Ag Weather Forum
Drought Outlook Mixed Following Heavy Winter Storms
Following the very active spell of winter storms during the end of 2022 and the start of 2023, the outlook for drought in much of the northern and western United States is much better than at the start of winter.
A special drought assessment report by the Natural Resources Conservation Service (NRCS) in late January after the series of nine atmospheric river events included these key points: The snow water equivalent for the California Region is 215% of normal, the Great Basin is 206% of normal, and the Upper and Lower Colorado River Basins are 146% of normal and 218% of normal, respectively.
These storms improved drought conditions by increasing soil moisture throughout much of the West, especially in California. The amount of water stored in many reservoirs increased, but some are still well-below historical averages for this time of year.
The full Western U.S. drought outlook is available here: https://www.drought.gov/….
Across the Midwest, the drought outlook is notably variable. The latest NRCS Midwest drought assessment noted these highlights: "Currently, 19% of the Midwest region is in drought (moderate to exceptional), which is 28% less than eight weeks ago in late November."
Despite the improvement in some areas, extreme to exceptional drought (D3 to D4) persists across northwest Iowa. Moderate to severe drought (D1 to D2) also remains across Minnesota and Michigan.
"Northwest Iowa, Minnesota and western Wisconsin have received above-normal precipitation since Dec. 1, 2022. This precipitation has been helpful to add water to the landscape. However, the ability to improve drought and replenish soil moisture, which was very low at the end of fall, is limited when the ground is frozen. Unfortunately, it is too early to determine the full benefit of the winter precipitation thus far," said the report.
Forecasts through spring focus the best precipitation chances on the Ohio Valley and Great Lakes, and equal chances of above normal, normal and below-normal precipitation elsewhere in the Midwest.
For the full Midwest drought outlook, go here: https://www.drought.gov/….
That mixed outlook is also in evidence across the Plains from north to south. Northern Plains areas have either drought easing or drought removal in the 90-day outlook. But the Central and Southern Plains are expected to either continue in drought or have drought conditions intensifying. The latest Southern Plains drought assessment features very little improvement from weakening La Nina conditions in the Pacific Ocean. The region has seen some drought easing, from about 96% in drought in late October to 87% in drought according to the Jan. 31, 2023 Drought Monitor.
"Dynamical model guidance and statistical tools continue to depict a La Nina-related precipitation pattern through FMA (February-March-April) 2023. Impacts on the primary storm track and precipitation due to La Nina are forecast to linger even if negative SST (sea surface temperature) anomalies across the equatorial central Pacific begin to weaken," the U.S. Climate Prediction Center's latest seasonal outlook said.
Implications for crop moisture at the start of the 2023 growing season are that Southern Plains winter wheat will exit dormancy with limited moisture for post-dormancy growth. In addition, drought prospects in the Western Corn Belt suggest that irrigation will be in high demand for 2023 with its associated stress on groundwater supplies in areas where aquifer drawdowns have been greatest.
Bryce Anderson can be reached at Bryce.Anderson@dtn.com
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