A Fab February for Flakes? | News
When I shared some of our long range thoughts about the winter back in early December, I presented my rationale for suggesting that our best shot at serious and sustained winter weather this season would come in February.
If you are new to this blog I would ask you to read the previous blogs so as to help add perspective as to where we stand today and to acquaint yourself with some meteorological jargon.
Today we are going to take a look at the month of February.
So, let’s see where we are: During the first week of the month we will be in a +PNA pattern which means a warm and dry ridge will rule most of the west, while a cold and potentially wet trough will dominate much of the east.
But a +PNA not being fed by arctic air is not that much of a scary thing when it comes to heavy winter weather. And it appears that is how the first few days of the month will go. That is not to say that there won’t be winter weather issues here between now and then, for there will be. But they may seem nastier only because of the lack of nasty weather this winter, not because they are inherently nasty.
Because air from Siberia will be directed back into Alaska and eastern Asia through the first few days of February, the air that reaches the continental United States will be primarily a polar/Pacific blend…chilly to be sure, but lacking in the bite that is so common during this time of the year. Simply put, anomalously cold air in Alaska and far eastern Asia does not “teleconnect” with unusually cold air in the central and eastern United States.
Also working against relentless bitter eastern cold is the state of convection in the Indian Ocean (the MJO) and recent solar activity.
All that being said, our analogue forecast has served us well this season and we are sticking with it, feeling that conditions are doing to turn in February.
In fact, the most recent ensemble runs of our three super computers (an ensemble is a blend of the same computer model program, run with slightly different initial conditions, to represent the chaotic nature of the atmosphere) are all suggesting that: the NAO and AO are trending negative; the lobe of the Polar vortex over AK will either weaken or detach from the main lobe over northern Canada in early February allowing for a cross polar flow; and, serious cold that looks to be coming to western Europe in about a week is often a precursor to like conditions in the eastern U.S. about a week to ten days later. These all teleconnect well to some significant winter weather issues in the eastern states as we move deeper into the month. We also think that March could live up to its reputation in Rochester of being a stormy and wintry month.
Given how warm and snow-free this winter has been around here, I am not ready to just go full-bore into a “sound the alarm, Old Man Winter is coming” mode just yet. But when this rationale is combined with our analogue forecast methodology, it all would sure fit pretty nicely, wouldn’t it?
So, look for spurts of wintry weather now through the first few days of February. Then, anytime from the 5th on, look for the winter lion to do some roaring. And I wouldn’t be at all surprised to see a harsh winter weather pattern lock in for a couple of weeks, especially later in the month.