Back at the beginning of August I released my preliminary winter 2012-13 outlook. I am now releasing my official Winter 2012-13 forecast with a few tweaks. A few months ago, it appeared that we were heading towards a strong El Nino pattern for the winter season. Now, that appears NOT to be the case. Instead, neutral to weak El Nino conditions are now forecast. That does have implications on the forecast, most noticeably along the northern tier and Upper Midwest.
I have modified my analog years, too, and these now include the winter seasons of
Several of these seasons are pretty strong fits based on current and forecast trends with the winter of 1976-1977 the strongest. I have done a calculated blend of these analog years to comprise this years outlook.
In my preliminary outlook, I was forecasting temperatures to be slightly above normal from Washington to the U.P. of Michigan. Based on the fact the El Nino conditions will be weaker, the Slightly Above Normal temperatures have been squeezed to only encompass the Pacific Northwest. I am also increasing the coverage of the Slightly Below Normal temperatures to cover much of the eastern 1/2 of the U.S. I have also increased the area of Below Normal temperatures to encompass the Ohio Valley but I am forecasting the depth of the cold, with respect to normal, to not be as excessive.
With regards to snowfall, the biggest change to the forecast was in the northern tier, again. Snowfall will likely be near to a bit above normal for most locations from the Rockies eastward. I will provide a detailed breakdown of the snowfall forecast for several locations this week.
I will also provide a more detailed, site specific, breakdown to the temperature forecast later this week, too.