13 Utility of the relationship between ENSO phase and tornado activity in Integrated Warning Team planning

Tuesday, 19 July 2011
Salon B (Asheville Renaissance)
Barbara Mayes Boustead, NOAA/NWS, Valley, NE

The El Niño-Southern Oscillation (ENSO) is known to affect synoptic patterns across the continental United States, particularly by its impact on the upper tropospheric jet stream position, which in turn affects mid-tropospheric ridge and trough locations and thus areas favorable for temperature and precipitation anomalies. These global circulation patterns influence synoptic weather patterns, which in turn influence regional severe weather activity. Though it is one of several factors associated with the potential for severe weather, the synoptic environment plays a key role in severe weather potential by providing favorable ingredients for the development of severe convection. While ENSO is one of many factors that influence global circulations, and by distillation may have a less distinguishable influence on the synoptic pattern, coherent signals occur in the synoptic environment, based on ENSO phase, that influence the potential for severe convection in the north central United States.

Seasonal predictions of severe weather potential are not much aid for daily operations, but they can be used in longer-range decision-making by the members of the Integrated Warning Team (IWT): emergency managers, the media, and National Weather Service meteorologists. The IWT is able to increase its preparedness for seasons that have the potential for above normal convective activity by awareness of seasons when the probability is higher than usual. Steps by all members of the IWT can include advancing the schedule for training activities, creating contingency staffing plans, and increasing public safety and awareness messages. The study is an example of the use of climate-related information to an audience not traditionally associated with climate applications.

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