Felicia not weakening; new African wave may develop

By: Dr. Jeff Masters , 3:12 PM GMT on August 08, 2009

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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

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Quoting Stormchaser2007:


Thats what I was thinking...especially if Avila gets to write it.


You think alot don't you...
Member Since: January 14, 2007 Posts: 17 Comments: 4140
Quoting pottery:
Just playing with your head, WS.
You are part of what makes this blog go round, and round, and round...
heheheheh


Hi Pottery, hope you made it through the rain okay.
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Quoting Drakoen:


I'll need therapy if this fizzles.


LOL. That new feature is the best shot yet for development.
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A closed low at the surface that extends upwards to 700mb

Wow that would be one heck of a feat if it can pull that off after only a day on water i remember waiting here for days for a storm to get a closed low....really quite impressive
Member Since: August 29, 2006 Posts: 22 Comments: 1339
Quoting Weather456:
A better question would be Ana's first public advisory heading, whether it be this wave or any future disturbance.

...FINALLY THE FIRST NAMED STORM OF THE 2009 SEASON HAS ARRIVE...


Thats what I was thinking...especially if Avila gets to write it.
Member Since: June 9, 2007 Posts: 4 Comments: 15718
1262. Drakoen
Yea that's what I was talking about StormChaser. Nice graphics BTW
Member Since: October 28, 2006 Posts: 57 Comments: 29714
Anyone think this is possible by 8pm tmrw?
Member Since: July 14, 2009 Posts: 51 Comments: 1715
Hi-res GFS has a nice surface low in about 6 hours.

Member Since: June 9, 2007 Posts: 4 Comments: 15718
1259. Drakoen
Quoting kmanislander:
A lot of bloggers will need therapy if this wave fizzles


I'll need therapy if this fizzles.
Member Since: October 28, 2006 Posts: 57 Comments: 29714
Member Since: January 14, 2007 Posts: 17 Comments: 4140
FLOOD WATCH
NATIONAL WEATHER SERVICE HONOLULU HI
334 PM HST SAT AUG 8 2009

...FELICIA TO BRING HEAVY RAINS TO PORTIONS OF THE STATE...

HIZ012>028-091445-
/O.NEW.PHFO.FF.A.0003.090810T1600Z-090812T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MOLOKAI WINDWARD-MOLOKAI LEEWARD-LANAI MAKAI-LANAI MAUKA-
KAHOOLAWE-MAUI WINDWARD WEST-MAUI LEEWARD WEST-
MAUI CENTRAL VALLEY-WINDWARD HALEAKALA-LEEWARD HALEAKALA-
HALEAKALA SUMMIT-KONA-SOUTH BIG ISLAND-BIG ISLAND NORTH AND EAST-
KOHALA-BIG ISLAND INTERIOR-BIG ISLAND SUMMITS-
334 PM HST SAT AUG 8 2009

...FLASH FLOOD WATCH IN EFFECT FROM MONDAY MORNING THROUGH
TUESDAY AFTERNOON...

THE NATIONAL WEATHER SERVICE IN HONOLULU HAS ISSUED A

* FLASH FLOOD WATCH FOR KAHOOLAWE...LANAI...MAUI...MOLOKAI AND
THE BIG ISLAND

* FROM MONDAY MORNING THROUGH TUESDAY AFTERNOON.

* ABUNDANT MOISTURE ASSOCIATED WITH FELICIA IS EXPECTED TO PRODUCE
EXTREMELY HEAVY RAINFALL WITH THE POTENTIAL FOR WIDESPREAD FLASH
FLOODING INCREASING ON MONDAY AND CONTINUING INTO TUESDAY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PEOPLE IN FLOOD PRONE AREAS NEED TO PREPARE NOW FOR THE POSSIBILITY
OF TORRENTIAL RAINS ASSOCIATED WITH FELICIA. ROCK AND MUDSLIDES ARE
ALSO POSSIBLE ONCE THE HEAVY RAIN BEGINS.

IT IS IMPORTANT TO REMEMBER THAT HEAVY...FLOODING RAINFALL COULD
OCCUR EVEN WELL AWAY FROM THE CENTER OF FELICIA.

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

&&

$$

BURKE/R BALLARD
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A lot of bloggers will need therapy if this wave fizzles
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1254. Drakoen
Quoting louisianaboy444:
Does the GFS show a closed low at the surface or just a closed low all together?


A closed low at the surface that extends upwards to 700mb.
Member Since: October 28, 2006 Posts: 57 Comments: 29714
A better question would be Ana's first public advisory heading, whether it be this wave or any future disturbance.

...FINALLY THE FIRST NAMED STORM OF THE 2009 SEASON HAS ARRIVE...
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Quoting louisianaboy444:
Does the GFS show a closed low at the surface or just a closed low all together?


Typically when we refer to closed low, its at the surface.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting weathersp:
Somtimes I fell that this blog is like a popularity contest in a jr high school...

*Caution* The truth may hurt *Caution*




Thats exactly what I was thinking.
Member Since: June 9, 2007 Posts: 4 Comments: 15718
As sick as it sounds, this blog seems to run more smoothly when there is a system developing lol
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Does the GFS show a closed low at the surface or just a closed low all together?
Member Since: August 29, 2006 Posts: 22 Comments: 1339
1247. JRRP
Quoting Stormchaser2007:


I wonder how they'll choose their wording.

A)Conditions are favorable for gradual development
-OR-
B)Conditions are favorable for slow development.



may be B
Member Since: August 16, 2007 Posts: 0 Comments: 5078
Quoting Stormchaser2007:


I wonder how they'll choose their wording.

A)Conditions are favorable for gradual development
-OR-
B)Conditions are favorable for slow development.




I would go with A, but there always room for B with the NHC.
Member Since: Posts: Comments:
Somtimes I feel that this blog is like a popularity contest in a jr high school...

*Caution* The truth may hurt *Caution*


Member Since: January 14, 2007 Posts: 17 Comments: 4140
Quoting Drakoen:
If you go by the GFS 18z it should have a closed low soon.


Hi-res GFS has a closed low in 3 hours.
Member Since: June 9, 2007 Posts: 4 Comments: 15718


Pretty well insulated from the dust.
Member Since: September 22, 2005 Posts: 18 Comments: 2229
Given all these conditions and not to mention strong model support I reiterate the likelihood, in my opinion, of this being our first named storm. No guarantees, but the best so far.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting P451:
Until Tomorrow...


...Water Vapor Loop (24 hrs)



Very nice images so far!

Props to you
Member Since: June 9, 2007 Posts: 4 Comments: 15718
1240. Drakoen
If you go by the GFS 18z it should have a closed low soon.
Member Since: October 28, 2006 Posts: 57 Comments: 29714
Quoting SouthALWX:

add stormW to make it a top 7 =P


those 7 are certainly my list...
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Quoting Weather456:


most likely


I wonder how they'll choose their wording.

A)Conditions are favorable for gradual development
-OR-
B)Conditions are favorable for slow development.


Member Since: June 9, 2007 Posts: 4 Comments: 15718
Quoting Drakoen:


Mid level is above 850mb. Between 850mb and 400mb.


Ah, okay.
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Thank you Extreme And Weather456 , As Always

Been Here Since 2005..

I know Who to Actually Pay Attention to:

Top 6:
Extreme
Weather456
Drak
Ike
Pat
Hurricane23


Can i at least make the top ten lol i might not be the smartest cookie in here but i will never feed you bull
Member Since: August 29, 2006 Posts: 22 Comments: 1339
Quoting Stormchaser2007:

Ouch lol


Poor stormchaser :( lol
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting Stormchaser2007:
Hopefully the NHC will acknowledge this by tomorrow.



most likely
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The infrared images on the southeast band of "pre-Ana", for the first time, are showing a new stronger precipitation intensity level.
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Quoting sammywammybamy:


Thank you Extreme And Weather456 , As Always

Been Here Since 2005..

I know Who to Actually Pay Attention to:

Top 6:
Extreme
Weather456
Drak
Ike
Pat
Hurricane23


add stormW to make it a top 7 =P
Member Since: August 27, 2008 Posts: 0 Comments: 1497
Quoting sammywammybamy:


Thank you Extreme And Weather456 , As Always

Been Here Since 2005..

I know Who to Actually Pay Attention to:

Top 6:
Extreme
Weather456
Drak
Ike
Pat
Hurricane23


Ouch lol
Member Since: June 9, 2007 Posts: 4 Comments: 15718
Quoting Stormchaser2007:
Hopefully the NHC will acknowledge this by tomorrow.


It should be within the range of the Wide View Satellite by tomorrow.
Member Since: May 16, 2009 Posts: 1 Comments: 1231
1226. Dakster
Maybe this will get Stormw back from his "weekend off".

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Looks like favorable easterlies for the next few days.

Member Since: June 9, 2007 Posts: 4 Comments: 15718
1224. Drakoen
Yes I am happy that we actually have something with a decent shot of developing. It's about time.
Member Since: October 28, 2006 Posts: 57 Comments: 29714
Interesting wave train lining up behind this one.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting kmanislander:


Monster ??.

Just another wave to track. Let's see how it is doing in 48 hrs.


Also, waves just coming off of the continent usually are still aquainted to the land... If it gets past say 27W and is still going then it's going to have a chance to make somthing out of itself.
Member Since: January 14, 2007 Posts: 17 Comments: 4140
Quoting sammywammybamy:


Well Kman ,

If you look at frame..

It has Blown up ..

it actually looks better then it was exiting africa..

But , I am going to go with a 30% chance of a Td forming in the next 12-24 Hours

And a 50% Afterwards Slowly Increasing


Yes it has blown up but it is also just barely offshore the African coast.

Could this be the one ??

Perhaps.
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Hopefully the NHC will acknowledge this by tomorrow.

Member Since: June 9, 2007 Posts: 4 Comments: 15718

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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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