92L still a threat to develop; Igor a hurricane; TD 12 forming near Africa

By: Dr. Jeff Masters , 2:18 PM GMT on September 12, 2010

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Tropical disturbance (92L) over the Central Caribbean, a few hundred miles south of the Dominican Republic, remains a threat to develop into a tropical depression. Satellite loops this morning show 92L may be starting to form a surface circulation, and an Air Force Hurricane Hunter aircraft will investigate 92L this afternoon to see if a tropical depression is forming.

The storm has only a modest area of heavy thunderstorm with limited low-level spiral banding and upper-level outflow, thanks to an infusion of dry air last night that disrupted the storm. Long range radar out of Puerto Rico shows that heavy rains are affecting that island, but there is no rotation to the radar echoes evident. Wind shear over 92L is low, 5 - 10 knots. The waters beneath are hot, 29.5°C, and these warm waters extend to great depth. Water vapor satellite loops show a large area of dry air lies to the north and west of 92L, and this dry air could interfere with development at times over the next few days.


Figure 1. Morning satellite image of 92L.

Track forecast for 92L
The disturbance is moving west to west-northwest at 15 mph, and steering currents favor a continuation of this motion for the next three days. Model support for development is scattered. The GFS and NOGAPS models do not develop 92L. The GFDL and ECMWF models predict development, with a track taking 92L into Belize or Mexico's Yucatan Peninsula on Wednesday. On this track, the southern Dominican Republic can expect heavy rains of 3 - 6 inches today through Monday morning; southern Haiti can expect similar rains tonight through Monday night, and Jamaica and the Cayman Islands can expect heavier rains of 4 - 8 inches Monday and Tuesday. Eastern Cuba can expect rains in the 2 - 4 inch range. Once 92L crosses the Yucatan, the ridge of high pressure steering it is expected to remain in place, forcing 92L to a second landfall in Mexico south of the Texas border.

Intensity forecast for 92L
NHC is putting the odds of 92L developing into a tropical depression by Tuesday at 50%; I'd put them higher, at 70%. However, time is running out for 92L to become a hurricane before hitting the Yucatan Peninsula on Wednesday. Given the current disorganized state of 92L, it would be difficult for it to intensify quickly enough to become a hurricane by then. The storm may also suffer another of its mysterious evening collapses, where it loses most of its heavy thunderstorm activity. However, the SHIPS model predicts wind shear will remain low, 5 - 10 knots, through the period, and water temperatures are certainly warm enough to support development. The main detriment to intensification is likely to be dry air, and 92L could wrap in some of the dry air to its northwest at times, slowing down development. There are a number of research flights being made into 92L this afternoon that should help long-term efforts to make better predictions in the future on whether or not disturbances like this will develop or not.


Figure 2. Morning satellite image of Igor.

Igor
Hurricane Igor appears destined to become a large and powerful major hurricane over the Central Atlantic in the days to come. Wind shear is low, 5 - 10 knots, and is expected to drop below 5 knots for the next five days. Waters are warm, 28°C, and will warm to 29°C by Wednesday. Igor has moistened its environment enough to keep the dry air of the Saharan Air Layer (SAL) at bay. Igor is undergoing a period of rapid intensification today, and will probably be a Category 3 or 4 hurricane by Monday.

The track forecast for Igor remains unchanged. Igor will move west under the influence of a strong ridge of high pressure for the next 2 - 3 days, then turn more to the west-northwest then northwest in response to the steering influence of a broad trough of low pressure moving across the Western Atlantic on Tuesday and Wednesday. This should allow Igor to pass several hundred miles to the northeast of the Lesser Antilles. In the longer range, Igor may be a threat to Bermuda, and does have a small chance of making landfall on the U.S. East Coast or Canada. Climatology shows that about 15% of all tropical cyclones that have existed at Igor's current position have gone on to hit the U.S. East Coast; these odds are about 10% for Bermuda and 10% for Canada. The forecast steering pattern for the period 5 - 12 days from now from the ECMWF and GFS models shows a continuation of the pattern we've seen all hurricane season, with regular strong troughs of low pressure moving off the U.S. East Coast. This pattern favors Igor eventually recurving out to sea without affecting any land areas. Recent runs of the ECMWF model indicate that these troughs may not be as intense as previously thought, so it is possible Igor has a higher chance than usual to hit land than climatology suggests. One wild card may be the possible development of TD 12 behind Igor. If TD 12 develops into a hurricane, and moves close to Igor, as some of the models are suggesting, the two hurricanes could rotate around a common center, forcing Igor more towards the coast of the U.S. The long term fate of Igor is difficult to predict at this point.

Tropical Depression Twelve forms
Tropical Depression Twelve formed between the Cape Verdes Islands and coast of Africa this morning, and is already affecting the Cape Verdes with winds near tropical storm strength; sustained winds of 35 mph were recorded in the northwest Cape Verdes this morning. You can follow the progress of TD 12 through the Cape Verdes today using our wundermap.

Next post
I'll have a new post Monday morning, and perhaps late this afternoon if events warrant.

Jeff Masters

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I bet Igor is a Cat 5 by 11 probably is now!
Member Since: Posts: Comments:
Quoting doorman79:
Kman,

If and I know it's big if, Igor doesn,t fully feel the second trof. What whould be plan B tia


Plan B would be a short term motion for Igor to move WNW then NW followed by a turn back to the WNW. I wouldn't want to speculate beyond that for the time being.
Member Since: August 19, 2006 Posts: 0 Comments: 16278
2094. MZT
Yeah, he is gunning for Isabel's peak. 165MPH on Sept 11, 2003.

It is very rare to see CAT5 in the Atlantic.
Member Since: September 24, 2005 Posts: 0 Comments: 796
Member Since: September 2, 2009 Posts: 130 Comments: 21372
Quoting all4hurricanes:

I see a pink frosted donut, cat 5 coming up
*Churn*
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Poll time!

Is Igor currently a Category 5 Hurricane?

A. Yes
B. No

Will the NHC send out a Special Advisory to upgrade him to a Category 5?

A. Yes
B. No

I say A B
Member Since: July 6, 2010 Posts: 113 Comments: 34481
Igor is an absolutely violent hurricane. It's living up to it's name.
Member Since: August 9, 2009 Posts: 10 Comments: 5134
Quoting Stormchaser2007:
Comrade Igor

The baddest Russian hurricane since "Ivan The Terrible".

Igor has an intense and large ring of thunderstorms surrounding the eye. He also has barely any banding features.
Member Since: September 2, 2009 Posts: 130 Comments: 21372
2087. hydrus
Quoting WeatherNerdPR:

Compared to the storm's overall size, Igor's eye is pretty big.
Igor is an impressive hurricane. And will become even more impressive in the next 24 hours...Mother Natures power is astonishing.
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2086. hydrus
Quoting WeatherNerdPR:

Compared to the storm's overall size, Igor's eye is pretty big.
Igor is an impressive hurricane. And will become even more impressive in the next 24 hours...Mother Natures power is astonishing.
Member Since: Posts: Comments:
2085. Walshy
Quoting Hurricanes101:


I would disagree, he has very little banding associated with him

I consider Igor annular or very close to it



I asked Drakoen a page or two back but it got missed. Dr. Masters Blog shows Igor weaker with much better banding. Now, it appears to be much shorter banding to non existent with and up to CAT4 now. Man, this brings back bad memories of Isabel.

Member Since: May 17, 2009 Posts: 2 Comments: 908
2084. dmaddox
easily Cat. 5... IMO..
Member Since: May 5, 2007 Posts: 0 Comments: 445
Quoting CosmicEvents:
KMan...that spin, such as it is, with 92L. You said 16, 73. Is that where you see it? I see something at 17,73


Run this visible loop at close to max speed and you will see that the clouds near 16.5 N are moving from E to W near 73. The "center" is just S of that cloud motion.
Member Since: August 19, 2006 Posts: 0 Comments: 16278
Kman,

If and I know it's big if, Igor doesn,t fully feel the second trof. What whould be plan B tia
Member Since: August 11, 2010 Posts: 0 Comments: 895
Member Since: June 9, 2007 Posts: 4 Comments: 16038
2079. Patrap
IGOR CIMSS


Animated ADT Loop
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2078. Max1023
Quoting Vero1:


It needs to chill out!


More like Warm up! lol

Igor looks stronger than Earl ever did. On the last frame the eye completely clears out and the eyewall cools. This looks like a 5 now.
Member Since: July 22, 2008 Posts: 1 Comments: 286
Comrade Igor

The baddest Russian hurricane since "Ivan The Terrible".

Member Since: June 9, 2007 Posts: 4 Comments: 16038
Quoting MZT:
We've been discussing this much of the day. The NHC has declared him non-annular. But many here feel like he's close.


I think this morning he was not annular, but if you look at the loop you see the intense ring of convection increasing around the big eye and the bands decreasing
Member Since: March 10, 2010 Posts: 1 Comments: 8694
Member Since: July 6, 2010 Posts: 113 Comments: 34481
That trough coming out from US will have to reach at least 21N going down, to have some effect on Igor.... right now it's too north....
Member Since: August 2, 2010 Posts: 22 Comments: 10052
2073. Vero1
Quoting CybrTeddy:
Check out that perfect ring of -70C convection.


It needs to chill out!
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Quoting CybrTeddy:
Hurricane Ear-- er, Igor.

Lol.
Member Since: August 9, 2009 Posts: 10 Comments: 5134
2071. MZT
Quoting Hurricanes101:


I would disagree, he has very little banding associated with him

I consider Igor annular or very close to it
We've been discussing this much of the day. The NHC has declared him non-annular. But many here feel like he's close.
Member Since: September 24, 2005 Posts: 0 Comments: 796
Igor is amazing and will check back around 8pm EDT. I will come up with my updated maps and forecast discussions then.
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2069. dmaddox
Igor has no plans to move North of due west any time soon IMO....
Member Since: May 5, 2007 Posts: 0 Comments: 445
Quoting hydrus:
It was an attempt at humor...I am in a good mood today, but I hate cat food now. I read the ingredients on the can and there is no cat in it....They lied...


Well your humor worked on me. I was rolling! Hahahaha!! Thanks!
Member Since: Posts: Comments:
KMan...that spin, such as it is, with 92L. You said 16, 73. Is that where you see it? I see something at 17,73
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Check out that perfect ring of -70C convection.
Member Since: July 8, 2005 Posts: 259 Comments: 25168
AFRICA IS ALIVE....

Member Since: August 2, 2010 Posts: 22 Comments: 10052
2064. Patrap
There is a ADT Page for the ANNULAR Numbers and He isnt ATM.
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Member Since: September 2, 2009 Posts: 130 Comments: 21372
2062. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15707
Quoting Max1023:


Igor is not annular, he has outer bands.


I would disagree, he has very little banding associated with him

I consider Igor annular or very close to it
Member Since: March 10, 2010 Posts: 1 Comments: 8694
Hurricane Ear-- er, Igor.
Member Since: July 8, 2005 Posts: 259 Comments: 25168
2059. JRRP
Igor the terrible
Member Since: Posts: Comments:
Quoting plywoodstatenative:
Drak, the question becomes did she originally have a surface circulation already and was just waiting for timing before doing something. If we remember there was something of the system before and now its firing again. Doorman posted something that showed off the infrared on the storm and it appeared to have just such.

Kman thoughts on Igor and his track?


If you run this WV loop

you will see the first trough which is pretty flat lifting out to the N of Igor and pass him by. The second trough is pushing offshore the NE US and is amplifying much deeper to the S than the outgoing trough. This should do two things. The first is create a break in the sub tropical ridge. The second is to strengthen the ridge offshore the East coast that will follow behind it and that ridge should then serve as a blocker to Igor heading towards the US coastline much like Earl was blocked.

The NHC seems to have a good handle on the track IMO subject to the evolution of the features I have just mentioned.
Member Since: August 19, 2006 Posts: 0 Comments: 16278
2057. Patrap
IGOR Floater - Rainbow Color Infrared Loop

TFP's are available
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Quoting StSimonsIslandGAGuy:
HAARP is just a loony conspiracy theory.


Igor is looking great!
.......i don't know man,question how many pictures of punch whole clouds have you seen prior to 1990?????,answer: zero
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2055. Max1023
Quoting bwat:
I hate to use this word, because it so un often that it happens, but does anyone else agree with me in saying that Igor looks to be becoming annular? From the definition on wiki, he seems to be fitting all of the requirments. Can someone inform me more?


Igor is not annular, he has outer bands.
Member Since: July 22, 2008 Posts: 1 Comments: 286
2054. will40


mad IGOR
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2053. bwat
I hate to use this word, because it so un often that it happens, but does anyone else agree with me in saying that Igor looks to be becoming annular? From the definition on wiki, he seems to be fitting all of the requirments. Can someone inform me more?
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Quoting aislinnpaps:


Is that what is coming off Africa soon?


U betcha.
Member Since: July 6, 2010 Posts: 113 Comments: 34481
Member Since: June 9, 2007 Posts: 4 Comments: 16038
2050. Patrap
Quoting sunlinepr:
Quoting: Patrap 10:44 PM GMT on September 12, 2010 Hide this comment.
I was I mile or 2 west of this video as we went thru Elena in 85 in Long Beach,Mississippi.

EXCELENT VIDEO


Hard to think it was 25 years ago now.

I was 25 then,..on Leave from the USMC.

Was my first Eyewall Punch since Betsy when I was 5,,and it would be
nuther 20 till Katrina in 2005.

A Bad 20 year trend one could say.
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2049. Max1023
Quoting MiamiHurricanes09:
Absolutely beautiful.



I'd buy him a ring but:

1. I'm a straight guy

2. He already has one... of -75 degree convection!

3. I wouldn't be able to afford it.
Member Since: July 22, 2008 Posts: 1 Comments: 286
Quoting Stormchaser2007:
Wow. Anyone know what the strongest Hurricane at Earl's position was?


probably Isabel
Member Since: March 10, 2010 Posts: 1 Comments: 8694
Quoting Stormchaser2007:
Impressive training of systems.

**FULL IMAGE



Is that what is coming off Africa soon?
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FTR, Isabel's track. Be interested to see an overlay of their--Isabel and Igor-- respective tracks thus far


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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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