Hawaii braces for Felicia; 99L near the Cape Verdes Islands may develop

By: Dr. Jeff Masters , 3:55 PM GMT on August 10, 2009

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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.

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Looks like TD2 could pull a Frances/Jeane track.
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3188. WAHA
Quoting hurricanemaniac123:
Now we have TD 2, here's my predicition:

TD 2 becoming a TS 60-80%
TD 2 becoming a Hurricane 10-30%
TD 2 becoming a fish storm 50%
TD 2 hitting land 50%

If it is a fish storm, can i eat it?
UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 11 AUG 2009 Time : 124500 UTC
Lat : 14:26:19 N Lon : 29:06:02 W


CI# /Pressure/ Vmax
1.5 /1012.0mb/ 25.0kt


Final T# Adj T# Raw T#
(3hr avg)
1.5 1.5 1.5

Latitude bias adjustment to MSLP : +0.0mb

Center Temp : +5.1C Cloud Region Temp : -29.8C

Scene Type : USER DEFINED INITIAL CLASSIFICATION

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

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Link

The recently emerge wave look healthy...
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3185. WAHA
Now TD Two has an eye.
Now we have TD 2, here's my predicition:

TD 2 becoming a TS 60-80%
TD 2 becoming a Hurricane 10-30%
TD 2 becoming a fish storm 50%
TD 2 hitting land 50%
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Quoting Acemmett90:

isn't that the path frances took


Similar. But this shouldn't even touch that strength.
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Click on image to view original size in a new window



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3180. WAHA
Quoting CybrTeddy:
Morning everyone? TD2 eh?

Speaking in a canadian accent, eh?
BIG spread:

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Morning everyone? TD2 eh?
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3176. KEEPEROFTHEGATE (Mod)
UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 11 AUG 2009 Time : 124500 UTC
Lat : 14:26:19 N Lon : 29:06:02 W


CI# /Pressure/ Vmax
1.5 /1012.0mb/ 25.0kt


Final T# Adj T# Raw T#
(3hr avg)
1.5 1.5 1.5

Latitude bias adjustment to MSLP : +0.0mb

Center Temp : +5.1C Cloud Region Temp : -29.8C

Scene Type : USER DEFINED INITIAL CLASSIFICATION

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

****************************************************


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Quoting TampaSpin:
Morning all....i see we have now got soon to be Ana.....no surprise here!

Yep. It was looking small but pretty well organized last night. I noticed it had a closed CoC on quikscat last night, and looked remarkably similar to TD1. It is going to have a struggle ahead against the SAL, but the first really organized wave usually does.
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3174. WAHA
Quoting marknmelb:


Is this TD#2 or what's behind TD#2 ???

no idea
Quoting dfwWxDude:
Good morning,
If this is TD2, what was TD1?
Thanks, back to lurking ;)

TD one was in May, a few days before june. Look it up on wikipedia.
The NHC cut out their 'development if any' line for the 52W wave.

SHOWER AND THUNDERSTORM ACTIVITY ASSOCIATED WITH A TROPICAL WAVE
LOCATED ABOUT 600 MILES EAST OF THE LESSER ANTILLES REMAINS
DISORGANIZED. DEVELOPMENT OF THIS SYSTEM IS LIKELY TO BE SLOW AS
IT MOVES WESTWARD AT 10 TO 15 MPH. THERE IS A LOW CHANCE...LESS
THAN 30 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS.

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Quoting dfwWxDude:
Good morning,
If this is TD2, what was TD1?
Thanks, back to lurking ;)


A short lived TD in May off the North Carolina coast.
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Morning guys! Lots to talk about this morning...looks like the entire east coast will be on alert here soon. Wonder when the local Mets will start talking about this stuff.
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Good morning,
If this is TD2, what was TD1?
Thanks, back to lurking ;)
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Quoting futuremet:
Post - 3019: Wind field map



Is this TD#2 or what's behind TD#2 ???
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Quoting Chicklit:

Oh puhleese. There's less to be bored about now than there was the entire two months into the season and the NHC showed restraint then. They're not a bunch of bloggers speculating. They're professional meterologists with lists of specific requirements that have to be met before they'll call anything. We've seen cases where they won't call a TD because there is no COC but there's everything else. So they must have found the COC and whatever else has to go into a TD and called it what it was. By the way, the areas at The Windwards and out by 50W are still code yellow and looking pretty thin. Not saying they won't develop, but obviously the NHC isn't jumping the gun on anything. They haven't classified the wave behind TD2 yet, have they?


I think 50w and 60w are dead. Looked way more promising yesterday. For TD2, NHC just looks at the data and makes their judgment based on hard facts (not wrong at all). Just saying they're not taking into account that it is basically surrounded by dry air/SAL.
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Morning all....i see we have now got soon to be Ana.....no surprise here!
Member Since: September 2, 2007 Posts: 179 Comments: 20448
3166. WAHA
I wonder when Drakoen is coming.
TD2 ADT
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I believe we need to keep a close eye on the Caribbean.
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3163. WAHA
Quoting KimberlyB:
Good morning everyone and holy crap!

Did anyone happen to save any of the adrenaline you pumped into 99 overnight, cause I sure could use it? lol

Yes, that crap is indeed holy. Look how much it changed in just 18 hrs!
bbl
Prayers for the people of Shiao Lin.
Link
BD: They don't classify based upon whether something will make landfall, US or elsewhere. Think of scientific classification, high school biology. If something has certain characteristics, then it is named something.
That's how they do it. Trough, wave, depression, tropical storm, hurricane, typhoon, etc., all have to meet certain criteria in order to be named.
The Weather Channel says they are "the hurricane authority;" here it's Dr. Jeff Masters and the NHC. They are the hurricane authorities and don't make irresponsible statements because they're "bored." It's just offensive and a little silly to me.
When you see what's happening in China in the aftermath of Marakot you fully realize that while we're hobbyists watching tropical systems, and that is sort of a game, there is nothing funny or trivial about what can happen to a community, island, state or nation if and when a powerful storm hits. Actually, it's human misery at its worst. Anyway, have a great day.
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3160. BDAwx
Quoting Chicklit:
Oh puhleese. There's less to be bored about now than there was the entire two months into the season and the NHC showed restraint then. They're not a bunch of bloggers speculating. They're professional meterologists with lists of specific requirements that have to be met before they'll call anything. We've seen cases where they won't call a TD because there is no COC but there's everything else. So they must have found the COC and whatever else has to go into a TD and called it what it was. By the way, the areas at The Windwards and out by 50W are still code yellow and looking pretty thin. Not saying they won't develop, but obviously the NHC isn't jumping the gun on anything. They haven't classified the wave behind TD2 yet, have they?


My bad didn't mean to quote there (trying to work the iPod) but I stand by my statement... Because I don't expect TD2 to affect/effect the US.
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3159. KEEPEROFTHEGATE (Mod)
Quoting StormW:
Good morning!
morning storm
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Good morning everyone and holy crap!

Did anyone happen to save any of the adrenaline you pumped into 99 overnight, cause I sure could use it? lol
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Ill have a "Bill" wave update every 2 hours hopefully.
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Quoting nrtiwlnvragn:


Shifting west. Not a good sign but they will change (hopefully back east).
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3155. KEEPEROFTHEGATE (Mod)
809

WHXX04 KWBC 111125

CHGQLM

ATTENTION...NATIONAL HURRICANE CENTER



NCEP COUPLED GFDL HURRICANE MODEL FORECAST MADE FOR



TROPICAL DEPRESSION TWO 02L



INITIAL TIME 6Z AUG 11



DISCLAIMER ... THIS INFORMATION IS PROVIDED AS GUIDANCE. IT

REQUIRES INTERPRETATION BY HURRICANE SPECIALISTS AND SHOULD

NOT BE CONSIDERED AS A FINAL PRODUCT. PLEASE SEE THE TPC/NHC

OFFICIAL FORECAST.





FORECAST STORM POSITION



HOUR LATITUDE LONGITUDE HEADING/SPEED(KT)



0 14.2 27.9 270./ 9.9

6 15.1 28.7 317./11.9

12 15.5 30.3 283./15.3

18 15.9 32.2 283./18.9

24 15.7 33.6 260./13.9

30 15.6 35.2 268./15.1

36 15.4 36.9 260./16.4

42 14.9 38.3 251./14.6

48 14.8 39.7 266./13.4

54 14.8 41.2 272./15.3

60 14.6 42.2 256./ 9.8

66 14.6 43.5 272./12.7

72 14.9 44.9 283./13.1

78 15.2 46.2 283./13.6

84 15.5 47.4 283./11.6

90 15.9 48.7 289./13.3

96 16.7 49.8 305./12.8

102 17.6 51.4 300./18.2

108 18.3 52.9 294./15.7

114 18.6 54.9 278./19.0

120 20.0 56.3 314./19.4

126 20.6 58.0 291./16.7
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Latest dynamical.

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Quoting Stormchaser2007:
Quick 'Bill' wave update as of 12Z

It appears that the 850mb vort max is moving off the coast now. We should see a slow to gradual organization trend for the next 48 hours as this generally moves WNW. Conditions appear excellent for organization due to all the moisture left behind from TD2. Shear is about 8 knots and should stay to 5-15 knots throughout the next 72 hours. We should see the NHC mention this by later today.



Morning,

Yaah looks more dangerous than TD2!
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Quoting Stormchaser2007:
Quick 'Bill' wave update as of 12Z

It appears that the 850mb vort max is moving off the coast now. We should see a slow to gradual organization trend for the next 48 hours as this generally moves WNW. Conditions appear excellent for organization due to all the moisture left behind from TD2. Shear is about 8 knots and should stay to 5-15 knots throughout the next 72 hours. We should see the NHC mention this by later today.



Thanks Stormchaser2007, this is where the real game begins!
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3150. WAHA
Quoting caribbeansurvivor1:
Good morning to everyone! The "Atlantic sleeping beauty is very awake now! Wow!! I went to bed at 1 am and there were just two investement and now are 3!! 99l still fighting with the shear and SAL! Going west to the Antilles!! Like other guys said...no good feeling!

99 is now Two, dude.
Well woke up to what you are seeing now. It looks like it is time to track.
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Ok The GFS that shows a "son of Andrew" next weekend hitting south Florida. Was that TD#2 or what is behind TD#2 ???
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Quoting Stormchaser2007:
Quick 'Bill' wave update as of 12Z

It appears that the 850mb vort max is moving off the coast now. We should see a slow to gradual organization trend for the next 48 hours as this generally moves WNW. Conditions appear excellent for organization due to all the moisture left behind from TD2. Shear is about 8 knots and should stay to 5-15 knots throughout the next 72 hours. We should see the NHC mention this by later today.



Thanks for the info.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quick 'Bill' wave update as of 12Z

It appears that the 850mb vort max is moving off the coast now. We should see a slow to gradual organization trend for the next 48 hours as this generally moves WNW. Conditions appear excellent for organization due to all the moisture left behind from TD2. Shear is about 8 knots and should stay to 5-15 knots throughout the next 72 hours. We should see the NHC mention this by later today.

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3144. WAHA
...or at least doesn't hit land.
O1C at Central Pacific becomes

TS MAKA

Date : 11 AUG 2009 Time : 123000 UTC
Lat : 13:56:15 N Lon : 171:46:59 W


CI# /Pressure/ Vmax
2.9 /1001.0mb/ 43.0kt


Final T# Adj T# Raw T#
(3hr avg)
2.9 3.1 3.7
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mornin' Senior Chief
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Good morning to everyone! The "Atlantic sleeping beauty is very awake now! Wow!! I went to bed at 1 am and there were just two investement and now are 3!! 99l still fighting with the shear and SAL! Going west to the Antilles!! Like other guys said...no good feeling!
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3140. WAHA
Quoting extreme236:
So anything new on this "Bill" wave?

Well, it probably won't be "Bill" if you ask me.
Good Morning StormW how are you today?
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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.