As you can tell by now; I've been looking well out in time and space the evolution of the upper wind pattern projections and resultant surface expectations for the emergence of March. And thus; the headline for this write-up or blog. It does look like March will arrive as a cold lion but stormy, we'll have to just wait and see that far out.
Curiously; the seeds of March's weather and temperature trends actually were planted several months ago in my Winter Outlook; sent last November.
"Letter n /next to the analogue winter years at Detroit/ - A cold November preceded these winters in all of Southeast Lower Michigan - like this present November. Interesting, half of the winters were also preceded by a cold November. In, the other winter years; the temperatures in November were normal or above normal temperature. Next to the years under Precipitation column /Detroit/; you will notice a "m" next to seven of the years; that indicates a below normal, cold March".
That was seven analogues out of 12; or a near 60% chance of a colder, below normal March. This is a pretty decent analogue projection - but we'll have to wait and see. Colder Marchs occurred in 1915, 1941, 1964, 1969, 1980, 2003 and 2005; so pretty much scattered throughout the years. Snowfalls for March and April analogues can be seen in the snowfall section.
Winter Analogues
OK, on to next week, the last week of February into the first few days of March...
While milder weather will be welcome relief as the weekend approaches, it will be accompanied by showers - maybe a strong thunderstorm or two on Saturday- before moderately colder air arrives on potentially very strong gusty winds late Saturday into Sunday. Meanwhile; the atmosphere will be recharging further north for a couple of aggressive Arctic plunges. At this time, it appears the first will arrive the last few days of February; while the second arrives rather quickly on the heels of the first, during the first few days of March. While no major storms are expected to accompany them, I wouldn't ignore that possibility. The models need to get a better sampling of the progression and dynamics of the atmosphere that far out - basically a week. At this point, we are interested in the prediction of the likelihood of a pattern change evolving next week and not so much, the particulars - as it's too early. In addition; this time it doesn't look like the core of the Arctic air will come overhead as in late January's visit from the Polar Vortex as that should hold further north.
Most meteorologists and weather enthusiasts would immediately note the possibility of an Omega/Greenland block developing next week in the northern sections of North America. Interestingly; the milder Pacific subtropical jet also remains strong and should also be a player later next week and the following. This is exactly the pattern we have seen all winter and has induced the roller-coaster pattern seen so vividly this winter.
Omega Blocks tend to stall the atmosphere's general progression east and thus, lock-in ongoing patterns into place under them for their duration. Again; hang on as the bumpy ride looks to continue into at least mid March. It will be very interesting to see the evolution of the pattern and if it will actually develop into a strong block at the higher latitudes - and more importantly, if it holds. Both the GFS and Euro drop down a huge, strong Arctic High pressure on the back of the second Arctic surge during March's first weekend.
GFS outlook the first of March...
Euro is very similar that far out...
The outlook for March from the CFS seems to agree with the extended guidance and also the analogues take on March.
More updates on my Facebook Weather Historian page on this pattern change next week if warranted.
I'd like to thank Jane Herrick for allowing me to use her recent beautiful picture of Lake Superior from Duluth on my blog!
Making weather fun while we all learn,
Bill Deedler - SEMI_WeatherHistorian
