Disturbed weather in Eastern Atlantic (Is invest 95L)

[Aric Dunn]

Aric, what do you think about this?

[img]http://a.imageshack.us/img714/7877/movie9262355.gif

Well Im not sure if you saw my post from this morning where Made a image of the surface analysis? but the greatest vorticity this morning was farther west and has shifted east a little. there is two areas at least this morning that had small eddy's. the overall system is embedded in the ITCZ and is quite elongated with multiple waves interacting. the farthest east portion a little better curvature. This what I think should happen... the farthest east part should begin moving wnw while the western portion drops wsw and at some point in the next 2 days a LLC should form in the middle of a tilted SW to NE trough of low pressure... basically what we are looking at now just tilted. if you turn on the surface obs and ship reports you can see the low level flow. but will see these things are tricky and with so many little vorticity it will be hard to pin point a LLC forming until we get a some decent organized convection.

[abajan]

Some spin is definitely evident in this loop.
We need to watch this for sure.

[Vortex]

slowly coming together this evening...should be some beauty in the days to come.

[Vortmax1]

slowly coming together this evening...should be some beauty in the days to come

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Yes, I agree.
This one might be something to look at for sure!

[gatorcane]

There is no question we will get a named system out of this.

Kudos to the gfs which saw this over a week ahead of time.

[MiamiHurricanes10]

Based on vorticity product and satellite imagery I would say that an area of low pressure has developed with PGI31L. It remains weak in my eyes at the moment.

[KWT]

Yeah its slowly coming together, I think Aric has it pretty much spot on in terms of how this one will evolve, probably will take another 24-36hrs to come together but no doubts something comes from this IMO...

I think 95L is coming tomorrow...

[gatorcane]

Why not declare 95l now? This is a shoe-in for development

[CalmBeforeStorm]

Why not declare 95l now? This is a shoe-in for development

You were one of those kids that didn't want to wait till Christmas to open their presents, right?

[MiamiHurricanes10]

Why not declare 95l now? This is a shoe-in for development

You were one of those kids that didn't want to wait till Christmas to open their presents, right?

There is no specific criteria for it to be called an invest or not, as long as the forecaster in charge thinks that the area has a chance of becoming a tropical cyclone. This should be an invest by now in my eyes because it definitely has a chance to develop.

[Aric Dunn]

Why not declare 95l now? This is a shoe-in for development

because the requirements for an invest have not been met.. all the components have only really been in place today needs about 24 hours ... so an invest will come tomorrow

[KWT]

Why not declare 95l now? This is a shoe-in for development

Can't be long away I'd imagine, given its upto 20% they usually invest after a few rounds of those sorts of figures....but I suppose there is no rush because the models are in such good agreement there isn't much of a need to see what the other statistical/dynamic models are doing so no rush...

[CalmBeforeStorm]

Why not declare 95l now? This is a shoe-in for development

You were one of those kids that didn't want to wait till Christmas to open their presents, right?

There is no specific criteria for it to be called an invest or not, as long as the forecaster in charge thinks that the area has a chance of becoming a tropical cyclone. This should be an invest by now in my eyes because it definitely has a chance to develop.

But only us hurricane nerds feel the need to rush the process. In the real world there is absolutely no rush.

[Vortex]

Looking much better by the hour...Invest on the way!

[MiamiHurricanes10]

Why not declare 95l now? This is a shoe-in for development

because the requirements for an invest have not been met.. all the components have only really been in place today needs about 24 hours ... so an invest will come tomorrow

There are no requirements or rules for an invest to be designated. Please link those "requirements".

[Blown Away]

It's really annoying they won't declare this area an invest!

[cycloneye]

But it continues to be test invest PGI-31L.

[Aric Dunn]

Why not declare 95l now? This is a shoe-in for development

because the requirements for an invest have not been met.. all the components have only really been in place today needs about 24 hours ... so an invest will come tomorrow

There are no requirements or rules for an invest to be designated. Please link those "requirements" please.

an area of interest should persist for 24hours ... for some reason the link to NRL requirements I had no longer work seems they changed their site. The only thing i can find is the TCFA checklist.. let me keep looking..

[Aric Dunn]

This was from last year... its not what i was looking for but all i can find at the moment.

With the disturbed weather in the GOM in recent days, and the possible recon mission that was scheduled, I saw some people asking if it qualified the area for an Invest and someone asking what actually determines designating an area an Invest, so I emailed the NHC early Friday afternoon when development, although unlikely, was still possible. My original email and his response are pasted below. I then asked if he minded if I post his response on here and he said sure and thanked me for asking.

Hi,

I see that there's a possible recon mission for tomorrow for the disturbed weather in the GOM. I understand that it could be canceled if you don't think a low center is forming and that's it's scheduled ahead of time just in case. My question is since there's a possible recon mission, might that qualify this area of potential development as an Invest? What are the criteria for an Invest?

Thank you,
Kelly ******

Kelly,

An "invest" is defined as the following:

A weather system for which a tropical cyclone forecast center (NHC, CPHC, or JTWC) is interested in collecting specialized data sets (e.g., microwave imagery) and/or running model guidance. Once a system has been designated as an invest, data collection and processing is initiated on a number of government and academic web sites, including the Naval Research Laboratory (NRL) and the University of Wisconsin Cooperative Institute for Meteorological Satellite Studies (UW-CIMSS). The designation of a system as an invest does not correspond to any particular likelihood of development of the system into a tropical cyclone; operational products such as the Tropical Weather Outlook or the JTWC/TCFA should be consulted for this purpose.

If the forecasters have reason to believe that an area of disturbed weather might develop into an organized tropical system (environmental conditions favorable, forecast models show development, observations show some organization, etc) then an invest is usually declared.

In the case over the weekend, I don't believe any of the above were noted for the Gulf of Mexico system.

Best wishes,

Christopher Juckins
Meteorologist / Webmaster
National Hurricane Center
Web: http://www.hurricanes.gov
Mobile web: http://www.hurricanes.gov/mobile
Email: nhcwebmaster@noaa.gov

[MiamiHurricanes10]

an area of interest should persist for 24hours ... for some reason the link to NRL requirements I had no longer work seems they changed their site. The only thing i can find is the TCFA checklist.. let me keep looking..

The TCFA checklist has nothing to do with whether or not an invest is tagged. Fact is, there isn't any requirement. As long as the forecaster in charge at the NHC is interested in the area and wants to run model plots, etc... If it is the forecasters' preference to wait for 24 hours of persistent convection, it's his choice. As for me, I've seen plenty of convective persistence already.

Sometimes, the reason that an invest has not been tagged is the lack of a good center fix, which appears to be the problem in this case.