African wave 99L may develop; Felicia threatens Hawaii; record rains from Morakot

By: Dr. Jeff Masters , 3:20 PM GMT on August 09, 2009

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A strong tropical wave with a high amount of spin moved off the coast of Africa yesterday, and has a good chance of becoming the first named storm of the 2009 Atlantic hurricane season. The wave was designated 99L by NHC Sunday morning. Wind shear is moderate, about 10 knots, and sea surface temperatures are moderately warm, about 27 - 28°C. There is a large area of dry air to 99L's north, but this is not currently interfering with the storm's organization. This morning's QuikSCAT pass showed a nearly closed surface circulation, stretched out along two axes. The storm can now be classified as tropical depression using the satellite-based Dvorak classification technique, but the surface circulation will have to show better definition before 99L can be classified as a tropical depression. Top winds were in the 20 - 30 mph range, as estimated by QuikSCAT and the Dvorak satellite estimates.


Figure 2. Visible satellite image of disturbance 99L.

Wind shear is expected to be low, 5 - 10 knots, tonight through Tuesday. SSTs will remain relatively constant at 27°C, so conditions favor development. NHC has given 99L a moderate (30 - 50% chance) of developing into a tropical depression by Tuesday morning, which is a reasonable forecast. The UKMET, GFS, and NOGAPS models all develop 99L into a tropical depression 1 - 4 days from now. The dry air of the Saharan Air Layer may become a problem for 99L 2 -4 days from now, as the storm moves slightly north of due west. It is too early to say if 99L will recurve north of the Lesser Antilles Islands or not, since it will be at least 6 days before the storm makes it that far.

The GFS model predicts development of a new tropical wave coming off the coast of Africa about 6 - 7 days from now.

Felicia weakens to a tropical storm, still a threat to Hawaii
Tropical Storm Felicia has weakened steadily over the past 24 hours, thanks to cool sea surface temperatures and increasing shear. Recent satellite imagery shows that wind shear is beginning to affect the storm, with strong upper-level winds from the west pushing the storm's heavy thunderstorm activity all to the east side of the center.


Figure 2. History of hurricane activity over Hawaii since 1950. Hawaii islands have been hit by only 9 tropical cyclones of tropical depression or greater strength, with 4 others passing withing 75 miles of an island. Image credit: NOAA Coastal Services Center.

Sea surface temperatures (SSTs) under Felicia are 25°C, well below the 26°C threshold typically needed to sustain a hurricane. SSTs will slowly increase to 26°C by the time the storm reaches Hawaii, though. Wind shear has increased to a moderate to high 20 knots, and is expected to increase further to 30 knots by Monday morning. The high shear combined with the cool SSTs should reduce Felicia to tropical depression strength by the time the center reaches the Hawaiian Islands Monday night. The wind speed probabilities forecast shows about a 40% chance Felicia will still be a weak tropical storm when it moves through the islands Monday night, and 40% chance it will be a tropical depression. If Felicia does hold together that long, it would be only the tenth tropical cyclone of tropical depression or higher strength to affect the islands since 1950 (Figure 1). Large swells from Felicia are already affecting the Big Island, and a high surf warning has been posted for the Big Island. Felicia or its remnants should bring heavy rain, flash flooding, and mud slides to the islands beginning Monday morning, and a Flash Flood Watch has been posted for most of the islands.

Typhoon Morakot hits China
Typhoon Morakot hit China this morning as a tropical storm, lashing the mainland with very heavy rain. Yesterday, Morakot hit Taiwan, dumping up to 80 inches of rain on the island over a 2-day period, according to news reports. The world 2-day rainfall record is 98.42", set at Reunion Island on March 15 - 17, 1952, so the Typhoon Morakot 2-day totals are some of the highest ever measured in the world. The highest 1-day rainfall total ever recorded on Taiwan occurred Saturday at Weiliao Mountain in Pingtung County, which recorded 1.403 meters (4.6 feet or 55 inches) or rain. Nine the ten highest one-day rainfall amounts in Taiwanese history were reached on Saturday, according to the Central Weather Bureau. Three are dead and 31 people missing on the island, and Morakot also killed 23 people in the Philippines.

I'll have an update on Monday.

Jeff Masters

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I dont think Drak was being arrogant in his statement lol


Man what is with all the sensitive people tonight? lol


Hes right lol i mean i can hang here but some stuff thrown at me on here still throws me for a loop i have a long way to go but that's the fun
Member Since: Posts: Comments:
2278. KEEPEROFTHEGATE (Mod)
Quoting jrweatherman:
You should be of some use when you are into your 3rd or 4th year

It's arrogant statements like that is why you.........I need not say anymore.
stating the facts is something your not surpose to do come on i have no formal met training but i even know you need at least 5 years behind ya before you can even consider yourself one lighten up jesus this place is really startin to piss me off
Member Since: July 15, 2006 Posts: 170 Comments: 53536
I've heard good things about ULM, my USA professors seem to think highly of it, though with the coastal weather research center they feel they are the premier tropical weather school in the area and I agree. We just got a couple ULM transfers because of that.
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Quoting louisianaboy444:
How is University of Louisiana Monroe, anyway? I'm currently searching for some good Louisiana colleges for meteorology.

If you want to get a degree and have the best experience ULM is your place (I sound like a recuriter lol) but really they are big on Meteorology here thats what the school is known for we have a whole building dedicated to it we have on air forecasting contests and many extra activities like getting in the field with professors and doing hands on stuff its truely awesome


I see, I will look into that then. It sounds like an ideal place. Thank you.
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Cya Kman
Member Since: August 2, 2006 Posts: 0 Comments: 1240
I am out for tonight. Will be back tomorrow to see where matters stand !

Take care all.
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What are your career plans Drak?
Member Since: Posts: Comments:
Quoting jrweatherman:
You should be of some use when you are into your 3rd or 4th year

It's arrogant statements like that is why you.........I need not say anymore.


I dont think Drak was being arrogant in his statement lol


Man what is with all the sensitive people tonight? lol
Quoting jrweatherman:
You should be of some use when you are into your 3rd or 4th year

It's arrogant statements like that is why you.........I need not say anymore.


save your energy
Member Since: July 24, 2005 Posts: 407 Comments: 19076
How is University of Louisiana Monroe, anyway? I'm currently searching for some good Louisiana colleges for meteorology.

If you want to get a degree and have the best experience ULM is your place (I sound like a recuriter lol) but really they are big on Meteorology here thats what the school is known for we have a whole building dedicated to it we have on air forecasting contests and many extra activities like getting in the field with professors and doing hands on stuff its truely awesome
Member Since: Posts: Comments:
Quoting KoritheMan:


How is University of Louisiana Monroe, anyway? I'm currently searching for some good Louisiana colleges for meteorology.


Good Question, That's where I plan on going unless I get a scholarship out of state.
Member Since: September 7, 2008 Posts: 17 Comments: 1604
Quoting Acemmett90:


2.(n) -A depraved individual who sits in front of a computer all day and posts flames of an idiotic or pseudo-intellectual nature on public forums and private websites. Many of these people actually become emotional about what is said on the afore-said mediums and feel it is their duty to punish those who disagree with them. They too may pursue this object in an obsessive-compulsive manner.



Thanks, Believe me when I say I am well familiar with obsessive compulsive behavior and the difficulties it can bring.

I really don't post much as I don't really know much about weather. Don't want to upset anyone. Thanks for the other response also. Now if we were on a different blog talking about mathematical equations..........
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2261. Dakster
Quoting Drakoen:


I don't think so. He's gonna need to brush up on the U.S. History for that lol


Yep... Just ask Sarah Palin about that..
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2259. KEEPEROFTHEGATE (Mod)
Quoting wunderkidcayman:
when does D-MAX start for 99L
if convective refire is to occur it should start around 11 peak around 3 edt
Member Since: July 15, 2006 Posts: 170 Comments: 53536
You should be of some use when you are into your 3rd or 4th year

Yeah i was very knowledgeable before i got into college so everything i learned these past few years i pretty much already knew it was just the basics i didn't get into the hard stuff yet...all that atmospheric math...yikes
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Quoting louisianaboy444:
I have no intention to be an operational Meteorologist,I changed majors a couple months ago. There are other more important goals I must accomplish in life...

haha i'm the complete opposite i'm in my 2nd year of college at The University of Louisiana Monore i been wanting to be a Meteorologist all my life i plan on getting my Masters


How is University of Louisiana Monroe, anyway? I'm currently searching for some good Louisiana colleges for meteorology.
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2256. Drakoen
Quoting hunkerdown:
Nice way of talking around the question...I see a politician in your future :)


I don't think so. He's gonna need to brush up on the U.S. History for that lol
Member Since: October 28, 2006 Posts: 57 Comments: 30181
Quoting Acemmett90:

an half an hour or an hour from now


DMAX occurs around sunrise, which over by 99L is in about 4-5 hours

but convection commonly starts to build at this point
have a good night all I am out...enjoy all the fun. See ya in the morning after DMax and when the panic starts.
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Quoting Stormchaser2007:


You really gotta stop.


He is on the fast track to being 29.
Member Since: September 7, 2008 Posts: 17 Comments: 1604
Quoting futuremet:


lol I should. I won't since most people recognize me by that name.

No worries, just messin with ya.
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Quoting futuremet:


I have no intention to be an operational Meteorologist,I changed majors a couple months ago. There are other more important goals I must accomplish in life...
Nice way of talking around the question...I see a politician in your future :)
Member Since: August 15, 2008 Posts: 0 Comments: 2515
Quoting HaboobsRsweet:

Then you should change your name if you arent going to be a future met. Just for the record Penn State is the best school out there haha.


lol I should. I won't since most people recognize me by that name.
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2245. Drakoen
Quoting louisianaboy444:
I have no intention to be an operational Meteorologist,I changed majors a couple months ago. There are other more important goals I must accomplish in life...

haha i'm the complete opposite i'm in my 2nd year of college at The University of Louisiana Monore i been wanting to be a Meteorologist all my life i plan on getting my Masters


You should be of some use when you are into your 3rd or 4th year
Member Since: October 28, 2006 Posts: 57 Comments: 30181
when does D-MAX start for 99L
Member Since: June 13, 2009 Posts: 2 Comments: 11761
Quoting sammywammybamy:
Even More Intresting...

This north of the cape Verde islands

Station 13002
Prediction and Research Moored Array in the Atlantic
Location: 20.45N 23.13W
Conditions as of:
Sun, 9 Aug 2009 20:00:00 UTC
Winds: NE (40°) at 17.1 kt
Air Temperature: 77.9 F
Water Temperature: 78.6 F

So you just showed low level rotation and the center is much farther south as I expected. Probably hanging around 12N
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Quoting caneluver:
kman.....nothing on the horizon? read storms updated blog


You really gotta stop.
Member Since: June 9, 2007 Posts: 4 Comments: 15876
2241. DDR
Lets hope the gfs is wrong about its forcast storm behind 99l.We can do without another Ivan like storm.
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Quoting HaboobsRsweet:
I am sticking to south FL and maybe even the Gulf for this first wave. It is going to follow all the others and ridging is building in. I am going with the Ensembles over the ever changing GFS and 20 other models.


1992 is an analog year and andrew was the first storm and did miss the shortwave connection and.... well you know.
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2239. KEEPEROFTHEGATE (Mod)
Quoting kmanislander:
2194. KEEPEROFTHEGATE 8:55 PM EST on August 09, 2009

Good evening to you. Quite lively here tonight.

For now, it looks like me against all the models on whether 99L will enter the Caribbean LOL
its hard just to have a little chat i'am watchin posting in between
Member Since: July 15, 2006 Posts: 170 Comments: 53536
I have no intention to be an operational Meteorologist,I changed majors a couple months ago. There are other more important goals I must accomplish in life...

haha i'm the complete opposite i'm in my 2nd year of college at The University of Louisiana Monore i been wanting to be a Meteorologist all my life i plan on getting my Masters
Member Since: Posts: Comments:
Quoting Drakoen:


No line on the horizon


14 miles from sea level and my home is 5 feet above !
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Quoting futuremet:


I have no intention to be an operational Meteorologist,I changed majors a couple months ago. There are other more important goals I must accomplish in life...

Then you should change your name if you arent going to be a future met. Just for the record Penn State is the best school out there haha.
Member Since: Posts: Comments:
Autistic2: a troll is a blogger who's whole purpose of the posting is to shock, aggravate, or instigate someone else.

such as: its dead or it will never go north, or it will never develop. '

Sometimes they are the ones who are making that little snide remarks at others, such as: well you should know, or if you think about it more, always insinuating that the person doesn't really know what they are talking about.

Those are the trolls, and everyone should run rught away from them.

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2233. Drakoen
Quoting futuremet:


I have no intention to be an operational Meteorologist,I changed majors a couple months ago. There are other more important goals I must accomplish in life...


What are you going to do?
Member Since: October 28, 2006 Posts: 57 Comments: 30181
2232. Drakoen
Quoting caneluver:
kman.....nothing on the horizon? read storms updated blog


No line on the horizon
Member Since: October 28, 2006 Posts: 57 Comments: 30181
Quoting Autistic2:



Quoting Acemmett90:

yah think welcome to troll playland

Forgive me. I am still learning computerese, what exactly id a Troll. Is there a concrete answer? I don't do well with abstracts and that is one reason I am here. Plus I love the weather!


I just realized why i didn't get the virus...Lucky me....i have him on ignor list.....LOL
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Quoting FloridaTigers:
Hey Drak and Futuremet, what school are you guys gonna go to? FSU? UM? Out of state?


I have no intention to be an operational Meteorologist,I changed majors a couple months ago. There are other more important goals I must accomplish in life...
Member Since: Posts: Comments:
I am sticking to south FL and maybe even the Gulf for this first wave. It is going to follow all the others and ridging is building in. I am going with the Ensembles over the ever changing GFS and 20 other models.
Member Since: Posts: Comments:

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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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