From the Colorado Department of Natural Resources (Megan Holcomb/Tracy Kosloff):
Water Year 2019 was characterized by a near average temperature and was the 34th wettest year in a 125-year period. Multiple state records were established in 2019, such as the March 13th bomb cyclone, the July 19th 115°F record at John Martin Dam, and the August 13th hail storm over eastern Colorado.
The start of Water Year 2020 (WY2020) saw dramatic temperature swings statewide: from the warmest September on record (Sep. 2019) to the 4th coldest October on record (Oct. 2019), marking one of the largest rank jumps on record and one of the state’s biggest changes in monthly average temperature. Grand Junction experienced the coolest Oct. on record while Alamosa and Pueblo experienced the 2nd coolest Oct. on record.
The 90-day Standardized Precipitation Index (SPI) from August 26 – November 23 shows notable precipitation deficits in the western half of the state. According to the U.S. Drought Monitor, released November 21, D0 (abnormally dry), D1 (moderate drought), and D2 (severe drought) collectively cover 75% of Colorado. Compared to the start of the Water Year 2020 (Oct. 1) the drought monitor shows degregations of 1-2 classes in the southern and western quadrants of the state. The long term ENSO forecasts are trending toward neutral conditions remaining into the summer (entirety of WY2020). With no El Niño or La Niña forecast to dominate large-scale patterns, the outlook remains a bit more uncertain for the winter. NOAA’s Climate Prediction Center shows warmer than average temperature outlooks December through February, and near-normal precipitation outlooks for the majority of the state. Northern basins may lean toward slightly above average precipitation these next three months. Reservoir storage remains near to above normal (95 to 126% of average) in all major basins and is 109% of average statewide. Water providers and water users did not report any unusual impacts or concerns at this time.