# File lib/wx/groups.rb, line 234
      def initialize(raw)
        r = /^([-+]|VC)?(MI|PR|BC|DR|BL|SH|TS|FZ)?((DZ|RA|SN|SG|IC|PE|PL|GR|GS|UP)*|(BR|FG|FU|VA|DU|SA|HZ|PY)*|(PO|SQ|FC|SS|DS)*)$/
        raise ArgumentError unless raw =~ r

        case $1
        when '-'
          @intensity = :light
        when nil
          @intensity = :moderate
        when '+'
          @intensity = :heavy
        when 'VC'
          @intensity = :vicinity
        end

        @descriptor = $2

        @phenomena = []
        s = $3
        until s.empty?
          @phenomena.push(s.slice!(0..1))
        end
      end