Potentially dangerous 92L steadily developing; Igor nears hurricane strength

By: Dr. Jeff Masters , 3:04 PM GMT on September 11, 2010

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A tropical disturbance (92L) over the Eastern Caribbean, a few hundred miles south of Puerto Rico, is steadily organizing and appears likely to develop into a tropical depression by tonight or Sunday morning. Satellite loops show an impressive and expanding region of heavy thunderstorms, with good spiral banding and respectable upper-level outflow on all sides. Long range radar out of Puerto Rico shows that heavy rains are now affecting that island, but there is no rotation to the radar echoes evident. However, the rain bands are becoming more intense and more organized. San Juan, Puerto Rico reported a heavy rain squall at 8:44 am this morning, and radar estimates suggest two inches of rain fell in this squall just southeast of San Juan. Wind shear over 92L is low, 5 - 10 knots. The waters beneath are at near-record warmth, 30°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-northwest at 11 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 Mexico's Yucatan Peninsula on Wednesday. The HWRF model has a more northwesterly track, taking 92L over the Dominican Republic, Haiti, and Cuba, but this model has been trending too far north in its tracks. I expect 92L will follow a path south of the islands, bringing it near or just south of Jamaica on Monday, then into the Yucatan Peninsula on Wednesday. On this track, the southern Dominican Republic can expect heavy rains of 3 - 6 inches tonight through Monday morning; southern Haiti can expect similar rains Sunday through Monday, and Jamaica and the Cayman Islands can expect heavier rains of 4 - 8 inches Monday and Tuesday. Eastern Cuba will probably escape 92L's heaviest rains in this scenario (Figure 2.)

Intensity forecast for 92L
I can't find any reason to doubt this will be a tropical storm by Sunday or Monday, and potentially a Category 1 or 2 hurricane by Wednesday, if 92L avoids passage over Hispaniola and Cuba. The SHIPS model predicts wind shear will remain low, 5 - 10 knots, through the period, and makes 92L a Category 1 hurricane by Monday night. 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. The first Air Force Hurricane Hunter mission into 92L is scheduled for Sunday afternoon, but there will be a research mission by the National Center for Atmospheric Research G-V jet today that will give us valuable information on 92L's large scale environment and potential for development.


Figure 2. Forecast rain amounts from 92L from the 2am EDT Saturday run of the GFDL model. This model predicts most of 92L's heaviest rains will miss Haiti, but will affect Jamaica, the Cayman Islands, and the Yucatan Peninsula. Image credit: Morris Bender, NOAA/GFDL.

Igor
Tropical Storm Igor is very close to hurricane strength, and appears destined to become a large and powerful major hurricane over the Central Atlantic in the days to come. Wind shear is moderate, 15 - 20 knots, waters are warm, 28°C, and Igor has moistened its environment enough to keep the dry air of the Saharan Air Layer (SAL) at bay. Igor will track west under the influence of a strong ridge of high pressure for the next three days, then turn more to the west-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 has a slight chance of making landfall on the U.S. East Coast or Canada. Climatology shows that about 10% 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 5% for Canada. The forecast steering pattern for the coming two weeks from the GFS model 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. The odds of Igor hitting land in the U.S. or Canada are probably close to their climatological 10% and 5% probabilities, respectively.

Elsewhere in the tropics
A new tropical wave (Invest 93L) emerged from the coast of Africa yesterday, and is already showing signs of organization. Most of the models predict 93L will develop into a tropical depression 2 - 4 days from now, and NHC is giving 93L a 30% chance of developing by Monday.

Next post
This may be my only post today; I'll have a new post Sunday morning.

Jeff Masters

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Wow

Member Since: June 9, 2007 Posts: 4 Comments: 15921
Well folks, we have now OFFICIALY surpassed last years storm season.

Last year we maxxed out with TS Ida.

I have a feeling we haven't seen anything yet.

Dave
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UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 12 SEP 2010 Time : 121500 UTC
Lat : 17:42:12 N Lon : 44:45:49 W


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


Final T# Adj T# Raw T#
5.9 5.9 5.9

Latitude bias adjustment to MSLP : +2.0mb

Estimated radius of max. wind based on IR : 29 km

Center Temp : +3.8C Cloud Region Temp : -64.2C

Scene Type : EYE

Positioning Method : RING/SPIRAL COMBINATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

Member Since: Posts: Comments:
Quoting surfmom:
That's why we're in here this morning.....only way to know what's going REALLY going on - hummmmm, well you still have to "select" your sources


Morning, Surfmom. Exactly. I found this place after Rita and just read during the season since. Then I was reading all year, so finally just joined. I wish I'd known about here in 05, I don't think I would have been caught off guard so much back then with Rita.
Member Since: August 22, 2009 Posts: 0 Comments: 3150
Quoting Stormchaser2007:
Very close, if not already at T 6.0


lol He's so small!
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Quoting TheDawnAwakening:
Yes WeatherNerdPR, they did miss the island, but now it appears Igor could be the one to hit the island.

One thing I noticed: Colin & Fiona's paths are almost identical. Also, at what intensity would Igor be when at his closest point to Bermuda?
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Very close, if not already at T 6.0

Member Since: June 9, 2007 Posts: 4 Comments: 15921
2414. surfmom
Quoting breald:


I thought the stronger he is the further North he would go. I could be wrong though.
LOL - maybe I need espresso this AM - just got confused (which is easy - i belong in the back of the class)
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Tropical Depression Twelve.

Member Since: June 9, 2007 Posts: 4 Comments: 15921
Good morning!

Igor looking nice (or should I say naughty) this morning.


I also see we have TD 12.
Member Since: Posts: Comments:
Yes WeatherNerdPR, they did miss the island, but now it appears Igor could be the one to hit the island.
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I think Igor should become a major hurricane later today.

Member Since: June 9, 2007 Posts: 4 Comments: 15921
Quoting TheDawnAwakening:
I believe three storms have threatened Bermuda, one was a hurricane.

Yet Danielle took a sharp turn, and Colin and Fiona fizzled before they reached the island.
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2408. surfmom
Quoting aislinnpaps:
Good morning, everyone. Woke up and glanced at the paper this morning and they have Earl heading west and is 'one to watch'. Nothing about the track has him turning north eventually or that he won't be giong into thr GOMEX. They don't mention anything else in the tropics. Gotta love the media sometimes.
That's why we're in here this morning.....only way to know what's going REALLY going on - hummmmm, well you still have to "select" your sources
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Quoting Sfloridacat5:


Bermuda is constantly under the gun from Atlantic forming Tropical Systems. Lucky for Bermuda, its a small target in a big ocean. How many storms have threatened Bermuda just this year?

Danielle, Colin and Fiona.
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I believe three storms have threatened Bermuda, one was a hurricane.
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Quoting breald:


I am hoping it stays west of Bermuda and east of the east coast. Otherwise Bermuda is in deep doo-doo.


He needs to go far to the west to spare Bermuda any impacts, the eastern side of the storm is the most dangerous and strongest side of the storm, as well as potentially the widest where tropical storm force winds extend to great distances. You want the hurricane to recurve east of Bermuda. Threat for a Bermuda impact is increasing.
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Quoting breald:


I am hoping it stays west of Bermuda and east of the east coast. Otherwise Bermuda is in deep doo-doo.


bermu must track closely. hoping for some surf again in the carib. :D
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Quoting breald:


Typical, all I care about is my own little land statement. Bermuda, can get a hug whopping from this storm. You can go now.


Bermuda is constantly under the gun from Atlantic forming Tropical Systems. Lucky for Bermuda, its a small target in a big ocean. How many storms have threatened Bermuda just this year?
Member Since: Posts: Comments:
Quoting Stormchaser2007:
TD 12 at 11am is definite for anyone who hasn't seen it already...

AL, 12, 2010091212, , BEST, 0, 125N, 208W, 30, 1006, TD

TROPICAL CYCLONE TWELVE (AL122010) 20100912 1200 UTC

Will apparently start at 35mph, 1006mb according to that.
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just a comparison.


Member Since: August 23, 2008 Posts: 0 Comments: 1918
2399. breald
Quoting serialteg:


dont go dory on me

remember EARL


I am hoping it stays west of Bermuda and east of the east coast. Otherwise Bermuda is in deep doo-doo.
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OFCI just short of Category 5

AL, 11, 2010091212, 03, OFCI, 0, 177N, 449W, 85, 0, HU, 34, NEQ, 120, 80, 80, 120,
AL, 11, 2010091212, 03, OFCI, 0, 177N, 449W, 85, 0, HU, 50, NEQ, 50, 40, 30, 40,
AL, 11, 2010091212, 03, OFCI, 0, 177N, 449W, 85, 0, HU, 64, NEQ, 30, 15, 15, 20,
AL, 11, 2010091212, 03, OFCI, 12, 179N, 475W, 92, 0, HU, 34, NEQ, 132, 98, 89, 129,
AL, 11, 2010091212, 03, OFCI, 12, 179N, 475W, 92, 0, HU, 50, NEQ, 57, 47, 35, 49,
AL, 11, 2010091212, 03, OFCI, 12, 179N, 475W, 92, 0, HU, 64, NEQ, 34, 27, 24, 24,
AL, 11, 2010091212, 03, OFCI, 24, 181N, 499W, 100, 0, HU, 34, NEQ, 147, 118, 104, 143,
AL, 11, 2010091212, 03, OFCI, 24, 181N, 499W, 100, 0, HU, 50, NEQ, 67, 57, 45, 61,
AL, 11, 2010091212, 03, OFCI, 24, 181N, 499W, 100, 0, HU, 64, NEQ, 39, 34, 37, 29,
AL, 11, 2010091212, 03, OFCI, 36, 184N, 520W, 110, 0, HU, 34, NEQ, 164, 133, 123, 153,
AL, 11, 2010091212, 03, OFCI, 36, 184N, 520W, 110, 0, HU, 50, NEQ, 77, 69, 59, 74,
AL, 11, 2010091212, 03, OFCI, 36, 184N, 520W, 110, 0, HU, 64, NEQ, 42, 37, 43, 32,
AL, 11, 2010091212, 03, OFCI, 48, 190N, 537W, 118, 0, HU, 34, NEQ, 176, 148, 137, 161,
AL, 11, 2010091212, 03, OFCI, 48, 190N, 537W, 118, 0, HU, 50, NEQ, 87, 79, 69, 83,
AL, 11, 2010091212, 03, OFCI, 60, 197N, 553W, 126, 0, , 34, NEQ, 181, 158, 138, 166,
AL, 11, 2010091212, 03, OFCI, 60, 197N, 553W, 126, 0, , 50, NEQ, 96, 84, 74, 89,
AL, 11, 2010091212, 03, OFCI, 72, 207N, 567W, 129, 0, HU, 34, NEQ, 184, 163, 138, 168,
AL, 11, 2010091212, 03, OFCI, 72, 207N, 567W, 129, 0, HU, 50, NEQ, 101, 86, 77, 91,
AL, 11, 2010091212, 03, OFCI, 84, 218N, 581W, 130, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 11, 2010091212, 03, OFCI, 96, 229N, 595W, 130, 0, HU, 34, NEQ, 0, 0, 0, 0,
AL, 11, 2010091212, 03, OFCI, 108, 239N, 610W, 130, 0, , 34, NEQ, 0, 0, 0, 0,
AL, 11, 2010091212, 03, OFCI, 120, 248N, 626W, 130, 0, HU, 34, NEQ, 0, 0, 0, 0,
Member Since: June 9, 2007 Posts: 4 Comments: 15921
2397. breald
Quoting help4u:
I see we have a fish with one giant eye.


Typical, all I care about is my own little land statement. Bermuda, can get a hug whopping from this storm. You can go now.
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Quoting breald:


I thought the stronger he is the further North he would go. I could be wrong though.


dont go dory on me

remember EARL
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TD 12 at 11am is definite for anyone who hasn't seen it already...

AL, 12, 2010091212, , BEST, 0, 125N, 208W, 30, 1006, TD

TROPICAL CYCLONE TWELVE (AL122010) 20100912 1200 UTC
Member Since: June 9, 2007 Posts: 4 Comments: 15921
Quoting CybrTeddy:
International Space Station is going to get an excellent glimpse of Igor shortly and TD12, guess I better watch NASA TV.


That will be cool.
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Quoting RecordSeason:
2387:

Eh? Unless DR radar shows something pretty amazing, I don't think 92L is threatening TD status just yet.

PR radar and Cuban Radar show pretty much nothing worth mentioning.


except we in ponce pr finally getting some noteworthy rain since the first 5 minute rain/wind band of earl
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SHIPs brings Igor up to 150mph.

Brings TD12 to 85mph.
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Cat 3 at 11 looks possible. Cat 2 is definite.

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.1.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 12 SEP 2010 Time : 114500 UTC
Lat : 17:41:34 N Lon : 44:38:51 W


CI# /Pressure/ Vmax
5.7 / 957.2mb/107.2kt


Final T# Adj T# Raw T#
5.7 6.0 6.0


Member Since: June 9, 2007 Posts: 4 Comments: 15921
2388. help4u
I see we have a fish with one giant eye.
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I think that at 11 we will have TD 12 and at 5 we will have TD 13
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hmmmmmmm....

Comments Limit Reached
This entry now contains the maximum number of comments and no more comments are allowed.

 
..............

I hadn't seen that message in a while, things must be "heating up".
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2385. Vero1
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Quoting CybrTeddy:
The eye isn't that big, its just Igor's pretty small.


You're right. One degree is about 70 miles, so it looks like a normal 25-mile eye. Should have checked my facts.
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2383. Vero1
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2382. Ryuujin
Quoting breald:


I thought the stronger he is the further North he would go. I could be wrong though.


Normally that is true, but the have to be massively powerful to bust a High pressure.
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The stronger the storm the more likely the northern movement
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Post 2372 - Awww, it's so cute. :D
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2379. Ryuujin
Quoting Relix:


There is no way he's missing this hole:



Unless that high over Texas is pushed to the east by that huge trof west of it, which the would force it to join with the high over the Atlantic. To me that is a scarier picture than a more comforting one.
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2378. breald
Quoting Ryuujin:
Since Igor is already so strong, wouldn't that reinforce the idea that he'll pump the ridge above him, which in turn will push him further west?


I thought the stronger he is the further North he would go. I could be wrong though.
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Sipping coffee now. Do ya'll think Julia will be born in the Carib or off Africa?
Member Since: August 22, 2009 Posts: 0 Comments: 3150
Quoting CybrTeddy:
The eye isn't that big, its just Igor's pretty small.



The paradox of such a large eye, and such a small storm gives the appearence that the eye is enormous.
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International Space Station is going to get an excellent glimpse of Igor shortly and TD12, guess I better watch NASA TV.

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2373. Vero1
TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN SEP 12 2010

...SPECIAL FEATURES...

THE CENTER OF HURRICANE IGOR AT 12/0900 UTC IS NEAR 17.7N 44.4W.
IGOR IS MOVING WESTWARD 16 KT. THIS POSITION IS ABOUT 990 NM TO
THE EAST OF THE NORTHEASTERN CARIBBEAN SEA ISLANDS. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 992 MB.
THE MAXIMUM SUSTAINED WIND
SPEEDS ARE 70 KT WITH GUSTS TO 85 KT. PLEASE READ THE LATEST NHC
INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/
WTNT31 KNHC AND THE FULL FORECAST AND ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. STRONG RAIN-
SHOWERS AND THUNDERSTORMS ARE FROM 16N TO 19N BETWEEN 42W AND
48W. OTHER RAINSHOWERS AND THUNDERSTORMS ARE FROM 10N TO 14N
BETWEEN 30S AND 47W...AND FROM 18N TO 22N BETWEEN 30W AND 47W.

A 1008 MB LOW PRESSURE CENTER IS NEAR 16N69W...ABOUT 180 NM TO
THE SOUTH OF THE DOMINICAN REPUBLIC. STRONG RAINSHOWERS AND
THUNDERSTORMS COVER THE AREA FROM 14N TO 18N BETWEEN 67W AND 74W.
LOCALLY HEAVY RAINFALL IS POSSIBLE IN THE VIRGIN ISLANDS...
PUERTO RICO...AND HISPANIOLA DURING THE NEXT DAY OR SO. THESE
RAINS MAY CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES...
ESPECIALLY IN MOUNTAINOUS TERRAIN. IT IS POSSIBLE THAT
A TROPICAL DEPRESSION MAY FORM DURING THE NEXT 48 HOURS.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 17N19W 8N20W MOVING
WESTWARD 10 KT. A 1006 MB LOW PRESSURE CENTER IS ALONG THE WAVE
NEAR 13N. IT IS POSSIBLE THAT THIS FEATURE MAY TURN INTO
A TROPICAL CYCLONE DURING THE NEXT 24 HOURS...AND IT MAY BE
NECESSARY TO ISSUE ADVISORIES AT ANY TIME TODAY. ANYONE WHO IS
IN THE CAPE VERDE ISLANDS SHOULD MONITOR CLOSELY THE PROGRESS
OF THIS SYSTEM IN CASE WATCHES OR WARNINGS ARE REQUIRED. PLEASE
READ THE LATEST TROPICAL WEATHER OUTLOOK UNDER AWIPS/WMO HEADERS
MIATWOAT/ABNT20 KNHC FOR MORE DETAILS. NUMEROUS STRONG
RAIN-SHOWERS AND THUNDERSTORMS ARE FROM 13N TO 17N BETWEEN 18W
AND 23W...RIGHT AT THE EASTERN EDGE OF THE CAPE VERDE ISLANDS.

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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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