The end of January signals storms, Arctic air
Meteorologist
Wednesday, January 28, 2015, 1:33 PM - In the wake of a stormy week in eastern Canada, a fresh shot of Arctic air will mean a frigid start to February for many. Will anyone manage to hang on to the remains of the January thaw? Read on to find out.
As the ongoing nor’easter departs mid-week, a ridge of cold (though not truly Arctic) high pressure will set up shop over the East. With this cold air mass in place, attention will turn to a new storm system developing over the Missouri River valley which will bring widespread snowfall from southern Ontario through Quebec late this week and impact Atlantic Canada into the weekend.
The following image captures the new storm beginning to wind up over the Missouri River Valley on Wednesday evening.
As moisture from this system begins to overspread the cold air in place at the surface, snow will begin to break out over southern Ontario on Thursday morning, increasing in coverage from west to east throughout the day. Though it’s a bit early in the game to begin discussing specific accumulations, a large swath of 5-10 cm seems likely, with locally higher amounts. The details of exactly where the most snowfall will occur will come into better focus as we get closer, but this forecast image for Thursday evening illustrates the widespread snowfall potential (in shades of blue).
The storm will continue to push east on Friday, and by Friday night will be bringing snow, rain, and wind to the Maritimes. The exact track of the system will determine exactly where the rain/snow line sets up, but many of the same areas of New Brunswick, Nova Scotia, and PEI expecting big snow totals from Tuesday’s system could be in the crosshairs once again.
Though this storm won’t have quite the pressure gradient to work with that the early week system has, winds will still be a significant concern this weekend for coastal areas. This snapshot from Saturday morning shows gusts of 70-90 km/h (in shades of orange) will be possible from this storm.
The storm wraps up over Newfoundland and Labrador on Sunday, but this will not bring the end of our active storm track for Eastern Canada. The long range forecast models, as well as the overall atmospheric pattern, suggest that the early part of February will remain active for the East. Though the details at this stage are still unclear, it’s possible that we could have our next system on the board developing by late this weekend.
Arctic Air Returns
This next image shows the atmospheric pattern setting up for the first part of February, and for those of you who have been following the long-range forecast throughout the winter, it should look awfully familiar.
After a brief breakdown of the west coast ridge that allowed our January thaw to take hold, the pattern should revert back to the set up which has given us several brutal arctic outbreaks so far this year. Once again, the influence of the Pacific source region is confined to the west, while cross-polar flow will open the way for an attack of Siberian cold.
This image shows the effects of this setup on temperatures as we move into February. Areas of green and blue show forecasted surface temperatures below seasonal, and the highlighted area shows the core of the coldest air, where temperatures will average more than 8°C below normal for an extended period of time. As this forecast guidance illustrates, almost all of Canada will be heading into a cold period as we move into February. The only areas that should hold on to near or slightly above normal temperatures will be Southern BC and southwestern Alberta, where the Pacific influence will remain in place.