NOUS41 KWBC 071426



Technical Implementation Notice 13-13

National Weather Service Headquarters Washington DC

1025 PM EDT Fri Jun 7 2013


TO:       Subscribers:

          -Family of Services

          -NOAA Weather Wire Service

          -Emergency Managers Weather Information Network


          Other NWS Partners and Employees


FROM:     Kevin Schrab      

          Chief, Observing Services Division

          Office of Climate, Water, and Weather Services


SUBJECT:  Three Alaska Sites to Terminate their Automated

          Radiotheodolite Tracking (ART) and Radio Direction

          Finding Radiosondes (RDF) upon Installation of the

          Radiosonde Replacement System (RRS) Starting

          August 20, 2013


Three Upper Air (UA) sites in Alaska are scheduled to begin RRS

service in the next four months in 2013.




KOTZEBUE       70133      PAOT      20 Aug 2013

MCGRATH        70316      PAMC      30 Aug 2013

COLD BAY       70350      PACD      24 Sep 2013


These UA sites may be out of service for as long as 10 days. The

NWS UA observations will gather meteorological data from Global

Positioning System (GPS) radiosondes of a new type, the LMS-6. 

The assigned equipment code is 48208. The leading 4 indicates a

correction is applied for solar and infrared exposure. The 08

suffix indicates automatic satellite navigation. This code

appears immediately after the heading, 31313, in the TTAA, TTBB,

TTCC and TTDD messages.


The NWS describes the RRS release point location with the

National Geodetic Survey (NGS) OPUS solution. This is a datum

combination that relies on North American Datum of 1983 (NAD83)

for latitude and longitude; the release point elevation is based

on North American Vertical Datum 1988 (NAVD88) with the GEOID03

model. By contrast, the GPS radiosonde flight information of

latitude and longitude and altitude will rely on the world

geodetic system of 1984 (WGS84) standard.


Parts of the UA coded messages will be significantly longer with

RRS conversion. NWS has coordinated with its partners on the

longer length of these messages.


The format of the messages will be the same WMO format for coded

UA messages used with the MicroArt legacy system. The number of

levels in the coded messages will be two to three times greater

for the TTBB and TTDD. As a result, the SGL and ABV categories of

AWIPS text products will increase in size. The number of levels

in the TTAA, TTCC, PPBB and PPDD parts will be relatively

unchanged. These changes reflect updated coding practices and

higher resolution level selection criteria. The maximum size

limits of the parts of the coded messages are as follows:


     TTAA:   15 Levels         

     TTCC:   10 Levels        

     TTBB:  135 Levels         

     TTDD:   40 Levels

     PPBB:   40 Levels   

     PPDD:   40 Levels


In addition, the 31313 message indicator associated with various

parts of the message will be included with each part of the

thermodynamic message parts.


For additional information on the message requirements, see the

WMO 306 Manual on Codes (International Codes): Volume I.1 Part A,

Alphanumeric Codes, and Volume II Regional Codes and National

Coding Practices. Users can find information on the levels

selection criteria used in NWS coding software online at:


If you have questions or feedback, please contact:


  Neal Dipasquale

  NWS Acting Director, Field Systems Operations Center

  Silver Spring, Maryland

  301-713-0039 Ext. 155



NWS National Technical Implementation notices are online: