Brett Anderson

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Quick Update on the Crazy Weather

October 23, 2013; 5:48 PM ET

I apologize for not posting a blog earlier this week, especially for such an active pattern.

Paul Pastelok, who is our lead long range forecaster here at AccuWeather.com, along with Bob Smerbeck, who is one of our best forecasters and myself are currently attending NOAA's 38th annual climate diagnostics and Prediction Workshop down at the University of Maryland.

Paul and I attended this same event last year in Fort Collins, Colorado. The event further educates us on the latest science and modeling efforts from the Climate Prediction Center, GFDL and other agencies across the U.S., Canada and other countries across the world.

Once again, we have gained a good deal of information and I will share some of that with you at a later date.

I will be back in the office on Friday.

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Quick update on the weather (sorry, no graphics since I am doing this remotely

The Wednesday session was shorter so I have found some time to look at the weather and post a quick summary of my thoughts.

Keep in mind, I have been posting some comments on the pattern this week on my twitter @BrettAWX, which is easier to do when I am on the road or in one of the sessions.

1. Unseasonably cold air crossing the Great Lakes through early Friday will continue to produce pockets of accumulating snow, especially over the higher terrain not too far south and east of Georgian Bay in Ontario.

I can see several centimeters of snow accumulating in the region outlined between Markdale, Ont to Borden and Shelburne through early Friday. The best chance for accumulating snow will be at night and in the morning, then some of the snow will melt during the daylight hours.

Areas just west of Highway 11 in the Gravenhurst region might also get a small, slushy accumulation into early Friday.

For the rest of southern/eastern Ontario, there will be some snow showers and flurries mixed in with rain showers, but with little or no accumulation as temperatures will be far enough above freezing.

Downwind and right along the lake shores the precipitation will be mostly rain

showers as the lake water temperatures are at least +13 C. and that will warm the surface air over the land close to the lake.

2. A storm will bring a cold rain to Nova Scotia tonight and early tomorrow. Even though it may look cold enough aloft for some snow on the western edge of the storm, the low level temperatures will be too warm to support frozen precipitation.

3. A significant clipper storm will dive southeast into Ontario Friday night. I believe there could be a brief period of steady, wet snow from Sudbury to North Bay, Ont during the Friday night to Saturday morning time period before it changes to rain as the low level temperatures rise with the southerly flow increasing. A place like Timmins will likely see mostly snow with a small accumulation.

For Ottawa and the Saint Lawrence Valley this event will be rain as the temperature should rise enough during the day Saturday before the precipitation starts.

4. A significant cold front will push south through the Prairies Sunday into Sunday night as an Arctic high quickly builds in behind the front.

As the front moves in there will likely be a brief period of rain from Alberta to Saskatchewan starting in the north and quickly progressing to the south through the evening. As the cold air charges in the rain will quickly go over to snow with a general 3-6 cm in northern Alberta and Saskatchewan Sunday and 6-12 cm over southern Alberta with locally higher amounts over the foothills and mountains.

Roads in this region could get slick in a hurry later Sunday as the temperature crashes. Expect temperatures to drop to near -7 to -9 C. over Alberta by early Monday morning.

The reason this will not be a big storm is that the front will be moving quickly and the upper-level circulation associated with the front waits to strengthen over western Montana.

Also, it will get quite windy behind the front with gusts in excess of 65 kmh from southern Alberta into south-central BC.

5. Dry pattern holds over BC into Tuesday, then some light precipitation possible mid-week next week as the western ridge breaks down.

6. The overall pattern looks noticeably milder across eastern Canada and the eastern U.S., especially after November 5th as the cold retreats well to the northeast as the NAO goes positive. I also expect a return to more normal mid/late fall conditions (meaning more rain) over BC.

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com

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About This Blog

Brett Anderson
Brett Anderson covers both short-term and long-term weather and storm forecasts for Canada in this blog for AccuWeather.com.