Katie Giannakopoulos

Weather and Climate Systems

Katie Giannakopoulos

Characterizing Wintertime Temperature Whiplash in the US Southern Plains

May 1st, 2024

3:00 pm / NWC 1350

Abstract: Rapid extreme temperature swings, termed “temperature whiplashes”, can cause significant socioeconomic impacts on energy, agriculture, and transportation. Few studies have considered temperature whiplashes, however most consider global, continental, or other large domains. These analyses suggest that certain locations within the domain may experience greater temperature swings, one being the United States Southern Plains. By honing in on a specific area and considering temperature whiplashes on a regional scale, more skillful, long-lead prediction and mitigation of these events may be improved. This study focuses on characterizing temperature whiplash events in the Southern Plains region of the United States, specifically during the winter months (December-February). This seminar will focus on swings from anomalously warm temperatures to anomalously cold temperatures. Using the ERA-5 dataset from 1950-2023, the Temperature Swing Index, defined as the standard deviation o
f the 24-hour difference filtered 6-hourly 2-meter temperature, is calculated and area-averaged across the Southern Plains. Days where the Temperature Swing Index exceeds the 90th percentile are termed “high swing days” (HSD). Temperature whiplash events are selected by examining each HSD, and considering the longevity and persistence of the overall temperature trend and the signs of the temperature anomalies up to 4 days before and after the HSD. This definition yields 45 anomalously hot to cold whiplash events from 1950-2023. Composites of the geopotential height field at multiple pressure levels and lags illustrate large-scale atmospheric evolutions and key features that could enhance long range predictability. Additionally, enhanced stratospheric-tropospheric interactions such as wave reflection are identified as a possible precursor to these events. By establishing the characteristics of temperature whiplash events and their precursors, there is the opportunity to improve predictability of these extreme events and determine how they may change in a changing climate.