Jul-Aug Temperature Breakdown
The slow start to monsoon activity was reflected in persistent heat that lingered across the US Southwest for much of July and August (Fig. 1). High pressure and sub-optimal ridge position had the effect of boosting daily temperatures and preventing optimal flow of moisture into the region. This lack of moisture flow is one explanation for the drier than normal monsoon. After a run of record warm temperatures July10-13 (see July 2020 SWCO for details), temperatures briefly cooled in mid-to-late July during one of the only periods of widespread storm activity. By late July and through most of August, temperatures remained well above normal, including several record warm days (Fig. 1). There have been some intermittent storm events, but little widespread storm activity that we often associate with a more typical monsoon. This lack of rain is contributing to the much warmer than normal temperatures across the Southwest, as rain events provide some relief from the summer heat.