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 IKE:


Jeez...I wonder who.....initials W.....S......


Exactly.
Member Since: June 9, 2007 Posts: 4 Comments: 15946
1167. IKE
Quoting 2manytimes:
sad, but so very true


Jeez...I wonder who.....initials W.....S......
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Quoting Stormchaser2007:
It better not make it too far north or we'll have to put a suicide watch up for some people here.
sad, but so very true
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If this amazing wave in fact becomes a threat to the coast it will take so long to get here that there is plenty of time for people to get out of the way. It's wild that a WAVE brings out so much excitement in some people. That must be because they have never had to respond to the aftermath if a storm like Rita and Katrina, I am a H-60 Flight Mechanic who had to ride out Katrina and then go out and rescue the people who were stranded. WHO COULD GET EXCITED ABOUT ONE OF THESE STORM? I look to this web site and blog for knowledgeable and informed professionals to post what is going on out there, Maybe it's time to put away all the hype, what do you think?
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Quoting WeatherStudent:
thanks ex, cause i really love your daily unput on this blog.


um daily unput?

as in you enjoy when he doesnt participate? lol
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1162. Drakoen
Quoting FirstCoastMan:
Drakoen what is the lastest on the african wave that is coming off the coast...TIA


Look at page 23 at my post.
Member Since: October 28, 2006 Posts: 57 Comments: 30615
Quoting Drakoen:
CIMSS confirms the lower to mid level cyclonic circulation on the eastern portion of the convection.


Yep

Member Since: June 9, 2007 Posts: 4 Comments: 15946
Drakoen what is the lastest on the african wave that is coming off the coast...TIA
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1159. eye
Looks like it has relocated N again, even closer to the islands...and naturally they almost never go due W...more like WNW. Being that far N already, something bound to pick it up or it will find a weakness between the two highs.
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1158. IKE
"unput" LOL!
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*headaches*
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Dakster:
To everyone in Hurricane alley... I would be disappointed to learn that any of you are not prepared WELL in advance. Every year I make sure I replace supplies... Lived down here too long to not be prepared. I only have sympathy for someone who has recently moved into Hurricane Alley.


I have a plan and know exactly what I will do and where we will go. No pressure, No Unnecessary stress.


If this amazing wave in fact becomes a threat to the coast it will take so long to get here that there is plenty of time for people to get out of the way. It's wild that a WAVE brings out so much excitement in some people. That must be because they have never had to respond to the aftermath if a storm like Rita and Katrina, I am a H-60 Flight Mechanic who had to ride out Katrina and then go out and rescue the people who were stranded. WHO COULD GET EXCITED ABOUT ONE OF THESE STORM? I look to this web site and blog for knowledgeable and informed professionals to post what is going on out there, Maybe it's time to put away all the hype, what do you think?
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1154. HadesGodWyvern (Mod)
1150. presslord 1:35 AM GMT on August 09, 2009
remember....it's bikini season....

---
oh no, don't even go there
Member Since: May 24, 2006 Posts: 51 Comments: 46158
1153. hahaguy
Quoting CybrTeddy:


Press, this might be a little off topic.. but when can I meat your lady friend that Jeff Masters posted back in '08. :P rofl. She looked mighty young.


Please don't make him bring that picture out LOL.
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1151. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #1
TROPICAL DEPRESSION
9:00 AM JST August 9 2009
=========================================

Subject: Tropical Depression In Sea South Of Japan

At 0:00 AM UTC, Tropical Depression (996 hPa) located at 26.3N 136.3E has 10 minute sustained winds of 30 knots with gusts of 45 knots. The depression is reported as moving north-northwest at 15 knots.

RSMC Dvorak Intensity: - - -

Forecast and Intensity
======================
24 HRS: 32.1N 134.7E - 35 knots (CAT 1/Tropical Storm)
Member Since: May 24, 2006 Posts: 51 Comments: 46158
remember....it's bikini season....
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1149. pottery
Just playing with your head, WS.
You are part of what makes this blog go round, and round, and round...
heheheheh
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Quoting presslord:
jeffs....all that is fine and dandy....but...

WHERE'S IT GONNA HIT?!?!?!


cat 5 landfall in manhattan OMG IT COULD HAPPEN TOMORROW
Member Since: July 29, 2006 Posts: 28 Comments: 1800
Quoting Stormchaser2007:
It better not make it too far north or we'll have to put a suicide watch up for some people here.

LOL. I hadn't thought of that... and I think you may be right.
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1146. Drakoen
CIMSS confirms the lower to mid level cyclonic circulation on the eastern portion of the convection.
Member Since: October 28, 2006 Posts: 57 Comments: 30615
Quoting presslord:
pottery....I loooove you...


Press, this might be a little off topic.. but when can I meat your lady friend that Jeff Masters posted back in '08. :P rofl. She looked mighty young.
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1144. IKE
Quoting pottery:
Hello, WeatherStudent.
How nice to see you here, again.
By now you should realise that all the people on this blog are conspiring to keep you in the dark about Certain Things.
One that immediately comes to mind, is the glaring fact that this wave that is near Africa, is coming straight at you. And there is really nothing that you can do about it.
Close down your computer right now. You may be in Grave Danger. And dont turn it back on until December.


LOL!
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Quoting louisianaboy444:
is it possible to see a 1008 mb surface low in the next 12 to 24 hours thats what one of the NHC surface maps were predicting...


Your correct. A 1010 mb low is forecast along this feature over the next 24 hrs.

Member Since: July 24, 2005 Posts: 407 Comments: 19076
1141. Drakoen
It just needs to stay south of 18N.
Member Since: October 28, 2006 Posts: 57 Comments: 30615
Quoting P451:

Could there be a little bit of a westerly movement on the last frame?
Member Since: May 16, 2009 Posts: 1 Comments: 1231
Member Since: June 9, 2007 Posts: 4 Comments: 15946
Quoting WeatherStudent:


hey guys, you two meteorologically fine gentlemen have me on ignore? :(


No.
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1136. eye
456, it is because they only want to see the people that agree with them or stroke their egos by asking for their expert knowledge (ie Drak not ignoring WeatherStudent). It is kinda like tweeter, they only want to see their true followers!
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I think the Azores high will keep it from going out to sea in the near term now long range who knows
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pottery....I loooove you...
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It better not make it too far north or we'll have to put a suicide watch up for some people here.
Member Since: June 9, 2007 Posts: 4 Comments: 15946
is it possible to see a 1008 mb surface low in the next 12 to 24 hours thats what one of the NHC surface maps were predicting...
Member Since: Posts: Comments:
1129. pottery
Hello, WeatherStudent.
How nice to see you here, again.
By now you should realise that all the people on this blog are conspiring to keep you in the dark about Certain Things.
One that immediately comes to mind, is the glaring fact that this wave that is near Africa, is coming straight at you. And there is really nothing that you can do about it.
Close down your computer right now. You may be in Grave Danger. And dont turn it back on until December.
Member Since: Posts: Comments:
should continue moving west.

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1126. Drakoen
5-10 knots of wind shear over the system per the latest cimss. 850mb continues to improve. Sustaining lower level convergence and upper level divergence along the wave axis.
Member Since: October 28, 2006 Posts: 57 Comments: 30615
1125. eye
too far N already, hopefully will become Ana look impressive like Felicia and go harmlessly out to sea.
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I am amazed at such lengthy ignore lists. After 4 years here, only 1 person made it. I just see posts and looked the other way.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1123. Drakoen
Continues to be impressive:
Member Since: October 28, 2006 Posts: 57 Comments: 30615
1121. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Warning #46
SEVERE TROPICAL STORM MORAKOT (T0908)
9:00 AM JST August 9 2009
=========================================

Subject: Category Two Typhoon In Taiwan Strait

At 0:00 AM UTC, Severe Tropical Storm Morakot (975 hPa) located at26.1N 120.6E has 10 minute sustained winds of 60 knots with gusts of 85 knots. The storm is reported as moving north at 7 knots

RSMC Dvorak Intensity: T3.0

Storm-force Winds
==================
90 NM from the center

Gale-force Winds
================
400 NM from the center in southern quadrant
300 NM from the center in northern quadrant

Forecast and Intensity
=========================
24 HRS: 28.3N 121.7E - 55 knots CAT 2/Severe Tropical Storm)
48 HRS: 32.5N 121.9E - 45 knots (Cat 1/Tropical Storm)
72 HRS: 35.4N 124.4E - EXTRATROPICAL LOW

---
forecasted to track along the eastern China coast and make landfall in Korea...
Member Since: May 24, 2006 Posts: 51 Comments: 46158
its supposed to go more northerly till it reaches the effects of the Azores high, then moves more westerly

yeah thats what i see also
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1119. eye
extreme, though you cant see this, if you cant stand the heat for your predictions, get out of the kitchen!
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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.