8:30 AM CDT | November 19, 2017
Our current weather pattern began in the first week of October and continues to develop. Based on the recurring cycle theory, a unique weather pattern develops each fall and cycles through the following summer. We will not know its cycle length until we see the features noted in the first week of October return. What did we see at the start of the pattern? We saw two fairly strong systems move across the Plains from October 6th through the 10th. This is a loop of the systems as they tracked through the region.
Within the next 14-18 days, we should see a similar scenario repeat with more energy coming out of the Western US. Once this happens, we will have a general idea of the cycle length. A few long-range weather models suggest some pieces of energy moving into the Plains from the west during the November 29th to December 6th time-frame. We will be watching the trends.
Also worth noting is that the Arctic Oscillation has finally dropped into negative territory. The index became negative yesterday and has continued today. This is the much-anticipated dip that we have been discussing for weeks. For more information on the Arctic Oscillation, see previous posts on the homepage. What is important to note is that when the AO is negative, blocking increases in the Arctic region which usually forces the jet stream to dip southward. The effects of it going negative are typically not seen for several days. We will have to see how this all sets up sometime after the Thanksgiving holiday. Hopefully, we see a more active period return with better opportunities for moisture. You can get the latest on the blog and Facebook page.