The great melt of the snowpack across much of the Midwest is almost complete as temperatures fly into the 40s and 50s across a great expanse.
Records in Waterloo, Iowa and Rockford, Illinois, among several other locations, are in jeopardy Thursday afternoon as temperatures pushing into the 50s along and even north of I-80. While short-term the temperatures will remain above normal, the longer term is a bit questionable.
We discussed the cooler mid/late February last week in my last post.
While the temperatures we are dealing with today likely will be gone, just how cold do things get? Looking at long-range forecast models, the American GEFS and European Ensembles both are hinting at cooler weather in the southern/southeastern US by Feb 14-16.
Meanwhile, in the Midwest/Great Lakes, there have differing views on above-normal or near-normal temperatures. This is in part due to the fact forecast parameters we use to get a handle on long-term trends are not real strong one way or the other. Also a lack of snowpack northwest of the region that would help chill the air that comes south.
The NAO and AO teleconnections, which are quite useful for long-range forecasts, show a dip into negative territory (this does not mean negative temperatures, this is just an index for patterns). When these both follow that same path, in winter this tends to be a colder signal for the central US. However, both are not very amplified with it dropping to a mean of about -2.
This not very strong dive is part of the reason the models are likely inconsistent with the strength of the cold, and why I am a little pessimistic as well.
One thing missing is snow cover. Above you can see the updated snow depth across the US and southern Canada. Vast stretches of the Plains and Canadian Prairie have little if any snow. The later we get into the winter season, the more big cold outbreaks rely on snow to modify airmasses. Without this snowpack, things just cannot get as extremely cold.
As days get longer and the sun angle increases headed into the spring equinox, it’s that much harder to get a cold outbreak.
I am watching things closely…
-Meteorologist Nick Stewart