Manteca-Lathrop-Ripon experienced its second driest fall since rainfall records started being kept in the mid-1800s.

 The 0.09 inches of rain the South County received between Sept. 1 and Nov. 30 was 4 percent of average according to the National Weather Service’s Fall 2020 Climate Summary released on Wednesday.

At the same time the area experienced its second warmest September when it came to average daily temperatures at 77.2 degrees while the average high was 93.3 degrees. The temperature reached 111 degrees on Sept. 7. That eclipsed the previous record of 110 degrees set in 2017.

In addition the number of 100 degree days was above average as well doubling to four for September.

Then on Nov. 10 the South County tied the record low of 32 degrees set in 2011.

The snapshot of an unusually dry autumn underscores the fact all of San Joaquin County was listed as being in severe drought at year’s end by the United States Department of Agriculture’s Drought Monitor. That also applies to the Central Sierra watershed — the Stanislaus, Merced, and Tuolumne rivers — that supply the water needs of Northern San Joaquin Valley agriculture and many urban users.

Almost all of the San Joaquin Valley is in severe or moderate drought. The Sacramento Valley is split between extreme drought and severe drought.

Going forward the outlook is not promising for rain.

The 30-day outlook through Feb. 6 currently calls for six days of precipitation. There are six days of light rain anticipated currently. If that holds, that means the South County could slip into severe drought.

The more critical need for California is snow given the Sierra snowpack meets 30 percent of the state’s water needs for cities and farming. The statewide snowpack thanks to late December storms had a 90 percent water content of the average for Jan. 2.

About 75% of California’s annual precipitation occurs from December through February, mostly from atmospheric rivers which are long plumes of moisture originating far out in the Pacific Ocean.  

The existence of El Nino weather conditions in the Pacific Ocean are being closely monitored by water managers.  El Nino conditions often produce drought conditions.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com