91L no concern; more postcards from the AMS hurricane conference

By: Dr. Jeff Masters , 1:12 PM GMT on April 18, 2012

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I'm in Ponte Vedra Beach, Florida this week, where the world's hurricane experts are gathered to attend the 30th Conference on Hurricanes and Tropical Meteorology of the American Meteorological Society. Most of the Hurricane Specialists from the National Hurricane Center are here, and they are keeping an eye on the waters a few hundred miles east of Bermuda, where an extratropical storm has cut off from the jet stream and is slowly acquiring tropical characteristics. This system was designated Invest 91L last night by NHC. Ocean temperatures are around 20°C (68°F) in the region, which is well below the 26°C usually needed for a tropical storm to form. Wind shear is a high 20 - 30 knots. Nevertheless, 91L has managed to develop a small amount of heavy thunderstorm activity near its center, and may continue to show more organization as it moves slowly southeastward over the next day or two. I give 91L a close to 0% chance of becoming a named storm in the next two days, and NHC seems to have stopped issuing new products for the system. By the end of the week, 91L should get picked up by a trough of low pressure and move off to the northeast. The storm is not a threat to any land areas.


Figure 1. Morning satellite image of Invest 91L. The island of Bermuda is seen at the left side of the image.

Global tropical cyclones and climate: current signal
Now, I'll summarize a few of the excellent talks given at this week's AMS hurricane conference. Dr. Greg Holland of the National Center for Atmospheric Research talked about the impact of global warming on hurricane intensities. Using data beginning in 1975, the beginning of the satellite era, he showed that while the total number of hurricanes globally has decreased in recent years, the proportion of hurricanes that are of Category 4 - 5 intensity has increased by 40%. He showed that this change could be related to a 0.8°C increase in global temperature during the period. He concluded that when hurricanes form, they are finding that it is easier for them to reach higher intensities.

Sensitivity of the strongest hurricanes to ocean surface warmth
Dr. Jim Elsner of Florida State University showed that observations indicate a sensitivity of hurricane winds of 8.2 m/s +/- 1.19 per degree Centigrade of ocean warmth, using data in the Atlantic from 1981 - 2010 (for oceans areas warmer than 25°C.) Using a high resolution model (HiRAM) with 50 km resolution, a sensitivity of only 1.5 +/- .6 m/s was found, calling into question the usefulness of current models for assessing future hurricane activity.

How will climate change affect hurricane tracks?
Angela Colbert of the University of Miami used 17 global climate models, the BAM hurricane tracking model, and the Atlantic historical HURDAT data base to see how hurricane tracks might change in the future. She classified storms as either straight moving (which tend to hit the Caribbean or U.S. Gulf Coast), recurving landfalling (U.S. East Coast impacts), or recurving ocean storms that miss landfall. She projected a 6% increase in recurving ocean storms and an 8% decrease in straight-moving storms by the end of the century, due to climate change. A decrease of 1- 2 storms per decade is predicted for the Caribbean and Gulf of Mexico, and an increase of 1 - 2 storms per decade in the waters of the mid-Atlantic, and along the East Coast of Florida. This occurs primarily because of an increase in westerly winds over the Central Atlantic, and to a lesser degree, an eastward change in genesis location closer to the coast of Africa. Both of these factors would tend to increase the number of recurving storms.

Jeff Masters

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Quoting WxGeekVA:


I sea what you did there...

I'm glad that someone is paying attention....
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Quoting aspectre:
487 TropicalAnalystwx13 Hot Dogs and Chocolate Syrup?

Ya know, I tried to Plus that... but just couldn't stomach it.

LOL.
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Quoting aspectre:
How would you know? We could be bouys and grids.


Actually aspectre, nothing would surprise me on this blog.
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487 TropicalAnalystwx13 Hot Dogs and Chocolate Syrup?

Ya know, I tried to Plus that... but just couldn't stomach it.
Member Since: August 21, 2007 Posts: 0 Comments: 4860
Quoting spathy:


I think it has something to do with the active ring of fire # 2.
The one around S America.
But I will refer to George Nory!

That's about as good a reason as any.
Well done!
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Quoting pottery:

Well, I was trying to stay with the Nautical Terms LOL.


I sea what you did there...
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Tropical Atlantic wind shear

Eastern Pacific wind shear
Member Since: November 6, 2010 Posts: 9 Comments: 7459
Quoting pottery:
Greetings, Eldest One.



Oh, and you, too,pott!!
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Quoting spathy:
Groth,,, Any thoughts on an early start to Fl rainy season?


I thought we had our rainy season last Thursday. You mean there may be more?????
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Quoting TropicalAnalystwx13:

Hot Dogs and Chocolate Syrup?

Well, I was trying to stay with the Nautical Terms LOL.
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It was a quiet season 100 years ago. I was bored then, too!

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Have you guys checked out whats going on over Northern South America?
Feeding in to 91L and all.
Street flooding in the city here this afternoon, with thunder and stuff.

Weird Weather this, for a dry season....
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Quoting pottery:

Or Tugs and Lighters.
Or Thugs and Blighters.
Endless computations...

Hot Dogs and Chocolate Syrup?
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Quoting spathy:


Isnt that bouys and Guls?

Or Tugs and Lighters.
Or Thugs and Blighters.
Endless computations...
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Got .21 in the rain bucket just about 15 minutes ago in western orange county. It's the first rain in a longtime here.
Member Since: October 26, 2011 Posts: 0 Comments: 2651
How would you know? We could be bouys and grids.
Member Since: August 21, 2007 Posts: 0 Comments: 4860
Quoting Grothar:
Hello boys and girls.
Greetings, Eldest One.
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Member Since: November 6, 2010 Posts: 9 Comments: 7459
Hello boys and girls.
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35.1n52.6w, 35.2n54.1w, 35.3n55.6w, 35.1n57.3w, 33.9n58.5w, 32.7n59.2w, 31.9n59.0w, 31.3n58.2w
91L has made the turn SouthSouthEastward then SouthEastward as predicted by BAMM then BAMD

MEO is Roanoake,NorthCarolina -- MIA is Miami,Florida -- BDA is Bermuda
Member Since: August 21, 2007 Posts: 0 Comments: 4860
LinkLoop
Evening folks
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Quoting presslord:


That does it! I'm callin' George Noory at 10 sharp!
I thought there would be a loud boom or crashing sound .
Member Since: September 27, 2007 Posts: 1 Comments: 19521
Quoting wxmod:


But that wouldn't help solve the world water crisis, would it?


Why build in a desert? It won't rain! There would be no shortage if we lived where it's naturally meant to be... Well at least untill we can pump massive amounts of salt water to desalinate it. Idk that's my opinion on water shortage im not sure what y'all were even talking about anyway:) night blogger buds!
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Quoting weatherh98:
It may be so dry in Florida that we could se a ts don "situation"

Noooooooooo
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Quoting hydrus:
I cant believe I am doin this.....343. hydrus 10:20 PM GMT on April 18, 2012 4

Quoting Some1Has2BtheRookie:


Should you look closely at the map, there is a small circle around presslord's house. The name given to this circle is ......... wait for it ............... The Carolinas!

hydrus,s post....Press will now destroy the universe the second he reads your post. you have done it.:)



That does it! I'm callin' George Noory at 10 sharp!
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Quoting winter123:
I really hate the NHC pre-season. 91L has had sustained convection over the center for many hours. Just slightly sheared from the west. I've seen many worse looking named storms than this in June, July, even August. Many of them last year looked worse.
shortwave loop

Ikr.
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Quoting presslord:

yea...Are you referring to anything in particular?
I cant believe I am doin this.....343. hydrus 10:20 PM GMT on April 18, 2012 4

Quoting Some1Has2BtheRookie:


Should you look closely at the map, there is a small circle around presslord's house. The name given to this circle is ......... wait for it ............... The Carolinas!

hydrus,s post....Press will now destroy the universe the second he reads your post. you have done it.:)

Member Since: September 27, 2007 Posts: 1 Comments: 19521
Quoting TropicalAnalystwx13:

It has very little thunderstorm activity in 26 °C waters and 40 knots of wind shear. It does not need to be mentioned in anything, it won't develop.

agreed
Member Since: November 6, 2010 Posts: 9 Comments: 7459
It may be so dry in Florida that we could se a ts don "situation"
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Member Since: November 6, 2010 Posts: 9 Comments: 7459
Quoting hydrus:
Good evening Press. Have you read the previous posts this evening.?

yea...Are you referring to anything in particular?
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Quoting HurrikanEB:


Albany, New York:
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MUCH NEEDED RAINFALL EXPECTED THIS WEEKEND.... QPF AMOUNTS ARE HIGHLY IN QUESTION. AT THIS TIME...LOOKING AT SIGNIFICANT MULTI-DAY RAINFALL EVENT WITH
POTENTIALLY UP TO 5 INCHES OCCURRING.
PRECIPITATION SO FAR THIS YEAR
IS ABOUT HALF OF WHAT IT SHOULD BE. PRECIPITATION ACROSS THE AREA IS
RUNNING AROUND 5 TO 6 INCHES BELOW NORMAL.

Should be enough to just about end this drought in the northeast.


I live near Albany. I would bet the Mohawk river is at a record low for April. The shallower channels are completely dry. I will be taking a bunch of pictures on Friday and post them right here. Ironically this will be also a potentially record breaking rain next week. First noreaster this winter? Oh wait, It's April :P
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Quoting presslord:
This should clear it all up for you:
Good evening Press. Have you read the previous posts this evening.?
Member Since: September 27, 2007 Posts: 1 Comments: 19521
462. wxmod
Quoting RTSplayer:


Silly rabbit.

If the government was working on non-nuclear super weapons to put in space, etc, the COIL laser with a gigantic solar panel for re-charging (by reversing the combustion reaction that the power plant uses,) would be a much more efficient weapon.

the COIL laser has an effective range of at least 400 miles and could destroy a ship, tank, aircraft, missile, or even a factory with meter precision even after compensating for atmospheric deflection.

You could put dozens of these things in space for a fraction of the cost of your ridiculous weather modification conspiracy theory, and about the only possible way to shoot them down would be for the enemies to have similar powered lasers of their own.

This is why our military is in the process of developing rail guns and laser weapons to be retro-fitted to our ships, since at this point the only known way to counter them is to have better lasers and rail guns of your own.


But that wouldn't help solve the world water crisis, would it?
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Member Since: September 27, 2007 Posts: 1 Comments: 19521
Quoting winter123:
I really hate the NHC pre-season. 91L has had sustained convection over the center for many hours. Just slightly sheared from the west. I've seen many worse storms than this in June, July, even August. Many of them last year looked worse.
shortwave loop

It has very little thunderstorm activity in 26 °C waters and 40 knots of wind shear. It does not need to be mentioned in anything, it won't develop.
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April 18 SST Anomaly
Member Since: November 6, 2010 Posts: 9 Comments: 7459
This should clear it all up for you:
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Quoting MAweatherboy1:

Northeast here :)

Annapolis - liking the rain - dry means more salinity, more Jellyfish, not trotting down to Home Depot yet for plywood though...
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Member Since: September 27, 2007 Posts: 1 Comments: 19521
I really hate the NHC pre-season. 91L has had sustained convection over the center for many hours. Just slightly sheared from the west. I've seen many worse looking named storms than this in June, July, even August. Many of them last year looked worse.
shortwave loop
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Quoting JrWeathermanFL:

2 invests before May. I wouldnt say a fast start, but I'd say one that has showed promise for what might shape up later.

We were talking about the tornado season, lol.
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Quoting wxmod:
From the 1996 military document: Weather as a force multiplier - Owning the weather by 2025




Silly rabbit.

If the government was working on non-nuclear super weapons to put in space, etc, the COIL laser with a gigantic solar panel for re-charging (by reversing the combustion reaction that the power plant uses,) would be a much more efficient weapon.

the COIL laser has an effective range of at least 400 miles and could destroy a ship, tank, aircraft, missile, or even a factory with meter precision even after compensating for atmospheric deflection.

You could put dozens of these things in space for a fraction of the cost of your ridiculous weather modification conspiracy theory, and about the only possible way to shoot them down would be for the enemies to have similar powered lasers of their own.

This is why our military is in the process of developing rail guns and laser weapons to be retro-fitted to our ships, since at this point the only known way to counter them is to have better lasers and rail guns of your own.
Member Since: January 25, 2012 Posts: 32 Comments: 1501
It seems like bad weather always comes on the weekend in Florida. We need the rain though.
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About JeffMasters

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