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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101. Drakoen 4:25 PM GMT on August 10, 2009    
Quoting futuremet:
Drakoen, did you see how close the isobars are?


Yes I did. Obviously a hurricane.
Member Since: October 28, 2006 Posts: 57 Comments: 29012
102. extreme236 4:25 PM GMT on August 10, 2009    
I am interested to see if they renew the TCFA.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
103. Orcasystems 4:25 PM GMT on August 10, 2009    
Quoting watchingnva:


or out to sea, or mexico...or or...it never develops fully...


or .. or ... or

I think the wait is going to be killing a few people on here.
Member Since: October 1, 2007 Posts: 77 Comments: 26105
104. SavannahStorm 4:26 PM GMT on August 10, 2009    
Quoting WAHA:

If not SC, possibly GA or FL


GA? Nah, never happens. Not in a million years.

Well... thirty years at least.
Member Since: September 22, 2005 Posts: 18 Comments: 2140
107. StormFreakyisher 4:27 PM GMT on August 10, 2009    
Quoting sammywammybamy:



I live in South PB county ..

And Ike Was Forcasted as a Cat 4/5 to Make Landfall Over me......

It Scared Me..
-----------------------------------------
Then it Spared Me By moving south hiting cuba ...

The Worst Worst Case Senerio is a Ivan Sized Storm Making Landfall in Ft.Laturdale..

(Giving the Highest winds to All 3 Major Cities)

Heading West ..

Into the Gulf and Making Landfall in Galveston

Really?I live in SPBC too,in Boca Raton.You?And that would be disasterous if a storm like that came but I'd imagine it more deadly if it would kind of ride along the coast from south to north starting from Miami to West Palm, that way everyone experiences the worst of the eyewall.:o
Member Since: May 16, 2009 Posts: 0 Comments: 684
110. TampaSpin 4:27 PM GMT on August 10, 2009    
Quoting sammywammybamy:


Thank You ,

And Is it True That Typically on El Nino years Florida tends to get hit hard

(Andrew 1992)

And why ?


Wouldn't want to say typically yes for Florida...IT all depends on the Bermuda/Azores high and how strong they are. Anything that is near the Caribbean or Bahamas is always a threat for someone.
Member Since: September 2, 2007 Posts: 176 Comments: 19767
111. watchingnva 4:27 PM GMT on August 10, 2009    
Quoting Orcasystems:


or .. or ... or

I think the wait is going to be killing a few people on here.


i agree fully...patience is not something that alot of people on this site have much of...
Member Since: September 7, 2005 Posts: 3 Comments: 1310
112. canesrule1 4:28 PM GMT on August 10, 2009    
Looking at current steering patterns and several models i believe that 99L will start to do WNW and then do a NW track but then it will bump into a high pressure system and begin a westward track between the Latitudes of 22 and 27, long story quick a track like this:

114. Drakoen 4:28 PM GMT on August 10, 2009    
Member Since: October 28, 2006 Posts: 57 Comments: 29012
115. WAHA 4:28 PM GMT on August 10, 2009    
Quoting SavannahStorm:


GA? Nah, never happens. Not in a million years.

Well... thirty years at least.

Tammy hit Georgia
116. weathersp 4:28 PM GMT on August 10, 2009    
I can already tell that the wave that's behind 99L will be a big one...

In size that is... Diameter, radius, area.. etc.

NexSat, NRL/AFRICA/Overview
Member Since: January 14, 2007 Posts: 17 Comments: 4112
117. 7544 4:28 PM GMT on August 10, 2009    
cmc wants to show a buzz saw crossing the atlantic and the gfs just might do the same
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120. WxLogic 4:29 PM GMT on August 10, 2009    
Good a new Blog... thx Doc.
Member Since: August 14, 2008 Posts: 4 Comments: 4720
121. 69Viking 4:29 PM GMT on August 10, 2009    
Quoting KYhomeboy:
The feature approaching Barbados continues to fire up heavy convection. If you look at the visible loop you can clearly see a circulation (though apparently elongated. Link


I see the circulation and the fact that storms started firing near the circulation towards the end of the loop. This could be the sleeper that nobody is talking about because they're worried about 99L which is 6 days away from any land interaction!
Member Since: August 25, 2006 Posts: 0 Comments: 2268
122. futuremet 4:29 PM GMT on August 10, 2009    
Quoting sammywammybamy:


Can you Please Post the Image For All of us.. Or Link.. Image is Better

Thank you


That has got to be a cat 4 or 5...

Member Since: July 19, 2008 Posts: 43 Comments: 4049
125. AussieStorm 4:30 PM GMT on August 10, 2009    
Quoting Drakoen:

Member Since: September 30, 2007 Posts: 5 Comments: 13764
126. SavannahStorm 4:30 PM GMT on August 10, 2009    
Quoting WAHA:

Tammy hit Georgia


Tammy made landfall near Jacksonville Beach, but I was referring to hurricanes, anyway.
Member Since: September 22, 2005 Posts: 18 Comments: 2140
127. bwi 4:31 PM GMT on August 10, 2009    
Little Barbados system starting to fire all around.
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128. BenBIogger 4:31 PM GMT on August 10, 2009    
Pre Bertha

Member Since: March 19, 2009 Posts: 0 Comments: 1419
129. serialteg 4:31 PM GMT on August 10, 2009    
Quoting 69Viking:


I see the circulation and the fact that storms started firing near the circulation towards the end of the loop. This could be the sleeper that nobody is talking about because they're worried about 99L which is 6 days away from any land interaction!


my boogieboard awaits with expectation :D
Member Since: August 22, 2006 Posts: 2 Comments: 1966
132. canesrule1 4:32 PM GMT on August 10, 2009    
Quoting Acemmett90:

that would suck entirly and it not even funny
im not trying to be funny, im showing u what i believe and what i have concluded with current steering patterns and the high pressure, anyways this is not going to be cat 5 its going to be a cat 1 maybe, so it gets bullied like a skinny little boy.
134. Drakoen 4:32 PM GMT on August 10, 2009    
Area near the Lesser Antilles is no concern to me. Too dry.
Member Since: October 28, 2006 Posts: 57 Comments: 29012
135. extreme236 4:32 PM GMT on August 10, 2009    
Quoting sammywammybamy:


Boca Raton..

Im Not rich though ... Lol ..

I disagree..

The Worst Possible Outcome is a Landfall in Ft.Laturdale..


Rember when wilma hit ..

The Eyewall hit us... West Palm .. Miami...

Now Imagine that but a Cat 4 or 5..


Just because the GFS is spinning up its landfall theories again doesnt mean this is definitely going to one specific area, especially something hasnt formed yet.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
136. RyanFSU 4:33 PM GMT on August 10, 2009    
The latest 12Z GFS run is more interested in "Bill" or the wave after the current Invest. For a global model, this storm is really ramped up in 5-6 days, and definitely would be a hurricane if this forecast pans out. The mesoscale models are worthless for this second development.

Member Since: February 13, 2005 Posts: 0 Comments: 308
138. CycloneOz 4:33 PM GMT on August 10, 2009    
Quoting Acemmett90:

it would be bad all of PBC government buildings are on the intercoastle and less than a block away from water and im on the barrier island of palm beach


WPB landfall would have me at 301 N. Olive Ave, West Palm Beach, FL in the Governmental Center parking structure.
Member Since: August 26, 2006 Posts: 10 Comments: 3154
139. AussieStorm 4:34 PM GMT on August 10, 2009    
Member Since: September 30, 2007 Posts: 5 Comments: 13764
140. WxLogic 4:34 PM GMT on August 10, 2009    
Well as expected... as we move through the day(s) the models are starting to show a more real representation of the strength of the AB High(s).
Member Since: August 14, 2008 Posts: 4 Comments: 4720
142. SavannahStorm 4:34 PM GMT on August 10, 2009    


12Z GFS at 216 hours. Notice 99l/Ana? off the East Coast, may cause enough weakness in the ridge to recurve the "Beast", hopefully.
Member Since: September 22, 2005 Posts: 18 Comments: 2140
143. Drakoen 4:35 PM GMT on August 10, 2009    
Again the pattern over the next two weeks favors east coast hits. The Bermuda high ridge builds westward and a trough sets up over the eastern Plains region.
Member Since: October 28, 2006 Posts: 57 Comments: 29012
144. canesrule1 4:35 PM GMT on August 10, 2009    
i think that 99L will be classified as a TD before Wednesday.
146. JRRP 4:35 PM GMT on August 10, 2009    
oh God again to the carib
Member Since: August 16, 2007 Posts: 0 Comments: 4357
148. IKE 4:35 PM GMT on August 10, 2009    
9 days from now....

Member Since: June 9, 2005 Posts: 23 Comments: 37070
149. watchingnva 4:35 PM GMT on August 10, 2009    
we should be getting a floater setup this afternoon as 99l approaches 30w...

barbados system is firing off some decent convection trying to wrap up around the coc/llc...i wanna see if it can continue to do this throughout the day and night...
Member Since: September 7, 2005 Posts: 3 Comments: 1310
150. weatherneophyte 4:36 PM GMT on August 10, 2009    
Ok, I can in no way comment on any weather systems, but I do spend a lot of time lurking here and learning. I do have a question. I posed to my wife that it seems that hurricanes always make landfall at night in the US. She thought it was a ridiculous statement, but couldn't remember a hurricane making landfall in the daytime. Is there a scientific reason for this, or is it just a matter of blind luck?
Member Since: September 28, 2006 Posts: 0 Comments: 37
151. canesrule1 4:36 PM GMT on August 10, 2009    
Quoting sammywammybamy:
Canesrule1


That Is Not Funny!!!!!!!!!

bro calm down!, lol, i'm giving u what models say and what the steering is, im not lying.

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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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