Chris,
I can only quickly answer some of these based on time.
My response to someone else today, which somewhere along the line I
guess generated some debate, not certain why or why this is important
but see down below.
> As outlined in the National Hurricane Operations Plan in section
> 4.3.3, the numbering system is as follows:
>
> 01-49 Fixed Cyclone Numbers (tropical and subtropical)
> 50-79 Reserved use for the responsible TC Forecast Center
> 80-89 Test or Training - most processing ignores these, not always.
> 90-99 Invests or simply put areas of interest.
>
> Invests are generally, not always assigned by the duly appointed TC
> Forecast Center; however, DOD (such as the Navy or Air Force) also has
> the ability to assign an Invest, track it or update it. This is per
> agreement in inter-agency Memorandums of Agreement or Understanding
> (MOAs or MOUs) dating back close to a decade and routinely updated every
> year at several inter-agency (DOC, DOD, DHS, etc) conferences and
> working groups.
>
> So in a nutshell, Invests are basically areas of interest controlled
> by either primarily NWS or DOD or both depending upon their respective
> need. NHC and CPHC does not conduct or utilize 90-series as tests per
> established rules, maybe the Navy or someone else did in the Atlantic
> and if so, I was unaware of such a test. I would have to find out if
> Pearl Harbor USN NMFC or Norfolk USN NMFA.
>
> As for 80-series, you never see them because they are internal and
> generally deal with comms checks, quick training, model initialization
> or model end to end checks, etc. Although, you might see some of those
> decks appear on the public ftp sites - this is by design to ensure data
> gets to the different end distribution points.
> My second question is in regards to what qualifications are necessary
> for an area to be declared an invest and be given a number (90-99). Is
> there a checklist for declaring invests? Is an invest declared
> completely by a meteorologist or is there some automation to it? Is it
> a somewhat subjective process?
At NHC and CPHC, we do have internal Duty Manuals that outline
procedures to declare Invests along agreements with DOD on how this is
approached - these are more specific than NWS Directives, etc. Invests
to some extent have some threshold that needs to be reached, persistence
of convection, wind speeds or some other factors. But this also enters
into the subjective call area and thats where the experience of the
forecaster enters into the equation.
DSNS - decay SHIPS *not* using IR profile predictors
SHNS - SHIPS *not* using IR profile predictors
The IR predictors from GOES and Meteosat have greatest positive impact
within the first 48 hrs. Think of DSNS and SHNS as controls that allow
us post-season to analyze the impact of the satellite assimilation into
SHIPS. Again, we tell people to look closely at the verification of all
models. This is quite important and performance is rigorously evaluated
here on all relevant TC related forecast models (statistical and
dynamical). As a side note, some model information in the ATCF data
sets are either prototype or parallel test run stuff, when it says do
not use, then its very wise to not use it since there is generally no
statistics on the performance.
http://www.nhc.noaa.gov/verification/index.shtml> Is "AN01" the GFS Ensemble -01 member?
> Is "AC00" the GFS Ensemble Control?
Yes, and sorry, I need to update the public version of the techlist. My
fault on that one, I will update that as time permits.
> My third question involves 6 hour position fixes. Is the center
> position determined by a computer sometimes or is it always determined
> by a meteorologist? Is the strength automatically estimated?
>
Please clarify? Do you mean how they arrive at the 6 hour best track
points, intensity and structure? If that is the case, that is arrived
at using subjective and objective techniques/analyses and the forecaster
can use either a blended approach or make a judgment call using their
experience since they know the strengths and weaknesses of all these
methods. We utilize object best tracking algorithms, but due to
sampling issues and other limitations, these methods can not generally
match the skill of an experienced forecaster at times. As just a junior
forecaster and programmer with 8 years here, the experience factor is a
big factor and the forecaster provides added value.
Ok, thats the quick take and is much as I can add given my time
constraints. I hope that helps a bit.
Good luck.
-- Chris Sisko
