Dr. Jeff Masters' WunderBlog

Hawaii braces for Felicia; 99L near the Cape Verdes Islands may develop
Posted by: Dr. Jeff Masters, 3:55 PM GMT on August 10, 2009 +4
A strong tropical wave (99L) is just south of the Cape Verdes Islands, 800 miles off the coast of Africa. This morning's QuikSCAT pass showed a nearly closed surface circulation, stretched out along one axis. The satellite saw winds of up to 45 mph in a band of heavy thunderstorms well south of the Cape Verdes Islands. The islands have seen winds of only 10 - 15 mph and some occasional rain showers thus far from the disturbance. Heavy thunderstorm activity associated with 99L died down this morning, but appears to be making a comeback late this 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 that is interfering with the storm's organization, though.


Figure 1. Current satellite image of disturbance 99L.

Wind shear is expected to be moderate, 5 - 15 knots, through Wednesday. SSTs will remain relatively constant at 27°C, but the dry, stable air of the Saharan AIr Layer (SAL) to 99L's north will be problem for it. NHC has given 99L a moderate (30 - 50% chance) of developing into a tropical depression by Wednesday morning, which is a reasonable forecast. Most of the models show some weak development, but none of them predict 99L will become a hurricane. It is too early to say if 99L will recurve north of the Lesser Antilles Islands or not, since it will be at least 5 days before the storm makes it that far. It is unusual, though, for storms forming this far north to make it all the way across the Atlantic to hit the Lesser Antilles Islands.

The GFS and ECMWF models are predicting the possible development of a new tropical wave coming off the coast of Africa late this week.

Felicia continues to weaken, but is a flash flooding 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 loops show that strong upper-level winds from the west have pushed the storm's heavy thunderstorm activity to the northeast side of the center, exposing the surface center as a swirl of low clouds. Felicia's relatively meager heavy thunderstorm activity is steadily moving away from the center of the storm.


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 Tuesday. Wind shear has increased to a high 30 knots, and is expected to increase further to 40 knots by Tuesday. The high shear combined with the cool SSTs should continue to weaken Felicia today. I give a 30% chance that the shear will completely rip away Felicia's heavy thunderstorm activity by the time the storm reaches Hawaii, leaving only a swirl of low-level clouds that will not cause significant flooding problems. The wind speed probabilities forecast shows about a 25% chance Felicia will still be a weak tropical storm at 3 am Hawaiian time Tuesday morning, and a 15% chance the storm will have dissipated. 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 2). Large swells from Felicia are already affecting the Big Island, and a high surf warning has been posted for east-facing shores of the Big Island and other Hawaiian islands. Felicia or its remnants may bring heavy rain, flash flooding, and mud slides to the islands beginning this afternoon, and a Flash Flood Watch has been posted for most of the islands.

Links to follow:
Long range radar from the Big Island
Wundermap for Hawaii

I'll have an update Tuesday morning.
Categories: Hurricane
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1252. Drakoen 10:15 PM GMT on August 10, 2009    
Quoting presslord:
OK...I've got a poll for us...

Is JFV

(A) Really like this?

or

(B) Just pretendingn in ordern to bait us?

I'm truly conflicted on this...and I value y'alls input...


A. It must be. 100% sure.
Member Since: October 28, 2006 Posts: 57 Comments: 29010
1253. TheCaneWhisperer 10:15 PM GMT on August 10, 2009    
Quoting CybrTeddy:


The models do look rather scary on that wave.
How many models develop this CV Hurricane btw? Little lazy to find links ;)


GFS / GFDL / HWRF / CMC / ECMWF to name a few
1254. DDR 10:16 PM GMT on August 10, 2009    
LoL Press
That's a definate A in my book.
Member Since: April 27, 2007 Posts: 13 Comments: 1473
1256. Alockwr21 10:17 PM GMT on August 10, 2009    
My guess is going to be between florida and North Carolina.
Member Since: September 12, 2007 Posts: 0 Comments: 724
1258. Dakster 10:17 PM GMT on August 10, 2009    
I thought StormMaster Baits us all the time...
Member Since: March 10, 2006 Posts: 0 Comments: 4917
1259. FLHurricaneChaser 10:17 PM GMT on August 10, 2009    
Looks like the islands could be in for a wicked storm
1261. ssmate 10:18 PM GMT on August 10, 2009    
Quoting presslord:
OK...I've got a poll for us...

Is JFV

(A) Really like this?

or

(B) Just pretendingn in ordern to bait us?

I'm truly conflicted on this...and I value y'alls input...


Unfortunatly I've thought about this for a long time and I truly think it's B. He's like the Lex luther of this Blog, a Mad Genius.
Member Since: July 17, 2008 Posts: 0 Comments: 347
1262. KEEPEROFTHEGATE (Mod) 10:18 PM GMT on August 10, 2009    
Quoting Drakoen:


Why are you smiling at me? That is creepy. Do that to StormW
freakin you out
Member Since: July 15, 2006 Posts: 143 Comments: 40334
1263. presslord 10:18 PM GMT on August 10, 2009    
yea...disturbing though it may be, I think I have to go with "A"...
Member Since: August 13, 2007 Posts: 0 Comments: 10377
1264. CybrTeddy 10:18 PM GMT on August 10, 2009    
Quoting TheCaneWhisperer:


GFS / GFDL / HWRF / CMC / ECMWF to name a few


Thanks, do they all bring it to Hurricane strength?
Member Since: July 8, 2005 Posts: 253 Comments: 20178
1266. reedzone 10:19 PM GMT on August 10, 2009    
Well my local meteorologist on channel 6, Tom Sorrels mentioned the two waves near Africa. He's gonna be showing some model runs soon. The 18Z GFS continues to show the consistant storm heading westward to the Islands. I'm thinking it will have the Gulf Coast on it's target on this run :).

He just mentioned that the GFS devlops the big wave coming off the coast of Africa but he also mentioned this "Keep in mind folks, this is more then 3,000 miles away, we have alot fo time to watch this before or if it impacts us"
Member Since: July 1, 2008 Posts: 13 Comments: 7247
1267. presslord 10:20 PM GMT on August 10, 2009    
WS...you can vote, too...
Member Since: August 13, 2007 Posts: 0 Comments: 10377
1268. Drakoen 10:19 PM GMT on August 10, 2009    
Quoting presslord:
yea...disturbing though it may be, I think I have to go with "A"...


Nobody can be that penchant if that is not their true personality.
Member Since: October 28, 2006 Posts: 57 Comments: 29010
1270. system645 10:20 PM GMT on August 10, 2009    
so is 99l officially gone or is there still a strong chance/likelihood that it will be a TS??
1274. eyesontheweather 10:21 PM GMT on August 10, 2009    
RE; JFV. Last year I would just read and follow the blog, but some people here were just ruthless to that guy. He would just keep askin the same question 100 time to 100 different bloggers. I would laugh ALOT....
Member Since: August 25, 2008 Posts: 0 Comments: 613
1275. mobilegirl81 10:23 PM GMT on August 10, 2009    
Any sign of that barbados convection diminishing?
Member Since: August 31, 2008 Posts: 0 Comments: 833
1276. Dakster 10:22 PM GMT on August 10, 2009    
Quoting WeatherStudent:


I'll plee the fifth, PressLord, :)


Now that's funny. I thought WS would plead No Contest...
Member Since: March 10, 2006 Posts: 0 Comments: 4917
1277. alaina1085 10:22 PM GMT on August 10, 2009    
Our local met just said the system closer to the carribean is headed for the gulf...lol.
Member Since: August 2, 2006 Posts: 0 Comments: 1234
1278. Patrap 10:22 PM GMT on August 10, 2009    
Member Since: July 3, 2005 Posts: 370 Comments: 111244
1279. presslord 10:22 PM GMT on August 10, 2009    
pleAD!!!!!!!!!!!!!! for God's sake, it's pleAD!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Member Since: August 13, 2007 Posts: 0 Comments: 10377
1280. bajelayman2 10:22 PM GMT on August 10, 2009    
Quoting DDR:
Good evening from Trinidad
I cant believe i missed it,but 4.5 inches of rain fell in an hours time,in Northern areas,many are counting their loses this evening.Wat a thing,eh.
I feel it for those People in Barbados,looks like more rain from that Low tomorrow.geeeze


Wow DDR, that's a lot of rain. While it has been raining most of the am, this afternoon was not so bad. We have specific low-lying areas, but generally do okay in times of flooding. Lots of stalled cars on the roads etc, but not too bad otherwise.

It is still REALLY dark and overcast though.

I have not seen a system this strong for a while, which makes my gut say, that this will develop.

Hope T&T recovers okay.
Member Since: August 13, 2007 Posts: 0 Comments: 468
1281. Cotillion 10:23 PM GMT on August 10, 2009    
A long shot in curiousity, possibly...

Anyone know when the NHC (or NOAA/CDC, whomever's in charge of it) will update (or indeed, if any bright spark can calculate it by some formulae) the AMO values? Interested to see how the trend is going. (What with 5 straight months until June [which was just about positive] of negative values - most since 1994 - and strongest negative readings since 1994 too. Before the current phase of positivity of AMO.)

Maybe went overboard on the parentheses..
Member Since: August 23, 2008 Posts: 7 Comments: 5300
1284. FLWeatherFreak91 10:23 PM GMT on August 10, 2009    
Quoting KEEPEROFTHEGATE:
no virus here either
ihave
anti v
spy ware
mal ware
fraud protection
pop up blocker
features i pay 10 bucks a month for i also run ie win vista pro
Well, after your current computer is overrun with viruses (the usual death of a windows PC) you should invest in an Apple computer that can do everything and more your computer does now, but without worrying about viruses. Just a suggestion ;)
Member Since: December 1, 2006 Posts: 2 Comments: 3458
1285. ALCoastGambler 10:23 PM GMT on August 10, 2009    
Quoting Dakster:


Now that's funny. I thought WS would plead No Contest...
Now that's FUNNY
1286. ssmate 10:23 PM GMT on August 10, 2009    
Quoting presslord:
pleAD!!!!!!!!!!!!!! for God's sake, it's pleAD!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


See, that was done on purpose.
Member Since: July 17, 2008 Posts: 0 Comments: 347
1288. TheCaneWhisperer 10:25 PM GMT on August 10, 2009    
Quoting CybrTeddy:


The models do look rather scary on that wave.
How many models develop this CV Hurricane btw? Little lazy to find links ;)


GFS / GFDL / HWRF / CMC / ECMWF to name a few
Quoting CybrTeddy:


Thanks, do they all bring it to Hurricane strength?


I'm not one to use models for intensity but, the parameters are lining up in it's favor. The GFDL and HWRF were ran focused on 99L and picked up on the area behind, HWRF a little later. I would want to see a run on the specific invest.
1289. casadunlap 10:24 PM GMT on August 10, 2009    
Hillllareous!!
Member Since: August 12, 2008 Posts: 2 Comments: 26
1290. Dakster 10:24 PM GMT on August 10, 2009    
Weather Question.

What year did the first named storm form the latest?

What date did that Storm form on?
Member Since: March 10, 2006 Posts: 0 Comments: 4917
1292. louisianaboy444 10:24 PM GMT on August 10, 2009    
So that wave is coming off tomorrow? It should be an interesting day...do the models spin it up immediately?
Member Since: August 29, 2006 Posts: 17 Comments: 1215
1293. JLPR 10:24 PM GMT on August 10, 2009    
wow the GFS is predicting a monster =O

Member Since: September 4, 2007 Posts: 36 Comments: 5223
1295. alaina1085 10:25 PM GMT on August 10, 2009    
Quoting FLWeatherFreak91:
Well, after your current computer is overrun with viruses (the usual death of a windows PC) you should invest in an Apple computer that can do everything and more your computer does now, but without worrying about viruses. Just a suggestion ;)


I want a MAC soooo bad!
Member Since: August 2, 2006 Posts: 0 Comments: 1234
1296. FLWeatherFreak91 10:25 PM GMT on August 10, 2009    
Quoting reedzone:
Well my local meteorologist on channel 6, Tom Sorrels mentioned the two waves near Africa. He's gonna be showing some model runs soon. The 18Z GFS continues to show the consistant storm heading westward to the Islands. I'm thinking it will have the Gulf Coast on it's target on this run :).

He just mentioned that the GFS devlops the big wave coming off the coast of Africa but he also mentioned this "Keep in mind folks, this is more then 3,000 miles away, we have alot fo time to watch this before or if it impacts us"
Sounds like a very legitimate report.
Member Since: December 1, 2006 Posts: 2 Comments: 3458
1297. fmbill 10:25 PM GMT on August 10, 2009    
Quoting presslord:
pleAD!!!!!!!!!!!!!! for God's sake, it's pleAD!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


I think "plee" might be right if the "5th" refers to a drink :-)
Member Since: May 27, 2008 Posts: 0 Comments: 365
1298. reedzone 10:25 PM GMT on August 10, 2009    
Quoting alaina1085:
Our local met just said the system closer to the carribean is headed for the gulf...lol.


yeah Tom Sorrels said that to on local 6. He said models split it up and one part heads to the Gulf.
Member Since: July 1, 2008 Posts: 13 Comments: 7247
1299. Cavin Rawlins 10:26 PM GMT on August 10, 2009    
Quoting DDR:
Good evening 456
Major flooding today,what do you make of this area over Barbados.


I is producing quite a bit of rainfall over the Southern Antilles but at this point only see little to slow development.
Member Since: July 24, 2005 Posts: 407 Comments: 19076

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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.

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