Tuesday, 24 January 2012: 9:00 AM
Linking Extreme Winter Precipitation to Medium Range Temperature Risks in the United States
Room 345 (New Orleans Convention Center )
This presentation will show leading and following atmospheric patterns associated with extreme winter precipitation event in the Northeastern U.S. Extreme precipitation events were determined using 5-day area-average precipitation amounts from NOAA's unified precipitation dataset. A total of 25 events were analyzed in detail using the NCEP Reanalysis dataset from 15 days prior to until 20 days after events. Parameters evaluated include 500-hPa heights, surface temperatures, and precipitable water both in anomaly and normalized space. A multi-scale composite analysis was also conducted
Results show consistent precursor signals in the North Pacific, with high-latitude blocking preceding many events. The following atmospheric response shows a consistent large-scale change in the North Atlantic, with an Arctic Oscillation transitioning negative. This circulation adjustment results in an increased risk of cold temperatures in the southeastern U.S 10 to 15 days after heavy precipitation events in the Northeast U.S. Thus, these results may be useful in evaluating subseasonal temperature risk assessment.