Disturbance 98L probably no threat to land

By: Dr. Jeff Masters , 1:46 PM GMT on September 18, 2009

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A tropical disturbance (98L), is located midway between Africa and the Lesser Antilles Islands. This disturbance has a well-defined surface circulation, and has developed a modest amount of heavy thunderstorm activity overnight. This morning's QuikSCAT pass (Figure 1) shows a complete, circular wind pattern around the low pressure center of 98L, but top winds were only 25 mph. Wind shear is moderate, about 15 knots, and Sea Surface Temperatures are 28°C, which is about 2°C above the 26°C threshold needed to support a tropical cyclone. There is a large amount of dry air to the north and west of 98L, and this dry air is interfering with development.

The global computer models predict differing amounts of wind shear in the path of 98L as it moves west-northwest at 10 mph over the next three days. The ECMWF, GFS, and UKMET models do not develop 98L, while the NOGAPS, GFDL, and HWRF do. The models that do develop 98L predict that a strong trough of low pressure will turn 98L to the northwest and then north beginning on Monday, with the result that 98L misses the Lesser Antilles Islands by at least 500 miles. Given the moderate or higher wind shear in 98L's path, and dry air to the northwest, the system should develop only slowly. NHC is giving 98L a medium (30 - 50%) chance of developing into a tropical depression by Sunday. At this time, it does not appear that 98L will ever threaten any land areas.

The remains of Hurricane Fred are still spinning away, near 25N 66W, about 900 miles east of Florida. Wind shear is 20 knots, which is marginal for development, and there is very dry air surrounding ex-Fred on all sides. None of the computer models develop ex-Fred, and it will have a tough time regenerating with so much dry air and wind shear. The remains of Fred should move over Florida Monday night or Tuesday morning.


Figure 1. Morning QuickSCAT image of the Atlantic, showing the well-defined surface circulation of disturbance 98L. Image credit: NOAA/NESDIS.

One year anniversary of Hurricane Ike
I've been focusing this week on the 20th anniversary of Hurricane Hugo, but we also passed the one year anniversary of Hurricane Ike. Many areas along the Texas and Louisiana coast affected by Ike have fully recovered, but recovery efforts will still take many more years in other areas. In Galveston, which suffered $3.2 billion in damage, 75% of the businesses have reopened, and 95% of the population has returned. Boston.com has posted a very nice series of clickable images that show before and after scenes of some of the areas that have recovered from Hurricane Ike.

Ike washed away huge sections of beach and dunes that helped protect the Texas coast from more serious damage, and this week the state legislature approved $135 million in funds to help replace these critical natural protection systems. The restored beaches will probably last ten years, barring another strike by a hurricane of Ike's stature. Texas considers two-thirds of its 367-mile shoreline to be critically eroding, which it defines as a historical rate of more than 2 feet a year. Much of this erosion can be blamed on sea level rise. Global sea level rose seven inches over the past century, and is expected to rise at least that much over the coming century.


Figure 2. Villagers in Haiti plant one of their "Million Tree Campaign" trees. Image credit: Lambi Fund of Haiti.

Hurricane relief donations
There hasn't been a need for new hurricane-related disaster relief efforts this year, in stark contrast to 2008. However, the charities we rely on to provide disaster relief still require funds to operate in quiet years, and I encourage you to consider a donation at this time to one of my two favorite disaster relief charities. Portlight.org, which was very effective at helping out isolated, under-served communities in the wake of Hurricane Ike, is committed to raising $12,000 to purchase and outfit a mobile kitchen. This kitchen will be capable of feeding up to 2,000 people two hot meals per day in post-disaster situations. The Lambi Fund of Haiti has launched its "Million Tree Campaign", which aims to use local labor to plant a million trees over the next three years along severely deforested slopes in Haiti. Both of these charities wrote to me several times last year about the stunning generosity readers of this blog showed with their donations. Thanks!

Twenty years ago today
As Hurricane Hugo approached the U.S. Virgin Islands in the early morning hours of September 18, 1989, the storm slowed down to 10 mph. The slower speed allowed Hugo to punish the island of St. Croix with the worst beating of any location along the hurricane's destructive path. At 2am local time on September 18, 1989, Hurricane Hugo's eyewall struck St. Croix, bringing incredibly ferocious Category 4 winds, sustained at 140 mph. The hurricane's gusts were remarkably violent, and many residents witnessed tornado-like vorticies barreling across the island as the hurricane raged about them. A storm surge of 2 - 3 feet, topped by battering waves 20 - 23 feet high, assaulted the coast, adding to the destruction. Wunderground member Mike Steers wrote me to describe his experience on St. Croix: "Hugo was incredible. Many vortexes came in that night. The roar and intensity of the winds that night were incredible. When the eyewall came over, we were forced to take refuge in the bathroom as the rest of the house came apart. The pressure was so low outside the house that all of the water was sucked out of the toilet and an air draft was created through the toilet. Just when I thought it was as bad as it would get, the intensity of it all dialed up even higher. Dozens and dozens of times, my ears would violently pop due to rapid pressure changes. The next morning, of course, the devastation was unbelievable. In my front yard was a 18-foot boat with an outboard on it, that had been picked up from a marina two miles away. I had lost my house, and job, the Seaplane company I was a pilot for. After a couple months, I had to leave everything behind. In some respects, after 20 years, there an many aspects of the society that have yet to recover". Two people were killed on St. Croix, 80 injured, and 90% of the buildings were damaged or destroyed. Damage estimates for St. Croix were astronomical, over $1 billion, and the island's entire infrastructure was virtually wiped out. Six weeks after the hurricane, only 25% of the public roads had been cleared, and only 25% of the island had power.


Figure 3. GOES visible satellite image of Hurricane Hugo taken on September 18, 1989. Note the lack of cloud cover on the hurricane's southwest side, indicating that strong upper-level winds from the southwest were likely creating wind shear, weakening the storm. Image credit: Google Earth rendition of the NOAA HURSAT data base.

As Hugo departed St. Croix, strong upper-level winds from the southwest created wind shear that weakened the storm to a Category 3 hurricane with 130 mph winds. The upper level winds also caused Hugo to accelerate to 15 mph and turn more northwest. The eye passed over Puerto Rico's Vieques Island at 8am and over Fajardo on the extreme northeastern tip of Puerto Rico at 9am. On Culebra Island, an island twelve miles east of Fajardo, a gust to 170 mph was recorded by the ship Night Cap in the main harbor. The south-facing harbor received sustained southerly winds in excess of 120 mph for several hours as Hugo roared by to the south. The resulting wave "set-up" created a storm surge in excess of 13 feet in the supposedly hurricane-proof harbor. A large portion of the Caribbean's charter boat fleet, some 200 boats, was sheltering in Culebra's harbor, and 136 of these boats were badly damaged or sunk. Over 80% of the wooden structures on both Culebra and Vieques were destroyed.


Figure 4. Damage on St. Croix (two top photos), Culebra Island (bottom right), and Puerto Rico's Roosevelt Roads Navy Base (bottom left), after Hurricane Hugo. Image credit: NOAA Photo Library.

Along the northeastern coast of Puerto Rico, waves up to ten feet high riding on top of a 3 - 4 foot storm surge caused severe coastal flooding of low-lying areas. Hugo's winds tore into Puerto Rico's El Yunque rainforest, downing thousands of trees. The agricultural sector was devastated, with nearly all of the island's banana and coffee crops wiped out. Twelve deaths in Puerto Rico were attributed to Hugo, six of which occurred in the southern city of Guayama where some residents were electrocuted by downed power lines. Nearly 28,000 people were left homeless by the storm, and damage to the island exceeded $1 billion.

Storm chaser Michael Laca was at Luquillo Beach on the northeast shore of Puerto Rico, and has posted a remarkable 28-minute video on YouTube of Hurricane Hugo footage.

Jeff Masters

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Quoting tornadodude:


yeah, oh well, its no big, I'm unbanned :P


i got banned for posting pictures of unusual clouds...go figure!
Member Since: Posts: Comments:
It's friday night and nothing to do! Looks like im stuck with yall and the fred-ex tonight. haha.
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Quoting JLPR:


XD
everything is good
im ussually here late at night, that's why you don't see me :)

and how is everything there?


well for now the dry weather is over and the rains are here...spent over 2 hours in traffic and flood to get from work to home but i finally made it. Other than that i can't complain...life good :)
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Quoting MiamiHurricanes09:
07L's shower activity has diminished but you must remember it is D-MIN. The environment in front of 07L should become conductive for rapid intensification, Models are anticipating a Florida landfall, and reliable models more toward south Florida. We should continue to monitor 07L for the possible development into a TD in the next 96 hours or so. Right now development is not too anticipated but either way 07L must be monitored.

Below is the latest shear tendency map, and the latest satellite imagery on 07L:



all though 07L is looking very poor on satellite it should still be monitored. Right now it is located around 69W and 22N (approximate):




-MiamiHurricanes09


We just finished stating how the shear maps are wrong lol and rapid intensification is not likely
Quoting pearlandaggie:


hey, not to burst your bubble, but there's a LOT tougher stuff headed your way if you going the meteorology route! :) just preparing ya...


yeah, no doubt :/
Member Since: June 28, 2006 Posts: 25 Comments: 8360
986. JLPR
18/1745 UTC 13.5N 40.2W T1.0/1.5 98L

not bad

and yeah, I know it isn't new =P
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Quoting BurnedAfterPosting:


oh please it was a funny joke, wasnt really too much off topic and he didnt swear at all

loosen your girdle up a bit will ya? lol


i didnt say he did, but try swearing and check your luck in a bit
Member Since: August 22, 2006 Posts: 2 Comments: 1988
Quoting pearlandaggie:


well, certain people get banned for the same infractions that others don't. also, if you don't conform to a certain groupthink, you could also be banned.


yeah, oh well, its no big, I'm unbanned :P
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting tornadodude:


haha it was tough stuff :) I do try to be a generally respectable blogger


hey, not to burst your bubble, but there's a LOT tougher stuff headed your way if you going the meteorology route! :) just preparing ya...
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982. JLPR
very broad area of low pressure over the Cape Verde Islands

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Quoting OSUWXGUY:
So initially I thought that the circulation associated with Fred was getting compressed/squished from the west...

On closer evaluation, you can watch the dry air eroding the deeper precipatable water on the western side of Fred...pretty dramatic stuff...



wat website u get this from?
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980. JLPR
Quoting TriniGirl26:


Wow. So do we in T&T :P What a coincidence :) i'm just joking...how u doing? long time no see


XD
everything is good
im ussually here late at night, that's why you don't see me :)

and how is everything there?
Member Since: Posts: Comments:
07L's shower activity has diminished but you must remember it is D-MIN. The environment in front of 07L should become conductive for rapid intensification, Models are anticipating a Florida landfall, and reliable models more toward south Florida. We should continue to monitor 07L for the possible development into a TD in the next 96 hours or so. Right now development is not too anticipated but either way 07L must be monitored.

Below is the latest shear tendency map, and the latest satellite imagery on 07L:



all though 07L is looking very poor on satellite it should still be monitored. Right now it is located around 69W and 22N (approximate):




-MiamiHurricanes09
Member Since: Posts: Comments:
Quoting tornadodude:


the thing is, I posted it when there was nothing in the Atlantic, according to the NHC, no yellow areas or anything


well, certain people get banned for the same infractions that others don't. also, if you don't conform to a certain groupthink, you could also be banned.
Member Since: Posts: Comments:
Quoting CanesWorldCanesWorld:


It was for that long equation thingy he placed on here the other day.... it confused a lot of us so we all decided to flag him...lol...just kidding..
tornado is one of the good eggs on here


haha it was tough stuff :) I do try to be a generally respectable blogger
Member Since: June 28, 2006 Posts: 25 Comments: 8360
976. beell
Quoting Weather456:


you kinda of took my thoughts and said them.


I'm wearing my aluminum foil hat!

But anyway! 45 knots at 200mb from the north, at least 10-15 at 850mb from the SE/ESE on the 18Z GFS analysis (00Z) hr gotta yield more than 20 knots if you believe the model.
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Quoting Weather456:


didnt say he's dead, thats just what is occurring now.


I know I was playing devils' advocate, I think if anything Ex Fred has shown to be a fighter, if it can get better conditions it may just do something
Quoting JLPR:


Well here in PR we pronounce it

E-gore
=)


Wow. So do we in T&T :P What a coincidence :) i'm just joking...how u doing? long time no see
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Quoting BurnedAfterPosting:
oh well 456, shear maps are wrong

bye bye Fred? lol


didnt say he's dead, thats just what is occurring now.
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Quoting TriniGirl26:


what u do wrong? u're normally one of the good ones...(No offense SW if u around)


It was for that long equation thingy he placed on here the other day.... it confused a lot of us so we all decided to flag him...lol...just kidding..
tornado is one of the good eggs on here
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Quoting LoneStarWeather:

Then half of what I've seen/read on here should've resulted in a ban.


well I was referring to images posted - as for discussion well that is to be seen.
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oh well 456, shear maps are wrong

bye bye Fred? lol
Quoting Weather456:


it comes under inappropriate images - basically anything thats not weather related.

Then half of what I've seen/read on here should've resulted in a ban.
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Quoting InTheCone:
The fun pics. are fine when it's quiet(I got banned for posting a comic pic. of Cantore last year), but not when it's "BUSY"....

During active periods of hurricane season, these rules will be strictly enforced. Violations will be met with a minimum 24 hour ban


the thing is, I posted it when there was nothing in the Atlantic, according to the NHC, no yellow areas or anything
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting beell:



And shear is probably a good bit stronger than shown on the shear charts.


you kinda of took my thoughts and said them.
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Quoting LoneStarWeather:

Why did that get you banned?


it comes under inappropriate images - basically anything thats not weather or topic related.
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Quoting serialteg:


off topic, swearing (even PG-13 words) gets you the Big B


oh please it was a funny joke, wasnt really too much off topic and he didnt swear at all

loosen your girdle up a bit will ya? lol
963. beell
Quoting Weather456:
Upper winds are being funneled over Fred between an upper ridge over the Bahamas and an upper low east of Fred's circulation. The system appears to be shredded to pieces.



And shear is probably a good bit stronger than shown on the shear charts.
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The fun pics. are fine when it's quiet(I got banned for posting a comic pic. of Cantore last year), but not when it's "BUSY"....

During active periods of hurricane season, these rules will be strictly enforced. Violations will be met with a minimum 24 hour ban
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Quoting TriniGirl26:


Laughing, sighing and shaking head :) Don't tell me...u forgot to read the Admin Notice which is written in RED :P


haha im color blind...... not really

Quoting LoneStarWeather:

I've read/seen a lot worse than that on here and it didn't result in a ban. Maybe it was because it was a copywrited pic??


heck, idk, its ok tho
Member Since: June 28, 2006 Posts: 25 Comments: 8360
960. JLPR
Quoting java162:


how do you pronounce "IGOR"?

isn't it wierd??


Well here in PR we pronounce it

E-gore
=)
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Quoting LoneStarWeather:

Why did that get you banned?


off topic, swearing (even PG-13 words) gets you the Big B
Member Since: August 22, 2006 Posts: 2 Comments: 1988
Quoting tornadodude:


I dont know, I guess maybe its because I go to purdue and Dr. Masters went to Michigan. rival schools lol

I've read/seen a lot worse than that on here and it didn't result in a ban. Maybe it was because it was a copywrited pic??
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Quoting tornadodude:


hahaha well, I posted a picture of shaq wearing swim goggles. my caption said he was testing out the SST's :P


Laughing, sighing and shaking head :) Don't tell me...u forgot to read the Admin Notice which is written in RED :P
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llc in the western blob

Member Since: August 22, 2006 Posts: 2 Comments: 1988
Quoting LoneStarWeather:

Why did that get you banned?


I dont know, I guess maybe its because I go to purdue and Dr. Masters went to Michigan. rival schools lol
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting java162:


how do you pronounce "IGOR"?

isn't it wierd??


thats russian for u...its almost as bad as dutch. And yes i have license to say that...my brother in law is from Holland
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Quoting tornadodude:


hahaha well, I posted a picture of shaq wearing swim goggles. my caption said he was testing out the SST's :P

Why did that get you banned?
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Quoting TriniGirl26:


what u do wrong? u're normally one of the good ones...(No offense SW if u around)


hahaha well, I posted a picture of shaq wearing swim goggles. my caption said he was testing out the SST's :P
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting tornadodude:


oh, well I was on today, I got banned the other day


what u do wrong? u're normally one of the good ones...(No offense SW if u around)
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Quoting Weather456:


yea which is coming from some sheared clouds to the north.


yup I want to see how Ex Fred does once shear relaxes tomorrow
Quoting BurnedAfterPosting:


The circulation is under the high clouds at 26N 68W


yea which is coming from some sheared clouds to the north.
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Quoting TriniGirl26:


that day fly fast boy...i could have sworn i saw u online a couple hours ago :P LOL


oh, well I was on today, I got banned the other day
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting TriniGirl26:


that will work...lol....but i think the name a "little" to long :)


how do you pronounce "IGOR"?

isn't it wierd??
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Quoting tornadodude:


haha yeah i got banned for a day


that day fly fast boy...i could have sworn i saw u online a couple hours ago :P LOL
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Quoting CanesWorldCanesWorld:

muerto el blog-o


yeah :P
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Hurricane, if you're there, I was doing something, so that was why I wasn't on Chat.
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Quoting tornadodude:
wow, this blog is dead

muerto el blog-o
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Quoting TriniGirl26:


u were missing? don't mind me. i now come online. was in rain, flood and traffic for over 2 hours this evening.


haha yeah i got banned for a day
Member Since: June 28, 2006 Posts: 25 Comments: 8360

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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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