for posting I was going back to zzzzzzzzzzzz
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1439. Fshhead
Hey Pat,
SP dropped this video link in Cals blog to a tribute to Carl Sagan they had down here. James Randi is what I am listening to now. Pretty interesting..


Carl Sagan Tribute
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1438. Patrap
Member Since: July 3, 2005 Posts: 428 Comments: 129795
ADVISORY ISSUED

000
WTNT31 KNHC 090833
TCPAT1
BULLETIN
HURRICANE IDA ADVISORY NUMBER 22
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112009
300 AM CST MON NOV 09 2009

...IDA WEAKENS SLIGHTLY...

A HURRICANE WARNING REMAINS IN EFFECT FOR THE NORTHERN GULF COAST
FROM PASCAGOULA MISSISSIPPI EASTWARD TO INDIAN PASS FLORIDA. A
HURRICANE WARNING MEANS THAT HURRICANE CONDITIONS ARE EXPECTED
SOMEWHERE WITHIN THE WARNING AREA WITHIN 24 HOURS. PREPARATIONS TO
PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION.

A TROPICAL STORM WARNING AND A HURRICANE WATCH REMAIN IN EFFECT FOR
THE NORTHERN GULF COAST FROM GRAND ISLE LOUISIANA EASTWARD TO WEST
OF PASCAGOULA MISSISSIPPI...INCLUDING NEW ORLEANS AND LAKE
PONTCHARTRAIN. A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM
CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 24
HOURS. A HURRICANE WATCH MEANS THAT HURRICANE CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA...IN THIS CASE WITHIN 24 HOURS.

A TROPICAL STORM WARNING REMAINS IN EFFECT FOR THE NORTHERN GULF
COAST FROM EAST OF INDIAN PASS FLORIDA TO AUCILLA RIVER FLORIDA.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...INCLUDING POSSIBLE
INLAND WATCHES AND WARNINGS...PLEASE MONITOR PRODUCTS ISSUED BY
YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE.

AT 300 AM CST...0900 UTC...THE CENTER OF HURRICANE IDA WAS LOCATED
NEAR LATITUDE 25.1 NORTH...LONGITUDE 87.9 WEST OR ABOUT 285 MILES...
460 KM...SOUTH-SOUTHEAST OF THE MOUTH OF THE MISSISSIPPI RIVER AND
ABOUT 375 MILES...605 KM...SOUTH OF PENSACOLA FLORIDA.

IDA IS MOVING TOWARD THE NORTH-NORTHWEST NEAR 16 MPH...26 KM/HR. A
TURN TOWARD THE NORTH AND AN INCREASE IN FORWARD SPEED ARE EXPECTED
DURING THE NEXT 24 HOURS...FOLLOWED BY A TURN TOWARD THE NORTHEAST
ON TUESDAY. ON THE FORECAST TRACK...IDA IS EXPECTED TO MOVE ACROSS
THE GULF OF MEXICO TODAY...AND APPROACH THE NORTHERN GULF COAST
TONIGHT OR EARLY TUESDAY.

DATA FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE
THAT MAXIMUM SUSTAINED WINDS HAVE DECREASED TO NEAR 90 MPH...150
KM/HR...WITH HIGHER GUSTS. IDA IS A CATEGORY ONE HURRICANE ON THE
SAFFIR-SIMPSON SCALE. ADDITIONAL WEAKENING IS FORECAST DURING THE
NEXT 24 HOURS. HOWEVER...IDA IS STILL EXPECTED TO BE A HURRICANE
WHEN IT APPROACHES THE GULF COAST TONIGHT OR EARLY TUESDAY.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 35 MILES...55 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 200
MILES...325 KM.

THE ESTIMATED MINIMUM CENTRAL PRESSURE BASED ON DATA FROM THE
HURRICANE HUNTER AIRCRAFT IS 988 MB...29.18 INCHES.

RAINS WILL BE INCREASING WELL IN ADVANCE OF IDA ACROSS THE CENTRAL
AND EASTERN GULF COAST...BUT WILL BECOME STEADIER AND HEAVIER
LATER TODAY INTO TUESDAY. TOTAL STORM ACCUMULATIONS OF 3 TO 6
INCHES WITH ISOLATED MAXIMUM STORM TOTALS OF 8 INCHES WILL BE
POSSIBLE THROUGH TUESDAY FROM THE CENTRAL AND EASTERN GULF COAST
NORTHWARD INTO THE EASTERN PORTIONS OF THE TENNESSEE VALLEY AND THE
SOUTHERN APPALACHIANS.

A DANGEROUS STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS 4 TO 6
FEET ABOVE GROUND LEVEL ALONG THE COAST NEAR AND TO THE EAST OF
WHERE THE CENTER MAKES LANDFALL. NEAR THE COAST...THE SURGE WILL BE
ACCOMPANIED BY LARGE AND DESTRUCTIVE WAVES.

...SUMMARY OF 300 AM CST INFORMATION...
LOCATION...25.1N 87.9W
MAXIMUM SUSTAINED WINDS...90 MPH
PRESENT MOVEMENT...NORTH-NORTHWEST OR 335 DEGREES AT 16 MPH
MINIMUM CENTRAL PRESSURE...988 MB

AN INTERMEDIATE ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE
CENTER AT 600 AM CST FOLLOWED BY THE NEXT COMPLETE ADVISORY AT 900
AM CST.

$$
FORECASTER BRENNAN/KIMBERLAIN

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It's time to get a few more hours shut eye. I fell asleep right after the Saints game. FEMA won't be handing out checks in NOLA this week but we have one heck of a football team. GO SAINTS!
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1435. Patrap
IDA Steering Layer 300-850mb - West Atlantic - Latest Available
Member Since: July 3, 2005 Posts: 428 Comments: 129795
1434. Fshhead
The NOGAPS makes sense till it gets to NY, Boston lat. It looks like a whip at the end. LOL
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1433. Patrap
Floater - Rainbow Color Infrared Loop
Member Since: July 3, 2005 Posts: 428 Comments: 129795
Quoting Fshhead:
HamWeather

The CMC here must be smokin' crack!! ;)
The longterm of a couple others is also suspect of a smokin' something too... HAHAHA!!


The Nogaps seems to make the most sense overall. Mobile Bay landfall then carried on to the NE.
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1431. drj27
so where are they saying ida is going to make landfall first it was mobile /pcola im in destin does anyone have an idea thanks
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1430. Fshhead
HamWeather

The CMC here must be smokin' crack!! ;)
The longterm of a couple others is also suspect of a smokin' something too... HAHAHA!!
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1429. emguy
Patrap...your loop confirms that she is severly de-coupled. I understand why the Hurricane Hunters are finding the steep rise in pressure. I thought she'd actually turn into the shear and make it steer. She did at the mid levels. That mid-level circulation is headed for Tampa. The storm tops are still blowing off the the SW from the center, which has been something pretty amazing to me through the life of this storm. Overshooting cloud tops are apparently facing a differential flow.
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1428. Patrap
Floater - Rainbow Color Infrared Loop
Member Since: July 3, 2005 Posts: 428 Comments: 129795
STAY OUT OF THE GULF!!!

Now that's some good advice. Must be funny to see that rolling in, in the deserted dark...

Rolling back to sleep here whilst one can...
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1426. Fshhead
SFWMD model page

Looks like the models are really tightening up....
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1425. Patrap
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Quoting jpritch:
homeless, yes, the coc is clearly well west of the forecast track. It's a race at this point. At the speed it's going, it has a good chance of sliding a bit farther west before it gets turned north.


Oh thank goodness I wasn't imagining it. :) Looked like it missed its points to me too. I agree about the race. But I can't believe LA is not in the cone at least.
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1423. Patrap
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1422. xcool
she cat 1
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Quoting emguy:
KoritheMan...she hasn't made landfall yet...and she's probably not going to be a cane when she does. Sounds like these stats may hold on for another day.


Yeah, I'm not actually expecting her to make landfall at hurricane intensity. I've analyzed this storm very closely, and from what I see, I think she'll landfall as a 55 kt (65 mph) storm.

Still though, even if the hurricane force sustained winds subside prior to landfall, gusts to hurricane force will still be possible in the heavier squalls. Additionally, extratropical transition typically means a broadening of the wind field.

This is still dangerous.
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There is a beach break, about 3-4 feet.

Dark at night out here and I can make out some whitecaps out there, but I can't tell the size.

Chop chop chop...

BIG SIGN PULLING IN:

STAY OUT OF THE GULF!!!
Member Since: August 26, 2006 Posts: 10 Comments: 4101
Morning everybody.

Guess this was a bad weekend for me to take off... lol.

Two things I'm adding to the discussion.

1, We've had pretty steady easterly winds here this weekend due to the pressure gradient between us and Ida. We've also had mostly overcast skies and lower temps all weekend, a welcome change from last week's summer-like temperatures.

2, This has been an unusual year. Just when everybody thought the season was just about done, up pops this Ida, a persistent storm that seems determined to defy convention.

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Quoting Fshhead:
HAHAHAHAHAHAHA!!!!!
Man I was lurkin here earlier today & they were all swearing it was turning towards the East. Always trying to outthink the NHC. Ummm think I will take the NHC over some blogger any day!!
Sooooo I think quite a bit of crow is on the menu.. ;)




I saw that today. Kinda funny.
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1417. jpritch
homeless, yes, the coc is clearly well west of the forecast track. It's a race at this point. At the speed it's going, it has a good chance of sliding a bit farther west before it gets turned north.
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Quoting CycloneOz:
Doug! I'm under the beach ball!




Whats the surf?
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1415. emguy
KoritheMan...she hasn't made landfall yet...and she's probably not going to be a cane when she does. Sounds like these stats may hold on for another day.
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Hi, glad to see there's a few people up, hi, x-cool - I crashed on couch, just woke up, I'm kind of out of it, blurry-eyed...it's 3 am here and I'm not going to be able to stay awake 'til 4. Where are we, I see it's a Cat 1 now.
May I have a quick update, pls.? Is landfall supposed to be in Mobile area?
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1413. Patrap
Quoting CycloneOz:


I pulled in actually, but the cook was outside smoking a cig.

There was something that creeped me out when I drove by him, so I just left.

The Waffle House was not busy.


Careful round there,some late night action is Possible in the wee hours OZ.
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Doug! I'm under the beach ball!
Member Since: August 26, 2006 Posts: 10 Comments: 4101
1411. Fshhead
HAHAHAHAHAHAHA!!!!!
Man I was lurkin here earlier today & they were all swearing it was turning towards the East. Always trying to outthink the NHC. Ummm think I will take the NHC over some blogger any day!!
Sooooo I think quite a bit of crow is on the menu.. ;)
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Yo Bro..
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Quoting Patrap:


Is the Waffle House Busy?


I pulled in actually, but the cook was outside smoking a cig.

There was something that creeped me out when I drove by him, so I just left.

The Waffle House was not busy.
Member Since: August 26, 2006 Posts: 10 Comments: 4101
1408. Patrap
Quoting Fshhead:
LOL Evening Kori, interesting stats there...

Pat forget the pie, pass the bird Please!
HAHA!


I do have a Link for 3 crow recipes when needed..
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1407. Fshhead
LOL Evening Kori, interesting stats there...

Pat forget the pie, pass the bird Please!
HAHA!
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1406. xcool
cmc ? hmm
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I've been planning to go fishing today in Manchac, LA. With the rain and wind I probably gonna chicken out though. The fish really bite when the pressure starts dropping though. I might still give it a try when Ida starts her turn to the NE. Looks like she is falling apart pretty fast.
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1404. Patrap
Quoting CycloneOz:
CycloneOz Live From Pensacola Beach:

Current Conditions:

Wind: East- 15 mph steady
Upper Level Clouds - Movement from SW --> NE
Humidity: 87%
Temperature: 68F

Very eerie here on the beach. Seems to be completely deserted as the public parking lots are empty.

No sign of chasers. They'd be here where I am right now.

Ida is beginning to decline.

Interesting storm...and an interesting evening here on the beach


Is the Waffle House Busy?
Member Since: July 3, 2005 Posts: 428 Comments: 129795
It looks like its going alot westward than they think. Wow, it got even with the NE edge of that big lower level thing in the sw gom and hooked a left. Glad its weakening though
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CycloneOz Live From Pensacola Beach:

Current Conditions:

Wind: East- 15 mph steady
Upper Level Clouds - Movement from SW --> NE
Humidity: 87%
Temperature: 68F

Very eerie here on the beach. Seems to be completely deserted as the public parking lots are empty.

No sign of chasers. They'd be here where I am right now.

Ida is beginning to decline.

Interesting storm...and an interesting evening here on the beach
Member Since: August 26, 2006 Posts: 10 Comments: 4101
Quoting Fshhead:
Its supposed to be time to focus on Turkeys & X-Mas, not a freaking hurricane. LOL


Tell me about it. o_O

This is the first time, to my knowledge, that a hurricane has made United States landfall in November during an El Nino year since 1925, and the first time a hurricane has struck the United States in November since 1985's Hurricane Kate.
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1400. Patrap
Morn fsh..yup I totally agree.
Pass the Pie please.
Member Since: July 3, 2005 Posts: 428 Comments: 129795
ugh just land fall somewhere whats next after NW does an ENE jog...
Member Since: September 6, 2009 Posts: 2 Comments: 3784
1398. Fshhead
Evening Pat & Everyone else!!
You would think Ida is close to Miami & stronger, its real breezy here. Sure glad she is winding down some. Its supposed to be time to focus on Turkeys & X-Mas, not a freaking hurricane. LOL
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1397. xcool
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1396. xcool
i was rigth
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1395. Patrap
Cat 1
90 mph

Nw at 12
New Advisory
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1394. xcool
yeap try she
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1393. Patrap
Ida not the same gurl she was 6 Hours ago,although there is a Warmer Eddy right under the CDO right now,so maybe a convective Burst thru Dawn or D-max.

But time isnt in her favor anymore.
Member Since: July 3, 2005 Posts: 428 Comments: 129795
--------------------------------------------------------------------------------
Conditions at 42001 as of
(12:50 am CST)
0650 GMT on 11/09/2009: Unit of Measure: English Metric Time Zone: Station Local Time Greenwich Mean Time [GMT] British Summer Time [GMT+1] Eastern Greenland [GMT-1] Azores [GMT-2] Western Greenland [GMT-3] Atlantic Standard [GMT-4] US/Eastern Standard US/Central Standard US/Mountain Standard US/Pacific Standard Alaska Standard [GMT-9] Hawaii-Aleutian Standard [GMT-10] Samoa Standard [GMT-11] International Date Line West [GMT-12] Western European [GMT+0] Central European [GMT+1] Eastern European [GMT+2] Moscow [GMT+3] USSR Zone 3 [GMT+4] USSR Zone 4 [GMT+5] USSR Zone 5 [GMT+6] USSR Zone 6 [GMT+7] China Coast [GMT+8] Japan Standard [GMT+9] Guam Standard [GMT+10] GMT+11 International Date Line East [GMT+12]
Click on the graph icon in the table below to see a time series plot of the last five days of that observation.

Wind Direction (WDIR): E ( 80 deg true )
Wind Speed (WSPD): 25.3 kts
Wind Gust (GST): 33.0 kts
Wave Height (WVHT): 15.7 ft
Dominant Wave Period (DPD): 11 sec
Average Period (APD): 8.3 sec
Atmospheric Pressure (PRES): 29.79 in
Pressure Tendency (PTDY): -0.06 in ( Falling )
Air Temperature (ATMP): 79.2 °F
Water Temperature (WTMP): 80.2 °F
Combined plot of Wind Speed, Gust, and Air Pressure
INFO FROM BUOY 180 NM SOUTH OF MISS. RIVER
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Quoting Patrap:


Looks like she tried to blow up one more time.
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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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