Bhutan gets new AA=BT/CCCC=BTBH; Astana, Kazakhstan gets new CCCC=UAST

Messages flowing on the GTS (WMO's Global Telecommunication System) are identified by the abbreviated heading,
starting with two coded words called TTAAii CCCC (more correctly T₁T₂A₁A₂ii is the formal name, but suffix letters are often omitted in everyday communications).

In most cases CCCC represents the originating center. It is often
confused with ICAO's location indicator, since they are the same for
many countries (for example RJTD is Tokyo JMA), but they are controlled
separately now and actually different for some countries (the Bureau of
Meteorology at Melbourne is called AMMC on GTS, but ICAO indicator for
Australia begins with Y, for example Melbourne Airport is YMML). The
first two letters usually represents the country: once a CCCC is
allocated, the country may use other CCCC codes starting with the same
first two letters (there're exceptional collisions).
The AA is another system of country code. For example
TTAAii=SMJP01 means (S) surface (M) main-hour synoptic reports from
(JP) Japan.

Bhutan is being connected to GTS now, and thus needed both AA and CCCC
codes to create new heading of their data, which will probably be
something like SMBT01 BTBH (the number ii can be different).

Astana seems to be an additional originating center in addition to
Almaty (UAAA). Kazakhstan already has AA=KZ so no allocation is done
this time.

Below is excerpt from the operational newsletter of WMO:
http://www.wmo.int/pages/prog/www/ois/Operational_Information/Newsletters/current_news_en.html
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# GTS regulatory or guidance material

## Allocation of data designators T1T2A1A2ii CCCC for use in abbreviated
headings of meteorological messages

Effective immediately include the following geographical designator A1A2
for use in the abbreviated heading T1T2A1A2ii CCCC:

* Country Name: Bhutan
* RTH Centre: New Delhi (India)
* Country/Territory (AA) designator: BT
* Location indicator (CCCC): BTBH

* Effective immediately include the following new CCCC:
* Country Name: Kazakhstan
* Addition Centre from Kazakhstan: Astana
* Location indicator (CCCC): UAST

Published: 29 January 2015