Statistics - Invests that make it to TD

[kevin]

Does anyone have any statistics about the percentage of invests that make it to TD status? Are there a greater percentage of invests that classify in the active season as compared to early/late?

Furthermore, when did the whole 'invest' thing begin and are there standards as to the designation or is it arbitrary based on subjective observation?

Much thanks!

[WindRunner]

Dang it, I thought you were giving out those stats, so I clicked on this the moment I saw it . . . oh well. I'd like to know as well if anyone has the info or even knows a place to get invest records from easily, I'd certainly be willing to do the research myself when I got a chance as this is something that I've thought to myself several times recently.

[TWTC]

No such statistics exist I beleive as Invests are defined basically as areas of interest and no such records are kept on such data for any long period of time. Bascially, Invests get worked up formally by each respective Tropical Cyclone Forecast Center's (JTWC, CPHC and NHC) computing systems and they kick off sat floaters (NRL TC page) and then they run guidance (Beta-Advection, CLIPER, Barotropic models, SHIPS) to get an early look at possible tracks and get a glimpse at intensity. If development occurs, then all that history is retained. For non-starters, the data is likely ditched.

The Invest nomenclature was likely derived by the Navy or Air Force and was probably just utilized across the board by all TC forecast centers. Some forecast centers probably have some criteria probably depending upon their responsibilities. Maybe the Navy has assets to protect so they might need request Invests on disturbances nearing 20 kt for ship routing purposes. Others might have criteria based on the persistance of convection or indications of a low level circulation. Its difficult to say unless you know what their standard operatiing procedures are.

So in a nutshell. INVESTS = "Area of Interest" nothing more and is probably mostly subjective and for monitoring purposes...

[kevin]

Sorry for the frustration Windrunner, but that was kind of the response I hoped/expected. It seems like a good thing to have on record as a kind of baseline for the attentive weather watchers to use. Depending on the results would either increase or decrease the general significance our community gives to them. One would also like to know the number of storms which skipped the invest designation and went straight to 'wtf, storm.'

Thanks TWTC for the info. I hope the data is stored somewhere though!

[kevin]

Perhaps this should be moved to the new question forum?

[WindRunner]

Well, I've always tried to avoid doing this, but you could look over the model output data from the past few years and compile some stats from that . . . if you really, really, wanted to. Of course the data on that only goes back so far as well (2001 on the NHC servers, but that doesn't seem to be accesible, so it's 2005 on the Ohio State page), and you would have to infer the progression of an invest to depression+ or use the lat/lon to check it . . . and that's just a pain. It might make for a nice research project, though.

[Scorpion]

For this year, it shouldnt be that hard. I believe that we started at 90L with Alberto, Chris was 99L, and TD-4 was 96L. So that would be 17 invests so far, and 4 developing into TD's. About 24%.

[Jim Cantore]

What was it last year? 11/11??

[clfenwi]

Last year the first group of ten had a 'hit rate' of 50%, and the second set had a rate of 70% (or perhaps 80% there was one invest that I couldn't figure out whether it developed... it was classified on August 20 and one knows how hectic things got after that). In 2004 the first set of 10 had a hit rate of 10%.

The archives of this forum are fairly useful for this task... though it takes some patience... the big problem, as Windrunner notes, can be concording an invest with a storm that developed.

As far as your other question goes, this is the only documented guidance I've found on Invests... it's talking about the responsibilities of the various departments and agencies and gives this duty to the Department of Defense:

"Initiate, monitor, and update satellite invest areas on the tropical cyclone
satellite websites provided by the Fleet Numerical Meteorology and
Oceanography Center (FNMOC) and the Naval Research Laboratory (NRL),
Monterey, California. TPC/NHC and CPHC will coordinate with JTWC on the
initiation of desired invest areas and will provide JTWC numbers for invest
areas as required."