1. Overview Northern hemisphere extra-tropics El Niño Seasonal Climate – Winter 2009-10 Mike Blackburn Seasonal Climate Discussion, 14 April 2010

2. Winter in the UK DJF averages Reading: T max, T min DJF 0910 Temperature Mean 1.6°C 2.1°C below 1971-2000 average Precipitation (%) Total 249mm 75% of average Mike Stroud

3. European anomalies - DJF NOAA Climate Prediction Center TemperaturePrecipitation (% normal)

4. Surface air temperature December 2009January 2010February 2010 DJF average Persistence Warm Arctic + sub-tropics NOAA ESRL

5. Westerly winds – DJF climatology U 250hPaU 850hPa NOAA ESRL

6. U 250hPaU 850hPa NOAA ESRL Westerly winds – DJF 2009/10

7. U 250hPaU 850hPa NOAA ESRL Westerly winds – DJF 2009/10 anomalies

8. Percentage of days with significant anomaly of same sign (>15m) Z500 – persistence…. NOAA Climate Diagnostics Bulletin Persistence (%) December 2009January 2010February 2010 Monthly Mean (dm)

9.  First month for which 60% anomaly correlation reached 10 days for Europe and northern hemisphere …and February forecast skill www.ecmwf.int

10. Arctic Oscillation (AO) North Atlantic Oscillation (NAO) Z500 P MSL P MSL anomaly NCEP reanalysis DJF 2009/10 Z500 anomaly

11. NAO and AO time-series NOAA CPC DJF average Arctic Oscillation (AO) North Atlantic Oscillation (NAO) Z500 P MSL

12. El Niño NOAA ESRL SST anomaly DJF 09/10 OLR anomaly DJF 09/10 NOAA Climate Diagnostics Bulletin