anchor.diff:          currw = karman / log((domain%z(2:nx-1,1,2:ny-1)-domain%terrain(2:nx-1,2:ny-1)) / domain%znt(2:nx-1,2:ny-1))
           ! use log-law of the wall to convert from surface to 10m height
           lastw = log(10.0 / domain%znt(2:nx-1,2:ny-1)) / karman
  -        domain%ustar(2:nx-1,2:ny-1) = domain%Um(2:nx-1,1,2:ny-1) * currw
  -        domain%u10(2:nx-1,2:ny-1) = domain%ustar(2:nx-1,2:ny-1) * lastw
  -        domain%ustar(2:nx-1,2:ny-1) = domain%Vm(2:nx-1,1,2:ny-1) * currw
  -        domain%v10(2:nx-1,2:ny-1) = domain%ustar(2:nx-1,2:ny-1) * lastw
  +        domain%ustar(2:nx-1,2:ny-1) = domain%Um   (2:nx-1,1,2:ny-1) * currw
  +        domain%u10  (2:nx-1,2:ny-1) = domain%ustar(2:nx-1,2:ny-1)   * lastw
  +        domain%ustar(2:nx-1,2:ny-1) = domain%Vm   (2:nx-1,1,2:ny-1) * currw
  +        domain%v10  (2:nx-1,2:ny-1) = domain%ustar(2:nx-1,2:ny-1)   * lastw
           
           ! now calculate master ustar based on U and V combined in quadrature
           domain%ustar(2:nx-1,2:ny-1) = sqrt(domain%Um(2:nx-1,1,2:ny-1)**2 + domain%Vm(2:nx-1,1,2:ny-1)**2) * currw
  
positive.code:             dt = compute_dt(domain%dx, domain%u, domain%v, domain%w, CFL, cfl_strictness=options%cfl_strictness)
              ! set an upper bound on dt to keep microphysics and convection stable (?) not sure what time is required here. 
              dt = min(dt,120.0) !better min=180?
              
              ! Make sure we don't over step the forcing period
              if ((model_time + dt) > end_time) then
                  dt = end_time - model_time
  
negative.code:             ! step model_time forward
              model_time = model_time + dt
              domain%model_time = model_time
              
              if ((abs(model_time-next_output)<1e-1).or.(model_time>next_output)) then
                  call write_domain(domain,options,nint((model_time-options%time_zero)/options%out_dt))
                  next_output = next_output + options%out_dt
              endif
              
          enddo
          
      end subroutine step
  