Ida takes aim at the U.S. Gulf Coast
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
Reader Comments
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Been watching that for Hours and Im in agreement on that issue.
I hope it's that far west.
Encouraging news.
I don't see anyone left on here talking about it going NNE or NE...lol. Or hitting peninsula Florida.
Yeah me too. This is a complicated set up, but thats how it looks to me.
But you stick with your obs and thats all one can do here. Fishing and wishing is for the Birds,,or crows.
Always best to call it like ya see it in my book.
Floater - Funktop Color Infrared Loop
I didn't get to this site until last year. But I searched the doc's blogs for 2005. A week before Rita hit the GFS had it nailed exactly. I don't know if they varied from it but it was right that day. I didn't see Ritas sats til last year. We also had a fast developer bomb out on our coast. But thank heaven Humberto was no Wilma. But he sirprised everyone. Lol.
Not sure it will make landfall as a cane.
Yes Ida is still surprising me. Just by being a hurricane that far in the gulf and in November! Lol. Well it has been interesting following this one. Of course some of the models made me dizzy. I never seen such looping tracks. But like I said just 1 year here. :)
Will it wind down before Landfall?
Say it like it iz for now,789
And it races off to the west/northwest.
Water vapor loop says it all.
Looks like extratropical may have started.
Thats what The Intensity showed at the 06Z run,..Peaked now,,then spreads out and down in Mph
Late Cycle run.
Early Cycle 06Z
I'd say both. And her demise has even showed up on the funktop I've been following.
I was wondering, did the BOC low become extra tropical? It got a lot bigger throughout the day.
Take it EZ,.always fun to watch a Fray evolve..
Looks like it's all combining into one extra-tropical low....
Check back in a couple of hours, to see what's left of Ida.
Oh ok. Thanks that's what the models were showing. I just thought the BOC low would be smaller.
Mobile Long Range
Sweet dreams Ike. :)
Ida shows up in the right Hand corner
NEXRAD Radar
New Orleans, Storm Relative Mean Radial Velocity 1.45 Degree Elevation Range 124 NMI
You don't have to, for she will already be knocking on your door lol.
Floater - Rainbow Color Infrared Loop
The dry air is certainly hastening the conversion into a tropical cyclone. Cold air entrainment will be more significant in a asymmetrical tropical cyclone. Ida will start to interact substantially with the shortwave in about 3-6hrs.
Tropical Cyclone Formation Alert (0900z 09NOV)
===============================================
An area of convection (92B) located near 11.1N 71.3E or 300 NM west-northwest of Cochrin, India. Animated infrared satellite imagery shows multiple bands of deep convection starting to consolidate about the low level circulation center, which is well defined in a 0400z Quikscat Pass. Upper level analysis reveals the system is under the subtropical ridge axis in an area of low to moderate vertical wind shear with fair radial outflow.
Maximum sustained winds near the center is 25-30 knots with a minimum sea level pressure of 1002 MB. Due to the increased convective consolidation, the potential for this disturbance to form into a significant tropical cyclone within the next 24 hours is UPGRADED GOOD
Floater - Dvorak Infrared Loop
Tropical Cyclone Advisory #8
TROPICAL DEPRESSION 27
18:00 PM JST November 9 2009
=========================================
SUBJECT: Tropical Depression near Wake Island
At 9:00 AM UTC, Tropical Depression (1002 hPa) located at 20.8N 160.6E has 10 minute sustained winds of 30 knots with gusts of 45 knots. The depression is reported as moving east at 6 knots
RSMC Dvorak Intensity:
Forecast and Intensity
======================
24 HRS: 25.2N 164.4E - 35 knots (CAT 1/Tropical Storm)
---
*JTWC has issued its final advisory on this system expecting the system to dissipate overseas.. hmm
TC ADVISORY
DTG: 20091109/0600Z
TCAC: TOKYO
TC: Depression 27
NR: 4
PSN: N2035 E16035
MOV: E 10KT
C: 1002HPA
MAX WIND: 30KT
FCST PSN 6HR: 09/1200Z N2055 E16135
FCST MAX WIND 6HR: 35KT
FCST PSN 12HR: 09/1800Z N2155 E16225
FCST MAX WIND 12HR: 35KT
FCST PSN 18HR: 10/0000Z N2325 E16305
FCST MAX WIND 18HR: 35KT
FCST PSN 24HR: 10/0600Z N2455 E16400
FCST MAX WIND 24HR: 35KT
RMK: NIL
NXT MSG: 20091109/1200Z =
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