West Drought Summary
During the past two weeks, PNPs in most of California remained below the 25th percentile. At 30-day and 60-day timescales, the PNP pattern reveals isolated areas of 150% or more in the Sierras, southwestern, and far southern California. Rivers and streams remain in the lowest quarter of the observed distribution statewide. Firefighting resources have been taxed severely this week with the wildfires raging across north-central California; especially in and around Santa Rosa (Sonoma and Napa Counties). Precipitation that fell in the past 1-2 weeks favored the trimming away of some D0 in western New Mexico this week. However, D0 was retained in much of Caltron and Cibola counties, based on ACIS SPIs out through the past 120-days, low stream flows, and AHPS PNPs out to 60-days. In Arizona, the short-term drought status report for September, produced by the State Drought Monitoring Technical Committee, provided a recap of the Southwest Monsoon season. It noted that the majority of monsoon season rainfall fell between mid-July and early-August. This was followed by below-average rainfall and warm temperatures, which contributed to late-summer dryness. With the monsoon season therefore ending earlier than usual, much of southeastern, eastern, and central Arizona ended up with D0. In western Colorado, small-scale improvements were made thanks to beneficial precipitation that fell during the past two weeks. All short-term SPIs, and most longer-term SPIs are now showing conditions have returned to near-normal in these areas. Some one-class improvements were made in central and northeastern Montana this week. Reassessment of conditions next week in western and southeastern Montana may yield additional changes as well.
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