Blog post from Bob Henson on Tennessee flash flooding, Henri and all the tropical activity going on
Posted by
Chris in Tampa on 8/23/2021, 9:55 pm
https://yaleclimateconnections.org/2021/08/henri-drenches-northeast-death-toll-at-21-in-catastrophic-tennessee-flash-flood/
I check Google News a lot each day and their blog was the fourth item in the news headlines as of posting this:
https://news.google.com/
Out of all the things he covers in the blog post, we haven't talked about the remnants of Linda over Hawaii right now. Not much convection with it like it was yesterday. Current satellite:
https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G17§or=hi&band=13&length=24
I actually got an email from someone a few hours ago wondering why some sites don't have data on it any longer and my site is among the ones that do:
http://tropicaleastpacific.com/models/models.cgi?basin=ep&year=2021&storm=12
It's because the best track system is updated for it still even though there are currently no advisories for it.
Here is the email I sent to the person asking me about where I get data from for Linda:
The data comes directly from the NHC's ATCF system, which is also used
by the CPHC:
https://ftp.nhc.noaa.gov/atcf/
You can learn more about that system here:
https://www.nrlmry.navy.mil/atcf_web/
The U.S. Navy has a site that has best track data for the low here:
https://www.nrlmry.navy.mil/TC.html
(because they are the ones that developed the ATCF system)
The folder where best track data is stored is this one:
https://ftp.nhc.noaa.gov/atcf/btk/
All best track data for the Atlantic, East Pacific and Central Pacific
originate from this location.
The specific file we get data from on for that low is here:
https://ftp.nhc.noaa.gov/atcf/btk/bep122021.dat
I should note that when available, advisory data should be considered
the primary source for data. While best track data comes from the
NHC/CPHC, advisory data is official and might contain intensity
changes not yet reflected in best track data. However, sometimes best
track data might show an intensity change that is likely to be
reflected in a subsequent advisory. In those particular instances,
consider that it is not a guarantee that what is reflected in the best
track data is what will be reflected in the next advisory. The NHC
changes best track data occasionally for active storms, including past
positions. (when data they may not have had previously for example
indicates they should make a change) After a storm is done, they may
also change the data.
Eventually, best track data is the official record:
https://www.nhc.noaa.gov/data/#hurdat
But during a storm, when advisories are being issued, consider the
advisory data to be what is official.
As for Linda, we continue to track the low since best track data
continues to be posted for it. The designation for Linda in the best
track data is "LO", which means "low".
You can see how to read the raw best track file from the page here:
https://www.nrlmry.navy.mil/atcf_web/docs/database/new/abdeck.txt
This is how our site, and others, decode the data from these best
track data files. Our site only ever has best track data. We do not
currently download and process advisory data. So if a site uses
advisory data they might not mix in best track data too unless it is
for invest areas. This folder is where invests originate as well. (90
to 99) Since those are for areas that have no advisory data yet, this
folder ("btk") is the only place to get invest data.
We add the name "Linda" in parenthesis since it isn't currently noted
as having one of the tropical or subtropical designations. |
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