Southwest U.S. Extreme Heat - June 1990

A pre-monsoon anticylone became established over the southwest U.S. in late June 1990. During the period June 25-28, numerous records were set. On June 26, Phoenix,AZ recorded a record maximum temperature of 122F and Downtown Los Angeles a record 112F.  Both 500 hPa heights and 850 hPa temperatures were 2 SDs above climatology near the center of the upper high.