Looking back over the course of the last couple of months, the general theme of being active and warm is apparent. While not all areas saw above-average temps and rainfall for both months, many active and hot periods have ensued. Since we have entered into the last month of Meteorological Summer, I want to take some time to look ahead and relay my thoughts on the remainder of summer. Whether we like it or not, Autumn will be here before we know it, so I will discuss my thoughts on Autumn and even throw out some early musings about the upcoming winter.
Looking at the remaining 28 days of Summer, I see quite a bit of warmth, but nothing too overwhelming. Utilizing some of our organic forecasting methods as well as looking at climatology, I think it is safe to say that we will end the month at least a degree or two above-average in many locales. In the more immediate term, after a period of above-average temps we are going to be slipping back to near or slightly-below average temperatures for August 5th thru the 8th. However, looking overseas, we see a very strong ridge currently parked over Mongolia and Manchuria, which does not budge until around the 7th. This is a good indication that a period of warmer, possibly well-above average, temperatures will ensue by mid to late next week. Beyond this period, we look at what occurred in the Bering Sea to help determine what will occur after the mid-point of August. Over the last few days, the 500mb pattern in the Bering Sea has been fairly baggy with near normal heights. Therefore, I would expect pretty benign conditions with near-average temperatures for the third and early part of the fourth week in August, with a weak cold front possible around the 17th, which could spark off some showers and thunderstorms. Following that, the next item worthy of noting is the return of a fairly deep trough to the eastern half of the Bering Sea, which is likely a good indication of a sharp cool-down around the 25th of August.
All-in-all, I do not think we are going to see August average extreme one way or the other. When it is all said and done, slightly above average temperatures are likely, with potentially drier than average conditions for most areas. Rainfall is a tough call though as dealing with summertime thunderstorms means very localized rainfall totals. So one location may end up above-average, while another location in close proximity is below-average.
Looking into Autumn and beyond it begins to get a bit tricky. However, that said, I do believe we see a relatively warm Autumn this year. When transitioning from an El Nino to a La Nina, we tend to see a split flow develop in the Autumn months which leads to warmer than average and potentially drier conditions. As we head into September, we will begin to see more extreme temperature swings as the jet stream re-amplifies with the lowering sun angle. In fact, we are losing an average of 2-3 minutes of sunlight per day thru early November as the earth has begun to quickly tilt back on its axis, which is the same reason the jet stream begins to re-amplify in earnest by mid to late September. The temperature contrasts from north to south cause these high-altitude winds to increase, thus causing a more amplified pattern, and increased temperature swings. However, due to the developing La Nina, which will likely keep us warmer than average, with fewer troughs digging in and bringing cooler airmasses.
So all-in-all, I am expecting a warmer and possibly drier Autumn to take place this year, though nothing too extreme. That does not mean we will not have cool-periods, but overall we will see warmer than average conditions. The only exception to these rules may be in November, the last month of Autumn, as we could see Old Man Winter begin to try and bulldoze his way into the picture a bit early this year.
Brief Winter Musings
There are a large number of factors that go into trying to accurately forecast the upcoming winter season. However, there are several indications that areas from the northern Great Plains into western Great Lakes may see a rather rough winter this year. One of the years being mentioned as an analogue by some is the winter of ’83 – ’84. This winter featured the coldest December on record for much of the state of Minnesota. While this analogue might look good to winter-lovers such as myself, I want to caution you from buying too heavily into these suggestions. No two seasons are ever alike, and I have a hard time buying into the extreme ’83 – ’84 analogue. Just to put that year into perspective, the average December temperature in Minneapolis is 19.7°F and the coldest December of the last ten years was 2013 when Minneapolis had an average temperature 12.4°F. In December of 1983, the average temperature in Minneapolis was 3.7°F, the coldest ever recorded since 1872. Should history repeat itself, again I do not think it will, the December of 2013 would be warm compared to what Mother Nature has in store!
What I do see is an active and potentially colder than average winter for the region. We should see an active storm track in or near the region for much of the winter, especially the first half, with a potentially front-loaded winter this year. Only time will tell, but those winter-lovers out there, you should keep a close eye on this winter season as we get closer!