According to the April 18, 2017, U.S. Drought Monitor, moderate to extreme drought continued to cover 8.2% of the contiguous United States for a second week. Areas in extreme drought also held steady for a third week at around 0.1%. Exceptional drought, the worst category, continued to remain absent from the Lower 48 for the 13th consecutive week.
The “big picture” circulation pattern during this U.S. Drought Monitor week consisted of an upper-level trough over the northeast Pacific, which forced an upper-level ridge downstream over the eastern half of the contiguous United States and to the north over Alaska.
This pattern resulted in cooler-than-normal temperatures for the week across most of the West Coast and Pacific Northwest, and much warmer-than-normal temperatures across the rest of the contiguous United States and much of Alaska. The ridge over Alaska kept the weather drier than normal. But, weather systems moving in the circulation across the contiguous United States brought Pacific moisture and above-normal precipitation to much of the West Coast to Northern Rockies.
As they crossed into the Plains, the weather systems tapped Gulf of Mexico moisture to bring above-normal precipitation across the Southern Plains to western Great Lakes and parts of the Ohio Valley. The rest of the West, and the Southeast to Northeast, were mostly drier than normal for the week. Drought and abnormal dryness contracted beneath the rains in the Southern Plains, but expanded in the Southeast and parts of the West where precipitation has been below normal for the last several months.
In addition to Drought.gov, you can find further information on the current drought as well as on this week’s Drought Monitor update at the National Drought Mitigation Center. See their recent news releases.
The most recent U.S. Drought Outlook is available from NOAA’s Climate Prediction Center and the U.S. Department of Agriculture provides information about the drought’s influence on crops and livestock.