Ntxw wrote:With the way things are setting up over the Pacific, I only see two years that really stick out. 1976 and 1977 as analogs thus far when trying to match SST's. Some pre 1950 years but data back then isn't reliable. 2009 is next best fit. Should have a better feel in October looking at atmospheric responses.
Right. Here's a NWS webpage that really highlights what you're speaking of in terms of analogue years, especially 1976-77:http://www.erh.noaa.gov/iln/climo/summa ... ld1977.php
Good ol' NWS-Wimington, responsible for Cincinnati and the home of one of my favourite unis, Miami University in Oxford.
What led to this extreme period of cold temperatures? A very amplified pattern, meaning troughs of low pressure and ridges of high pressure at all levels of the atmosphere were far stronger than normal for the time period. The Ohio Valley, unfortunately resided underneath an extremely strong and deep trough of low pressure, what was in fact a very displaced Polar Vortex, which is a feature common in most winters over higher latitudes in Canada. Below is a chart of the average deviation from normal of the 500mb surface through this period. Hues of purple indicate that these 500mb heights were significantly lower than normal, in some cases over 200 meters below normal. These values are extremely significant and rare when considering a 30-day average. This overall weather pattern is the ideal setup for outbreaks of frigid air in the eastern United States. A west coast ridge of high pressure (yellow hues) and extreme blocking (very strong ridge of high pressure in red hues) just off the east coast of the United States near Greenland.
Notice that we have a *similar* pattern setting up here. I say similar because it isn't exactly the same. In the winter of 1976-77 we had blocking over the NE Pacific and Greenland, but the blocking was far stronger over and just west of Greenland during that period of time. Whilst it remains too early to say that the current pattern will remain as it is, I'm in agreement that this is a good analogue and something to watch as time passes.