Above Medford OR this morning the coldest 500 mb temperature of the 2010-11 winter was observed with -36.9 deg C.  Here is a list of the five coldest Medford  soundings this winter at 500 mb (~18,000 ft):

1. -36.9 on 7 April 2011
2. -34.5 on 26 Feb 2011
3. -33.7 on 19 Mar 2011
4. -33.5 on 17 Mar 2011
5. -33.5 on 30 Dec 2010

The 500 mb map from this morning can be viewed here.