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

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

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.


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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3287. SouthALWX
2:04 PM GMT on August 11, 2009
GFS 6z just poofs ther bermuda high at the end of the run? Didn't even allow for retrograde? Maybe I'm looking at it wrong but I don't think thats the setup that gets a right-hook west fl coast strike. I see the trough slididing down to pull it, but I don't think the bermuda would just disappear quite like that, would think it would shunt the trough somewhat NW as it came in.
Member Since: December 31, 1969 Posts: Comments:
3286. Alockwr21
2:01 PM GMT on August 11, 2009
The action is still far far away from the east coast! Tracking will most likely change. We are days out from this impacting any part of the CONUS
Member Since: December 31, 1969 Posts: Comments:
3285. cg2916
2:00 PM GMT on August 11, 2009
New blog!
Member Since: December 31, 1969 Posts: Comments:
3283. Gumbogator
1:57 PM GMT on August 11, 2009
TD # 2 is already a tropical storm(pressure wise). 1006 MBs. It has such a looong trip to make. Depending on the track depends on the strength.
Member Since: December 31, 1969 Posts: Comments:
3282. KEEPEROFTHEGATE (Mod)
1:57 PM GMT on August 11, 2009
Quoting CycloneOz:


Today's his birthday. His present of significant tropical activity arrived same day.

Gotta love that Karma!
he's got 3 big presents from atlantic each one bigger than the first if yer there ws happy b day
Member Since: December 31, 1969 Posts: Comments:
3279. 7544
1:55 PM GMT on August 11, 2009
anyone just waking up the 06 gfs

Link
Member Since: December 31, 1969 Posts: Comments:
3278. TampaSpin
1:55 PM GMT on August 11, 2009
Quoting StormW:
Somebody wanna tell the ECMWF model to knock it off!

ECMWF


Ouch........too many showing the same thing now StormW.....
Member Since: December 31, 1969 Posts: Comments:
3277. Stormchaser2007
1:55 PM GMT on August 11, 2009
Quoting futuremet:


Here ya go Draky

Link

Already sent him it.
Also thats the wrong one lol
Member Since: December 31, 1969 Posts: Comments:
3275. Drakoen
1:56 PM GMT on August 11, 2009
Quoting presslord:
Drak...Any luck with your computer?


I just woke up. Haven't taken a stab at it yet.
Member Since: December 31, 1969 Posts: Comments:
3274. Claudette1234
1:54 PM GMT on August 11, 2009
It is clear in less than 24hrs TD2 will be TS ANA.
Conditions now are good for develop.
Member Since: December 31, 1969 Posts: Comments:
3273. alaina1085
1:54 PM GMT on August 11, 2009
How is everyone's computers? Drake did you ever get yours back up and running?
Member Since: December 31, 1969 Posts: Comments:
3272. cchsweatherman
1:54 PM GMT on August 11, 2009
Good morning everyone! See that we now have Tropical Depression 2. Its not surprising considering the impressive closed surface circulation that developed last night and convection came back some last night to help put it over the edge. Only seeing some gradual strengthening as we go into the future.
Member Since: December 31, 1969 Posts: Comments:
3271. futuremet
1:53 PM GMT on August 11, 2009
Quoting Drakoen:
StormChaser, can you send me a link to the view off the African coast from the Navy please.


Here ya go Draky

Link
Member Since: December 31, 1969 Posts: Comments:
3270. IKE
1:53 PM GMT on August 11, 2009
Quoting ackee:
does any one think the wave at 50W will develop


It could.

Appears centered near 13.5N and 52.5W.
Member Since: December 31, 1969 Posts: Comments:
3268. presslord
1:53 PM GMT on August 11, 2009
Drak...Any luck with your computer?
Member Since: December 31, 1969 Posts: Comments:
3267. rwdobson
1:52 PM GMT on August 11, 2009
Quoting heliluv2trac:
whats the time frame of the wave getting in the gulf and where is it going n nw wnw w


print out a map of the atlantic basin and throw darts at it. this will give you a forecast with equal skill to anything the models, or bloggers, are telling you now.
Member Since: December 31, 1969 Posts: Comments:
3266. Stormchaser2007
1:53 PM GMT on August 11, 2009
Quoting heliluv2trac:
we need new blog and whats the time frame of the wave getting in the gulf and where is it going n nw wnw w


The Doc should have an update soon.
Member Since: December 31, 1969 Posts: Comments:
3265. ackee
1:51 PM GMT on August 11, 2009
does any one think the wave at 50W will develop
Member Since: December 31, 1969 Posts: Comments:
3264. Stormchaser2007
1:51 PM GMT on August 11, 2009
Quoting Drakoen:
I think the NHC track will have to be shifted to the south and west


I concur.

Model support is slowly shifting.

The weaker this stays the more south it travels.
Member Since: December 31, 1969 Posts: Comments:
3262. heliluv2trac
1:50 PM GMT on August 11, 2009
we need new blog and whats the time frame of the wave getting in the gulf and where is it going n nw wnw w
Member Since: December 31, 1969 Posts: Comments:
3261. Mikla
1:50 PM GMT on August 11, 2009
TD2 w/ some models, WV, SSTs, and SAL...
Member Since: December 31, 1969 Posts: Comments:
3260. BenBIogger
1:50 PM GMT on August 11, 2009
Quoting Drakoen:
I see that TD 2 has formed


Yup,

GFDL
Member Since: December 31, 1969 Posts: Comments:
3259. rwdobson
1:49 PM GMT on August 11, 2009
"Im surprised the news here in south florida wont talk about what models ae developing behind 99L."

Why surprised? The media shouldn't be talking about a storm that hasn't even developed yet. Any predictions as to this wave's fate are fraught with huge errors.
Member Since: December 31, 1969 Posts: Comments:
3258. Drakoen
1:49 PM GMT on August 11, 2009
I think the NHC track will have to be shifted to the south and west
Member Since: December 31, 1969 Posts: Comments:
3257. Stormchaser2007
1:49 PM GMT on August 11, 2009
Quoting Drakoen:
StormChaser, can you send me a link to the view off the African coast from the Navy please.


Yep. Gimmie a sec
Member Since: December 31, 1969 Posts: Comments:
3256. Drakoen
1:48 PM GMT on August 11, 2009
StormChaser, can you send me a link to the view off the African coast from the Navy please.
Member Since: December 31, 1969 Posts: Comments:
3253. Stormchaser2007
1:47 PM GMT on August 11, 2009
My 14Z 'Bill' wave update should be interesting.
Member Since: December 31, 1969 Posts: Comments:
3252. BenBIogger
1:46 PM GMT on August 11, 2009
Quoting WAHA:

How do you know?


Doesn't school start in Broward county today?
Member Since: December 31, 1969 Posts: Comments:
3251. 7544
1:45 PM GMT on August 11, 2009
count to 10 the gfsx 10 day

Link
Member Since: December 31, 1969 Posts: Comments:
3250. Stormchaser2007
1:44 PM GMT on August 11, 2009
Quoting Drakoen:
I see that TD 2 has formed


Barely..but yeah.

Member Since: December 31, 1969 Posts: Comments:
3248. mobilegirl81
1:44 PM GMT on August 11, 2009
Who posted the pic of WS? We need a side profile to check the size of that beek.
Member Since: December 31, 1969 Posts: Comments:
3247. HurricaneGeek
1:44 PM GMT on August 11, 2009
Good morning everybody.
I am quite surprised to see TD2. The NHC didn't mention anything about dry air in their discussion or outlook. They did however say that if it were to go a little bit further north than anticipated, it could be weaker. Stronger is it goes more south. No matter how much we know here, the NHC guys are the pros. I tend to think that because they didn't mention dry air/SAL it won't be a problem.
Member Since: December 31, 1969 Posts: Comments:
3246. heliluv2trac
1:43 PM GMT on August 11, 2009
post models
Member Since: December 31, 1969 Posts: Comments:
3245. Drakoen
1:43 PM GMT on August 11, 2009
I see that TD 2 has formed
Member Since: December 31, 1969 Posts: Comments:
3244. presslord
1:42 PM GMT on August 11, 2009
Quoting CycloneOz:


Today's his birthday. His present of significant tropical activity arrived same day.

Gotta love that Karma!


wonder if he took your advice about the candles...
Member Since: December 31, 1969 Posts: Comments:
3243. heliluv2trac
1:42 PM GMT on August 11, 2009
where is drak i hope he got his computer fixed we are going to need all the help we can get for the upcoming weeks
Member Since: December 31, 1969 Posts: Comments:
3242. TheCaneWhisperer
1:41 PM GMT on August 11, 2009
Quoting JamesGalloway:
Just now got online today. Anyone mentioned that a couple models develop the 50W wave and the CMC takes it into the Gulf?


The sneak attack was picked up by the GFDL as well.
Member Since: December 31, 1969 Posts: Comments:
3241. BobinTampa
1:41 PM GMT on August 11, 2009
Quoting jscs:


People are ready for a good story. Seems to me it's far too early to even say these storms will get named. Quiet year equals loud voices when anything forms.


very true. The local news likes nothing better than leading the newscast with the local weatherman breathlessly telling us how we're in the dreaded Cone of Uncertainty.
Member Since: December 31, 1969 Posts: Comments:
3240. caribbeansurvivor1
1:41 PM GMT on August 11, 2009
Thanks for enlighting me in the TD matter, can u do the same offering your opinion to my question? thanks!!
Member Since: December 31, 1969 Posts: Comments:
3239. WAHA
1:40 PM GMT on August 11, 2009
Quoting BenBIogger:


Right now he's in school.

How do you know?
Member Since: December 31, 1969 Posts: Comments:

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Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather

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