92L still a threat to develop; Igor a hurricane; TD 12 forming near Africa
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
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You better be careful, there's a woman following Igor
http://www.ssd.noaa.gov/goes/flt/t2/loop-wv.html
Today may be the day for a TD.
Stadium effect - check.
Beautiful storm - check.
large eye in comparison to the storm - check?
Realistically, we should start focusing our eyes in the Caribbean, where u live & where i live, well we both know too well that Oct. is the month! You had Wilma, & well I was no where in this world yet, but I had 1921 Tampa Bay Hurricane, Wilma, 1921... Wilma, 1921.
like Earl and Fiona
Actually--I love it when people say that--for purposes of comparison, ACE is rounded to the nearest whole number. 71.7 = 72; 72.285 = 72.
auhch! we are here
Temps in the Caribbean were at record levels (until this year).
REALLY enjoying the idea we are so powerful that we affect your behavior enough to blame us for it, LOL.
Excellent analysis. Thanks!
Looking at the satellite I'd say yes. If things continue this way, I'm guessing we'll see a renumber to TD13 this afternoon/evening.
It shows a large and powerful Hurricane building right outside Texas. Now, keep in mind, this is 2 weeks off and they chances of it being right are about 50/50 at best. Still, I wouldn't relax if I lived on the Gulf. ALWAYS pay attention to what is happening with the weather if you live down there this time of year.
Comparisons between 1950 and 2005 may not be completely fair because in 1950 many of the sensing technologies used nowadays had not been invented, yet. So some storms may not had been detected in 1950.
weaking flag off-check.
annular hurricane-not sure
fish-no way jose, besides Cape Verde already took the brunt for us and Bermuda yet to come.
re-curvature-I'm pretty confident in that "hint" "hint" at some point.
Comparisons between 1950 and 2005 may not be completely fair because in 1950 many of the sensing technologies used nowadays had not been invented, yet. So some storms may not had been detected in 1950.
Definition of Annular – 1. the shape your head takes looking at two wobbles during a hurricane, thereby saying for a fact that it has changed course. 2. the angle your head is at when you are trying to classify the shape of a hurricane.
Cheers!
It continues westward.
really i dont trust them remenber Earl?
Igor at 17.7 Notice the location of south eyewall and north eyewall
5 hrs later South eyewall remains exact same location North begins to drop
3 hrs later South eyewall still same latitude, while north wall comes south (contracting inward)
Two hours later, Igor at 17.6N - N eyewall dropped (contracted in) near 2 tenths of degree. S eyewall...exact same as 10+ hours earlier.
Last night amid pages and pages of comments that Igor was possibly begining to move south of west, I made a simple comment. "Igor was not moving south at all, as he was loosing his annular "look", his N eyewall was pulling in south, giving the illusion that he was jogging south". What a mistake. Some nasty comments came about and a comment or 2 about my "nautical ability" to note headings was made. My comment was simple and easy to understand - but the reaction was NASTY. So here is the "proof" I see required on here so much. Igor never moved south last night at all. As a matter of fact, the south eyewall moved along 17.5 for near 10 hours as if it were on "rails". THE PICTURES DONT LIE. The only thing that moved south was the north eyewall (contracting inward), not the storm. The storm heading remained exactly the same with a location drop (center point between the two walls) from 17.7 N to 17.6N over the near 10 hour period. The location dropped a tenth because the N wall dropped 2tenths (as seen above). Hence center point between N and south eyewall net a drop of a tenth of a degree. There was such a desire for some to see a south movement that my point was slammed bigtime. I didnt make a big deal about my comment, others did. So there (above) is the proof.......
ROFL - at 51 my years of power are LONG behind me! Compromise works much better at this stage of the game! :)
Of course, my MOM powers are ever increasing.....
Little more south & I think we could improve the odds for Igor to be a cat 5.. Lets hope he's not attracted by warm water:)
92L~ I could see being a TD or TS by Yucatan, strengthen in the BOC & hit this years popular spot in North Mexico.
Working. And trying to stay out of the worst of it without totally disrupting their schedule and wasting available fuel supply.
They dont like to admit it but we are always really in control
So, yes, long-track CV storms add a lot to ACE totals...though it should be noted that of the six most powerful 2005 storms--Dennis, Emily, Katrina, Ophelia, Rita and Emily--none were CV-type storms.
Very good. I enjoyed reading that. I hate models but like math it helps when you understand why the lines are going where they are going. Thank You
ummmm right.....
Igor
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)
Dynamic Models (More sophisticated models)
Andrew was suppose to spin out and away from the CONUS...but things changed.
plenty of time for the weather to change.
this is one of "those" storms.
name is Igor too. ya just get the feeling....ya know?
For this purpose, it is fair. There were no storms below 0.49 ACE between 1875 and 1969, correct (yet, this seemingly happens on a semi-regular basis in the past 10 years. Off the top of my head, the last year to have all storms above 1 in ACE was 1997). However, even if these 1-3 storms were missed, the ACE won't be massively different nor will the comparison. It'd just be 12 or so storms to an ACE difference of 2 or 3.
Rainbow
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