It was a messy night, but we are now on the warm side of the front and it feels like spring …for the time being!  By midday tomorrow, the trailing cold front will swing down with a wind shift to the north and another blast of very wintery temperatures.   On the bright side, it will be J

If I stopped there, I would probably have more friends than enemies;  but I would not be doing my job  if I didn’t tell you about what I’ve noticed in the upper levels of the atmosphere.

There is an area of vorticity off the west coast that seems to want to come together with an upper level trough taking shape over the American mid-west.  

Keeping in mind that, for us, the end result – weather at this coast- would be more than 160 hours from now, and that things could change,  I think we are in for an intense winter storm.  The forecast upper air pattern would support the development of a Nor’easter:

By Sunday, as the energy comes together over the American mid-west, a cold high coming across northern Quebec will settle over Labrador and become almost stationary!  The newly formed storm will push eastward, heading for Long Island NY, where the easterly air flow it will pick up moisture from the ocean and feed it back into the intensifying storm.

Back to the blocking high: I think it will develop a ridge, that'll extend southeastward from its centre; that’s a big part of the puzzle.  That ridge would block the storm from swinging out to sea and steer it up along the coast. 

By Tuesday night, we should start feeling its impact: snow and strengthening east to eventually northeasterly winds.   The blocking high will slow the system down and for that reason I think we could be in for a significant storm.  

Snowfall amounts could be in the 20-30 cm range with winds over 90 km/h.  Again, I hesitate to put any numbers when the system is a week away.  Please follow me here and nightly on CTV News for the very latest over the next few days.

 

Chief Meteorologist

Cindy Day