A Quick Glance At The Lhasa Apso By Alex De La Cruz
The rapid expansion of snow and ice in the high latitude regions this fall combined with the recent behavioral trends in the Pacific Ocean and high latitude regions has me thinking this winter will be on the colder side. Such a trend could quickly reverse itself of course, but if the high latitude blocking continues as it has over the past 2-3 months, the winter will behave more similar to 2010-2011 and very different verses last year. A heavy rain period in the same time frame will be over the South-Central US and portions of the Southeast US. A line of icy conditions in the same period will be in the Oklahoma area extending through the Southern Midwest and into extreme south portions of the Northeast. Parts of the the Northeast will also be in the ice danger risk at this time. The NAO continues to battle it out with the prevailing western upper trough and it appears as though we will get a more favorable out of this late week storm system when it passes.
The Arctic is warming more than twice as quickly than the global surface average. In the past several pre-season prognostications, I have generally biased the forecast toward the warmer side of the 30-degree average since it has been statistically unlikely to get a cold winter relative to this average in recent years. 1994-1995 was essentially a 1-month winter (February) with the rest featuring mild weather and a lack of snow. The first threat for real snow comes during the middle of next week with some accompanying cold weather. The basis for this comes from looking back at ENSO-neutral winters and seeing the trend toward drier than normal conditions over New England. On a larger scale however, I am most interested in contrasting some of these bigger trends year over year. This is a map issued today, outlining the projected hazards over the next week or so. Below is the expected precipitation map from The Weather Centre. I know many readers consider themselves closet weather enthusiasts and might have read about ice in the arctic regions decaying to the lowest total coverage ever recorded in September.
Last year, this ridge feature was fueled by the prevailing La Nina, a generally positive Arctic Oscillation (AO) and a Madden-Julian Oscillation that never “cycled”. In the same context, we saw a spike in sunspot numbers just three or four months into this year, which led to a large heat wave in June into July. At the end of last year, I had noted how destructive the upper level ridge in the mid-latitude Pacific was on the winter as a whole. 1961-1962 was a relatively neutral ENSO winter with a very negative PDO and it was generally cold with average snowfall. I am going to forecast “average” this year which may seem rather tame but relative to other pre-season forecasts and relative to a more recent 10-year average this is actually rather bold and quite cold. The clouds will prevent readings from climbing to above freezing levels at MRG Friday but any more sunshine this upcoming weekend should allow for temperatures to reach the 35-40 range during the afternoons. This storm will be so significant, the entire east US will likely be affected by this storm.
Rain will be in place across most of the East US, but the heaviest may be north of the Gulf coast, where the drought is not as severe. If you have been with this blog for a while now, you may recall the times I have brought up a correlation between storms in East Asia and storms in the East US 6-10 days later. The heavy snow risk, while not as dangerous, is still a hazard. We can see a band of heavy snow extending from the Central Plains back through the Midwest and Southern Great Lakes into New England. This autumn has featured one of the strongest negative indices going back 50 years and this sets up a very interesting dichotomy. I did stretch out the moderate snow areas on this precipitation map but drew back the heavier snow areas. In the below map made by The Weather Centre, I outline a new map, the Danger Map.