Hawaii braces for Felicia; 99L near the Cape Verdes Islands may develop

By: Dr. Jeff Masters , 3:55 PM GMT on August 10, 2009

Share this Blog
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.

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1289 - 1239

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66Blog Index

Hillllareous!!
Member Since: Posts: Comments:
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.
Member Since: Posts: Comments:
1286. ssmate
Quoting presslord:
pleAD!!!!!!!!!!!!!! for God's sake, it's pleAD!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


See, that was done on purpose.
Member Since: Posts: Comments:
Quoting Dakster:


Now that's funny. I thought WS would plead No Contest...
Now that's FUNNY
Member Since: Posts: Comments:
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: Posts: Comments:
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: Posts: Comments:
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: Posts: Comments:
pleAD!!!!!!!!!!!!!! for God's sake, it's pleAD!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Member Since: Posts: Comments:
1278. Patrap
Member Since: July 3, 2005 Posts: 426 Comments: 129093
Our local met just said the system closer to the carribean is headed for the gulf...lol.
Member Since: Posts: Comments:
1276. Dakster
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: 10572
Any sign of that barbados convection diminishing?
Member Since: Posts: Comments:
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: Posts: Comments:
so is 99l officially gone or is there still a strong chance/likelihood that it will be a TS??
Member Since: Posts: Comments:
1268. Drakoen
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: Posts: Comments:
WS...you can vote, too...
Member Since: Posts: Comments:
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: Posts: Comments:
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: 259 Comments: 24512
yea...disturbing though it may be, I think I have to go with "A"...
Member Since: Posts: Comments:
1262. KEEPEROFTHEGATE (Mod)
Quoting Drakoen:


Why are you smiling at me? That is creepy. Do that to StormW
freakin you out
Member Since: Posts: Comments:
1261. ssmate
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: Posts: Comments:
Looks like the islands could be in for a wicked storm
Member Since: Posts: Comments:
1258. Dakster
I thought StormMaster Baits us all the time...
Member Since: March 10, 2006 Posts: 0 Comments: 10572
My guess is going to be between florida and North Carolina.
Member Since: Posts: Comments:
1254. DDR
LoL Press
That's a definate A in my book.
Member Since: Posts: Comments:
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
Member Since: Posts: Comments:
1252. Drakoen
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: Posts: Comments:
1250. DDR
Good evening 456
Major flooding today,what do you make of this area over Barbados.
Member Since: Posts: Comments:
1248. Kylid
Im starting a petition to only let WeatherStudent post 3 times a day. I;ll be the first one to sign it.
Member Since: Posts: Comments:
1247. Drakoen
Quoting FirstCoastMan:
Drakoen can you give me the link for the 18z gfs..TIA

Link
Member Since: Posts: Comments:
Quoting TheCaneWhisperer:


Dry Air is killing 99L but, eliminating it in the process for 90L to be on Wednesday. With the moist environment, low shear and moderate SST's 90L could be a biggie.


The models do look rather scary on that wave.
How many models develop this CV Hurricane btw? Little lazy to find links ;)
Member Since: July 8, 2005 Posts: 259 Comments: 24512
I believe TWC has become very unreliable since being taken over by NBC
Member Since: Posts: Comments:
Quoting CaicosRetiredSailor:


Thanks Pat,
I run FFox3.5 here.


General Question:

Has anybody here using Firefox had an issue with "malware" from the WU site in these last couple of days?

CRS


I use firefox 3.5, I had issue earlier where it seemed like someone had controll over my mouse. Page keep jumping up and down. Switched to IE and it stopped. But no warnings.
Member Since: Posts: Comments:
Drakoen can you give me the link for the 18z gfs..TIA
Member Since: Posts: Comments:
1241. 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
Member Since: Posts: Comments:
1240. Drakoen
Quoting WeatherStudent:
Drakoen, :)


Why are you smiling at me? That is creepy. Do that to StormW
Member Since: Posts: Comments:
Quoting eyesontheweather:
Dr. Lyons says Barbados area is rain event only with unfavorable upper level winds and 99l is falling apart with no convection. "so enjoy your vacation in the islands" Hmmm, just thinkin, is he supplemented by the tourist industry down there?


Dry Air is killing 99L but, eliminating it in the process for 90L to be on Wednesday. With the moist environment, low shear and moderate SST's 90L could be a biggie.
Member Since: Posts: Comments:

Viewing: 1289 - 1239

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66Blog Index

Top of Page

About

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

Local Weather

Light Snow
36 °F
Light Snow