A nice band of snow moved across parts of Nova Scotia today, and now it's Newfoundland's turn. Expect a period of heavy snow (2-4 cm per hour) over southeastern Newfoundland later this afternoon into this evening, including the St. John's area. Total snowfall generally 12-22 cm, but some localized higher amounts.
This same system was a bust for forecasters and snow lovers for eastern New England (Boston to Portland) last night and this morning as the upper-level energy escaped to the east a little quicker than anticipated. Also, a small storm formed east of New Hampshire earlier this morning. Since this storm was stronger than predicted, it basically weakened the surface trough that was projected to set up across the region, thereby greatly limiting the amount of converging (rising) air and killing the chance for decent snowfall. This little storm will brush the Cape Sable area this afternoon with another round of snow for a few hours before it moves out into the open Atlantic.
A clipper storm will track east-southeast from Alberta to the northern U.S. Plains midweek, bringing a band of accumulating snow to the north of the path. There will also be the usual upslope snow into the Canadian Rockies (most on the western slopes in BC) with this feature.
The map below shows the expected snowfall from Wednesday evening through Thursday evening....
Models differ on outcome of eastern storm late this week......
The ECMWF model shows a significant coastal storm later Friday into the weekend from the Northeast U.S. into the Maritimes, leading to the potential for significant snowfall. The GFS model is weaker and much farther south and east, meaning no big storm. My feeling at this point is that we may be seeing the typical error of the GFS several days out that shows the energy quickly racing out into the Atlantic. I suspect we will see a gradual correction north and west over the next few days.
Current GFS Idea......
On the other hand, the ECMWF may be a bit too far north and west, especially with all this cold air in front of it.
Latest ECMWF idea.....
I lean closer, but not all the way to the ECMWF idea with the potential for a significant snow from the Middle Atlantic coast up into eastern New England then Nova Scotia/PEI and perhaps southern/eastern New Brunswick.
Arctic air will dominate across much of eastern Canada the rest of this week followed by a recovery for next week. But with that recovery in temperatures we may see a turn to stormier conditions for Ontario and Quebec. More on that later.
The new ECMWF weeklies are out and I will post them Wednesday morning.
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Storm snowfall forecast map for Monday/Tuesday and comments.
Latest weekly clues to the long range into early March.
Updated storm snowfall forecast map for Atlantic Canada for the storm today into early Saturday.
Storm snowfall forecast map for Friday into early Saturday over Atlantic Canada.
Stormy pattern shaping up for Atlantic Canada.
An update on the wintry mix coming into parts of eastern Canada tonight into Wednesday.