Igor an impressive Cat 4; 92L running out of time to develop; Julia forms
There are few sights in the natural world more impressive than a hurricane near maximum intensity. Hurricane Igor certainly fits that description this morning, as it flirts with Category 5 strength in the Central Atlantic. Igor's rapid intensification burst brought the mighty hurricane's winds to 150 mph, just shy of the 156 mph threshold for Category 5 status. Igor is the strongest hurricane in the Atlantic in three years. The last hurricane stronger that Igor was Category 5 Hurricane Felix of 2007.
Figure 1. Morning satellite image of Igor.
Intensity forecast for Igor
Wind shear is low, 5 - 10 knots, and is expected to remain low for the next four days. Waters are warm, 28.5°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. These conditions should allow Igor to remain at major hurricane status for the next four days. The hurricane will probably undergo one of the usual eyewall replacement cycles intense hurricanes commonly have, where the eyewall collapses and a new eyewall forms from an outer spiral band. This will weaken the hurricane by 10 - 20 mph when it occurs, but Igor will probably regain its lost intensity when the cycle completes. There's no evidence that an eyewall replacement cycle is imminent today, so Igor could potentially strengthen a bit more. However, I believe Igor has peaked, and will not reach Category 5 status today. By Saturday, when Igor should be nearing Bermuda, the trough of low pressure steering Igor northwestwards should bring moderate wind shear of 10 - 20 knots to the storm, weakening it.
Track forecast for Igor
The track forecast for Igor remains unchanged. Igor will move west under the influence of a strong ridge of high pressure until Tuesday morning, 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 appears likely to be a threat to Bermuda, and that island can expect tropical storm force winds as early as Friday. Igor 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 - 10 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 hitting the U.S. or Canada. While the trough expected to recurve Igor out to sea is not as sharp as the troughs that recurved Danielle, Earl, and Fiona, it should still be strong enough to keep Igor from hitting the U.S. However, Newfoundland, Canada could see a close pass. An examination of the tracks of the ten major September hurricanes that have passed closest to Igor's current location (Figure 2) reveals that one of these hurricanes went on to hit the Bahamas and Florida as a Category 2 storm, and another hit Newfoundland as a Category 1 storm. The other eight missed land. One wild card may be the intensification of Julia behind Igor. If Julia develops into a hurricane and moves close to Igor, as some of the models are suggesting, the two hurricanes could interact, affecting the track of Igor unpredictable ways. However, it currently appears the Julia will be much weaker than Igor, and will probably have little impact on her big brother's track.
Figure 2. Historical plot of the tracks of the ten major September hurricanes that have passed closest to Igor's current location.
Caribbean disturbance 92L
Tropical disturbance (92L) over the Central Caribbean, centered about 100 miles south of Jamaica, has changed little over the past day. The storm remains a threat to develop into a tropical depression, but time is running out for it to do so. Satellite loops this morning do not show a surface circulation, but 92L does have a moderate area of intense disorganized thunderstorms that are bringing heavy rain to Jamaica this morning. Kingston, Jamaica has picked up 0.67" of rain thus far this morning from 92L.
Figure 3. Morning satellite image of 92L.
Forecast for 92L
Wind shear over 92L is low, 5 - 10 knots, and is expected to remain low to moderate for the next five days. The waters beneath are hot, 29.8°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 has been interfering with development of 92L. NHC is putting the odds of 92L developing into a tropical depression by Wednesday at 40%. Given the current disorganized state of 92L, it would be difficult for it to intensify quickly enough to become any stronger than a tropical storm with 50 mph winds by Wednesday, when it will move over Belize and Mexico's Yucatan Peninsula. 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 several hundred miles south of the Texas border. A Hurricane Hunter aircraft is scheduled to investigate 92L this afternoon.
Julia
Tropical Storm Julia formed between the Cape Verdes Islands and coast of Africa yesterday, bringing some heavy rain squalls and gusty winds to the Cape Verdes, but no sustained winds of tropical storm force. Julia is headed northwest, out to sea, and it is unlikely that this storm will trouble any land areas . Shear is low enough over the next few days to allow Julia to become a hurricane, but shear will rise sharply 4 - 5 days from now, limiting the potential for Julia to become a major hurricane.
Elsewhere in the tropics
The NOGAPS model is calling for a new tropical depression to form off the coast of Africa 6 - 7 days from now.
Next post
I'll have a new post Tuesday morning.
Jeff Masters
Reader Comments
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I know about a Category 5.
Hurricane sustained Category 5 status the longest-60 hours, or a little over 2 days.
Nov 19, 2004 ... It became a tropical storm the following day. The system tracked rapidly .... It maintained major hurricane status until September 22, .... Ivan became the longest-lived intense hurricane on record (10.0 IHD) source:hurricane.atmos.colostate.edu/forecasts/2004/nov2004
I think I seen it somewhere say 10mph.
sheri
Hope you are right, that will be fantastic for everybody.
Office Space, dude
Looks to have made the turn.
Indeed. It surely would defy them wouldn't it. However....
2100 UTC SAT SEP 11 2010
FORECAST VALID 13/1800Z 17.9N 51.0W
2100 UTC SUN SEP 12 2010
FORECAST VALID 13/1800Z 18.1N 50.8W
These are archival forecasts for position from the NHC. I could post tons of these, but you get my point. How is it that the "models and the NHC boys with all their fancy toys" get this so wrong? And how could StormW be so right? Hmmm? Perhaps he may KNOW something you don't? Hmm?
Damn it...I can't get The Office out of my head long enough to remember the name...
Thanks flood!
That's what I'm doing. I wish there was a function to ignore everyone except ones you choose not to. My list is up to about 400 now, including you. Sorry, but I live in the zone and need accurate info when there's a storm coming.
what would that mean to us?
Knots Kilometers per hour Miles per hour
1920s
"Cuba" 1924 145 270 165
"Okeechobee" 1928 140 260 160
1930s
"Bahamas" 1932 140 260 160
"Labor Day" 1935 160 295 185
"New England" 1938 140 260 160
1940s
"Fort Lauderdale" 1947 140 260 160
1950s
Dog 1950 160 295 185
Easy 1951 140 260 160
Janet 1955 150 280 175
Cleo 1958 140 260 160
1960s
Donna 1960 140 260 160
Ethel 140 260 160
Carla 1961 150 280 175
Hattie 140 260 160
Beulah 1967 140 260 160
Camille 1969 165 305 190
1970s
Edith 1971 140 260 160
Anita 1977 150 280 175
David 1979 150 280 175
1980s
Allen 1980 165 305 190
Gilbert 1988 160 295 185
Hugo 1989 140 260 160
1990s
Andrew 1992 150 280 175
Mitch 1998 155 285 180
2000s
Isabel 2003 145 270 165
Ivan 2004 145 270 165
Emily 2005 140 260 160
Katrina 150 280 175
Rita 155 285 180
Wilma 160 295 185
Dean 2007 150 280 175
Felix 150 280 175
2100 UTC SAT SEP 11 2010
FORECAST VALID 13/1800Z 17.9N 51.0W
2100 UTC SUN SEP 12 2010
FORECAST VALID 13/1800Z 18.1N 50.8W
Those are minor, minor variations. At no point has Igor been outside of a two or three day cone. And the NHC gives specifics about how far W or N Igor is heading. SW does not have to do that. He generalizes that it is going to head further W (or could) and then leaves it up to interpretation as to what that means. The NHC is spot on with Igor.
wow.......
Yes, yes I did...it's interesting here in the DestinJeff vaults...smells funny, like frustration and old sweat socks, I think...and Thunderbird...there's a distinct tang of Thunderbird in the air...
PGI45L ^^^^^^ /
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