The overall pattern across North America over the next two weeks will dominated by a suppressed jet stream across the central U.S. which will allow cold air to continue to invade the Prairies and northern Plains.
Ongoing storm in the East
The storm that brought the ice to large portions of Ontario last night and this morning is bringing the snow to parts of eastern/northeastern Ontario and into Quebec now through this evening.
I do think enough warm air moves in aloft for some sleet in Ottawa and Montreal, which will reduce the potential for heavy snowfall. As we showed yesterday, snowfall amounts will steadily increase just to the north of these cities as precipitation will be mostly or all snow with over 25 cm in some areas.
Steady snow will also spread into the Maritimes this afternoon or evening with mixing or a change to rain along the south coast.
More snow for the Prairies
A Pacific system will dive southeastward this weekend spreading a band of accumulating snow across Alberta and western Saskatchewan from Saturday afternoon into early Sunday morning. Certainly could see widespread 2-8 cm with locally 15 cm across central and southern parts of Alberta.
A strengthening storm will then turn northeast toward northwest Ontario late this weekend and into Monday, likely putting southern Manitoba under the threat for heavy snowfall from Sunday afternoon into Monday morning. The track of this storm is favorable for significant snow from Brandon to Winnipeg, with the potential for 15-25 cm in some locations, while much of southern Manitoba gets at least a general 8-15 cm.
Will it ever warm up in the Prairies?
While there may be a day here and there that the temperature approaches normal across the Prairies, it appears that the next 10 to perhaps 14 days will remain unseasonably cold (6-12 C. below normal on average) as a persistent, upper-level high sits near the northwest coast of Alaska and forces the Arctic air directly down into the Prairies. The period from this Sunday to next Sunday looks to be the coldest relative to normal with this pattern.
The PSU EWALL GFS ensemble temperature anomaly plots below shows widespread colder than normal temperatures
Tuesday (April 16)
Next Sunday (April 21st)
There are signs that the upper high begins to break down after the 25th and that a more zonal flow of Pacific air starts to bring temperatures closer to normal. Let's hope!
Other impacts of the pattern
While the cold dominates across the Prairies it does look like a milder pattern will set up across Atlantic Canada next week. Hopefully, this will make our friend Brent in PEI a little happier.
Just took a look at the new ECMWF weekly long range and it is hinting at a return to more blocking over northeast Canada and Greenland in early May, which would keep much of central and southeastern Canada on the cool side the first two weeks of May relative to normal.
This type of pattern might also suppress the severe thunderstorm threat in early May across the southeastern U.S. as the higher dewpoints from the Gulf of Mexico get cut off.
Some forecast model clues through the end of August and an update on global sea surface temperatures.
Tornado threat into Tuesday from southeastern Saskatchewan to northwest Ontario.
Latest weekly clues to the long range forecast through mid-August.
Major storm for the Prairies early next week could bring heavy rainfall and severe thunderstorms.
Severe thunderstorm threat later Thursday and a general look at the upcoming weather pattern.
Latest long-range update and a look at global ocean temperatures.