Environment Canada's senior climatologist says he's surprised how long winter is lasting on the Prairies and warns cold temperatures could persist through the end of April.

David Phillips blames a polar vortex for the spring cold snap.

'Very yo-yoish'

"At this time of the year, it's often back and forth, up and coming, very yo-yoish kind of weather, where you're getting winter trying to hold on and summer wants to get a foothold," Phillips said Monday.

"And yet the war is being won by winter. Old Man Winter is clearly the bully in this particular situation and has got a grip on the entire West and is not letting go."

Temperatures on the Prairies were still in the negative double digits Monday with lows reaching –27 C with the wind chill in parts of Saskatchewan and Manitoba. In southern Alberta, a snowfall warning was calling for up to 20 centimetres of the white stuff.

A typical temperature in Lethbridge, Alta., at this time of year is 11 C, Phillips said. It was –7 C Monday afternoon. Other parts of the Prairies were as much as 16 degrees below normal.

Cold air like molasses

Phillips said the duration and intensity of cold the region is currently experiencing hasn't been felt since 1970.

Environment Canada's record low for April 2 in Saskatoon is –28 C, which was set in 1954. The temperature there on Monday morning was –21 C.

"This cold air, it's just entrenched. It's like molasses," Phillips said. "It's filled all the nooks and crannies."

The Weather Network's forecast centre manager, Doug Gillham, said a blocking in the atmosphere around Greenland and over Alaska is causing the chilliness.

While Phillips said it might not warm until toward the end of the month, Gillham anticipated temperatures will start approaching seasonal — upper single digits — by the middle to end of next week.

The conditions should delay spring runoff, he added.

The key, he said, will be not having a major swing in temperature mixed with heavy rain.