Written by: William R. Deedler, Weather Historian 11/17/2011
Interestingly when you are retired and not dealing with the daily grind and other stuff that comes up at the weather office, you actually get more of a chance to look at other weathermen's views on climate, the weather and in this case; their winter outlooks.
A very common gripe right now across the land is the relatively warm November and what does this foretell for the winter and their winter outlooks. I can't vouch for their outlooks but I can do a little more investigation on my own. Therefore, I went back and took all my analogue years at Detroit and plugged in the above normal Novembers that preceded the winters. Now mind you, November is only a little better than half way over but is does look like the month will average above normal looking at the extended models so we'll go with that assumption.
I found only three Novembers in the 16 analogues that averaged above normal and they were: 1928@42.5, 1964@44.9 (BTW: I feel 1964-65 is a good analogue winter along with 1974-75) and 1999@45.2 (new Nov normal now is 41.6). Here are the composite maps for those above normal Novembers and subsequent winter months that followed from my analogues. Note: pay attention to the below/above normal numerical departures since they change as some months/seasons were more extreme (like Jan for example).
As one can see just doing a quick scan, a
mild or warm November (in these analogues
anyway) did not foretell a mild winter. What
also is interesting is that the really cold air
did not really make headway into the country and take up residence until
sometimes as late as January when below
normal temperatures ruled in the north
(and what a change)! Decembers seemed to be the transition month relative to normal.
Some of you may be thinking: ok fine but with such a small sample of just three Novembers, how much does that really tell? I tend to agree, therefore I plugged in the normal to above normal Novembers and then, the sample jumped up to nearly half of my analogues (7 out of 16 but as you can tell, a cold November was still dominant). Anyhoo, when taking the normal to above normal Novembers in the analogue years, you get the following composites:
It's basically the same trend, Decembers were still somewhat mild but with a big change happening by mid to late December (or even as late as early January) which then persisted into February and even March with this bigger sample. I can recall some winters in these parts where the cold and snowy weather really didn't begin to around the holiday season with exact timing always a forecast issue. In my outlook I stated: the coldest weather relative to normal would be mid to/or late season and with this new data added, I'm sticking to it.
It seems this ole' switcheroo or flip-flop temperature trend was quite common when the
late autumn and even early winter season started out mild. I only had a few really mild
winters in the whole sample (but then again I have learned, never say never it CAN happen). The past trend here, however, does point to a notable change as the season evolves and like anything else, time will tell and we shall see.
Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian
