Felicia not weakening; new African wave may develop
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
Reader Comments
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TROPICAL WAVE IS ALONG 20W/21W S OF 18N MOVING W 15-20 KT. LATEST VISIBLE SATELLITE IMAGERY INDICATES THE WELL DEFINED LOW/MID LEVEL CYCLONIC CIRCULATION CENTER MOVING JUST E OF THE WAVE AXIS. THE WAVE AXIS IS EMBEDDED WITHIN THE MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE ASSOCIATED WITH THE LOW/MID LEVEL CIRCULATION COVERING THE AREA FROM 9N-16N BETWEEN 19W-24W.
it first will become 99L maybe at 8am or 2pm
Usually for the Atlantic, it goes Orange and then they declare.
very good analysis 456 of the african disturbance and the tropical wave to exit the african coast inthe next day or two. there is an area at 10n 44w with some cyclonic turning at the mid lvels, there is an anticyclone perched the northeast and it is under weak vertical shear, an earlier qs did indicate a surface low, the system is moving west south of the dry air to the north, and is moving towards an area of low shear for the next few days. this area looks suspicious to me and could have the potential to develop down the road. although the 850mb vorticity chart does not show much vorticity in the area ,i somehow expect it tncrease. What is your take on this area?
ECMWF shows something too still...
yeah makes a run at South Florida better restrict this model.:)
06z map
Hopefully WS won't see it.
Station 13001
Prediction and Research Moored Array in the Atlantic
Location: 11.49N 23W
Conditions as of:
Sun, 09 Aug 2009 10:00:00 UTC
Winds: WSW (240°) at 9.9 kt
Atmospheric Pressure: 29.88 in
Air Temperature: 76.8 F
Water Temperature: 81.3 F
24hr shear forecast
orange they have orange on the map !!!!!!!
oops...
LATEST VISIBLE SATELLITE IMAGERY INDICATES THE WELL DEFINED
LOW/MID LEVEL CYCLONIC CIRCULATION CENTER MOVING JUST E OF THE
WAVE AXIS. THE WAVE AXIS IS EMBEDDED WITHIN THE MOISTURE MAXIMUM
OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. CLUSTERS OF
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE ASSOCIATED
WITH THE LOW/MID LEVEL CIRCULATION COVERING THE AREA FROM
9N-16N BETWEEN 19W-24W.
TROPICAL WAVE IS ALONG 36W S OF 19N MOVING W NEAR 15 KT. WAVE
REMAINS EMBEDDED WITH A MOISTURE MAXIMUM OBSERVED IN TOTAL
PRECIPITABLE WATER IMAGERY AND A BROAD AREA OF CYCLONIC
CIRCULATION. THERE IS NO DEEP CONVECTION ASSOCIATED WITH THE
WAVE.
TROPICAL WAVE IS ALONG 46W/47W S OF 16N MOVING W NEAR 15 KT.
WAVE IS ALONG THE TRAILING EDGE OF A MOISTURE MAXIMUM OBSERVED
IN TOTAL PRECIPITABLE WATER IMAGERY WITH NO ASSOCIATED DEEP
CONVECTION.
TROPICAL WAVE IS ALONG 63W S OF 18N MOVING WNW NEAR 15 KT. WAVE
REMAINS IN AN AREA BENEATH AN UPPER RIDGE PARTIALLY MASKING THE
WAVE SIGNATURE AND ANY SHOWERS/CONVECTION IS MORE ASSOCIATED
WITH THE UPPER LEVEL FEATURE THAN THE WAVE ITSELF.
TROPICAL WAVE IS ALONG 84W/85W S OF 20N MOVING W NEAR 20 KT.
WAVE REMAINS ALONG THE TRAILING EDGE OF A MOISTURE MAXIMUM
OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY AND IS EMBEDDED IN
RATHER DRY STABLE AIR WITH NO ASSOCIATED DEEP CONVECTION.
I'm not more excitable WS more likely and me less likely!!!!!!!!!!!!!!
Please don't ask if it's going to hit the Caymans from 4,000 miles away and all will be fine.
That's the area the San Juan mets are focusing in on for a possible heavy rain event for that island by Thursday/Friday.
I didn't ask plus it is to far and we just got started with this system to be 75% sure where it will go
I didn't think you had.
It is in the ITCZ, it is also the area the ECMWF have been trying to slightly develop in the 0z run.
Invest looks like a certainty.
Impressive:
LOL.
Waiting on NHC to finish poker tourney and post TWO.:)
oh look who it is
I'm not going to ask until it reaches into the caribbean if it does
It's definitely looking more impressive.
99L within hours....maybe minutes.
possibly.
Monitor the the cape verde islands via Weather Undegroun. You should see winds start out of the NE veer from the SE.
Nice picture.
Yeah...the 0-0-0 season is about to end.
Notice use of zero "0" in top and not an "O"
Magnitude 7.1
Date-Time
* Sunday, August 09, 2009 at 10:55:56 UTC
* Sunday, August 09, 2009 at 07:55:56 PM at epicenter
* Time of Earthquake in other Time Zones
Location 33.144°N, 138.040°E
Depth 303.1 km (188.3 miles)
Region IZU ISLANDS, JAPAN REGION
Distances 165 km (100 miles) W of Hachijo-jima, Izu Islands, Japan
175 km (110 miles) S of Hamamatsu, Honshu, Japan
205 km (130 miles) S of Shizuoka, Honshu, Japan
320 km (200 miles) SSW of TOKYO, Japan
Location Uncertainty horizontal +/- 5 km (3.1 miles); depth +/- 8.9 km (5.5 miles)
Parameters NST=201, Nph=201, Dmin=668.8 km, Rmss=0.85 sec, Gp= 29°,
M-type=teleseismic moment magnitude (Mw), Version=7
Source
* USGS NEIC (WDCS-D)
Event ID us2009kcaz
Viewing: 1901 - 1951
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