Dry Areas Growing in the West
In contrast to the spring and early summer season of 2019, the spring and early summer of 2020 is much different regarding precipitation across the western USA. While 2019 was quite wet in the western states, 2020 has seen a trend toward drier conditions.
Below is the most recent drought status map as of late last week. Notice the red and brown areas across parts of the Southern and Central Rockies and portions of the Desert Southwest and Pacific Northwest.
Severe dryness has developed along and south of Interstate 70 in Colorado and into western Kansas, northern New Mexico and the Texas/Oklahoma Panhandle areas. A year ago at this same time most of the USA had adequate over above average soil moisture.
The graphic below shows drought status as of June 11, 2019.
Why the big change in precipitation patterns from a year ago? One culprit is the developing La Nina in the Pacific where sea surface temperatures are cooler than normal. The cooler subtropical waters tend to bring a drier trend to the western states and this year is no exception.