Summary

  As usual, there will be little or no rainfall in June.

• The marine layer will be deeper than normal across the coastal areas in June.

• Monsoonal showers and thunderstorms will be below normal July through September.

• Temperatures will be near normal through September.

Weather Discussion

June 1, 2021 - The weather pattern was progressive in May with a series of upper level troughs and ridges moving into the West Coast from the Pacific Ocean. Temperatures were near to above normal most of the month across the interior where there was abundant sunshine and temperatures were below normal across the coastal areas and coastal valleys where most mornings were overcast from the marine layer. Thus, areas above and inland from the marine layer received above normal temperatures, while areas affected by the marine layer received below normal temperatures for the month (Fig 1). There were no periods of widespread triple digit heat away from the Lower and Eastern Deserts which is quite unusual for May. Just like in April, almost the entire region received little or no rainfall for the month (Fig 2). Scattered light showers and isolated thunderstorms occurred over the Sierra on a few days as areas of low pressure moved into the Great Basin from the Pacific Northwest. These low-pressure areas also brought patchy light rainfall to the coastal areas from a very deep marine layer. Above normal temperatures across the mountains in both April and May caused the snowpack in the Sierra to completely melt (Fig 3). Winds were predominately onshore (from the south and west) the entire month and they became strong across the mountains and deserts as troughs moved from the Pacific Northwest into the Great Basin. There were no days with significant offshore winds the entire month.




Source: Predictive Services