Model Change Bulletin

                                   MCB#1                          09-18-95

                            SCREEN3 (dated 95250)


     This Model Change Bulletin initiates the use of the SCREEN3 model on the
SCRAM BBS.  Most of the changes made to SCREEN3 were performed to maintain
consistency with the Industrial Source Complex Short Term 3 (ISCST3) model.
The change from the SCREEN2 (dated 92245) to the current SCREEN3 is a revised
area source algorithm.  For details on this change, refer to the SCREEN3 User's
Guide.

     SCREEN3 will henceforth be identified by its name and a Julian date,
i.e.: SCREEN3 (dated 95250).  Future changes to this model will be identified
by an updated Julian date found on the first line of the model source code
and followed by a reference to a SCRAM BBS Model Change Bulletin (MCB#n) which
will explain the nature and contents of the changes.  All Model Change
Bulletins for this program will always be available for back reference on
this BBS.  In the future, notification of changes (MCBs) to this program will
be made in the SCRAM ALERTS section of this BBS immediately following the LOGON
procedure.