cieldumort
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Invest 92L has been tagged for the impressive Tropical Wave that has just rolled off the west coast of Africa with now some strong model support for slow tropical cyclogenesis out near the Cape Verde islands.
Would it ever be an uncanny irony should this feature actually become 2008's Bertha.
The far eastern Atlantic SSTs are running about 2 degrees C above normal, and shear is reasonably expected to lessen to even favorable levels as early as the end of this week. Stranger things have happened.
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cieldumort
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Edited by danielw (Tue Jul 01 2008 10:53 AM)
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allan
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On Wunderground, everyones calling it a fish storm already lol.. it's a wait and see deal.
However, I didn't know the low was this close to the coastline yesterday. It's gonna be an interesting week as we began tracking what could and what all the models are predicting to be our 2nd name storm of the season, Bertha.
(Off-topic material removed.)
Edited by danielw (Tue Jul 01 2008 10:57 AM)
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LoisCane
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Cape Verde storms are all "fish" storms as in they have a long way to swim before they get where they are going.. sort of like EPAC storms that threaten Hawaii.. takes a long time of watching for the few that hit.
Most do recurve but where..
If it forms and develops fast it will curve out to sea close to Africa.. like most do that come off spinning fast this time of year.
IF it stays low enough and travels west it will recurve but slower and the longer it takes to get there before it recurves often puts it in a place where it turns west again for a while.
Forward speed here is as big an issue as wind speed ...
Ships I believe keeps it west the last I heard. It could pull a bit wnw and then keep going west. Helps when they do that dip wsw for a day or so before heading back west.
Of more current interest is the bright spot of convection at the middle of the wave and note the long, strong banding on the southern part of it that looks almost like it's dragging an anchor along.
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http://hurricaneharbor.blogspot.com/
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M.A.
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As impressive as this wave looks. I'm still wondering if they are not jumping the gun with the invest tag. SST are marginal at best. The convection is not all that impressive since it hit the open water. I hate to say it, but the has taken alot of heat in the last few years. I'm wondering if they are pandering to the media with this wave. It looks to be media driven wave mongering. Last year we had a few waves that were discussed on this forum for 2 or 3 days before an invest was tagged.
As far out as this wave is, why not let it get off the coast and see if it holds together for a day or so? If it holds its own....Tag it. I would understand this if it were in the Leewards or Windwards, but its not even all the way off the coast of Africa.
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CoconutCandy
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Interesting Post. Since it's not strictly on topic, I've made my reply in the 'Everything and Nothing' forum.
http://flhurricane.com/cyclone/showflat....=true#Post80210
(Please leave the task of moderating to the site Moderators - they are the ones that determine what is on-topic and what is off-topic.)
Edited by Ed Dunham (Tue Jul 01 2008 04:21 PM)
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Ed Dunham
Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)
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I tend to agree with you - fully - because the latest 18Z consensus plot would put the storm in an area of moderate and increasing westerly shear at 96 hours. At that point, SHIPS has the system at 82kts - not likely at all. The early Invest tag surprises me - Invest means Investigate - I wonder how that would be done off the west coast of Africa? Don't get too wrapped up over this one quite yet - Atlantic wind shear still rules for awhile. Perhaps the intent was to prompt a little early season Hurricane Awareness.
ED
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allan
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It appears that convection is rebuilding near the center if you look at the latest IR image. Shear is a bit high as you head south of the low, yet it's only 20 knots. Barry (2007) formed in 30 knots of shear if I remember well. It's just a wait and see.. lets see what durinal max can do for the wave as it is nightime over there.
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Allan Reed - 18,9,5
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cieldumort
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I respectfully disagree with these assessments.
I'll explain why in a point by point refutation
On whether or not the wave merits an Invest tag -
"92L" is not merely some marginal open wave. It has had a weak, but very persistent Low fully associated with it while it crossed Africa, and now as it hit the open water.
In addition, while the convection is scattered and lacking in organization, there are already hints that upon hitting water the deepest convection was occurring within the heart of it.
Anticyclonic outflow - 92L already has some. Nothing like what one would expect to see for a tropical storm, but fairly impressive outflow for a Low that just popped out over water.
SSTs are actually plenty supportive in the extreme eastern Atlantic.. running a full 1.5 to 2.5 degrees C above average for more than a sufficient stretch of open ocean. Even where the anomaly drops off, the 26.5 isotherm covers plenty of area, so long as the system doesn't end too far north too soon.
Model support - When is the last time you saw a wave drop off the coast of Africa with this kind of model support from so many runs? Even if almost none of the above-listed features were not all present at once, this had to raise more than a few eyebrows over at the .
The SHIPS forecast of an 82knot hurricane within a highly-sheared environment brings up two points in my mind. First, in order for "92L" to follow the consensus track and be in that location at 96 hours, it would likely have to be a developed system to pull that far right so soon. Indeed, whatever the shear may or may not be at that location at that time is irrelevant to the question of whether or not a numbered tropical cyclone already has formed. Hypothetically-speaking, so it develops and hits a mean wall of shear. So SHIPS is a little out to lunch on its intensity at that point.. we would still be looking at a numbered TC.
OTOH, if "92" does not organize more, or organize fast enough, this expected turn may not materialize, which would then put a strong, but undeveloped wave in a nook of some pretty darn conducive environment in about 72-96 hours. Bingo-bango! We may very well have a numbered TC, anyway.. and in fact, one which may start to be of more interest than an early fish spinner.
Given all of the above and more, IMHO, has done the right thing by bringing attention to this feature so soon. As for "Investigating" it, there are at least plenty of ships, a few planes, and certainly some buoys and several land stations in and around the CVs. While they aren't going to task the 53rd anytime soon for 92L, perhaps some of their other resources and alliances will be tapped, if conditions warrant.
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LoisCane
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The early invest didn't surprise me as the models have been picking it up and it is one of the most perfectly formed Cape Verde waves I have seen in a long time. And, convection is not only hanging on but popping at the center of the wave.
The is not wave casting in order to get media hype. They often have highlighted waves coming off of Africa. They have even made a few Tropical Depressions this far out. And, if they fall apart..they will deal with it.
And investigation means they are investigating it.. it does not mean that they will be sending a plane out to it within 24 hours.
It is not merely a cluster of rain showers but a very, tightly wound wave with some sort of circulation at some level and model support. And, when you use the site and check it out on different levels with frequent updates you can see how worthy it is of an invest.
Takes a lot for a wave to look this good, takes more for a depression. Takes patience to watch a Cape Verde wave as they have a long, long road to go with many obstacles which is why many recurve.
And, any negative problems such as increased shear and low water temps will only inhibit it's intensification progress and if that does happen it will stay west bound most likely.
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http://hurricaneharbor.blogspot.com/
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Ed Dunham
Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)
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Hmm - good to read such animated dialogue in defense of this system - you have all raised some good points to ponder. Especially good to see such support for the - something usually quite rare on this site - please save some of that for later in the season. The use of the term 'fully' was not a good choice of words - I did not mean to imply agreement that the sole purpose of the Invest was for 'media hype' - far from it (for those of you who are familiar with my background at CPHC).
I had indeed checked the SSTs. The Atlantic, particularly the far eastern Atlantic, has warmed considerably in the past 6 weeks and these SSTs would easily support and maintain cyclonic development. Regarding the low center, it is not at all uncommon for easterly waves to exit the west coast of Africa with an open center of lower pressure - remember that on average only about one in ten become anything more than a tropical wave (and that is not to imply that 92L will not develop further - its just to educate the newer user on the site that may not be familiar with this statistic).
In support of the system, there is a narrow band of light shear below 18N latitude that extends westward to about 60W longitude. The GPS holds the system intact for about two weeks - the second of the two weeks can probably be ignored, i.e., its fodder for the Forecast Lounge long before that - but the first five or six days have some suggestion of support from an upper level high that will be in the vicinity of 50W longitude in a few days. At five days the GPS projects about 18N 44W (at 18Z), where westerly wind shear is anticipated to be around 30kts. However, below 18N the shear decreases rapidly (that narrow band that I mentioned), so if the system can stay at a lower latitude (and the upper high may keep 92L lower in latitude) then additional development is certainly possible.
"As for "Investigating" it, there are at least plenty of ships, a few planes, and certainly some buoys and several land stations in and around the CVs." There is sometimes a fine line between analysis and investigation, and these are indeed good data gathering methods (although unfortunately the buoys are limited and the ships are no longer plentiful because of the 'problems' in certain west African countries). The lack of frequent satellite data can often plague good investigation of tropical waves just off the west African coast, although does get far more data from that region today.
My earlier concern, and still a valid one, is that even the southern limits of the guidance package places the system mighty close to the stronger wind shear zone - strictly a matter of timing on intensity and forward speed, i.e., before or after it reaches the influence of the upper level high? While the overall structure looks good, organization is still going to require a few more days.
"When is the last time you saw a wave drop off the coast of Africa with this kind of model support from so many runs?" Two hurricanes come to mind; Jeanne in 1998 and Cindy in 1999. I was going to comment on the new met term 'bingo-bango', but then I'd have to edit my own post! Certainly one of the better and on-topic discussions that the Storm Forum has seen in quite some time.
Cheers.
ED
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M.A.
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As I stated in the previous post, I am not discrediting the structure of this wave. The wave WAS extremely impressive before exiting off the coast. I do believe that this wave is inching a little too far north and into the cooler waters, and a less favorable enviroment. Which actually will make me watch it even more now, being that the weaker this wave stays the further west it will travel with out the chance of a recurve. If this wave stays weak and makes it closer to the islands, then "Bingo- Bango" we have a lot to talk about.
My original post was more so directed at media and the influence they have gained on the . I feel that over the past few years the has been under the microscope from the media and the blind sheep that believe anything they hear on the TV or read in the paper. I still do believe that this pressure is why this wave was tagged so early. Our local newspaper has been running articles on possible development for over a week and then went as far as to tie it in with the chance of rain in our area. Its almost like they are resorting to scare tactics to get people perpared for hurricane season.
By the way I fully support the . I think we see improvement every year in their performance and accuracy.
Please use the PM function for messages.~danielw
Edited by danielw (Wed Jul 02 2008 10:08 AM)
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allan
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92L has reached Tropical Depression status, it is now NONAME02 and adviseries will be issued by 2 p.m. today.
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Allan Reed - 18,9,5
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Hurricane29
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Quote:
92L has reached Tropical Depression status, it is now NONAME02 and adviseries will be issued by 2 p.m. today.
That was an error from monterey.
Edited by Hurricane29 (Wed Jul 02 2008 03:14 PM)
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cieldumort
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When the Low pressure area that is now being tracked as 92L first emerged just off the coast it didn't even register with SSD on the scale. Since then, it has been up around T1.0 fairly consistently. It is clearly the expert opinion of SSD, then, that this Low has actually improved since fully emerging over water.
The tagging of 92L is not any sort of exception. Waves and other features that are perceived to have decent-enough odds at further organization are routinely tagged before they have amounted to much. Most recently, just last month "91L" was tagged, and was fair example of this. During the first half of June just last year a different African low was tagged "Invest 93L" right as it rolled off the west coast of Africa. There were no calls of "hype" or "caving in to the media hype" back then.
NHC is in and of itself not responsible for whatever some local media outlet does, as that is entirely within their own discretion. It is also probably extremely unlikely that some local Florida TV stations motivated to tag this feature. Had not tagged this feature, I would have been floored.
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Ed Dunham
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I think that we've probably had enough 'back and forth' on this. Additional discussion, if any, should center on 92L. The dialogue has drifted away from the system itself - and that goes counter to the purpose of the Storm Forum.
Thanks,
ED
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