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 homelesswanderer:


Hi Tex. :) Been mostly on lurk mode for the last couple days.


Homeless - You got mail. :)
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We'll see what happens tomorrow.

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Has another Cat 4 like Hazel from 1954 ever hit the US as late as did ?
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Quoting homelesswanderer:
Reason i thought of this is because local mets thought one side of the eyewall was colapsing, or dry air interference, but before landfall the eye reclosed...likely didn't make a difference other than maybe stronger winds, for the damage was already in process....

Ah ok. And you're right about the damage. Rita's eye went right through Orange County. But before she got there everything was already laid flat to the ground towards the south. I was frustrated for years because I couldn't find out where exactly the eye went. The radar bleeped out as she entered Orange Co. came back on just after she passed. Now I know why the NWS radar went out. Got that link somewhere. But don't know if you have it. A ply by play of Rita's approach. They din't get much past 2 am because the communications failed.


Rita was a monster. I think and look back at info about her major impacts occasionally but do not like to keep records of individual storms or damage. Some bad memories involved w/Rita. OTOH I am always willing to learn more so I'll take a look at the radar you send if you would like to share!!
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Quoting TexasHurricane:


Hi Homeless,

Haven't seen you here in a few days...


Hi Tex. :) Been mostly on lurk mode for the last couple days.
Member Since: August 15, 2008 Posts: 10 Comments: 3665
Also curious if Ex Fred looks so pathetic and is barely hanging on; then why has the pressure dropped from 1013mb to 1011mb and winds gone from 30mmph to 35mph today?
Quoting BurnedAfterPosting:


Only if there is a classified storm

Thank you! I wish Fred-Ex counted, especially since there are some people saying it"s coming here . . . .
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Quoting homelesswanderer:
Reason i thought of this is because local mets thought one side of the eyewall was colapsing, or dry air interference, but before landfall the eye reclosed...likely didn't make a difference other than maybe stronger winds, for the damage was already in process....

Ah ok. And you're right about the damage. Rita's eye went right through Orange County. But before she got there everything was already laid flat to the ground towards the south. I was frustrated for years because I couldn't find out where exactly the eye went. The radar bleeped out as she entered Orange Co. came back on just after she passed. Now I know why the NWS radar went out. Got that link somewhere. But don't know if you have it. A ply by play of Rita's approach. They din't get much past 2 am because the communications failed.


Hi Homeless,

Haven't seen you here in a few days...
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882. IKE
Quoting miajrz:

Thank you!! (But don't we always get something at 5? Living SoFla, I'm used to getting in front of some kind of screen around then.)


If there's a named system in the Atlantic...yes they update at 5 pm EDST and every 3 hours if watches and warnings are in effect. If not, it's every 6 hours.....5 pm, 11 pm, 5 am, and 11 am.
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If it goes in the area of low shear and the anticyclone... Fred will be a shoe in for a strengthening TS before landfall.
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Reason i thought of this is because local mets thought one side of the eyewall was colapsing, or dry air interference, but before landfall the eye reclosed...likely didn't make a difference other than maybe stronger winds, for the damage was already in process....

Ah ok. And you're right about the damage. Rita's eye went right through Orange County. But before she got there everything was already laid flat to the ground towards the south. I was frustrated for years because I couldn't find out where exactly the eye went. The radar bleeped out as she entered Orange Co. came back on just after she passed. Now I know why the NWS radar went out. Got that link somewhere. But don't know if you have it. A ply by play of Rita's approach. They din't get much past 2 am because the communications failed.
Member Since: August 15, 2008 Posts: 10 Comments: 3665
Quoting miajrz:

Thank you!! (But don't we always get something at 5? Living SoFla, I'm used to getting in front of some kind of screen around then.)


Only if there is a classified storm
Quoting IKE:


Next one is at 8:05 EDST.

Thank you!! (But don't we always get something at 5? Living SoFla, I'm used to getting in front of some kind of screen around then.)
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Quoting miajrz:
Please, could someone post the 5 0'clock (EDT) NHC Atlantic Tropical Weather Discussion? I'm a non-knowledgable lurker and I've rebooted, etc, but I still keep getting a screen showing only the 2:05. TIA.


There is no 5pm outlook or discussion

both outlooks and discussions are released by the NHC at 2am, 8am, 2pm, 8pm
875. IKE
Quoting miajrz:
Please, could someone post the 5 0'clock (EDT) NHC Atlantic Tropical Weather Discussion? I'm a non-knowledgable lurker and I've rebooted, etc, but I still keep getting a screen showing only the 2:05. TIA.


Next one is at 8:05 EDST.
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Who can forget Hugo ??? It kicked out butt in Charlotte !!
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I think i will be eating crow after it's all over with. Fred has that look now that he can really pop here in the next 48hrs.
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Please, could someone post the 5 0'clock (EDT) NHC Atlantic Tropical Weather Discussion? I'm a non-knowledgable lurker and I've rebooted, etc, but I still keep getting a screen showing only the 2:05. TIA.
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Quoting KEEPEROFTHEGATE:
YA that my area iam located on western end of lake ontario along the northern shoreline


ah ok, well I'm in northern Indiana, so not too far.

Alright guys, take care, I'm out
Member Since: June 28, 2006 Posts: 25 Comments: 8360
I see Fred is still struggling, which is good,i'm back in So. Fla for the weekend and rather not my Flight back up Sunday be canceled.
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Quoting tornadodude:


lower lakes?
YA thats my area iam located on western end of lake ontario along the northern shoreline
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Quoting pitviper:
Although I blog only once or twice a year, I lurk on a daily basis. My question is that with a wife who is dependent on oxygen 24 hours a day and living in Houston, Texas, what is the opinion of what will happen once Fred crosses Florida(if it does)and enters the GOM?


Hi. I'm from southeast TX too. You can register with 211. Also, another blogger EmmyRose (hope you don't mind Emmy) has had a lot of information for the Houston area concerning the tropics. She may know how to help even more. As far as where Fred may go if it crosses Florida is still up in the air. Just keep an eye on it. Even though that's frustrating. I know. The link below is about the 211 system.Hope this helps. :)

Link
Member Since: August 15, 2008 Posts: 10 Comments: 3665
Quoting KEEPEROFTHEGATE:
starting on oct 15 i will be setting up a detailed winter/severe weather blog to replace my tropical blog after 31 of nov still working out details of contends of blog but lower lakes region will be the main area with added areas of active weather as they occur hopefully if all goes well blog should be fully up and running as of nov 1st as i begin to phase out the 09 atl. hurricane season blog


lower lakes?
Member Since: June 28, 2006 Posts: 25 Comments: 8360
starting on oct 15 i will be setting up a detailed winter/severe weather blog to replace my tropical blog after 31 of nov still working out details of contends of blog but lower lakes region will be the main area with added areas of active weather as they occur hopefully if all goes well blog should be fully up and running as of nov 1st as i begin to phase out the 09 atl. hurricane season blog
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Quoting BurnedAfterPosting:
reed there are people out there have the opinion that Ex Fred has ZERO, ZILCH, ZIPPO chance of developing and thats fine

But those same people cant seem to handle that there are others who do feel it could have a shot and obviously it does or else the NHC wouldnt be paying attention to it.

They can think what they want, its never that cut and dry, however some think it is. Those people I dont hold in very high regard in terms of their opinion


Everyone is subjected to their opinion, but when they push it and say it's GOING TO HAPPEN, that's when it's wrong. Opinions, not facts. 07L may ramp up before landfall, not saying it's going to happen. I said Hurricane Bill might brush New England, yet people said I wished it up there. It was my opinion, wasn't stating a fact.
Member Since: July 1, 2008 Posts: 13 Comments: 7423
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Quoting rwdobson:
Ok, good weekend everyone, hope your favorite football teams win. My alma mater is trekking to Hattiesburg MS on Saturday and the prognosis is not good for us. Should be fun for the home fans though.


have a good one!
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Ok, good weekend everyone, hope your favorite football teams win. My alma mater is trekking to Hattiesburg MS on Saturday and the prognosis is not good for us. Should be fun for the home fans though.
Member Since: June 12, 2002 Posts: 0 Comments: 1589
Quoting Patrap:


Jesuit High Football,never Dull,on the road to Pontchatoula tonight.


Well, good luck! We (Purdue) play Northern Illinois tomorrow, Notre Dame next week, should be intersting
Member Since: June 28, 2006 Posts: 25 Comments: 8360
good afternoon

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Quoting rwdobson:
Wouldn't be shocked if it got designated a TD before landfall...it's possible in the future. Conditions for it may improve. But right now, the system is not looking good.


That's where I agree with you, it looks horrible lol. 20 knots really did it well.
Member Since: July 1, 2008 Posts: 13 Comments: 7423
Quoting tacoman:
burned you must have plenty of practice with that name..well my friend i can assure you if you know anything about tropical systems you have to agree this one looks shabby and is about to die any minute..get real..i wont get burned believe me..


I bet you would have said that in August 2005..
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reed there are people out there have the opinion that Ex Fred has ZERO, ZILCH, ZIPPO chance of developing and thats fine

But those same people cant seem to handle that there are others who do feel it could have a shot and obviously it does or else the NHC wouldnt be paying attention to it.

They can think what they want, its never that cut and dry, however some think it is. Those people I dont hold in very high regard in terms of their opinion
Wouldn't be shocked if it got designated a TD before landfall...it's possible in the future. Conditions for it may improve. But right now, the system is not looking good.
Member Since: June 12, 2002 Posts: 0 Comments: 1589
Quoting Patrap:
Evening T-dude,bout ready for a High School Football road trip tonight.


that sounds like fun, hope it is a good one!
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Evening T-dude,bout ready for a High School Football road trip tonight.
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Meanwhile in the West Pacific..
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Why so serious?? Know one knows what the weather will do in the future. Sure we have chances and models, but it doesn't all happen like they say it will. Look at Claudette or Katrina, anything can happen. I'm going to expect the unexpected with 07L, a TD or weak TS at landfall.
Member Since: July 1, 2008 Posts: 13 Comments: 7423
Sigh. And I thought I had it figured out. Thanks a lot! :P Lol. I knew she stalled right off shore but thought she was in a weakening phase at the time.

Reason i thought of this is because local mets thought one side of the eyewall was colapsing, or dry air interference, but before landfall the eye reclosed...likely didn't make a difference other than maybe stronger winds, for the damage was already in process....
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Quoting SWFLgazer:
Fred had Pebbles. Barney had Bam Bam.


lol
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Quoting BDAwx:
you know whats a scary thought?
around this time but in august four years ago we were watching the remnants of TD 10...




link
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting BDAwx:
looks like some of those small atoll - like islands are taking a pretty good amount of wind from Choi-Wan: Iwojima had an 86mph wind gust earlier today...


I hope that's the worst anyone sees from that storm. Just thinking how Fred has been around for a while. Choi-wan has too. It looks like it will finally weaken and head out Monday.
Member Since: August 15, 2008 Posts: 10 Comments: 3665
"All of the present indicators are a big go-ahead for this thing to begin to regenerate anytime now."

The current reality is anything but that, my friend. The present indicators are for a low probability of minor regeneration.

The convection is very stretched N-S on the IR loops.
Member Since: June 12, 2002 Posts: 0 Comments: 1589

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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.