Ed Dunham
Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)
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A tropical wave with good structure and modest convection has moved off of the west coast of Africa. The wave has a possible weak low center near 8N 20W at 24/18Z. Although the latitude is rather low it has some good upper air dynamics - except that easterly shear is moderate and increasing. SSTs are a cool 24C but moderate to about 28C near 10N 30W.
No development anticipated for a couple of days, but if the wave can remain intact, some slow development is possible on Sunday as the system moves over warmer ocean waters and wind shear declines.
ED
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LoisCane
Veteran Storm Chaser
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Loc: South Florida
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It has a large pocket that can be seen on visible imagery but becomes invisible on the water vapor. Big. Possibly by staying so weak it has a chance to get further across the ocean than it had otherwise. It can be viewed at still.
The banding structure is still visible on this long link:
[url=http://www.nrlmry.navy.mil/tc-bin/tc_home2.cgi?ACTIVES=08-WPAC-001.TCS001]http://www.nrlmry.navy.mil/tc-
bin/tc_home2.cgi?ACTIVES=08-WPAC-001.TCS001[/url],08-ATL-04L.DOLLY,08-EPAC-08E.GENEVIEVE,08-WPAC-
09W.NONAME,08-ATL-97L.INVEST&SIZE=Thumb&PHOT=yes&NAV=tc&YR=08&ATCF_BASIN=al&ATCF_YR=1&
YEAR=2008&ATCF_FILE=1/&CURRENT=20080724.2215.goes12.x.ir1km_bw.97LINVEST.20kts-1010mb-154N-
352W.95pc.jpg&AGE=Latest&ATCF_NAME=al971&ATCF_DIR=1&ARCHIVE=active&MO=JUL&BASIN=
ATL&STORM_NAME=97L.INVEST&STYLE=tables&AREA=pacific/southern_hemisphere&AID_DIR=/
data/www/atlantic/tropics/microvap/dmsp&DIR=/TC/tc08/ATL/97L.INVEST/windsat/rain/2degreeticks&TYPE=windsat&
PROD=rain&SUB_PROD=2degreeticks
I don't know how to make these smaller (sorry) but go to rain and the green button where it says 2 ticks.
For the people here not familiar with the site.. play around with it and you can see xrays sort of the wave.!
Perhaps if it starts to show some more convection .. a wait and see sort of thing.
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http://hurricaneharbor.blogspot.com/
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cieldumort
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Just a point of clarification. I believe Ed is referring to the wave that just rolled off Africa.
Invest 97L, linked above, is in fact already in the CATL, out around 15.5N 37W.
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craigm
Storm Tracker
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Loc: Palm City, Florida
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97L although lacking convection is definately evolving and is aproaching warmer SST's
http://moe.met.fsu.edu/cyclonephase/ukm/fcst/archive/08072418/7.html
Ed, I don't think your wave is at as low a latitude as you think and has lower surface pressure:
http://moe.met.fsu.edu/cyclonephase/ukm/fcst/archive/08072418/6.html
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Why I'm here:
Weather hobbyist
Edited by craigm (Fri Jul 25 2008 01:57 AM)
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Ed Dunham
Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)
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Loc: Melbourne, FL
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It is at low latitude - I put it at about 8N 23W at 25/00Z moving westward at a good clip. Here is a METEOSAT High Resolution Satellite Link. You will need to register, but it is a free service that is only updated every six hours.
Dundee Satellite Receiving Station, U.K.
The UKMET computerized analysis appears to be at the upper levels, but the satellite image shows that the wave is well below 20N. Although the updates are infrequent per international agreement, the resolution is superb.
ED
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danielw
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Really good estimation. It's still too far off of the "map" to earn a mention in the ATL TWD.
Excerpt from this morning's Atlantic Tropical Weather Discussion.
TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI JUL 25 2008
...TROPICAL WAVES...
AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 23N37.5W 16N39.5W
7N40W. A 1012 MB LOW PRESSURE CENTER IS ALONG THE WAVE NEAR
16N39.5W. AN UPPER LEVEL TROUGH IS ALONG 26N36W 23N40W 16N42W
11N46W. STRONG SHOWERS AND THUNDERSTORMS IN INDIVIDUAL CELLS
FROM 17N TO 18N BETWEEN 39W AND 41W. ISOLATED MODERATE SHOWERS
ARE ELSEWHERE FROM 15N TO 21N BETWEEN 38W AND 43W.
I believe this to be 97L? The northern most of the two current systems.
I don't know if the southern most system has been numbered as of yet but I would think it would probably earn the 98L designation in 24 hours.
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MichaelA
Weather Analyst
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Loc: Pinellas Park, FL
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NRL has apparently dropped 97L this morning and the new wave hasn't been picked up yet. The former 97L still has a noticeable cyclonic turning near 17N, 42W, but there appears to be some vertical shear going on. It is traversing into higher SSTs, though. I wouldn't count it out just yet.
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Michael
PWS
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cieldumort
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97L was dropped from greenball status on 's site, but they are still carrying the old info if you click on "All." It would not be surprising to see them greenball it later today should the current convective trends continue, and at that time the last 18 hours or so of data void would probably be brought at least somewhat current.
Shear over this feature appears to be running below 25 knots, which, in and of itself is not always prohibitive. However, 97L is also traveling through a region of very dry air, and so the shear keeps making it possible for the dry air to attempt to box it up in an early coffin. On the other side of the shear coin, the wave does seem to be experiencing some convective flare-ups, no doubt in part thanks to some of those winds. Ironically, this might help to start wrapping 97 up in a protective, moist shield, where it could start developing a little. It looks to be attempting to do so this morning.
The new wave off Africa interests me a good deal, as it is low enough that should it survive until about 35W, it could remain well south of the drier air and stronger shear that has been plaguing 97. Low-enough also that, should it develop into something, the odds of it re-curving before plowing into land somewhere might be pretty low.
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craigm
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Loc: Palm City, Florida
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Quote:
It is at low latitude - I put it at about 8N 23W at 25/00Z moving westward at a good clip. Here is a METEOSAT High Resolution Satellite Link. You will need to register, but it is a free service that is only updated every six hours.
Dundee Satellite Receiving Station, U.K.
The UKMET computerized analysis appears to be at the upper levels, but the satellite image shows that the wave is well below 20N. Although the updates are infrequent per international agreement, the resolution is superb.
ED
I stand corrected I think I was picking up on a mid level cyclone 500mb.
Fantastic link - your wave in high res looks like it has considerable outflow already and would suspect this will be 98L before too long. I wouldn't give up on X97L yet, especially the way this season has started although at that latitude it will feel any weakness in the ridge.
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Why I'm here:
Weather hobbyist
Edited by craigm (Fri Jul 25 2008 05:08 PM)
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MichaelA
Weather Analyst
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Loc: Pinellas Park, FL
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NRL has reactivated 97L. The convection certainly looks much more developed in the visible sat pictures this afternoon. The convection still appears to be well to the NE of the apparent low level CoC, though. There is not much organization left of the area just off the African coast as evidenced in the 18:15 Z vis pic this afternoon.
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Michael
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