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

Share this Blog
1
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 3496 - 3446

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85Blog Index

3496. xcool
buzzz rob
Member Since: Posts: Comments:
Quoting Ryuujin:


Man I don't know if you know how appreciated you are around here, but thanks. But like you said, if he EWRCs then we might get an explosion of RI after? Or do you think he's just going to sit on the edge of being a true monster for a bit?


Umm...Really? I mean what does it take to be a "true monster"...he's already there. Cat 4 and up is a "true monster" without question.
Member Since: Posts: Comments:
3494. Levi32
Quoting Ryuujin:


Man I don't know if you know how appreciated you are around here, but thanks. But like you said, if he EWRCs then we might get an explosion of RI after? Or do you think he's just going to sit on the edge of being a true monster for a bit?


It's hard to predict what will happen during an EWRC, but I still expect he will make a run at Cat 5 at some point during his life.
Member Since: November 24, 2005 Posts: 635 Comments: 26652
Levi...in your tropical tidbit yesterday you talked about a japanese model of some sort...and it had Igor beelining WEST because of a strong ridge...I may not be totally right in my explanation but I know you know what I'm talking about...anyway, do you feel that's what might be setting up right now?
Member Since: Posts: Comments:
3491. flsky
Quoting 1celia70:
..2 yrs ago ... i was waiting on ike to come ashore in houston galveston..... water everywhere.... so glad it moved just enough to the north of galveston ...because it was bad enough as it was... i was in galveston again today and it is hard to believe the water was at the top of the seawall...i will sleep well tonight...

I was doing disaster work in Galveston after that storm. I'm sorry you suffered so.
Member Since: Posts: Comments:
3490. Ryuujin
Quoting Levi32:


It is a sign of weakening when it is accompanied by warming cloud tops in the convective ring around the eye and a decay in overall cloud structure.


Man I don't know if you know how appreciated you are around here, but thanks. But like you said, if he EWRCs then we might get an explosion of RI after? Or do you think he's just going to sit on the edge of being a true monster for a bit?
Member Since: Posts: Comments:
Quoting KanKunKid:


Better alert Venezuela.
ha,;ha,that's a good one,maybe hurricane warnings for Chavez!!! Chavez would say," I knew it, the americans were going to throw that thing towards me!!"
Member Since: Posts: Comments:
Sorry F4 didnt catch that part. talking to my teen about the game
Member Since: Posts: Comments:
Quoting KanKunKid:


You mean your posts are juicy, cause it's eating them, right? It's not eating you, is it?


Er yeah thats what I meant SmileyCentral.com
Member Since: Posts: Comments:
Quoting PrivateIdaho:
I'm surprised I haven't received any comments on the Napolean Dynamite avitar....think I'll go back to Mr Potato Head...he looks more intelligent.
LOL, I haven't had any since I changed mine either. Must be because many are so eager to be the first to say something profound, that they pay no attention. They certainly don't have time to make good use of the auto-spellcheck feature or the "preview comment".
Member Since: Posts: Comments:
3484. 7544
imo anyone from fla to nc thats not worried about igor better second think i think hes going to surpise us all espicaly if the north turn dosent happen tom by miday and the islands should watch him carefully
Member Since: Posts: Comments:
..2 yrs ago ... i was waiting on ike to come ashore in houston galveston..... water everywhere.... so glad it moved just enough to the north of galveston ...because it was bad enough as it was... i was in galveston again today and it is hard to believe the water was at the top of the seawall...i will sleep well tonight...
Member Since: Posts: Comments:
Quoting KanKunKid:


You mean your posts are juicy, cause it's eating them, right? It's not eating you, is it?
Your internal filter just doesn't work at all does it....lol
Member Since: Posts: Comments:
3480. xcool


Member Since: Posts: Comments:
Angle of attack of the trough (left upper dark coming area) looks too pasive to make IGOR start moving WNW.... Maybe Igor will react to it, by moving WSW to avoid it.... Posible bad situation, that we will see tomorow.... Hope not...

Member Since: Posts: Comments:
3477. xcool
Member Since: Posts: Comments:
3476. Levi32
Quoting Ryuujin:
Is Igor's eye getting smaller? Isn't that a indication of further intensification?


It is a sign of weakening when it is accompanied by warming cloud tops in the convective ring around the eye and a decay in overall cloud structure.
Member Since: November 24, 2005 Posts: 635 Comments: 26652
3474. ch2os
Quoting KanKunKid:


A square can be shaped like an "L" too.


And "T" shaped even.
Member Since: Posts: Comments:
The NOGAPS and ECMWF build a very large ridge over the East Coast, blocking IGOR from going N. The GFS is now developing that same ridge. Not as strong as the NOGAPS/ECMWF one, but all the models are starting to agree that the fronts coming off the US are going to leave behind a ridge that could block IGOR. This will either leave IGOR in a weakly steered enviornment with a weak ridge (GFS) or will push it West (NOGAPS/ECWMF). Either way, it is not good if you own beachfront property.

GFS



NOGAPS



ECMWF

Member Since: Posts: Comments:
Quoting KanKunKid:


Maybe not even then.
Yeah, why ruin a perfect record at the very end?
Member Since: Posts: Comments:
Quoting AtHomeInTX:
Wow! I must be juicy. WU is eating my posts like candy! Lol.


lol..... :)
Member Since: Posts: Comments:
Danielle was gonna hit Bermuda right? Earl was going to plow into Montauk? Gaston was going to wreck havoc in the Carribean? Whole lotta wishing, but no verification..
Member Since: Posts: Comments:
Quoting AtHomeInTX:
Wow! I must be juicy. WU is eating my posts like candy! Lol.
Oh Lord, talk about grabbing the bullseye with 2 hands! ROFL
Member Since: Posts: Comments:
I'm surprised I haven't received any comments on the Napolean Dynamite avitar....think I'll go back to Mr Potato Head...he looks more intelligent.
Member Since: Posts: Comments:
Quoting Drakoen:
Igor looks like he's developing his spiral banding.


Is that a sign of something to come, or something sign of something he's doing now? Is it a sign of weakening / strengthening for example, or is it simply an observation?
Member Since: October 21, 2007 Posts: 27 Comments: 329
12z FIMZ

240hrs (Long-Range)

Member Since: Posts: Comments:
Quoting AussieStorm:

gee, someone needs to go back to school to learn there shapes.


And "their" shapes, also.
Member Since: Posts: Comments:
Quoting sunlinepr:
Hey, something strange going on.... You see that cloud region in the right area of this image, it is loc. around 20N 58 W, and it is STILL moving West. That means that the trough is not affecting it.... So that means that it won't affect IGOR.... if that's correct, We have a problem here.....

SHSHSHSH, I'm in Puerto Rico I'm trying to go to sleep, you are scaring me!!!
Member Since: Posts: Comments:
Must go. G'nite to all... hope we get no nasty surprises from either Igor OR 92L overnight....

Sleep tight!
Member Since: October 25, 2005 Posts: 19 Comments: 22305
Sorry about the caps but anytime Dallas loses in a good thing!
Member Since: Posts: Comments:
FIMZ is the only model showing Igor making landfall in the U.S
Member Since: Posts: Comments:
Wow! I must be juicy. WU is eating my posts like candy! Lol.
Member Since: Posts: Comments:
3454. xcool
dam blog
Member Since: Posts: Comments:
Sure, the angle of attack of the trough instead of making it turn WNW will make IGOR turn WSW, in order to avoid it.... Maybe then, if it gets taken over, it will begin its WNW movement, but it looks bad. We will see tomorow....

Quoting RecordSeason:
3416:

More importantly, look what direction all the dry air is moving just east of that patch of storms: I.E. South.

This is because there is part of the Ridge still in place there, which was seen on the steering layer map from a few hours ago. Haven't seen the updated one, but at any rate, this is why I believe Igor will continue to drift south of west for quite some time.

With cat4 and cat5 storms the eddies in water vapor imagery can give you clues about how a storm is being steered, because it can show you the orientation of ridges and troughs, and in this case, it suggests a continued southerly drift or turn to me.
Member Since: Posts: Comments:
Our favorite (TWC) says there is a new TROPICAL Low in the E CAR
XCOOL yes Dallas LOST!
Member Since: Posts: Comments:
3451. xcool
Member Since: Posts: Comments:
Quoting PSLFLCaneVet:
Wow.


Lol. It may be Igor stomping around.
Member Since: Posts: Comments:
whoops! Lol
Member Since: Posts: Comments:
3447. Ryuujin
Is Igor's eye getting smaller? Isn't that a indication of further intensification?
Member Since: Posts: Comments:
3446. xcool
Member Since: Posts: Comments:

Viewing: 3496 - 3446

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.