C$$$  MAIN PROGRAM DOCUMENTATION BLOCK
C
C MAIN PROGRAM: BCTEND       GENERATE BOUNDARY TENDENCIES FOR ETA
C   PRGMMR: ROGERS           ORG: NP22        DATE: 97-12-30  
C
C ABSTRACT: READS IN VALUES OF BASIC STATE VARIABLES FROM ETA OI
C   ANALYSIS AND AVN FORECAST AT ETA MODEL BOUNDARY POINTS AND
C   COMPUTES BOUNDARY TENDENCIES.  THIS VERISON IS SPECIAL FOR THE
C   EDAS; IT ASSUMES YOU HAVE 3 H AVN FORECAST FILES.
C
C PROGRAM HISTORY LOG:
C   ??-??-??  T BLACK
C   95-02-07  E ROGERS ADDED DOCBLOCK
C   98-06-10  E ROGERS CONVERTED TO FORTRAN 90
C
C USAGE:
C
C   INPUT FILES:
C     UNIT17     - BOUNDARY VALUES FROM AVN FORECAST
C     UNIT18     - BOUNDARY VALUES FROM ETA ANALYSIS
C
C   OUTPUT FILES:
C     UNIT51     - PRECOMPUTED BOUNDARY TENDENCIES
C
C
C   SUBPROGRAMS CALLED:
C     UNIQUE:    - BC6432
C
C   EXIT STATES:
C     COND =   0 - SUCCESSFUL RUN
C
C   REMARKS:
C
C ATTRIBUTES:
C   LANGUAGE: STANDARD FORTRAN 90
C   MACHINE: CRAY YMP/C90
C
C$$$