DATE: June 22, 1998
MEMORANDUM FOR: All Users of METAR/SPECI Observations And TAF Messages
FROM: OSO14x1 - Dave Mannarano
Ice Pellet Implementation Manager
SUBJECT: USA Code Change For Ice Pellets
Effective 0000 UTC, 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" will
be implemented at over 100 staffed Automated Surface Observing System
(ASOS) locations from August 1998 to October 1998. Although these
locations will have the capability to transmit ice pellets as "PL,"
they will be 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
obvservers who did not "get the word" and may incorrectly continue to use
the obsolete "PE" code after 0000 UTC, November 5, 1998. All deliquencies
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).
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 me at (301) 713-2093 or E-MAIL me at
Dave.Mannarano@xxxxxxxx.
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W/OSO14:DM 6/22/98