Midwest DEWS Research Webinar: Rapid Transitions in Precipitation Extremes

Introduction and Welcome

Speaker: Molly Woloszyn, NOAA's National Integrated Drought Information System (NIDIS), Cooperative Institute for Research in Environmental Sciences (CIRES)

• Today's webinar is going to present the results from a NIDIS-funded research study that analyzed the rapid transitions in precipitation extremes in the Midwest.
• About the National Integrated Drought Information System (NIDIS)
• Introduction of the researchers:
  • Dr. Trent Ford, Illinois State Climatologist, Illinois State Water Survey, University of Illinois
  • Dr. Liang Chen, Assistant Professor, Earth & Atmospheric Sciences, University of Nebraska-Lincoln

Transitions in Precipitation Extremes in the Midwest

Speaker: Dr. Trent Ford, Illinois State Climatologist, Illinois State Water Survey, University of Illinois

• Learn more about this research.
• Observed increase in Midwest precipitation and precipitation variability is projected to continue and intensify through the 21st century.
• Rapid transitions from wet to dry conditions have increased in frequency across the region, but are not happening more rapidly.
• Projections indicate a changing seasonality of extremes—more spring wetness and more summer dryness (at the 30-day timescale), associated with more frequent "wet spring" and "dry summer" atmospheric patterns.
• Projections indicate more wet-to-dry and dry-to-wet transitions, and more extremes overall at 30-day timescales.
• Projected changes in precipitation extremes are mostly associated with changes in the dynamic component of atmospheric circulation.
• Implications:
  • This idea that the "wets get wetter, dries get drier" has not been true in the Midwest at large. Observations and projections both indicate an overall wetting trend in the Midwest—especially at 3+ month timescales—with more intense monthly variability.
  • Flooding implications: This is mostly pointing to increased frequency and intensity of both pluvial and fluvial flooding events. This is likely going to continue creating challenges for emergency management and response.
  • The drought implications are more complicated. What we're seeing could possibly mean more frequent and intense short-term (<2 month) dry periods, juxtaposed with wetter and more frequent wet extremes at longer time periods.
  • It is not sufficient to say drier summers mean more impacts. Magnitude, timing, and spring wetness all need to be considered.
  • Use soil moisture to understand changes in water balance:
    • More Accurate Specification of Water Supply Shows Its Importance for Global Crop Production
    • The Terrestrial Water Cycle in a Warming World

Q&A and Closing

Moderator: Molly Woloszyn, NOAA/NIDIS, CIRES