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
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Tropical Cyclone Outlook
4:00 PM HST August 8 2009
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An area of thunderstorms (92C) centered about 625 miles south southwest of Hilo, Hawaii is moving west-northwest around 15 MPH.. Slow development is possible over the next two days
Tropical Cyclone formation Potential
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There is a low chance of this disturbance to form into a significant tropical cyclone within the next 48 hours
Not always.
i am not expert but INVEST is more easy
This was from 18Z right?
If it is correct, a surface low should be there by tomorrow morning at the latest.
Correct.
Anomalies in that part of the world getting a little more, er... anomalous.
And I hired this guy,
I added the ones this system fits and got 52... i made a few assumptions though, but it just needs a 39
It should by tomorrow...
Ya'll are agreeing??
(reaches for valium)
You have to remember the time zones it is later near the wave than it is in the U.S so it may be entering DMAX right about now....
Is it correct to say that since this has not developed the GFS didn't get to initialize correctly or not.
It's around 1-2 am out there
...
Drak...did you really think I was being serious? It's hard to convey "tongue and cheek" in text.
Enjoy your post, the only one I would actually add to the original list would be StormW
Until you see daylight over the AOI we haven;t reached Dmax.
GRLevel2 Analyst.
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