Weather-wise, 2020 was a year of extremes

At the beginning of a new year, it is common for meteorologists to pore over weather data from the previous year.

We like to view certain weather parameters, particularly temperature and rainfall, as they compare to 30-year normal values compiled by the National Weather Service.

The service updates data summaries at the end of each decade. The most recent “normal” database uses weather records for 1991-2010. For the Concord/Clayton area, the most representative data are measured at the Concord Airport.

Temperature statistics indicate it was another hotter than normal year. That trend was apparent in maximum, minimum and average temperature statistics.

Concord’s average daily maximum temperatures were above the 30-year normal for all months of 2020 except for March. For six of the above normal months, the average maximum temperature was greater than five degrees above normal.

Heat waves

There were two significant heat waves in 2020.The first strong heat occurred in mid-August. For four out of five consecutive days, recorded maximum temperatures reached 106 degrees.

A few weeks later, an even stronger heat wave baked the Bay Area. On Sept. 5, the maximum temperature reached 104 degrees. The worst was yet to come, with maximums of 110 and 112 on the following afternoons.

Turning the climate page to rainfall data, we find that 2020 was pretty dry. Monthly rainfall totals at Concord Airport were below average for each of the eight wettest months. February, normally one of the wetter months of winter, was bone dry. In fact, there was no measureable rainfall at Concord between Jan. 27 and March 8.

Unfortunately, that wasn’t the worst dry spell of 2020. During a six-month period between mid-May and mid-November, there were only four days with measurable rain, all measuring less than one-tenth of an inch.

Weather catastrophes

Our 2020 weather was not without significant weather-related catastrophes. The oppressive heat and parched earth conditions of 2020 resulted in a long and destructive wildfire season that got off to an early start.

A mid-August surge of moist subtropical air was the culprit. A strong jet stream current directed a band of moisture from a dying tropical storm toward the California coast with disastrous consequences.

When this plume crossed our coastal hills on Aug. 16, thunderstorms erupted like a series of cloud volcanoes. Thousands of lightning strikes ignited an unprecedented number of wildfires stretching from Southern California to the Oregon coast.

As a result, more than 4 million acres burned across our state. This broke the statewide burn record set in 2018 by more than 2 million acres.

Where there is fire, there is smoke. In the Bay Area, dense layers of wildfire smoke blanketed our neighborhoods like nothing I’d seen in my 40 years here. Hazardous air quality readings choked our area for nearly two months.

In summary, 2020 was a pretty lousy weather year, which added to the stress caused by the pandemic and political turmoil. However, as I write this, rain showers are cheerfully tapping on my office window.

Maybe it’s a sign that 2021 will be somewhat wetter, cooler and less conducive to firestorms.

Woody Whitlatch is a meteorologist retired from PG&E. Email your questions or comments to clayton_909@yahoo.com