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ARS Home » Plains Area » El Reno, Oklahoma » Oklahoma and Central Plains Agricultural Research Center » Agroclimate and Hydraulics Research Unit » Research » Publications at this Location » Publication #428893
Research Project: Impacts of Variable Land Management and Climate on Water and Soil Resources

Location: Agroclimate and Hydraulics Research Unit

Title: Surface and atmospheric anomalies associated with Central Great Plains extreme precipitation increases during winter

Author
item Flanagan, Paul
item MAHMOOD, REZAUL - University Of Nebraska

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/27/2025
Publication Date: 1/28/2026
Citation: Flanagan, P.X., Mahmood, R. 2026. Surface and atmospheric anomalies associated with Central Great Plains extreme precipitation increases during winter. Meeting Abstract. 106th American Meteorological Society Annual Meeting, Houston, TX Jan 25-29,2026.

Interpretive Summary:

Technical Abstract: There are intra-region differences in the hydro climatology of the Great Plains owing to and exemplified by the north to south increase in temperature and east to west decline in precipitation. Previous research has shown that the magnitude of extreme winter precipitation in the Central Great Plains is increasing, both locally and regionally. This research seeks to understand the physical mechanisms that influenced a region wide increase in extreme winter precipitation. To this end, station and reanalysis datasets were analyzed to link changes in extreme precipitation to changes in the atmospheric state in winter (December, January, and February). Station data analysis shows that there are increases in the frequency and magnitude of extreme precipitation events. Daily average temperature data analysis shows that extreme precipitation increases are connected to increases in station minimum temperatures on the day of the event with an absence of maximum temperature change. ECMWF Reanalysis 5 (ERA-5) findings support this understanding, with results showing a warm and moist environment prior to all winter extreme precipitation events. An analysis of ERA-5 data split into two temporal periods (1950 – 1984 and 1985 to present) shows small but impactful differences in the synoptic evolution of the atmospheric waves leading to the extreme precipitation event. Namely, ERA-5 geopotential height anomalies show that the southwestern US 500 mb trough is weaker after 1985, weakening the Great Plains 925 mb low and strengthening the eastern US 925 mb high. This scenario causes an enhanced southerly flow across the Great Plains, so even with reduced atmospheric forcing from the weakened trough (compared to before 1985 events), this creates an environment where extreme precipitation events incur more rainfall and are more frequent within the Great Plains. In the end, ERA-5 results confirm what is found in observations, that more moisture is present in the atmosphere during present day extreme precipitation events, leading to more impactful precipitation compared to what has occurred in past events. These results detail the changes in extreme precipitation during a typically dry period of the year for the Central Great Plains, thus providing information on the need for, or improvement to, soil sustainability practices in the region due to the continued use of crop rotations with winter fallow periods within the Great Plains.