NOUS40KWBC 131425
     FOS/NOAAPORT NOTICE NO. 1742   JULY 13... 2000
     
     ATTENTION    FAMILY OF SERVICES SUBSCRIBERS/NOAAPORT USERS
     
     SUBJECT  NOTICE OF INTENT TO CHANGE AVN MOS GUIDANCE
     
     EFFECTIVE WITH THE 1200 UTC FORECAST CYCLE ON JULY 18...2000... 
     GUIDANCE FOR CEILING HEIGHT AND TOTAL SKY COVER WILL BE
     ADDED TO THE NEW AVN MOS MESSAGES.  THESE MESSAGES ARE 
     IDENTIFIED WITH WMO HEADERS FOPA20... FOUS21-FOUS26... AND 
     FOAK37-FOAK39... AND ARE STORED AS MAV PRODUCTS IN THE AWIPS 
     TEXT DATA BASE.  THE CEILING HEIGHT AND TOTAL SKY COVER 
     GUIDANCE PROVIDE FORECASTS OF CATEGORIES OF CEILING HEIGHT 
     AND SKY COVER VALID EVERY 3 HOURS FROM 6 TO 60 HOURS AFTER 
     0000 OR 1200 UTC AND AT THE 66- AND 72-H PROJECTIONS.  THE 
     CATEGORICAL DEFINITIONS FOR CEILING HEIGHT ARE AS FOLLOWS
     1 - LESS THAN 200 FT... 2 - 200 TO 400 FT... 3 - 500 TO 900 
     FT... 4 -1000 TO 3000 FT...
     5 - 3100 TO 6500 FT... 6 -  6600 TO 12000 FT... AND 7 - GREATER 
     THAN 12000 FT OR UNLIMITED.  THE CATEGORICAL DEFINITIONS FOR 
     TOTAL SKY COVER ARE AS FOLLOWS  CL - CLEAR... SC - GREATER
     THAN 0 TO 4 OCTAS OF TOTAL SKY COVER... BK - GREATER THAN 4
     TO LESS THAN 8 OCTAS OF TOTAL SKY COVER... AND OV - 8 OCTAS OF 
     TOTAL SKY COVER.  MORE DETAILS ON THE NEW GUIDANCE MAY BE 
     FOUND AT THE FOLLOWING

                  HTTP/COLON//WWW.NWS.NOAA.GOV/TDL/SYNOP/MOS2000.HTM

     AT THE SAME TIME... EQUATIONS TO PREDICT THE CONDITIONAL 
     PROBABILITY OF PRECIPITATION TYPE /FREEZING... FROZEN... OR 
     LIQUID/ WILL ALSO BE IMPLEMENTED.  GUIDANCE FOR PRECIPITATION 
     TYPE WILL NOT BE DISPLAYED ON THE MESSAGE UNTIL SEPTEMBER 1. 
     PRIOR TO THAT DATE... ANOTHER NOTICE WILL BE ISSUED WITH 
     APPROPRIATE DETAILS.
     END
     NNNN