Sorry for those that received some wet snow today. It should stay out of Eastern Ont. Taking a look at the next 8 – 14 days things are looking similar to the current week. This means the cool blocking upper level pattern may take a little longer to break down than anticipated. This upper level is known as the -AO (North Arctic Oscillation) meaning that cold, dry, Arctic air (as a cold air low pressure or known as the Polar Vortex) is allowed to filter down through Canada and USA. You can read more about it here: https://climate.ncsu.edu/climate/patterns/NAO.html
First up from the NAEFS from EC shows a warm pattern out west and cool in Southern Ontario and Southern Quebec:
Next is the upper level height pattern from the Euro and the GFS:
The GFS has a more spread out heights pattern with a sharper jet stream allowing the cooler air to filter down more into Ontario, Quebec and the east coast. The Euro isn’t as aggressive with the pattern, but still cooler. Therefore the much below normal pattern that TWN is showing for the next 14 days is likely a little more GFS based.
Still even the GFS starts to break the pattern down by day 12 (Saturday May 7). This GFS ensemble image below of the surface temps (the larger picture in the middle, which is the mean or average of all the little pictures, which are individual potential model runs of the GFS model) shows a more normal outlook eventually:
Given that the models sometimes struggle with how long these events last, it will be interesting to see what happens with this pattern. Still I think slightly below temps and drier conditions will prevail for the next 2 weeks. Any rain that arrives will be scattered and not that moisture laden. Remember our average is now pushing 15c and climbing, so slightly below to normal temperatures can still result in a nice day this time of year.
If this pattern holds true it might be difficult to obtain the above normal outlook the long range models showed in my May outlook. But you have to remember they are very long range and far from perfect, if they were I probably wouldn’t be talking about them and EC and TWN would be right every time 😉 Still I’m going to stick with the May average about 1c above normal.