Climate Forecasting Unit Climate of the Month January-February 2012 Melanie Davis

Climate Forecasting Unit Outline 1) North Atlantic/European region 2) Arctic Ocean 3) Pacific/North American region 4) Tropical Pacific

Climate Forecasting Unit Outline 1) North Atlantic/European region 2) Arctic Ocean 3) Pacific/North American region 4) Tropical Pacific

Climate Forecasting Unit The North Atlantic Oscillation (NAO) Positive phaseNegative phase Source :

Climate Forecasting Unit Source: l Observed North Atlantic Oscillation (NAO) Index Based on monthly 500hPa height anomaly fields for the three-month period centered on each month during January December 've phase

Climate Forecasting Unit February hPa Geopotential Height Anomaly From NCEP/NCAR reanalysis % climatology Source : January 2012 NAO +'ve phase = strong subtropical high pressure, strong Icelandic low pressure NAO -'ve phase = weak subtropical high pressure, weak Icelandic low pressure

Climate Forecasting Unit Surface Precipitation Rate Anomaly from NCEP/NCAR reanalysis % climatology January 2012 February 2012 Source : mm/day NAO +'ve phase = wet winter in Europe, wet in USA, dry in N.Canada/Greenland NAO -'ve phase = moist air in Med., drier in N. Europe, snow in E. USA

Climate Forecasting Unit Surface Precipitation Rate Anomaly from NCEP/NCAR reanalysis % climatology January 2012 February 2012 Source : mm/day

Climate Forecasting Unit Surface Air Temperature Anomaly from NCEP/NCAR reanalysis % climatology January 2012 February 2012 Source : °C NAO +'ve phase = warm winter in Europe, mild in USA, cold in N.Canada/Greenland NAO -'ve phase = moist air in Med., cold in N. Europe, cold in E. USA, mild Greenland

Climate Forecasting Unit Surface Air Temperature Anomaly from NCEP/NCAR reanalysis % climatology January 2012 February 2012 Source : °C

Climate Forecasting Unit Outline 1) North Atlantic/European region 2) Arctic Ocean 3) Pacific/North American region 4) Tropical Pacific

Climate Forecasting Unit January 2012 February hPa Geopotential Height Anomaly from NCEP/NCAR reanalysis % climatology Source : NAO +'ve phase = strong subtropical high pressure, strong Icelandic low pressure NAO -'ve phase = weak subtropical high pressure, weak Icelandic low pressure

Climate Forecasting Unit January 2012 February 2012 °C Source : Surface Air Temperature Anomaly from NCEP/NCAR reanalysis % climatology NAO +'ve phase = warm winter in Europe, mild in USA, cold in N.Canada/Greenland NAO -'ve phase = moist air in Med., cold in N. Europe, cold in E. USA, mild Greenland

Climate Forecasting Unit Source : Arctic Sea Ice Extent (from NSIDC) Dec. 2011

Climate Forecasting Unit Arctic Sea Ice Extent (from NSIDC) Source : Jan. 2012

Climate Forecasting Unit Source : Arctic Sea Ice Extent (from NSIDC) Feb. 2012

Climate Forecasting Unit Source : Arctic Sea Ice Concentration Anomalies (from NSIDC) Dec. 2011

Climate Forecasting Unit Source : Arctic Sea Ice Concentration Anomalies (from NSIDC) Jan. 2012

Climate Forecasting Unit Source : Arctic Sea Ice Concentration Anomalies (from NSIDC) Feb. 2012

Climate Forecasting Unit Outline 1) North Atlantic/European region 2) Arctic Ocean 3) Pacific/North American region 4) Tropical Pacific

Climate Forecasting Unit Source: Based on monthly 500hPa height anomaly fields for the three- month period centered on each month during January December Observed Pacific North American (PNA) Index +ve phase +ve,-ve phase

Climate Forecasting Unit 500hPa Geopotential Height Anomaly From NCEP/NCAR reanalysis % climatology Source : February 2012 January 2012 PNA +ve phase = above normal pressure W.USA, below normal pressure E.USA PNA -ve phase = below normal pressure W.USA, above normal pressure E.USA

Climate Forecasting Unit Surface Air Temperature Anomaly from NCEP/NCAR reanalysis % climatology Source : °C February 2012 January 2012 PNA +ve phase = above av. temp. W.USA/Canada, below av. temp. S.Central/E.USA PNA -ve phase = below av. temp. W.USA, above av. temp. E.USA

Climate Forecasting Unit Source : mm/day Surface Precipitation Rate Anomaly from NCEP/NCAR reanalysis % climatology February 2012 January 2012 PNA +ve phase = above normal ppt. Gulf Alaska to Pacific NW.USA, below normal ppt. Upper Mid-W. USA PNA -ve phase = opposite ?

Climate Forecasting Unit Outline 1) North Atlantic/European region 2) Arctic Ocean 3) Pacific/North American region 4) Tropical Pacific

Climate Forecasting Unit Source :

Climate Forecasting Unit Source : ex3.shtml ex3.shtml

Climate Forecasting Unit January 2012 Source : KK K Surface Surface Temperature Anomaly from NCEP/NCAR reanalysis % climatology February 2012

Climate Forecasting Unit Source : mm/day Surface Precipitation Rate Anomaly from NCEP/NCAR reanalysis % climatology February 2012 January 2012

Climate Forecasting Unit What do we expect from the ENSO cycle? Source :

Climate Forecasting Unit Summary  NAO: weak, but getting more positive towards Feb 2012  Warmer Artic Ocean, Artic sea ice depletion  PNA: slightly positive, stronger in Feb 2012  La Niña prevails and forecasted to continue a few months