Sudden Stratospheric Warming and Vortex Intensification Monitoring at the Climate Prediction Center

Evaluations of past Sudden Stratospheric Warmings (SSW) and Vortex Intensifications (VI) have shown that impacts to circulation patterns in the troposphere were detected up to 60 days following such events. Sub-seasonal forecasts can benefit from knowing when such events will occur and if the troposphere will be impacted. Global climate and weather models have shown skill at forecasting these events 15-20 days prior to their occurrence. At the NOAA/Climate Prediction Center we provide a web page dedicated to monitoring SSW and VI precursors, the SSW and VI events themselves, and tropospheric fields that could be impacted. Forecasts of temperatures, winds, and eddy heat flux at multiple pressure levels in the stratosphere are provided out to 45 days using the NCEP Climate Forecast System (version 2), and out to 16 days using the Global Ensemble Forecast System (GEFS) and the deterministic Global Forecast System (GFS). Forecasts of tropospheric blocking events are also monitored which may precede SSWs. The phase of the El Nino Southern Oscillation (ENSO), Quasi-Biennial Oscillation (QBO), and Madden Julian Oscillation which have been shown to modulate the potential of SSW and VI to occur are also monitored and forecasts generated. Supporting sub-web pages provide background information about how precursors lead to SSW and VI events, SSW and VI mean characteristics, and tropospheric impacts following these events. Helpful links to major papers and other web pages discussing these events are also provided.