2020 in Southeast 'on the drier side', but not really unusual
We have been keeping daily rainfall records from our location in Westmoreland since March of 1997, with complete annual records from January 1, 1998. This gives us some perspective on when we have had a particularly wet year, and when we have not. 2020's rainfall total here was 33.88 inches.
That does put the year on the drier side, but not alarmingly so. Here are the statistics: In these 23 years, the driest year was 2001's 29.67 inches, followed closely by 2019's 29.75 inches. The wettest year during this span was 2012's 59.29 inches; coming in second was 52.28 inches in 2017, and third was 51.89 inches in 2016. Those are the only three years in this period getting into the 50's of inches, but it is clear that the trend is not really towards drier weather as the 23 years progressed.
That said, 2020 was the third year in a row with a relatively low total; 2019 recorded only 29.75 inches, as earlier noted, and 2018 recorded 35.35 inches. In this 23 year span, only 2000-2002 recorded a similar span of relatively dry years in a row (years with all three under 40 inches). If that tells us anything, it is that 2021 should probably come in over 40 inches.
So much for statistical prediction! As for 2020 – there were only three days all year with over an inch of rain in one day: 1.18 inches on January 28, 1.19 inches on November 13, and 1.77 inches on December 20. We've noticed that a substantial percentage of each year's rain, here, falls on just a few days. With more days with over an inch of rainfall, usually the higher the total for the year will be.
Returning to 2020's statistics, the rainiest month was January, with 9.55 inches – 28% of the year's rainfall. The second rainiest month was December's 5.44, followed closely by November's 5.30 inches; those three months accounted for 61% of the year's total. (If you keep your own records, you should know that our readings are taken at 4 p.m. each day on the date of record, so those who record daily at different times may come up with different daily totals, but presumably about the same monthly and annual totals.)
The first days of January, 2021, were quite rainy – leading to an "atmospheric river" event on the 11th and 12th which produced well over two inches of rain, and damaging winds gusting over fifty miles an hour in parts of Portland! It will be interesting to see how this year paces those in the recent past. We'll report to you occasionally on it.
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