USA and International Code Change For Ice Pellets

Effective 0000UTC, November 5, 1998 the Aviation Routine Weather Report/Aviation Selected Special Weather (METAR/SPECI) code formats used in the United States of America (USA) for reporting ice pellets will change from "PE" to "PL." New USA observing policy/procedures will require that only "PL" be used to encode ice pellets starting November 5, 1998. This change applies to all manual observing stations and automated observing stations where human augmentation is provided for reporting ice pellets. It does not apply to unstaffed automated observing stations which do not/cannot report ice pellets.

The dual capability to encode ice pellets as either "PE" or "PL" is being implemented at 158 staffed Automated Surface Observing System (ASOS) locations. Although these locations will have the capability to transmit ice pellets as "PL," they are instructed to only use "PE" until November 5, 1998. Furthermore, although the implementation on November 5, 1998 is planned to be a fully coordinated "turn-key" event, there may still be some observers who did not "get the word" and may incorrectly continue to use the obsolete "PE" code after 0000 UTC, November 5, 1998. All delinquencies will be corrected as soon as possible. As a precaution, users with automated decoders are urged to take appropriate steps now to recognize both "PE" and "PL" in the METAR/SPECI code.

Concurrent with the METAR/SPECI ice pellet code conversion (PE to PL) at 0000 UTC, November 5, 1998, the USA will also convert the Terminal Aerodrome Forecast (TAF) code format for ice pellets from "PE" to "PL." All USA TAFS which are valid on or after 0000 UTC, November 5, 1998 will use PL when referring to ice pellets. Again, as a precaution, users with automated decoders are urged to take appropriate steps now to recognize both "PE" and "PL" in the TAF code as well.

In addition, effective 0000 UTC, November 5, 1998, "PL" will be used to indicate ice pellets in USA SIGMETs, Convective SIGMETs, domestic and international Area Forecasts, and Center Weather Service Unit products (Center Weather Advisories and Meteorological Impact Statements).

The ice pellet code change from PE to PL is a world-wide change. The ICAO Council in March 1998 adopted Amendment 71 to ICAO annex 3, Meteorological Service for International Air Navigation Standards, and recommended practices which detail the aviation requirements for meteorological services. ICAO Annex 3 is identical to WMO Technical Regulations (C.3.1). These international documents were brought in line when WMO's Executive Council adopted these changes in June 1998. Although this is an international change, some member states may file exceptions and continue to report PE. It is for this reason that all decoders and computer databases which use or exchange international meteorological data be modified to recognize both PE and PL as legitimate indicators for ice pellets.

Additional updated notices will be provided as the ice pellet code change implementation date approaches. If you have any questions about this change please call David.Mannarano at (301) 713-2093 or E-MAIL - David.Mannarano@NOAA.GOV.

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