I guess it is complicated to determine whether something is official or not when it comes to an invest. What is an official invest?
You can have it tracked in the ATCF system as an invest (or even as a low that was a storm and has been downgraded) and not have models run on it every time. (even other than the 6Z missing data which they sometimes don't run for weaker systems.) I would think "This afternoon the National Hurricane Center stopped running computer forecast models on the system and so it is no longer considered a suspect area or invest area." is a bit incorrect because you can have models not run and have it still have updated best track points for it. Right now 90L has neither, which is why it is a bit unclear in this case. (If they always properly deactivated/deleted a file it would not be as confusing, but something they don't.)
I would still consider something a suspect area if it had a circle on it in the ATWO even if it were not tracked or even deleted in the ATCF system. I would not consider it an invest I suppose, but would consider it a suspect area. I'm not sure if there are two distinct definitions for that.
Here is the NHC definition of Invest and Tropical Disturbance:
"Invest:
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."
"Tropical Disturbance:
A discrete tropical weather system of apparently organized convection -- generally 100 to 300 nmi in diameter -- originating in the tropics or subtropics, having a nonfrontal migratory character, and maintaining its identity for 24 hours or more. It may or may not be associated with a detectable perturbation of the wind field."
From: http://www.nhc.noaa.gov/aboutgloss.shtml
I guess the problem is this, only weather hobbyists and weather professionals care about the invests for the most part when it comes to whether it is officially active or not, which is hard to tell sometimes. You can have something tracked as a wave in the Atlantic Tropical Weather Outlook (ATWO) and as a wave in the ATCF system too. But you can have something mentioned in the ATWO that is not yet an invest or may at the moment not be tracked as an invest, when it had been, but gets a mention in the ATWO. But this is all for weak storms that are not a depression. For anything the matters, and even a lot of stuff that may not, like some very weak depressions, the NHC will have advisories for it to say whether it is official or not in terms of that. Invests are below that level of importance and therefore it gets unclear sometimes its status because the whole process doesn't seem well publicized.
The advisory data comes out in products that the NHC goes over well. They could have an issue at times, but they update it quickly. The ATCF system gets very buggy and does not have the constant oversight that the NHC advisories do. They do work to fix it, but it definitely has bugs often and takes longer to fix. If the advisories have a problem, you get a corrected advisory. If something goes wrong in the ATCF system, you don't get a heads up. If it goes on long enough you email the NHC or you design a system to work around the errors and the things that are not errors (though they could be and you would not know) like the inbetween period when it no longer has position updates but is not yet deleted or deactivated. I guess the real answer is unless you hear from the NHC what they consider it to be, like actually directly from them or quoted in an interview, you don't really know and most people, other than us, wouldn't get into the details. You may even stump the NHC on whether 90L right now is an invest because it is not clear what an invest actually is. Do you have to have a recent position update to call it an invest? I don't know how that works. They only delete/deactivate when it seems like it really is dead, but even then sometimes they forget to put out that file.
It just depends how you define invest. 90L is an area of disturbed weather that is being tracked, not precisely at the moment to pick a single set of coordinates, just more broadly, so not at the moment in the best track system in the ATCF system but more broadly in the ATWO with a circle. |