Lettau 12Z pressure 1986 - 991.9 989.8 979.6 992.6 991.2 979.2 980.3 976.4 971.7 974.5 981.7 1987 992.5 988.8 986.1 987.9 983.2 986.1 991.2 974.8 988.2 976.8 978.2 985.6 1988 988.6 984.2 985.0 981.5 989.3 995.4 975.1 975.2 981.9 988.7 981.4 983.5 1989 984.7 985.1 982.9 987.5 968.9 979.6 977.6 982.8 981.0 973.2 975.7 989.4 1990 988.5 983.0 985.9 991.3 997.3 985.4 995.9 979.7 970.0 980.5 982.6 983.5 1991 982.4 989.2 980.3 984.4 987.0 989.5 991.1 - - - 983.9 995.2 1992 988.6 994.8 988.0 984.3 989.0 993.0 - - - - 977.6 982.9 1993 996.2 978.5 985.5 980.9 982.8 980.7 - - - - 979.3 984.0 1994 984.7 982.6 978.0 984.8 985.7 997.5 987.2 973.0 987.8 976.8 984.7 981.3 1995 981.2 981.1 991.0 982.0 980.6 986.6 - - - - 976.9 977.7 1996 985.9 - - - - - - - - - - 985.2 1997 988.5 - - - - - - - - - - - 1998 - - 981.8 974.3 982.2 - - - - - - - 1999 - 986.8 984.0 980.4 976.5 999.4 979.4 981.9 981.2 963.9 - - 2000 - - 983.0 982.2 982.4 984.5 979.3 982.6 987.2 975.6 - - 2001 - - 983.4 978.3 983.4 981.5 986.0 981.9 976.2 971.4 - - 2002 - - 990.1 979.5 992.2 994.0 986.8 977.6 985.9 990.0 - - 2003 - - - - - - 977.2 - - - - - 2004 - - - - - - - - - - - - 2005 - - 980.8 977.7 979.0 - 979.1 974.6 973.5 968.8 - - 2006 - - - - - - - - - - - - 2007 - - - - - - - - - - - - 2008 - - - - - - - - - - - - 2009 - - - - - - - - - - - -