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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Not only that but based on some of the long-range models i looked at late last night things should really start to pick up across the atlantic sometime next week.NAO will be going positive.
I didn't put the app there lol. That person is on my ignore list.
McAfee just came up with 10 warnings. It may just be me though. I have 7 other tabs open.
I don't use McAfee, it takes too much ram. Avira only uses 1MB of ram. It is very efficient too.
My backup AV is malwarebytes.
The 12z DAM forecast for cyclogenesis off the African coast south of the CV islands. A synoptic scale upper level anticyclone and forecast low SAL should allow this wave to develop. The DAM sides with the GFS, CMC, UKMET, and NOGAPS forecast. The DAM views the ECMWF as incorrectly handling the upper level easterlies.
Sounds like an interesting run...looks like a decent chance at some development over the next few days.
Anyones guess...It all just basically comes down to luck and chance at where the long wave pattern just happens to be when a hurricane just happens to come along.August is more likely to have ridging in the W. Atlantic than Sept or Oct, that's for sure (BUT) i have no faith in any forecast over 84 hrs. And the usual term for the long wave to be in any one general position is 6-10 days.
Adrian
Perhaps
GFS 06Z
ECMWF 00Z
Nice looking wave exiting the African coast I see. Conditions seems to be marginal to favorable across the atlantic right now and for the upcoming days. If this does develop, any idea on a general track. I understand that it might be a bit premature to ask, but what it the set up like in terms of the high and steering flow?
They must be on mine too :)
RU notifying admin? 10Q
Probably by tomorrow afternoon. When/IF they start mentioning it, they'll likely declare it an invest shortly after.
Probably the clearest ive seen the EATL in a while.
They will probably wait till it clears the coast completely first.
The GFS has been too inconsistent with its forecast regarding the NAO. The ECMWF's NAO forecast fluctuates less. So, I am leaning more towards the ECMWF's outcome.
Anyone have a comment about that flare up of thunderstorms in the Gulf? Is that just typical daytime heating flareup?
The ECMWF does better in the long-range. I would lean more towards it's forecast than the inconsistent GFS. At least for the time being.
Second to Fay.
True, but it only took Fay 5-6 days to form...its taken Ana 2 months lol
Thanks for taking the time to share your knowledge Drakoen. It's very helpful to those of us in what seems like a perpetual learning mode.
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