Dr. Jeff Masters' WunderBlog

Felicia not weakening; new African wave may develop
Posted by: Dr. Jeff Masters, 3:12 PM GMT on August 08, 2009 +1
Hurricane Felicia has not weakened today, and continues to hold its own in spite of cool sea surface temperatures beneath it. Recent satellite imagery shows that the tops of thunderstorms surrounding the eye have cooled slightly, indicating that the updrafts sustaining the eyewall are maintaining their strength. The appearance of the hurricane has improved some today, with the storm assuming a more symmetric appearance.


Figure 1. Current satellite image of Hurricane Felicia.

Sea surface temperatures (SSTs) under Felicia have now fallen to 24.7°C, well below the 26°C threshold typically needed to sustain a hurricane. SSTs will slowly increase to 26°C by the time the storm reaches Hawaii, though. Wind shear is expected to remain low to moderate, 5 - 15 knots, through Monday morning. By Monday night, shear will rise to 20 knots, and remain above 20 knots thereafter. The higher shear combined with the relatively cool SSTs should mean that Felicia will be rapidly weakening in its final 24 hours before reaching Hawaii. Several of the computer models continue to show that this shear will be high enough to tear Felicia apart before it reaches Hawaii, though it appears to me that Felicia's current strength and annular structure will help it resist the shear enough to allow the storm to hit Hawaii as a tropical depression with 35 mph winds. Regardless, Felicia will bring heavy rain Hawaii beginning on Monday morning, and these rains will have the capability of causing flash floods and mudslides. The Hurricane Hunters are scheduled to make their first low-level investigation of Felicia this afternoon (around 10 am Hawaiian time). The NOAA jet also flies into Felicia today, and will drop a series of dropsondes that will be used to gather data that will be fed into today's 12Z and 00Z computer model runs.

Typhoon Morakot hits Taiwan
Typhoon Morakot hit Taiwan yesterday, battering the island with Category 1 winds and heavy rain. The Taipei airport recorded sustained winds of 56 mph, gusting to 76 mph, at the peak of the storm. Morakot killed 6 on Taiwan and 10 in the Philippines, and is headed towards a final landfall on mainland China as a tropical storm later today. Storm chaser James Reynolds intercepted the storm and posted videos on typhoonfury.com and Youtube. Morakot is still visible today on Taiwan radar.


Figure 2. Visible satellite image of a spinning tropical wave leaving the coast of Africa. The image was taken at 8am EDT 8/8/09.

African tropical wave may develop
A strong tropical wave with a moderate amount of spin is moving off the coast of Africa this morning. The wave is under about 10 - 20 knots of wind shear and has sea surface temperatures beneath it of 27°C. These conditions are probably too marginal to allow development over the next two days. As the wave moves westward away from Africa over the next few days, wind shear should slowly decrease and the SSTs will warm, potentially allowing for some slow development. The UKMET, GFS, and NOGAPS models all indicate the possibility that this will become a tropical depression 3 - 5 days from now. The ECMWF model forecasts that strong easterly winds over the wave will create too much shear to allow development. The wave is well south of the Saharan Air Layer, so dry air and African dust should not interfere over the next 3 - 5 days. I give the wave a medium (30 - 50% chance) of developing into a tropical depression in the next seven days.

I'll have an update on Sunday.

Jeff Masters
Categories: Hurricane
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1651. Stormchaser2007 4:56 AM GMT on August 09, 2009    
Quoting btwntx08:
at 384 hr the gfs has potential bill hitting deep south tx/northern mx if that were to happen it would be great news cuse of the drought were having


If it would take that track than it would more than likely be a strong Hurricane due to the fact that SSTs are near 90-92 degrees.
Member Since: June 9, 2007 Posts: 4 Comments: 15245
1655. extreme236 4:58 AM GMT on August 09, 2009    
Quoting iceman55:
not good all if make in gom ??


Lets not worry about that too much now. Speculation on a system that hasn't even moved off the African coast yet.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1657. Tazmanian 4:59 AM GMT on August 09, 2009    
Quoting Stormchaser2007:

Landfall in Mexico.




WOW the GFS has storm evere where on that run
Member Since: May 21, 2006 Posts: 5088 Comments: 111327
1658. HurricaneJoe 5:00 AM GMT on August 09, 2009    
Can someone post a link to the GFS run? I'd like to see it.
1661. Tazmanian 5:02 AM GMT on August 09, 2009    
may be has we are posting links may be we can try too bookmark them
Member Since: May 21, 2006 Posts: 5088 Comments: 111327
1662. Tazmanian 5:02 AM GMT on August 09, 2009    
Quoting WeatherStudent:


Desqiciado diria yo, ese modelo no sirve para nada, absolutamente nada!!!



????
Member Since: May 21, 2006 Posts: 5088 Comments: 111327
1664. FLWeatherFreak91 5:03 AM GMT on August 09, 2009    
Quoting Stormchaser2007:
Possible curve band?

it sure is looking very good now, but I expect that it will die down significantly tomorrow during the morning and afternoon for a bit before regaining convection in a less sheared environment. Sure is looking much more promising than any other wave yet though.
Member Since: December 1, 2006 Posts: 2 Comments: 3458
1665. JLPR 5:04 AM GMT on August 09, 2009    
Quoting Tazmanian:



????


He said that the GFS was crazy and that it is useless
Member Since: September 4, 2007 Posts: 36 Comments: 5223
1666. JRRP 5:04 AM GMT on August 09, 2009    
Quoting HurricaneJoe:
Can someone post a link to the GFS run? I'd like to see it.

Link
Member Since: August 16, 2007 Posts: 0 Comments: 4304
1667. Stormchaser2007 5:06 AM GMT on August 09, 2009    
Quoting FLWeatherFreak91:
it sure is looking very good now, but I expect that it will die down significantly tomorrow during the morning and afternoon for a bit before regaining convection in a less sheared environment. Sure is looking much more promising than any other wave yet though.


Its in 5knots of easterly shear which is about the most favorable it can get. Convergence and divergence are good-great so convection shouldn't die down unless something drastically changes.
Member Since: June 9, 2007 Posts: 4 Comments: 15245
1669. HurricaneJoe 5:07 AM GMT on August 09, 2009    
Thank you JRRP
1670. BurnedAfterPosting 5:07 AM GMT on August 09, 2009    
Ok ok so poll time lol

What color circle would you like to use to hit the next person who does a poll about the TWO?

A. Yellow
B. Orange
C. Red
D. Pink with Purple polka dots
E. Throw the remnants of Karen at them

VOTE NOW!!
1671. winter123 5:08 AM GMT on August 09, 2009    
sigh, need to go to bed. when i wake up i'll be upset if it's not an invest. probably die like all the other african waves this season...
Member Since: July 29, 2006 Posts: 28 Comments: 1700
1672. Walshy 5:09 AM GMT on August 09, 2009    
Quoting BurnedAfterPosting:
Ok ok so poll time lol

What color circle would you like to use to hit the next person who does a poll about the TWO?

A. Yellow
B. Orange
C. Red
D. Pink with Purple polka dots
E. Thrown the remnants of Karen at them

VOTE NOW!!


F - Im not old enough to vote.
Member Since: May 17, 2009 Posts: 2 Comments: 618
1673. BurnedAfterPosting 5:09 AM GMT on August 09, 2009    
Quoting WeatherStudent:
Guys, the dimwitted model just contradicted itself on this latest run in regards to both of these storms. Ok, first, it takes Ana out to sea underneath a very powerful ridge. Secondly, it takes Bill due west under an anemic ridge. Those that not sound contradictory to y'all? Oh well, yet again, as Adrian would say, just for laughs, just for laughs. PLEASE!!!


actually the steering for the two systems looks fairly realistic to me
1675. stormdude77 5:10 AM GMT on August 09, 2009    
Quoting BurnedAfterPosting:
Ok ok so poll time lol

What color circle would you like to use to hit the next person who does a poll about the TWO?

A. Yellow
B. Orange
C. Red
D. Pink with Purple polka dots
E. Thrown the remnants of Karen at them

VOTE NOW!!


A
1677. HurricaneJoe 5:11 AM GMT on August 09, 2009    
B.
1679. SouthALWX 5:11 AM GMT on August 09, 2009    
Quoting BurnedAfterPosting:
Ok ok so poll time lol

What color circle would you like to use to hit the next person who does a poll about the TWO?

A. Yellow
B. Orange
C. Red
D. Pink with Purple polka dots
E. Thrown the remnants of Karen at them

VOTE NOW!!


Can I choose a diferent shape? maybe a cone with explosive powder perhaps enclosed together with a metal shell? ooooh n can I launch it with a pin travelling very quickly striking the opposite end of said case? ....>.> NHC will do what they want and are probably as sick of getting burned as we are when judging development this year. Wouldn't shock me if they skipped rings and went straight to TD once (if) the situation arises.
Member Since: August 27, 2008 Posts: 0 Comments: 1497
1680. Stormchaser2007 5:11 AM GMT on August 09, 2009    
A
Member Since: June 9, 2007 Posts: 4 Comments: 15245
1681. Walshy 5:12 AM GMT on August 09, 2009    
Im going with "A".
Member Since: May 17, 2009 Posts: 2 Comments: 618
1682. Stormchaser2007 5:12 AM GMT on August 09, 2009    
Member Since: June 9, 2007 Posts: 4 Comments: 15245
1683. BurnedAfterPosting 5:12 AM GMT on August 09, 2009    
Quoting SouthALWX:


Can I choose a diferent shape? maybe a cone with explosive powder perhaps enclosed together with a metal shell? ooooh n can I launch it with a pin travelling very quickly striking the opposite end of said case? ....>.> NHC will do what they want and are probably as sick of getting burned as we are when judging development this year. Wouldn't shock me if they skipped rings and went straight to TD once (if) the situation arises.


lol im wondering if you are the only one that realizes that I am not doing a poll about the TWO lol
1684. HurricaneJoe 5:12 AM GMT on August 09, 2009    
Just seems like this system has too much going for it. I think the NHC should/will see that.
1686. SouthALWX 5:13 AM GMT on August 09, 2009    
Quoting btwntx08:

extereme northern mx/deep south tx which thats my area

Good, that means you're safe. breathe easy lol.
Member Since: August 27, 2008 Posts: 0 Comments: 1497
1689. HurricaneJoe 5:13 AM GMT on August 09, 2009    
Oh, I misread the poll. I thought you wanted the color (chance) of the system developing. My bad.

A.
1691. SouthALWX 5:16 AM GMT on August 09, 2009    
Im going to assume they realize and are simply playing along. otherwise i may turn that "shape" on myself -_-
Member Since: August 27, 2008 Posts: 0 Comments: 1497
1692. SouthALWX 5:16 AM GMT on August 09, 2009    
Ok so I was wrong. -.- consider me dead for a while lol.
Member Since: August 27, 2008 Posts: 0 Comments: 1497
1693. winter123 5:17 AM GMT on August 09, 2009    
Quoting BurnedAfterPosting:
Ok ok so poll time lol

What color circle would you like to use to hit the next person who does a poll about the TWO?

A. Yellow
B. Orange
C. Red
D. Pink with Purple polka dots
E. Throw the remnants of Karen at them

VOTE NOW!!


I hit your mom with my... poll

er, C

:/ meh seriously going to bed now
Member Since: July 29, 2006 Posts: 28 Comments: 1700
1694. philliesrock 5:17 AM GMT on August 09, 2009    
Early, bold predictions:

-Current wave will go out to sea after becoming a TS
-Next wave will go into the Caribbean as a hurricane
Member Since: June 29, 2006 Posts: 65 Comments: 3197
1696. HurricaneJoe 5:18 AM GMT on August 09, 2009    
I'm just glad we finally have something to watch. Been an otherwise boring summer...
1697. Stormchaser2007 5:18 AM GMT on August 09, 2009    
20-30 minutes.
Member Since: June 9, 2007 Posts: 4 Comments: 15245
1699. HurricaneJoe 5:19 AM GMT on August 09, 2009    
Quoting Stormchaser2007:
20-30 minutes.


Until?
1700. SouthALWX 5:20 AM GMT on August 09, 2009    
My last hoorah before bed. If the GFS can make a prediction 9000 hours ahead of time and not be criticized to the point of implosion why can't I. First wave Tx/La border second central mexico. Oh and they'll both be category 7 with 900Meter storm surge... it could happen ...
Member Since: August 27, 2008 Posts: 0 Comments: 1497

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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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