Dr. Jeff Masters' WunderBlog

Hawaii braces for Felicia; 99L near the Cape Verdes Islands may develop
Posted by: Dr. Jeff Masters, 03:55 PM GMT del 10 Agosto 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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751. IKE 06:50 PM GMT del 10 Agosto 2009    
Quoting sporteguy03:
Ike found this from Melbourne's Afternoon Discussion:

Wed-sun...mid-latitude shortwave forecast to drift south through
Tennessee Valley at midweek looks to stall north of the state and
eventually washes out north of the region through the end of the
workweek. Consequently the subtropical ridge will become the bigger
player for the peninsula during this time period while moving
back north of the area Thursday. The ridge axis will lie north of
central Florida through the remainder of the extended forecast
opening up the tropics as the upstream focus.
Low-level flow will
remain fairly light with a daily sea breeze moving inland and thus
higher chances of showers and storms favoring the central and west
Central Peninsula after midweek. Still cannot rule out a small
threat for overnight and early morning showers along the
coast...especially the Treasure Coast. Shower and storm chances
are forecast to increase back to climatology by Thursday as deeper layer
moisture advects into the region through the weekend. High
temperatures will remain near climatology with upper 80s to near 90
degrees along the coast and lower 90s across the interior.

Rare for Melbourne to update they usually have one complete update.


I was just looking at that. Almost all state met offices are talking about it.
Member Since: Giugno 9, 2005 Posts: 23 Comments: 37044
752. presslord 06:50 PM GMT del 10 Agosto 2009    
"Woman" ?!?!?!?!?!?!?!?! whew...
Member Since: Agosto 13, 2007 Posts: 0 Comments: 10377
754. canesrule1 06:51 PM GMT del 10 Agosto 2009    
Quoting presslord:
"Woman" ?!?!?!?!?!?!?!?! whew...
LMAO
756. BrandiQ 06:52 PM GMT del 10 Agosto 2009    
Quoting presslord:


unfortunately....that is the proof read version...


WOW... That's a shame...
Member Since: Maggio 25, 2009 Posts: 0 Comments: 155
759. weathersp 06:53 PM GMT del 10 Agosto 2009    
Quoting presslord:
"Woman" ?!?!?!?!?!?!?!?! whew...


ya like you in that dress..
Member Since: Gennaio 14, 2007 Posts: 17 Comments: 4112
760. IKE 06:54 PM GMT del 10 Agosto 2009    
Quoting WeatherStudent:
What does that all mean, Ike? Potentially speaking here, that is.


Increased rain chances.
Member Since: Giugno 9, 2005 Posts: 23 Comments: 37044
762. 69Viking 06:54 PM GMT del 10 Agosto 2009    
Quoting BrandiQ:



You should proofread your post before you post....


He doesn't know how to type or proofread, all his posts are like that.
Member Since: Agosto 25, 2006 Posts: 0 Comments: 2247
764. TStormSC 06:54 PM GMT del 10 Agosto 2009    


What do you know, we got a little yeller fella out there now. Maybe at least a little SE rainmaker if nothing else.
Member Since: Luglio 15, 2007 Posts: 6 Comments: 205
766. canesrule1 06:55 PM GMT del 10 Agosto 2009    
Quoting Acemmett90:

i dont know weather to laugh or cry thats was so funny
LOL
768. ALCoastGambler 06:56 PM GMT del 10 Agosto 2009    
Quoting IKE:


I was just looking at that. Almost all state met offices are talking about it.
Ike when is the H supposed to build over AL, FL, or is it already building?
770. canesrule1 06:56 PM GMT del 10 Agosto 2009    
Quoting TStormSC:


What do you know, we got a little yeller fella out there now. Maybe at least a little SE rainmaker if nothing else.
i believe it will die out by tonight and well if it does make it then it could become something when it reaches the gulf of mexico's 90+ degree water, wait and see...
771. IKE 06:56 PM GMT del 10 Agosto 2009    
Member Since: Giugno 9, 2005 Posts: 23 Comments: 37044
772. BrandiQ 06:57 PM GMT del 10 Agosto 2009    
Quoting canesrule1:
oh be quiet i bet u, u can't type any better


Maybe not, but I can proofread my post before I post.
Member Since: Maggio 25, 2009 Posts: 0 Comments: 155
775. reedzone 06:58 PM GMT del 10 Agosto 2009    
interesting EURO.. shows the area in the lesser antillies, 99L, and pre-90L developing some.

Link
Member Since: Luglio 1, 2008 Posts: 13 Comments: 7247
776. WxLogic 06:59 PM GMT del 10 Agosto 2009    
Quoting IKE:
12Z ECMWF....


And so the train starts...
Member Since: Agosto 14, 2008 Posts: 4 Comments: 4667
778. IKE 06:59 PM GMT del 10 Agosto 2009    
Quoting ALCoastGambler:
Ike when is the H supposed to build over AL, FL, or is it already building?


Is now....

Member Since: Giugno 9, 2005 Posts: 23 Comments: 37044
781. extreme236 07:00 PM GMT del 10 Agosto 2009    
Quoting IKE:
12Z ECMWF....


Still shows 99L developing. I still think it has a chance but its obviously going to take some time.
Member Since: Agosto 2, 2007 Posts: 19 Comments: 19234
782. reedzone 07:01 PM GMT del 10 Agosto 2009    
The EURO is now the only model that develops the new AOL at the Lesser Antillies. It forms 99L and keeps it alive, then recurves it before heading to the USA but then allows a more westward track on the wave off Africa behind 99L. Might just get 90L and 91L by tomorrow.
Member Since: Luglio 1, 2008 Posts: 13 Comments: 7247
783. canesrule1 07:01 PM GMT del 10 Agosto 2009    
Quoting jasoniscoolman10:
u see 99L ON THIS MAP NOW.
not really just its "outer bands" wait till tomorrow
785. ALCoastGambler 07:02 PM GMT del 10 Agosto 2009    
Quoting IKE:


Is now....

Thought so but wasn't sure, thanks
787. Michfan 07:02 PM GMT del 10 Agosto 2009    
Time to see how many people get baited by WS. LOL.

See what you started IKE. Its all your fault for posting models.
Member Since: Settembre 7, 2007 Posts: 0 Comments: 1550
788. CypressJim08 07:02 PM GMT del 10 Agosto 2009    
How do I decide the posts I want to see?? Everytime I am on here it looks like the blog is filtering for me...It is really annoying!! Sorry if this is a simple fix but I am still learning to navigate on here. BTW is it worth the $10 to join? TIA
Member Since: Agosto 4, 2008 Posts: 0 Comments: 23
789. 7544 07:02 PM GMT del 10 Agosto 2009    
anyone thinks the gfs is under est the high pressure and anna and bill could get further west and not turn that fast up the east coast
Member Since: Maggio 6, 2007 Posts: 0 Comments: 5925
790. IKE 07:03 PM GMT del 10 Agosto 2009    
Quoting reedzone:
The EURO is now the only model that develops the new AOL at the Lesser Antillies. It forms 99L and keeps it alive, then recurves it before heading to the USA but then allows a more westward track on the wave off Africa behind 99L. Might just get 90L and 91L by tomorrow.


Think that's the wave near 45-47W it shows on the first frame. Takes it into the GOM as a wave.
Member Since: Giugno 9, 2005 Posts: 23 Comments: 37044
791. IKE 07:04 PM GMT del 10 Agosto 2009    
Quoting Michfan:
Time to see how many people get baited by WS. LOL.

See what you started IKE. Its all your fault for posting models.


I can't help how he reacts. Not my fault.
Member Since: Giugno 9, 2005 Posts: 23 Comments: 37044
792. reedzone 07:04 PM GMT del 10 Agosto 2009    
Quoting extreme236:


Still shows 99L developing. I still think it has a chance but its obviously going to take some time.


99L might just be like Hurricane Irene in 2005. Kept at TS strength, then weaking it to TD strength then back to TS strength until it got near Bermuda, then got a bit stronger, became a hurricane and headed out to sea. The EURO has sort of a similiar track from Irene as well with 99L.
Member Since: Luglio 1, 2008 Posts: 13 Comments: 7247
793. ALCoastGambler 07:05 PM GMT del 10 Agosto 2009    
Quoting 7544:
anyone thinks the gfs is under est the high pressure and anna and bill could get further west and not turn that fast up the east coast
There is no ANA and there is no BILL
794. Drakoen 07:05 PM GMT del 10 Agosto 2009    
Quoting extreme236:


Still shows 99L developing. I still think it has a chance but its obviously going to take some time.


I still think it has a chance especially if the Euro is latching on to it. May bet he most aggressive run yet with the system. It will probably take 24-48hrs
Member Since: Ottobre 28, 2006 Posts: 57 Comments: 29010
795. TheCaneWhisperer 07:06 PM GMT del 10 Agosto 2009    
Quoting IKE:
12Z ECMWF....


Not showing much except, and unfortunately, an all to familiar track for 90L? up the spine of the Caribbean Islands. Not much left of it after that. I've thought from the beginning and still do think that 99L will re-curve forming just ahead of the changes.
796. reedzone 07:06 PM GMT del 10 Agosto 2009    
Quoting IKE:


Think that's the wave near 45-47W it shows on the first frame. Takes it into the GOM as a wave.


Might be.. it's hard to pinpoint when the model starts at 75 hours lol
Member Since: Luglio 1, 2008 Posts: 13 Comments: 7247
797. wunderkidcayman 07:06 PM GMT del 10 Agosto 2009    
I hope you guys saw this
Member Since: Giugno 13, 2009 Posts: 2 Comments: 5417
798. BenBIogger 07:06 PM GMT del 10 Agosto 2009    
Quoting 7544:
anyone thinks the gfs is under est the high pressure and anna and bill could get further west and not turn that fast up the east coast


I think ANA will turn north before 55w.
Member Since: Marzo 19, 2009 Posts: 0 Comments: 1419
799. IKE 07:07 PM GMT del 10 Agosto 2009    
Quoting ALCoastGambler:
There is no ANA and there is no BILL


Amen. This is day 71 with 0-0-0. The only way I'm ever saying any system is named is when the NHC does ONLY.

PS...that goes for invests too.
Member Since: Giugno 9, 2005 Posts: 23 Comments: 37044
800. BurnedAfterPosting 07:07 PM GMT del 10 Agosto 2009    
Quoting TheCaneWhisperer:


Not showing much except, and unfortunately, an all to familiar track for 90L? up the spine of the Caribbean Islands. Not much left of it after that. I've thought from the beginning and still do think that 99L will re-curve forming just ahead of the changes.


not showing much? it develops 3 systems
801. canesrule1 07:07 PM GMT del 10 Agosto 2009    
Neither of the AOI are vertically stacked, bummer.

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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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