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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1645. Max1023
The GFS is not as good as the Euro models, the ensembles are even worse.
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and don't get me wrong, there are people who blindly ignore evidence and say a storm will hit here or there, trust me I know that

however most of those people pop up every once in awhile to get a rise out of others. All of the people I would consider regulars have shown evidence to support their predictions.

It would be great if for once instead of people calling each other out for their opinions, that people could actually have a civil discussion about their differing opinions.
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Ok guys, I'm off to work. I expect Igor to either remain at 140 mph. or maybe 150 mph. by 11 p.m.
As for the track/models, maybe a shift to the left as StormW would say ;)
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Quoting CybrTeddy:


Because they are fascinating to watch. If you don't like it you can leave.

I enjoy very much watching hurricanes like Igor, strong ones that pose no threats to human life. They are eye candy to hurricane observers.

Well stated
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I am still concerned that Igor could make an east coast close call or maybe landfall.
Member Since: February 12, 2007 Posts: 0 Comments: 479
1639. Walshy
Quoting tinkahbell:
What exactly constitutes a "fish storm"? I would think that if it affects land in any way it could not be termed a "fish"...right? Wrong?


It is a small world. Believe it or not, the so called fish hurricane Danielle indirectly killed people in rough surf. People who have a very slim chance of being hit want to call it a fish storm. Similar to a hurricane affecting Bermuda or Canada.

I believe if people are bored with fish storms then they may need to rethink if they even like meteorology. These people would be even more bored trying to forecast for land areas, sunny and dry for the next five days. That would drive them insane!

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Quoting dolphingalrules:


like andrew in 91

not that small
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1637. BVImom
Thanks Everybody - I appreciate the feedback. I guess I'll be glued to the blog for the next few days - it really is an exercise in patience.
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1636. scott39
Quoting IKE:


The track looks about the same as their previous track. It just keeps it heading in the same direction further. Looks like a northern Mexico landfall based on the NHC track(subject to change).
Does the COC seem farther N with 92L on Satt, than the latest coordinates? Its hard to tell.
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12z FIMZ has Igor making landfall in NC

222hrs (Long-Range)

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Quoting Walshy:


What about TD12 becoming a hurricane? May alter Igor's path further west?


Dr. Masters mentioned that.. I haven't really studied much on TD12, but I do believe it will become a Hurricane, but should head NW then north, out to sea.
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Igor looking awesome!
Member Since: February 12, 2007 Posts: 0 Comments: 479
1630. txjac
I just happen to thing that the term "fish storm" is annoying. Even if landfall isnt made there is still sometimes catasrophic effects on land that it passes by. I feel for the people that this happens to. By termining it a "fish storm" it just kind of says that we dont care about those not hit "directly"
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1629. Max1023
Quoting RecordSeason:




I don't like that grey in the Se quad... this looks like a 130 knot system to me.
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1627. IKE
Quoting scott39:
Is that synopsis farther N than previous forecasts?


The track looks about the same as their previous track. It just keeps it heading in the same direction further. Looks like a northern Mexico landfall based on the NHC track(subject to change).
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1626. angiest
Quoting HurricaneIsabel:


That's what was forecasted.


Only really after it became a foregone conclusion he would take a swipe at the east coast.
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1625. Bonz
9 named storms, 3 of which made it to cat 4. That's rather impressive.
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Quoting HurricaneIsabel:
What would a CAT 5 Direct hit do to Bermuda?


My fear is that we'll find out.

Actually, that's not correct. My fear is not a direct hit, but that the eye goes just west of them. THAT would be just horrible.
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1622. Max1023
Imho:

Fish Storm: A Tropical system that does not bring tropical storm conditions to any landmass. A direct hit as a depression also disqualifies a system from fish status.
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Quoting doggonehurricane:
I don't know why you all waste your time over these fish storms.


Because they are fascinating to watch. If you don't like it you can leave.

I enjoy very much watching hurricanes like Igor, strong ones that pose no threats to human life. They are eye candy to hurricane observers.
Member Since: July 8, 2005 Posts: 259 Comments: 23015
Very intense eyewall associated with Igor. Beginning to look like a high-end category 4.

Member Since: September 2, 2009 Posts: 130 Comments: 21032
I'm out for a while, folks. Gotta get stuff ready for work tomorrow....

I'll prolly check in again after 8 before 11 EDT to see what's up. Surely will be expecting 2 se Julia up there by then....

L8r...
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1616. Melagoo
Quoting tinkahbell:
What exactly constitutes a "fish storm"? I would think that if it affects land in any way it could not be termed a "fish"...right? Wrong?


... no landfall at all
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1615. Walshy
Quoting reedzone:
My forecast for Igor before I leave for work..

Looking at the water vapor, it appears to me that Igor should start moving more west-northwest to northwest around 20N, 55W. I think Igor takes a NW turn do to the second trough, then as a ridge builds, Igor may steer WNW south of Bermuda. After that, It's up in the air what else could happen. Another trough may recurve it, that being the best scenario to look at right now, or a weak trough lifts it north along the East Coast.

The forecast for Igor believe it or not is actually a VERY complicated forecast. The two troughs appear to me to be too far north to really recurve it, the third one which is coming out of Canada in a few days is the one that is supposed to do it all the way. The question is when and where. I believe Igor will move south of Bermuda, then start turning north from there. Also where will the high be? If the high shifts east and strengthens, Igor will become a problem for the southeast. I'm really skeptical of it recurving "harmlessly" out to sea at this time. I need a few more days to see how far west Igor can make it before the turn occurs.


What about TD12 becoming a hurricane? May alter Igor's path further west?
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1614. Max1023
If Igor goes a little left of track it will hit warmer water earlier. I don't see Earl hitting Category 5 until he gets to 29 degree water.
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Just a thought. Please do not zapp me yet ok, but my understanding for all I have heard was that due to Global Warming (whether man made or not who cares) Was supposed to creat more humidity or increased ammounts of water vapor in the atmosphere. Well looking at the water vapor satelite I see a very dry planet, and perhaps the reason why the caribean storms as of today are pretty much going poof. Please don't kill me for this just give me your two cents.
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1612. Melagoo
SOME ADDITIONAL
STRENGTHENING IS FORECAST DURING THE NEXT COUPLE OF DAYS.
... CAT 5 looks obvious now
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Quoting Legion:


Bermuda is in the middle of the crosshairs right now, if it gets anywhere near Bermuda it can't be called a fish storm.


Similar to FABIAN
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1610. scott39
Quoting IKE:
SYNOPSIS FOR THE GULF OF MEXICO
430 PM CDT SUN SEP 12 2010

.SYNOPSIS...A COLD FRONT WILL CLIP THE FAR N WATERS TONIGHT INTO
MON. A WEAK SURFACE TROUGH WILL LINGER OVER THE FAR SW GULF
THROUGH WED. A LOW PRES SYSTEM IN THE EASTERN CARIBBEAN JUST
SOUTH OF HAITI WILL MOVE INTO THE NW CARIBBEAN WED...POSSIBLY AS
A TROPICAL CYCLONE...INCREASING WINDS AND SEAS IN THE FAR
SOUTHERN GULF. THE SYSTEM IS FORECAST TO BE OVER THE YUCATAN
NEAR 20N90W THU MORNING AND MOVE NW TO NEAR 22N97W THROUGH LATE
FRI NIGHT.
Is that synopsis farther N than previous forecasts?
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What exactly constitutes a "fish storm"? I would think that if it affects land in any way it could not be termed a "fish"...right? Wrong?
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I showed much evidence on why I thought Earl was gonna swipe or maybe hit the Northeast. I was only 30-50 miles west of the actual track. I would have been right on if that jog to the east after hitting 75W never occurred. I appreciate those don't have me on ignore and read what I have to say :)
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Quoting txjac:


Personally Reed, I enjoy reading your take on things


Same here, for the life of me I cannot see why people bash reed's opinion.
Member Since: July 8, 2005 Posts: 259 Comments: 23015
Quoting CosmicEvents:
Thanks.
Really should have been "TD or not TD, that's the convection", but I thought that might be a little too punny.


Luv it!!! LOL ;-D
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1602. help4u
Post 1583 no need to worry about a storm moving a couple hundred miles to the west when it is over 1000 miles out in open waters.
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1600. IKE
SYNOPSIS FOR CARIBBEAN SEA AND TROPICAL N ATLC FROM 07N TO 22N
BETWEEN 55W AND 65W
530 PM EDT SUN SEP 12 2010

.SYNOPSIS...LOW PRESSURE NEAR 16N72W WILL MOVE TO NEAR 17N77W
MON AFTERNOON AND NEAR 18.5N82W TUE AFTERNOON. THERE IS A MEDIUM
CHANCE OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS. HURRICANE IGOR EAST OF THE AREA CENTERED NEAR
17.7N46.9W IS FORECAST TO MOVE INTO THE TROPICAL N ATLC TUE
NIGHT AND WED AS A MAJOR HURRICANE...THEN MOVE NORTH OF THE AREA
THU.
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1599. hulakai
1576 IMO still 50-50
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Quoting sunlinepr:


Hypnotizing Eye....




Indeed..
Member Since: August 4, 2010 Posts: 0 Comments: 166
Quoting reedzone:


Welcome to my world.. I mean, I'm not saying it won't recurve, but we need to state the possibilities here just incase Igor really doesn't recurve as expected. People need to be prepared just in case, we don't need any shockers..
Its because people like you wish for total destruction...you want a landfall...what do you call someone who wishes this...hmmmi can think of a few words...why don't they block comments like that?
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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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