More Details of the Winter Outlook

A preview of the winter forecast that is to be released later this week. It could get quite interesting this winter.
 

One thing I would like to mention is this: There are two VERY different scenarios (in my mind) that could play out. In one scenario, it becomes very similar to a hybrid El Nino winter, one in which a western ridge prevails over the Rocky Mountains and Western states, with a mean trough over the Central and Eastern United States. This would create a storm track across the Deep South and into the Western Atlantic, at which point some storms will travel up the coast and some will move out to sea. IF this scenario were true, then this would be the most common path of storm systems. This is already supported by what has happened this fall. What this would mean for the Midwest and Ohio Valley is a very cold and DRY winter, with a few periods of warmth as the Western ridge ejects eastward.  Areas along the Great Lakes would see above normal lake effect snowfall. Anywhere else in the Ohio Valley and Midwest would likely see a lack of precipitation and thus snowfall.

In Scenario TWO, this winter turns out similar to a La Nina winter hybrid. A strong Pacific jet stream sets up across the United States, with the development of a strong South-eastern ridge, while a cold Arctic air mass exists across the West and Western Canada. This would indicate a winter with near normal temperatures for the area (lower Great Lakes region), but above normal precipitation and near normal snowfall. Let me state this though: In this scenario, the first part of December will likely feature a split flow regime, indicating that the Lower Great Lakes and Midwest will probably be devoid of storm systems, but due to shallow arctic air masses, temperatures will likely be kept near to below normal. By very late December, the pattern transitions to a very strong Pacific jet, with a weak mean trough in the West, with a ridge of high pressure over the Northern Gulf of Mexico. This would put the storm track across the Midwest and through the North-eastern states. I believe that this has a likelihood of occurring due to the rapidly expanding snowpack across Western Canada and the Northern Plains. In that case, well below normal temperatures will prevail across the Northern Plains and the West, with near normal temperatures across our area, but with above normal precipitation. The East would feature near to above normal temperatures, but generally wetter conditions. I believe, if this scenario occurred, that this will last through mid-January or so, before transitioning to deeper Arctic pattern, in which the NAO/AO go strongly negative, and a backloaded winter would be the case for a good chunk of the East. February, in this scenario would be the best case for Nor'easters and monster snowstorms.

At this point, I really do not have much confidence in either of these. Either one may occur.

IN any case, I do believe this winter will likely be worse towards the end of the winter. At this point, its likely that once the winter turns for the worse over the area (cold arctic air), it will stay cold and dry. If Scenario two plays out (this is based off of the forecast that a Neutral ENSO will persist and could possibly become a weak La Nina by the end of the winter), then expect a warm, but possibly wet December through January, before colder weather builds into the region.

This is the less likely scenario in which a strong Pacific Jet stream works its way across North America.

The scenario in which the NAO/AO goes strongly negative during the months of January and February, leading to a back loaded winter.