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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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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1595. txjac
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..


Personally Reed, I enjoy reading your take on things
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1594. angiest
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..


Given how close Earl came to recurving after making landfall on the US east coast, you would think people would be a little more open to seeing the risk.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
1593. Max1023
So far the only major fish storm was Danielle. Earl hit the BVI, OBX and made landfall in NS. Alex and Bonnie made landfall, Colin went over bermuda as a TD, Fiona was not a major storm, neither was Gaston, Hermine made landfall in MX and Igor has hit the CV islands, and looks to either hit bermuda or Atlantic canada.
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1591. xcool
i'm just tired people/ call people wishcast all bull who give beep beep.do not personal attacks me jmojmo
Member Since: September 26, 2009 Posts: 2 Comments: 15620


Hypnotizing Eye....
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Sun beginning to set on a true monster.


Igor lived up to its name.
Member Since: July 8, 2005 Posts: 259 Comments: 23574
I'm on the Yucatan Pen. offshore working...do you think 92L will amount to anything...doesn't seem much hope for hurricane...
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Quoting Hurricanes101:


I am just tired of the fact that no one is every allowed to put forth the opinion that a storm may go further west than the models or the NHC predicts without being called a wish-caster, west-caster or being called out for wanting a US threat.



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..
Member Since: Posts: Comments:
1585. 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.
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Quoting Kearn:
Igor is such a small system...


like andrew in 91
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1583. will40
.UKMET AND ECMWF REMAIN TO THE LEFT OF THE CONSENSUS AND ARE
SLIGHTLY SLOWER...WHILE THE OTHER REGIONAL AND GLOBAL MODELS
SUGGEST A MORE PRONOUNCED WEAKNESS WITH TIME IN THE MID- TO
UPPER-LEVEL RIDGE.


.BUT STILL TO THE LEFT OUT OF RESPECT TO THE RELIABLE ECMWF
MODEL.

thats the two worrying parts of the discussion to me
Member Since: September 19, 2005 Posts: 2 Comments: 4110
1582. angiest
Quoting Hurricanes101:


I am just tired of the fact that no one is ever allowed to put forth the opinion that a storm may go further west than the models or the NHC predicts without being called a wish-caster, west-caster or being called out for wanting a US threat.



Ditto.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting Hurricanes101:


I am just tired of the fact that no one is every allowed to put forth the opinion that a storm may go further west than the models or the NHC predicts without being called a wish-caster, west-caster or being called out for wanting a US threat.

1000
Member Since: September 2, 2009 Posts: 130 Comments: 21091
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1579. help4u
Jason has pegged every storm right this season no one else is close.Has been calling these fish storms one right after the other.100% is hard to go aganist.Must know something the others on here don't.
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Waiting and waiting and waiting...

Member Since: September 10, 2007 Posts: 0 Comments: 10978
Quoting reedzone:


There's been alot of people stating that Igor WILL recurve away from the US.. Even when some of the good models trended west today, amazing.


I am just tired of the fact that no one is ever allowed to put forth the opinion that a storm may go further west than the models or the NHC predicts without being called a wish-caster, west-caster or being called out for wanting a US threat.

With Earl people said they felt he would move further south and west, and those people were called out for being west-casters. In the end they were right and the storm came much closer to the US than originally forecasted. Most people who feel a system will go further west, show evidence to support their opinion and they are still called out.

Member Since: March 10, 2010 Posts: 1 Comments: 7368
1574. xcool
beep beep getting older
Member Since: September 26, 2009 Posts: 2 Comments: 15620
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.
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Quoting MZT:

O RLY?

People in Texas probably thought they had "NO" chance of being hit by Ike for a while. Was supposed to be a Florida event...









OK, I cheated. Those are Rita pics. But the broader point remains. ;-)


SLICK!!! But very effective!!!
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Quoting Hurricanes101:
Wow lmao they nudge the track right and it means they arent buying into west-casting?

Seriously? lol


There's been alot of people stating that Igor WILL recurve away from the US.. Even when some of the good models trended west today, amazing.
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Quoting reedzone:


I'm very skeptical of this recurvature. Those two trough are too far north to really get Igor north. I think the UKMET, CMC, and EURO has the right idea.Kudos for the NHC on keeping a left bias on this one.


you are not allowed to have that opinion, because that is west-casting lol

*sarcasm off*
Member Since: March 10, 2010 Posts: 1 Comments: 7368
Quoting Stormchaser2007:
Why anyone still quotes Jason is beyond me.

+50
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1567. help4u
ALL experts have this going out to sea.
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Wow lmao they nudge the track right and it means they arent buying into west-casting?

Seriously? lol
Member Since: March 10, 2010 Posts: 1 Comments: 7368
Quoting moonlightcowboy:


;P
Thanks.
Really should have been "TD or not TD, that's the convection", but I thought that might be a little too punny.
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Quoting 1900hurricane:

I'm very confident that Igor will push us over 100.
I agree.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
1562. Max1023
Igor is NOT a fish storm, it already brought TS conditions to the Cape Verdes.

Also, Igor looks better and better on Dvorak.
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Quoting MiamiHurricanes09:
Season total ACE

01L (Alex): 6.7825
03L (Bonnie): 0.3675
04L (Colin): 1.9450
06L (Danielle): 21.7950
07L (Earl): 27.7750
08L (Fiona): 2.9400
09L (Gaston): 0.3675
10L (Hermine): 1.2725
11L (Igor): 5.4150
-------------------------------------
Total: 68.66

I'm very confident that Igor will push us over 100.
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Quoting BahaHurican:
Obviously still not completely convinced about that right turn, though. I wouldn't be surprised to see another left shift some time during the next 48....


I'm very skeptical of this recurvature. Those two trough are too far north to really get Igor north. I think the UKMET, CMC, and EURO has the right idea.Kudos for the NHC on keeping a left bias on this one.
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1558. Kearn
Igor is such a small system...
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if that thing in the caribbean does develop and heads over towards texas. Thats a problem for us, if that high blocks it from moving Northbound then the only option is westward for the time being.
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Season total ACE

01L (Alex): 6.7825
03L (Bonnie): 0.3675
04L (Colin): 1.9450
06L (Danielle): 21.7950
07L (Earl): 27.7750
08L (Fiona): 2.9400
09L (Gaston): 0.3675
10L (Hermine): 1.2725
11L (Igor): 5.4150
-------------------------------------
Total: 68.66
Member Since: September 2, 2009 Posts: 130 Comments: 21091
1555. Kearn
140 freaking mile an hour?!

OVERNIGHT?
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Quoting IKE:
THE NHC TRACK FORECAST IS NUDGED TO THE RIGHT OF
THE PREVIOUS FORECAST AFTER DAY 3...CLOSER TO THE TVCN CONSENSUS
MODEL...BUT STILL TO THE LEFT OUT OF RESPECT TO THE RELIABLE ECMWF
MODEL.


Hmm...nudged the track forecast to the right. I guess the NHC isn't buying into west-casting this afternoon.
Obviously still not completely convinced about that right turn, though. I wouldn't be surprised to see another left shift some time during the next 48....
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1553. help4u
West Hype casting.Earl was going west up until the time it missed the obx by 150 miles.It was going west the last 5 days of track but ran into invisible west wall.lol
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more of a hint a circulation than an earlier passLink
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1551. Hhunter


crapola
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Why anyone still quotes Jason is beyond me.

Member Since: June 9, 2007 Posts: 4 Comments: 15776
Hmmm.... doesn't look like NHC expects Julia 2 become a major...

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Igor might make it to Cat 5 status, but I'm not thinking this would happen until after its first EWRC which should occur within the next day or so.
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1546. IKE
Morehead City,NC extended...maybe this front gives Igor one last kick north and then NE........

LONG TERM /WEDNESDAY THROUGH SATURDAY/...
-- Changed Discussion --
AS OF 300 PM SUNDAY...NOT MUCH CHANGE IN EXTENDED FORECAST
THINKING FROM YESTERDAY. UPPER FLOW WILL REMAIN RELATIVELY ZONAL
UNTIL H5 HEIGHTS START TO RISE BY NEXT WEEKEND. GFS/ECMWF AND HPC
GUIDANCE INDICATE SURFACE RIDGE TO LINGER JUST OFFSHORE THURSDAY
BEFORE MOVING OFFSHORE THURSDAY NIGHT. THIS ALLOW A COLD FRONT TO
MOVE INTO THE REGION FRIDAY AND OFFSHORE EARLY SATURDAY.
CONTINUED
WITH SMALL POPS FOR THE FRIDAY THRU SATURDAY TIME FRAME...WITH
REMAINDER OF EXTENDED PERIOD DRY. TEMPS WILL REMAIN NEAR OR
SLIGHTLY ABOVE SEASONAL NORMALS.
-- End Changed Discussion --

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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.