By Reginald Stanley. Posted September 13, 2017, 11:48 PM.

September thus far has given way to more thunderstorms and humidity across the region, continuing the pattern from late August.

Numerous troughs and closed lows alternating with high pressure over Colorado since August has lead to frequent but short-lived heat waves quickly changing to overcast, muggy weather and back again. The resulting bouts of mid-level moisture over the region have spawned thunderstorms in favorable areas, particularly the mountains and deserts, occasionally drifting west into the Inland Empire. Such events notably occurred on September 3rd and 4th, between the 6th and 9th, and most recently on Monday the 11th. WeatherCurrents stations reported no more than 2/10 at best from these thunderstorms, and many did not record measurable rain at all. Anza reported the highest cumulative total for the month of September so far, with 0.37 inches. A particularly notable total of 0.60 inches, however, was reported by Peter Michas in East Highland on September 3rd. Thunderstorms mostly occurred in the morning and late afternoons.

An upper low over Central California brought relief to the region this week, leading to much milder weather and a deep marine layer. Drizzle is possible in favorable locations.