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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296. MZT
Quoting TheDawnAwakening:


He said 92L, unless he just fixed that.

No, we're done with that. I was confused because I thought he posted an image of 92L with a caption describing TD12. IE "losing the bubble"
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Hurricanes are good exsamples of...."Beauty kills"
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I wonder what my T number is right now,probably about 2.5, lol
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Quoting MiamiHurricanes09:
I'd say we're probably dealing with a category 3 hurricane right now.


I agree. Do you think he's undergoing RI?
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Quoting PensacolaDoug:




Earl had a left of track bias for days. This sure looks similar. Can't trust the wobbles! They get lots of people excited tho! If ya bet against the TPC/NHC on a regular basis, you'll lose a bunch of money!

Earl left track bias happened for 5 days straight and ended up re-curving and passing 20 North around 68W rather than the 50W initially forecast
Igors was forecast to pass 20N at 50W on Wednesday morning.
Thursday it was 55W
Friday 60W and looking very earl like.
Yesterday shifted back right to 55W and has been fairly stable since.
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These are very ominous.

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I'd say we're probably dealing with a category 3 hurricane right now.

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Quoting atmoaggie:
??? Is cool. (And I didn't know you were wrong about that, hadn't looked it up.)
I did Anadarco was not completed until 2002 so it wasn't around in 2001. Anyways thanks for all the great weather info and maps that you post.
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No in order for a hurricane to be a monster status, it needs to strengthen to category five hurricane status, then go through an EWRC and then expand in size and then restrengthen, but does not need to make landfall.
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Quoting doorman79:


Where u at Atmo? Ponchatoula here


Mandeville here
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Quoting CybrTeddy:


Eh, I have him on ignore.

Earl brought pretty strong winds to the United States too.
Here's a good video for proof of that.
Link


Havn't seen those high of winds in S Fla since 05. And that wasn't even half of what I experienced then. Don't miss it.
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T# for 92L have increased..
12/1145 UTC 15.7N 70.7W T1.5/1.5 92L
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281. Relix
53W should be the pickup point for Igor.
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Baha, I do not like that at all either. If he trends your way, half of him will be in my backyard as well.
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Man, he is looking very healthy.
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Quoting sailingallover:

I'm 90% sure 2 days at most and hoping to see a solid trend north starting tomorrow night per the GFS model.
I'm in St Thomas and right now with the Sat pics showing the trough that is supposed to re-curve igor northward in place although not extending as far south as I'd like I can't see igor not starting to head more NW in the the next 2 days.

Earl got kept south and pushed west more than th e models initially predicted because a strong extra tropical low reinforced the ridge. That is not happening this time.


dont like gfs..more west on igor folks..watch ukmet
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277. Relix
Igor already went up to his former position. That was a dumb wobble haha. 270 straight
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Quoting MZT:

Not unless it has learned teleportation.

TD12 IS OFF THE COAST OF AFRICA


He said 92L, unless he just fixed that.
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the only other thing it could be is a ULL transitioning to a regular low. Thats the only thing I can think of. Other than that, no clue.
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Didn't we all expect Igor to be a monster??? lol

Doesn't have 2 make landfall to be a monster....
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Quoting MiamiHurricanes09:
Yup. That T# would equal (roughly) to a 135mph category 4 hurricane.


Stunning. We shall we what the NHC does. I'd say 50/50 on a special advisory if this keeps up.
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Quoting weathermancer:


It was fish for the USA.
Canada got the eye come ashore just south of where I am.
1 person dead.
1,000,000 fish spun around in circles.



Eh, I have him on ignore.

Earl brought pretty strong winds to the United States too.
Here's a good video for proof of that.
Link
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Quoting IKE:
Models trending further south for 92L....Link


most likely a rain event for the northern Caribbean islands and the Yucatan Peninsula.
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Quoting MiamiHurricanes09:
Yup. That T# would equal (roughly) to a 135mph category 4 hurricane.

Now thats about right Igor a Cat 4

Taco :o)
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i think a special advisory will be issued on Igor before 5pm Eastern if this trend continues..
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Quoting BenBIogger:
Yesterdays 12z JMA had Igor heading towards the northern Bahamas.

168hrs (Long-Range)
Not liking that at all, atall...

Quoting plywoodstatenative:
Baha could be a left over remnant of Earl, remember those comments from a user about Earl early in the blog talk. Could that be what he was referring to?
Seems kinda low for an Earl remnant, IMO. Not sure what induced it; I just remember noticing it as I was "signing off" on Friday night and wondering if it would get a mention.
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Quoting CybrTeddy:
BLOG UPDATE
Hurricane Igor, TD12, 92L still a threat to develop 9/12/10

I like your updates. :)
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Quoting RecordSeason:
255 degrees heading

See here:



And here:


It looks between 265-270 degrees heading not 255
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Quoting ElConando:


This guy is bombing out.
Yup. That T# would equal (roughly) to a 135mph category 4 hurricane.
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BLOG UPDATE
Hurricane Igor, TD12, 92L still a threat to develop 9/12/10
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261. IKE
Models trending further south for 92L....Link
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Someone always has to stir the pot lol!
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Quoting MiamiHurricanes09:
Raw T# up to 6.1.

CI# /Pressure/ Vmax
5.9 / 952.4mb/112.4kt


Final T# Adj T# Raw T#
5.9 6.0 6.1


This guy is bombing out.
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Quoting sailingallover:

I'm 90% sure 2 days at most and hoping to see a solid trend north starting tomorrow night per the GFS model.
I'm in St Thomas and right now with the Sat pics showing the trough that is supposed to re-curve igor northward in place although not extending as far south as I'd like I can't see igor not starting to head more NW in the the next 2 days.

Earl got kept south and pushed west more than th e models initially predicted because a strong extra tropical low reinforced the ridge. That is not happening this time.
I can see that potentially happening. I'm more concerned about the 3 - 5 day period, since I'm not so convinced that trough will induce enough of a NW motion to keep Igor recurving at that point. And I'm not seeing much else out there to prevent an additional westward movement in the interim....
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Quoting weathermancer:


It was fish for the USA.
Canada got the eye come ashore just south of where I am.
1 person dead.
1,000,000 fish spun around in circles.


Exactly.

Earl was not a fish

"...TROPICAL STORM EARL MADE LANDFALL NEAR WESTERN HEAD NOVA SCOTIA
AROUND 10 AM EDT...1400 UTC. SEVERE TROPICAL STORM CONDITIONS
AFFECTING A LARGE PORTION OF THE PROVINCE..."


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Baha could be a left over remnant of Earl, remember those comments from a user about Earl early in the blog talk. Could that be what he was referring to?
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Yesterdays 12z JMA had Igor heading towards the northern Bahamas.

168hrs (Long-Range)
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Raw T# up to 6.1.

CI# /Pressure/ Vmax
5.9 / 952.4mb/112.4kt


Final T# Adj T# Raw T#
5.9 6.0 6.1
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Has Reed checked in yet?
I'd be curious about his track forecast for Igor.
He's usually very even-handed and unbiased with his East v. West forecast......
.
.
.
.
Hoist the RI and Sarcasm flag, matey.
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Quoting stillwaiting:
92l' center appears to be about a hundred miles south of the haiti/dr border,and looks to be moving nw,i wouldn't be suprised if it goes directly over jamacia...,

That's not good.
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Long range 6Z GFS still creates a Caribbean storm in a couple of weeks, but in a much different location that 0Z did. I wonder what 12Z will have.
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7544 we see with every other major hurricane that it wobbles here and there. The question is this, is this a continued wobble and track or just a system that is currently undergoing rapid development.
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Igor ACE=Skyrocketing
Currently- 4.07
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92l' center appears to be about a hundred miles south of the haiti/dr border,and looks to be moving nw,i wouldn't be suprised if it goes directly over jamacia...,
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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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