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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New surface map 00z
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000
WTPA32 PHFO 090257
TCPCP2

BULLETIN
HURRICANE FELICIA ADVISORY NUMBER 22
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP082009
500 PM HST SAT AUG 08 2009

...FELICIA MARCHING WESTWARD...TROPICAL STORM WATCHES ISSUED...

AT 500 PM HST...0300 UTC...A TROPICAL STORM WATCH HAS BEEN ISSUED
FOR THE BIG ISLAND OF HAWAII...AND FOR ALL OF MAUI COUNTY...WHICH
INCLUDES THE ISLANDS OF MAUI...KAHOOLAWE...LANAI...AND MOLOKAI.
A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN THE NEXT 48 HOURS.

INTERESTS IN THE REMAINDER OF THE STATE OF HAWAII...INCLUDING THE
ISLANDS OF OAHU...KAUAI...AND NIIHAU...SHOULD CLOSELY MONITOR
THE PROGRESS OF FELICIA. A TROPICAL STORM WATCH COULD BE REQUIRED
FOR THESE AREAS LATER TONIGHT.

AT 500 PM HST...0300 UTC...THE CENTER OF HURRICANE FELICIA WAS
LOCATED NEAR LATITUDE 20.1 NORTH...LONGITUDE 143.4 WEST OR ABOUT
760 MILES EAST OF HILO HAWAII AND ABOUT 940 MILES...EAST OF
HONOLULU HAWAII.

FELICIA IS MOVING TOWARD THE WEST NEAR 15 MPH AND THIS GENERAL
MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS. ON THIS
TRACK...FELICIA IS EXPECTED TO BE NEAR OR OVER THE HAWAIIAN
ISLANDS BY MONDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 85 MPH WITH HIGHER GUSTS. FELICIA
IS A CATEGORY ONE HURRICANE ON THE SAFFIR-SIMPSON SCALE. SLOW
WEAKENING IS FORECAST DURING THE NEXT COUPLE OF DAYS...AND FELICIA
COULD BECOME A TROPICAL STORM WITHIN THE NEXT 24 HOURS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 35 MILES FROM THE
CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 115
MILES.

THE ESTIMATED MINIMUM CENTRAL PRESSURE BASED ON RECENT AIR FORCE
RECONNAISSANCE DATA IS 982 MB...29.00 INCHES.

...SUMMARY OF 500 PM HST INFORMATION...
LOCATION...20.1N 143.4W
MAXIMUM SUSTAINED WINDS...85 MPH
PRESENT MOVEMENT...WEST OR 280 DEGREES AT 15 MPH
MINIMUM CENTRAL PRESSURE...982 MB

AN INTERMEDIATE ADVISORY WILL BE ISSUED BY THE CENTRAL PACIFIC
HURRICANE CENTER AT 800 PM HST FOLLOWED BY THE NEXT COMPLETE
ADVISORY AT 1100 PM HST.

$$
FORECASTER KNABB/R BALLARD





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As far as recurvature goes ... It's always a safe bet to say the longterm models will be wrong so ... guess whatever they say won't happen and you'll be far more accurate =P
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Quoting Thundercloud01221991:
TROPICAL STORM WATCH ISSUED
Quoting Thundercloud01221991:
TROPICAL STORM WATCH ISSUED


what?
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1414. JLPR
impressive wave =O
I would say we should have an invest tomorrow and a depression on Monday or Tuesday

and it looks like our wave at 55W gave up since it isn't developing any new convection yet
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Quoting Thundercloud01221991:
TROPICAL STORM WATCH ISSUED


for what?
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TROPICAL STORM WATCH ISSUED
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tuesday. By then if the wave is a TC the blog will crash so that's my guess.
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Quoting Funkadelic:
Based on the steering would chances are it would recurve right? Just making sure im reading maps correctly.


Too early too tell. It could curve out to sea or end up in the Caribbean.
Member Since: June 9, 2007 Posts: 4 Comments: 15776
1407. Drakoen
Quoting Funkadelic:
Based on the steering would chances are it would recurve right? Just making sure im reading maps correctly.


We don't know.
Member Since: October 28, 2006 Posts: 57 Comments: 29886
1406. Drakoen
Quoting winter123:


Will he stop doing the polls?
A. Yes
B. No
C. Maybe
D. On Tuesday


LOL!
Member Since: October 28, 2006 Posts: 57 Comments: 29886
Quoting hahaguy:
Will you stop doing the polls.


Will he stop doing the polls?
A. Yes
B. No
C. Maybe
D. On Tuesday
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It'll pick up soon enough
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Ah, ok I'll wait
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1400. HadesGodWyvern (Mod)
Philippines Atmospherical Geophysical Astronomical Services and Administration

Tropical Storm "KIKO" has accelerated as it moved out of the Philippine Area of Responsibility.

Tropical Cyclone Bulletin #19
============================
At 10:45 AM PhST, Tropical Storm Kiko (Morakot) located at 25.9N 119.8E or 580 km north northwest of Basco, Batanes has 10 minute sustained winds of 110 km/h (60 knots) with gustiness of 140 km/h (75 knots).

Additional Information
=====================
All Public Storm Warning Signal now lowered.

With this development and unless it recurves, this is the final bulletin for this disturbance.

However, Tropical Storm "KIKO" will continue to enhance the Southwest Monsoon and bring occasional to frequent rains over Extreme Northern Luzon.
Member Since: May 24, 2006 Posts: 50 Comments: 44726
Storm, what's your opinion on this system?
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1396. Drakoen
Quoting Stormchaser2007:


Alright, thanks.


Just South of 15N probably.
Member Since: October 28, 2006 Posts: 57 Comments: 29886
Quoting Drakoen:


Around 15N


Alright, thanks.
Member Since: June 9, 2007 Posts: 4 Comments: 15776
1390. Patrap
WunderMap

Cape Verde View,Night IR

Link to current view
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1389. hahaguy
Will you stop doing the polls.
Member Since: August 12, 2007 Posts: 2 Comments: 2838
1388. Drakoen
Quoting Stormchaser2007:


How much farther north do you think it'll move if at all until the Azores high affects it?


Around 15N
Member Since: October 28, 2006 Posts: 57 Comments: 29886
1387. sfla82
Quoting canesrule1:
for sure, i'm saying TD on monday. BTW lets do a poll!!!!

When do u think this will develop?

A. Tonight
B. Sunday
C. Monday
D. Tuesday
E. After Tuesday
F. Never


F...Never!
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Quoting canesrule1:

C
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err Roll Tide?

You know I should probably say the wave will fizzle because X X and X just to play devil's advocate ... but X's are hard to find .. I'll try anway..
Close/embedded in ITCZ ..

you know looking for excuses to fizzle it only makes me see more momentum for development..

Decent upperlevel divergence ..
Decent lowerlevel convergence ..
SSTs 26F+
5-15Knots max shear ..
decent 850mb vorticity, possible surface low
Divergence increase in the nearterm ..
Symmetrical appearance ..
Need I go on -.-
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Im going to say by Monday if the organization trend continues.
Member Since: June 9, 2007 Posts: 4 Comments: 15776
I think it'll be a depression tomorrow or Monday. All it needs is a bit more orginization and some persistency.
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1382. Drakoen
If it's not closed then it's a very sharply inverted wave with cyclonic curvature.
Member Since: October 28, 2006 Posts: 57 Comments: 29886
Quoting StormW:
Good evening!

Good evening StormW.
Member Since: Posts: Comments:
Quoting Drakoen:
I think we have a closed low at the surface. Or nearly closed. Sharp wind shifts are occurring.


Based upon all the observations in the area, I would have to agree. Would be surprised if this doesn't have a closed surface circulation.
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Quoting canesrule1:
for sure, i'm saying TD on monday. BTW lets do a poll!!!!

When do u think this will develop?

A. Tonight
B. Sunday
C. Monday
D. Tuesday
E. After Tuesday
F. Never


Late sunday nite so (B)

Taco
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Quoting Drakoen:


Previous RAMDIS imagery and quickscat confirm low level westerlies south of the system. Winds winds to the east of the system are coming from the southeast and winds north of the circulation are coming out of the east. Broad but closed/nearly closed low.


How much farther north do you think it'll move if at all until the Azores high affects it?
Member Since: June 9, 2007 Posts: 4 Comments: 15776
Quoting canesrule1:
for sure, i'm saying TD on monday. BTW lets do a poll!!!!

When do u think this will become a TD?

A. Tonight
B. Sunday
C. Monday
D. Tuesday
E. After Tuesday
F. Never
Member Since: Posts: Comments:
1375. Patrap
Maximum Potential Hurricane Intensity

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Quoting Drakoen:
I think we have a closed low at the surface. Or nearly closed. Sharp wind shifts are occurring.

Those are sharp wind shifts. Do we have any obs that can tell us what wind speeds are like in the convection.
Member Since: Posts: Comments:
Quoting Drakoen:
I think we have a closed low at the surface. Or nearly closed. Sharp wind shifts are occurring.
for sure, i'm saying TD on monday. BTW lets do a poll!!!!

When do u think this will develop?

A. Tonight
B. Sunday
C. Monday
D. Tuesday
E. After Tuesday
F. Never
Member Since: Posts: Comments:
It seems the wave has put on a nice burst of organization since it departed the coast.
Member Since: June 9, 2007 Posts: 4 Comments: 15776
1371. Drakoen
Quoting Stormchaser2007:


Indeed.

It'll be interesting to see what the surface map shows.


Previous RAMDIS imagery and quickscat confirm low level westerlies south of the system. Winds winds to the east of the system are coming from the southeast and winds north of the circulation are coming out of the east. Broad but closed/nearly closed low.
Member Since: October 28, 2006 Posts: 57 Comments: 29886
Looks like we will have are first 1 to track in the Atlantic


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