Ex Invest 93L in Central Atlantic

[Derek Ortt]

the convection is not firing over the center

it is firing in a band ahead of the center. Not the most favorable setup here either

[KWT]

Yeah in fact its a little like what 92L was like I reckon Derek. Still needs careful watching as its pretty low in latitude and the fact its so far east means its got plenty of time to do something.

as for the models, usually they are ok when it comes to tropical cycone formation but they have missed some totally before like Felix.

[Derek Ortt]

howeve,r the fact that the models were indicating TC genesis and have now backed of is telling that there is something indicating development is not likely

[KWT]

Could it just be that the models hits it so hard with shear in its first 24hrs of the run that it kills off the system totally whilst in the real world the shear only holds back and doesn't stop development I wonder?

[Ed Mahmoud]

Looks like some convection starting to form closer to apparent center, and kind of wrapping in.

Judging from SSD "Central Atlantic" loop. I hope a dedicated floater is set up for it shortly.


Off to the gym, perhaps when I return, maybe Derek will have a floater loop on his site linked here for our edification and education.

[cycloneye]

93L is now included in the Tropical Cyclone Formation Graphic:

[tolakram]

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http://www.ssd.noaa.gov/goes/east/catl/loop-vis.html

From a distance it sure looks like it's starting to wind up.

but looking at the AVN

http://www.ssd.noaa.gov/goes/east/catl/loop-avn.html

The convection around what appears to be the circulation is rapidly dying. Much like 92 I think this will mostly poof by this afternoon.

[hurricanetrack]

So what happened? The GFS especially was quite bullish on what is now 93L and it looked for a few runs there like we might not hear from Luis again until Xmas with the likes of the hurricane it had near P.R. Now, it looks doubtful that either of these two will develop- at least not yet. So that begs the question- why? We can throw out "because it is the model NCEP" as I remember other models showing robust development out of this system too. So a suite of models was on and now they are somewhat off, but not totally. What happened? What new information are the models "seeing" that has "changed their minds"? I know that tropical cyclogenesis is hard to predict but this is interesting and I, among others I am sure, would like to understand better why the model guidance acts like this sometimes. Who knows- perhaps we will see something like Felix last season where by there is a strong hurricane in the real world but a hump on the isobars on the GFS. Thoughts?

[cycloneye]

Mark,I back your statement 100%.I add this:

Reposted from 93L Model Runs thread.

What has happened that suddenly the models are backing off on development in the Atlantic,Those GFS latest runs look dead.Has the Atlantic turned unfavorable at the time the peak of the season starts? I think that the folks that do the forecasts for the different private and goverment entities have to be a little nervous about this as August looks like not an active month.September has to be very active to make ground from the not so active August.Ok,I will stop here,however, I am not downgrading the season,but I only base these words on what is happening now.

[Aric Dunn]

Im looking at derek with a funny look on my face.....???

93l well on its way to a depression!!

[tolakram]

000
ABNT20 KNHC 111732
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT MON AUG 11 2008

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A BROAD AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS
LOCATED OVER THE CENTRAL ATLANTIC OCEAN ABOUT 825 MILES EAST OF
THE WINDWARD ISLANDS. ALTHOUGH SHOWER AND THUNDERSTORM ACTIVITY
REMAINS LIMITED AT THIS TIME...ENVIRONMENTAL CONDITIONS APPEAR
FAVORABLE FOR GRADUAL DEVELOPMENT...AND THIS SYSTEM HAS THE
POTENTIAL TO BECOME A TROPICAL DEPRESSION DURING THE NEXT COUPLE OF
DAYS AS IT MOVES WEST-NORTHWESTWARD AT 15 TO 20 MPH.

A LARGE AREA OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A BROAD
LOW PRESSURE AREA IS CENTERED ABOUT 400 MILES SOUTHWEST OF THE
CAPE VERDE ISLANDS. THIS SYSTEM HAS BECOME A LITTLE BETTER
ORGANIZED TODAY...AND A TROPICAL DEPRESSION COULD FORM DURING THE
NEXT DAY OR TWO AS IT MOVES WESTWARD AT ABOUT 10 MPH.

ELSEWHERE.. TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER PASCH/STEWART

[Derek Ortt]

Looks like some convection starting to form closer to apparent center, and kind of wrapping in.

Judging from SSD "Central Atlantic" loop. I hope a dedicated floater is set up for it shortly.


Off to the gym, perhaps when I return, maybe Derek will have a floater loop on his site linked here for our edification and education.

I just kept the system in the invest_08 floater

[Scorpion]

Not sure what's going on with this season.. I mean if things can't get going now when will they? The GFS shows absolutely nothing for the rest of the month. This season is rapidly getting disappointing.

[Bane]

y'all are funny. we have already had 5 storms this year with 3 directly affecting the US. what a disappointing season none of them were cat 5s.

[HURAKAN]

[Derek Ortt]

So what happened? The GFS especially was quite bullish on what is now 93L and it looked for a few runs there like we might not hear from Luis again until Xmas with the likes of the hurricane it had near P.R. Now, it looks doubtful that either of these two will develop- at least not yet. So that begs the question- why? We can throw out "because it is the model NCEP" as I remember other models showing robust development out of this system too. So a suite of models was on and now they are somewhat off, but not totally. What happened? What new information are the models "seeing" that has "changed their minds"? I know that tropical cyclogenesis is hard to predict but this is interesting and I, among others I am sure, would like to understand better why the model guidance acts like this sometimes. Who knows- perhaps we will see something like Felix last season where by there is a strong hurricane in the real world but a hump on the isobars on the GFS. Thoughts?

This is not a surprise to me at all.

remember, the GFS NEVER had any consistency between runs. It was always developing a different feature in each run. That is why I was sounding the phantom cane alert over the week-end.

If I had to assign a percentage, I'd only give this a 10-15% chance of developing

[cycloneye]

From 2 PM Discussion:


A 1011 MB BROAD LOW PRES AREA IS LOCATED OVER THE EASTERN
ATLANTIC NEAR 11N29W. VIS SAT IMAGERY SHOWS SOME SIGNS OF
BANDING...INDICATING THAT THE SYSTEM HAS BECOME A LITTLE BETTER
ORGANIZED TODAY. A LARGE AREA OF SHOWERS AND THUNDERSTORMS
ACCOMPANIES THIS LOW...AND A TROPICAL DEPRESSION COULD FORM
DURING THE NEXT DAY OR TWO AS IT MOVES WESTWARD AT ABOUT 10
MPH.

http://asp1.sbs.ohio-state.edu/tropical ... scussions/

[Derek Ortt]

Im looking at derek with a funny look on my face.....???

93l well on its way to a depression!!

No, it is not. We have no convection near the weakening MLC.

Some friendly advice (hoping this sounds friendly, lol). Few systems become a TD, Aric. I have noticed that you sometimes jump the gun on development. If everything developed that you predicted, we'd be up to the T storm already. Need to be a tad bit more conservative. I can guarantee you then, that your accuracy will improve by leaps and bounds.

[vbhoutex]

"Splain me this please. What do you see that makes you give it a low percentage chance of developing when the NHC is saying it could become a TD within a few days? I am talking synoptics, etc. here as opposed to what the NHC generally has to say due to the parameters put on them.

I posted this while the others above it were asking the question quicker. Can you go into more detail?

[HURAKAN]

Loop: http://rammb.cira.colostate.edu/ramsdis ... is_floater

Nice loop.