Synoptic weather pattern controls on temperature in Alaska

Data from the National Centers for Environmental Prediction/National Center for Atmospheric Research and European Center for Medium-Range Weather Forecasts 40 year reanalyses are used to relate large-scale synoptic circulation patterns to local weather at several locations across Alaska. These results are compared to available National Weather Service observations to demonstrate the utility of this method such that it can be applied in future work at locations where local observations are not available. The focus of these comparisons is on surface observations of temperature. The results from the two reanalysis data sets match well to each other and to the observations. Synoptic patterns associated with warm/cold days at five National Weather Service stations representing different climate regions throughout Alaska are identified. In addition, a method to attribute a change in climate to circulation and noncirculation differences is applied to a known climate shift, the Pacific climate shift of 1976, which was associated with an increase in temperatures throughout Alaska. The results from this analysis show that general warming rather than changes in circulation is primarily responsible for the increase in temperatures after 1976.