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HUC
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Re: Wave with well defined mid level circulation off Africa

#61 Postby HUC » Sat Jul 21, 2007 12:04 pm

'canefreak,i think that we are underestimate the extension of the drought in West Africa during the last 35 years(begining in the earlier 70th).So,the outbreaks of dust in the Sal have becoming more frequent,despite the upper pattern over the Atlantic.So,when the HIGH is strongly oriented from Est(Africa ) to West (Antillies and Carribean),the saharian dust is invading the atmosphere. What i try to said :more studies should be maid over the intensification of the dust :it is or not a reality?It is only related to the strenght and position of the High?...
Thank's also for wxman57 for his analysis;really appreciate.
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Re: Wave with well defined mid level circulation off Africa

#62 Postby vacanechaser » Sat Jul 21, 2007 12:19 pm

great post wx57... very well writen and explained nicely... good job..



Jesse V. Bass III
http://www.vastormphoto.com
Hurricane Intercept Research Team
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Re: Wave with well defined mid level circulation off Africa

#63 Postby cycloneye » Sat Jul 21, 2007 1:10 pm

TROPICAL WAVE OFF THE COAST OF AFRICA ALONG 19W S OF 17N MOVING
W 15 KT. WELL DEFINED MID LEVEL CYCLONIC ROTATION IS ALONG THE
WAVE AXIS NEAR 13N WITH LITTLE TO NO EVIDENCE OF A SURFACE LOW
AT THIS TIME. CLUSTERS OF MODERATE CONVECTION ARE FROM 8N-12N
BETWEEN THE 18W-22W.


This is the 2 PM Discussion from TPC.
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Re: Wave with well defined mid level circulation off Africa

#64 Postby cheezyWXguy » Sat Jul 21, 2007 1:25 pm

Does anyone have a good satelite loop of this area other than the SSD one that updats only every 6 hours?
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Re: Wave with well defined mid level circulation off Africa

#65 Postby cycloneye » Sat Jul 21, 2007 1:28 pm

cheezyWXguy wrote:Does anyone have a good satelite loop of this area other than the SSD one that updats only every 6 hours?


Eumetsat

:uarrow: :uarrow:

Above is a great site where you can see updated images every half an hour.
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Re: Wave with well defined mid level circulation off Africa

#66 Postby cheezyWXguy » Sat Jul 21, 2007 1:39 pm

cycloneye wrote:
cheezyWXguy wrote:Does anyone have a good satelite loop of this area other than the SSD one that updats only every 6 hours?


Eumetsat

:uarrow: :uarrow:

Above is a great site where you can see updated images every half an hour.


Thanks cycloneye
one question though...are there any visible satelite images
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#67 Postby Aric Dunn » Sat Jul 21, 2007 1:42 pm

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Re: Wave with well defined mid level circulation off Africa

#68 Postby canegrl04 » Sat Jul 21, 2007 1:42 pm

cycloneye wrote:TROPICAL WAVE OFF THE COAST OF AFRICA ALONG 19W S OF 17N MOVING
W 15 KT. WELL DEFINED MID LEVEL CYCLONIC ROTATION IS ALONG THE
WAVE AXIS NEAR 13N WITH LITTLE TO NO EVIDENCE OF A SURFACE LOW
AT THIS TIME. CLUSTERS OF MODERATE CONVECTION ARE FROM 8N-12N
BETWEEN THE 18W-22W.


This is the 2 PM Discussion from TPC.


Sounds like they are allowing alittle leeway in terms of possible development.Lets see what happens.I don't have my hopes up just yet
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Re: Wave with well defined mid level circulation off Africa

#69 Postby perk » Sat Jul 21, 2007 1:54 pm

wxman57 thanks for the previous post. You specified the northern GOM as an area of concern in mid august. Does that mean we should be safe in the Houston/Galveston area or the western GOM.
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Re: Wave with well defined mid level circulation off Africa

#70 Postby gatorcane » Sat Jul 21, 2007 3:11 pm

greater heat content than 2005 Wxman? Nice post. I always enjoy reading your commentary. :eek:

I have to say that is one impressive wave for July - by this time in August I would give it a good chance of becoming a depression and eventually a hurricane in the MDR region. Now I give it about a 25% chance because of the fact it is early and SAL is still lingering which should eat away at the moisture and just leave a swirl at the mid levels.
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Re: Wave with well defined mid level circulation off Africa

#71 Postby 'CaneFreak » Sat Jul 21, 2007 3:21 pm

gatorcane wrote:greater heat content than 2005 Wxman? Nice post. I always enjoy reading your commentary. :eek:

I have to say that is one impressive wave for July - by this time in August I would give it a good chance of becoming a depression and eventually a hurricane in the MDR region. Now I give it about a 25% chance because of the fact it is early and SAL is still lingering which should eat away at the moisture and just leave a swirl at the mid levels.


Careful what you say....he said, "There is tremendous heat content across the Gulf and NW Caribbean (greater than 2005)"...he didnt say across the entire Atlantic. Just want to make sure we got that straight. Not bashing, just saying... :wink:
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Re: Wave with well defined mid level circulation off Africa

#72 Postby 'CaneFreak » Sat Jul 21, 2007 3:32 pm

HUC wrote:'canefreak,i think that we are underestimate the extension of the drought in West Africa during the last 35 years(begining in the earlier 70th).So,the outbreaks of dust in the Sal have becoming more frequent,despite the upper pattern over the Atlantic.So,when the HIGH is strongly oriented from Est(Africa ) to West (Antillies and Carribean),the saharian dust is invading the atmosphere. What i try to said :more studies should be maid over the intensification of the dust :it is or not a reality?It is only related to the strenght and position of the High?...
Thank's also for wxman57 for his analysis;really appreciate.


You are correct. A lot of research needs to be done in this field. However, studies done as recent as 2005 or 2006 (not sure which) showed that, in general, the stronger the Azores High, the stronger the winds that blow across the Saharan Desert (due to the pressure difference) and therefore the more dust that gets put into the air to kill the moisture that tries to rise into the mid and upper levels of the atmosphere. Just my 2 cents :D
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Re: Wave with well defined mid level circulation off Africa

#73 Postby HUC » Sat Jul 21, 2007 3:51 pm

Yes,and i added:to get dust over the Atlantic,you must have a lot of dust in the west Africa;so the more the desert extend,the more the dust is available ... :lol:
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Re: Wave with well defined mid level circulation off Africa

#74 Postby cycloneye » Sat Jul 21, 2007 7:09 pm

TROPICAL WAVES...
TROPICAL WAVE IS OFF THE COAST OF W AFRICA ALONG 20W/21W S OF
17N MOVING W 15 KT. WELL DEFINED LOW TO MID LEVEL CYCLONIC
ROTATION IS NOTED WITH CONVECTION CONFINED TO THE ITCZ.
CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE
FROM 9N-11N BETWEEN 19W-23W.


8 PM Discussion of wave by TPC.
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#75 Postby Cyclone1 » Sat Jul 21, 2007 7:52 pm

Whoa, LLC forming. Watch out. :eek:
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Re: Wave with well defined mid level circulation off Africa

#76 Postby wxmann_91 » Sat Jul 21, 2007 9:26 pm

wxman57 wrote:I explained in another thread (about what an active cycle is) that the "active" phase of the Atlantic Multidecadal Oscillation (warm-phase AMO) does not mean more named storms will develop. In fact, the Bermuda high tends to be a bit stronger during this warm phase, leading to a little stronger low-level shear in the deep tropics. I did a great deal of research into the numbers of named storms in warm vs. cool-phase AMO, thinking I'd find more named storms when the water was warmer. But that wasn't the case. I did find just slightly fewer named storms when the Atlantic heats up. But I did find that there was a higher percentage of hurricanes with warmer water, and the number of major hurricanes more than doubled with greater heat content (1.5-2.0 per season for cool phase, 5-6 for warm phase). So don't expect as many named storms each season as we've seen in the past 5-10 years. The average number of named storms in the Atlantic basin is close to 12. This accounts for the estimated 3.2 missed per season prior to satellite (research by Chris Landsea/Roger Pielke Jr.). You might remember that near the start of the last warm-phase AMO (began in 1926), there were some seasons with a tremendous number of named storms (1933). But, soon after, the numbers dropped. However, that's the period when the U.S. was pummeled by many big hurricanes (1940s-1960s). We're now approaching the same pattern as back in the 1940s-1960s. Less named storms, greater landfall risk is what climatology would suggest.

I'd made a web page about 5-6 years ago concerning the AMO and possible future impacts. It's still up:
http://myweb.cableone.net/nolasue/Florida/

I respectfully disagree with this part of your post, wxman57.

To start, when the AMO is positive, the SST's are warmer. This means more instability in the atmosphere, more thunderstorms, and more low level convergence. With more thunderstorms, LLC's are more likely to spin up, and with more low level convergence, subsidence, which causes high pressure, is reduced.

To support my above claim:

Maps below are sea level pressure anomalies from June-November.
Top map are anomalies of years after 1950 that have four or more months with the AMO above +0.2. Below maps are anomalies of years after 1950 that four or more months with the AMO below -0.15.

Image

Image

My second point, the last pronounced +AMO cycle was from 1931-1963, give or take a few years.
The modern satellite era did not begin until 1960. Before then, the only records of storms were from ships that were unfortunate enough to cross a storm's path, or storms that hit land.
Point: prior to 1995, there had only been a few years of semi-reliable data (1960-1963) in +AMO time periods. You can't make a conclusion based upon that small of a sample size.

I strongly believe that the AMO is one of the most important factors in the Hurricane Season. The fact that hurricanes need fuel is only a small piece. The bigger piece is the fact that warmer SST's --> more convection, instability --> more thunderstorms --> lowering of pressures and greater tendency for upper highs to develop --> greater chances of a TC developing.
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Re: Well defined low to mid level cyclonic rotation off Africa

#77 Postby windstorm99 » Sun Jul 22, 2007 6:24 am

NHC-8:05AM Discussion..

TROPICAL WAVE IS OVER THE CAPE VERDE ISLANDS ALONG 24W S OF 18N
MOVING W 10-15 KT. THE WAVE IS FAIRLY WELL ORGANIZED WITH
CYCLONIC TURNING COVERING A BROAD AREA. A SFC LOW MAY BE ADDED
ALONG THE WAVE AXIS ON THE 12Z SFC MAP
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Re: Well defined low to mid level cyclonic rotation off Africa

#78 Postby OURAGAN » Sun Jul 22, 2007 6:45 am

May me the first serious system coming from Afica, to watch.
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#79 Postby OURAGAN » Sun Jul 22, 2007 7:12 am

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Re: Tropical Wave south of Cape Verde/Possible surface low

#80 Postby cycloneye » Sun Jul 22, 2007 7:20 am

This site updates the images every half an hour.

Eumetsat

:uarrow:

This site updates the images every half an hour.
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