Nice high resolution image of the center of the intensifying Atlantic storm as it passed just southeast of Nova Scotia earlier today. Also, note the thin, curvy line on the right side of the image. That is Sable Island, which is located well off the southeast coast of Nova Scotia. As you can see, a dry slot (clear area) on the eastern side of the storm rotated up and over the island, allowing the sky to clear. Image courtesy of MODIS.

Here is a view of the island from aircraft. The island has a population of 5 and plenty of wild horses. Image courtesy of Wikipedia.


Some thoughts on the overall pattern into next week..............

--It will remain unseasonably mild from the Prairies through Quebec into most of next week, with temperatures well above-normal, especially during the middle of next week. I guess we could call it some late Indian Summer!

--Strong westerly flow in the mid and upper levels of the atmosphere will continue to direct, fast-moving, moisture-laden fronts through British Columbia into early next week. Ski areas should do well in terms of snow, especially mid and upper slopes. Expect drier conditions by midweek as the storm track shifts more into the Pacific Northwest.

--Much of Ontario looks toasty by November standards during the middle of next week.

By the following weekend (14th-15th).........

--Very cold pattern setting up over Alaska.
--Stormy pattern returns to BC, especially in the central and north.
--Still unseasonably mild over the Prairies.
--Most of Ontario looks dry and relatively mild.
--Chilly pattern returns to Atlantic Canada.

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A series of moist, Pacific fronts will continue to soak western portions of British Columbia through Saturday. There will be a brief break in the action on Sunday, before the next front swings in with more rain and wind for Monday.

I was looking at the forecasted atmospheric soundings through Saturday and they show a completely saturated atmosphere from the surface to 23,000 feet, which tells you that this front will be loaded with moisture.

How much rain are we talking about through Saturday?

Coastal range east of Vancouver, below the snow level........75-150 mm (3-6 inches)
Vancouver region.........30-60 mm
Western Vancouver Island....50-125 mm
Eastern Vancouver Island......15-25 mm

Snow levels in the Coastal range will slowly fall tonight through Friday and into Saturday. Snow levels will fall to near 3,000 feet during the day Friday and then to between 2,500 feet and 3,000 feet on Saturday.

Snowfall across the mid and high slopes of the Coastal ski areas will range from 30-90 cm through Saturday (1-3 feet).

The wind will not be too much of an issue (there have been many worse storms in terms of wind compared to this) through the period, but it does look like the coastal range will have their windiest period on Friday.

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Still a tough call on the snowstorm in Nova Scotia. We are pretty confident in the track, but there is still plenty of uncertainty with the precipitation type (rain vs. wet snow) and changeover times for Friday.

The low level temperatures will be critical to precipitation type over Nova Scotia and Prince Edward Island. One computer model is rapidly changing the rain over to a heavy, wet snow over central Nova Scotia during the day Friday, while another respected model is much slower to cool the low levels, resulting in a delay in the changeover, and thus, much less in the way of snowfall.

If you just look at the track, you would say that most of central and northeastern Nova Scotia, including PEI would get a heavy snowstorm, but we have to keep in mind that it is still early November and the ocean waters are still relatively warm. On the other hand, the storm will be intensifying and generating its own cold air as the rising air in the northwestern quadrant of the storm results in a strong cooling of the entire atmospheric column.

I am not going to fiddle with the snow map that I had from yesterday. I still think it is a good compromise, but let me state that I do believe there will be some interior and higher elevated areas over north central and northeastern Nova Scotia that will end up with at least 20 cm of snow by Friday evening.

The immediate south coast will see mostly rain out of this, as surface temperatures will not be cold enough, but it may go over to snow before ending later Friday.

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Everything is still on track for a coastal storm to intensify rapidly south of Nova Scotia and east of Cape Cod Thursday night. However, most of the computer modeling has trended a little farther south and east with the track, which would likely shift the axis of heavier snow into northern Nova Scotia, while leaving southern New Brunswick on the fringe.

The key to snowfall amounts will be the timing of the change from rain to snow over Nova Scotia and Prince Edward Island on Friday. Precipitation over southern New Brunswick should be mostly snow, but again, the bulk of it will be light. If it ends up very light, it may actually end up being a very light rain or drizzle, since the low levels of the atmosphere will be above freezing and smaller, lighter flakes of snow will have more time to melt before hitting the ground.

At this point, I think the Cape Breton Highlands stand the best chance for getting over 15 cm of snow. The wind will also be a major factor in this region as well.

Snow will taper off from southwest to northeast Friday evening over Nova Scotia.

This will be a rain event for southeastern Newfoundland Friday and Friday night, but I do think there will be a band of heavy snow accumulations up through central and northern Newfoundland.

Here is the map that we drew up earlier today..........

Any snow that does accumulate will be quickly wiped out by Sunday afternoon as southwesterly winds usher in a nice warming trend.

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Computer models are at this early stage surprisingly in very good agreement with the developing nor'easter later this week, which will impact New England and most of Atlantic Canada.

There is strong consensus for a rapidly intensifying storm tracking from east of Cape Cod to just south of Nova Scotia by Friday morning.

This type of storm and track would normally bring blizzard conditions to a large part of the Maritimes, extreme eastern New England and central Newfoundland during the winter, but it is still only early November, so low-level temperatures will be borderline due to the proximity of the still mild ocean water.

For most areas in the Maritimes, this storm will initially start as rain then change to a heavy, wind-blown, wet snow from northwest to southeast during the course of Friday as easterly winds gradually shift to the northeast and then north.

The storm will slowly weaken early Saturday as it tracks up toward eastern Newfoundland, so we are looking a a rain event over the Avalon Peninsula later Friday into early Saturday, but central and perhaps western parts of Newfoundland could be in for a prolonged period of snow and wind Friday night and into Saturday.

This storm is also going to be a big wind maker from Thursday night through early Saturday across the Maritimes. The strongest winds across the Maritimes will be from Friday afternoon through Friday night. In general, expect sustained winds of 40-60 km/h with gusts to 80-90 km/h from coastal New Brunswick through most of Nova Scotia and PEI. Just offshore and over some higher points, we may see gusts to 100 km/h.

I will produce a snowfall forecast map late Wednesday, as it is just a little too early to do that now, but I will list a few locations right now and what I think could happen (very preliminary)......

Saint John, NB....... The storm should be mostly snow here. Right now, I would lean towards snow beginning early Friday morning and then tapering off early Friday evening...... 7-13 cm of snow.

Fredericton, NB..... This area will be near the western and northern edge of the accumulating snow..... 5-10 cm

Moncton, NB.... Rain begins late Friday morning then changes to snow sometime in the afternoon. Snow tapers off Friday night....... 10-18 cm

Amherst, NS....... Rain changes to wet snow late Friday afternoon and continues into late Friday night..... 10-20 cm

Charlottetown, PEI... Rain to wet snow Friday evening. Snow tapering off late Friday night....... 8-15 cm

Yarmouth, NS...... Heavy rain mixing or changing to very wet snow Friday evening before ending Friday night..... tr-2 cm

Dartmouth, Halifax, NS....... Heavy rain Friday changing to heavy, very wet snow Friday evening then tapering off later Friday night....... 3-8 cm

Truro/New Glasgow, NS........ Rain changing to wet snow Friday evening then tapering off late Friday night...... 7-12 cm

Sydney, NS...... Mostly rain Friday p.m. and Friday night, but it may end as a burst of heavy, wet snow early Saturday...... nothing to 2 cm......

Somewhere between Moncton and interior, central Nova Scotia could end up with over 25 cm out of this one. Just not sure where that is right now.

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Also, a significant warm-up with strong, west to southwest winds across the Prairies Thursday and Friday.

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My interpretation of the weekly European long range model. What I describe is the mean pattern in a particular region for that week.

The week of Nov 9-15

--Very cold western Alaska.
--Cold, moist pattern for eastern Alaska.
--Wet Alaska Panhandle.
--Slightly milder and drier compared to normal over southern BC and the Pac. NW.
--Drier and warmer compared to normal from the southern Prairies through the U.S. Rockies.
--Wet over the Deep South and southeastern U.S. coast.
--Drier, but colder compared to normal from northern Ontario through Quebec.
--Dry pattern over the Midwest and Middle Atlantic region. Mild over the upper Midwest.
--Slighter cooler and stormier over Atlantic Canada.

The week of Nov 16-22

--Moist pattern over most of Alaska.
--Dry and mild throughout most of western Canada, including the Pacific Northwest.
--Wet compared to normal over California and the southwestern U.S.
--Dry pattern over Ontario with seasonable temps.
--Near-normal precipitation and temperatures over the northeastern U.S.
--Colder and stormier pattern over Atlantic Canada.
--Colder pattern over Quebec with near-normal precipitation.

The week of Nov 23-29

--Stormy, but mild over most of Alaska compared to normal.
--Well-above-normal temperatures and low precipitation over the Yukon Territory and BC.
--Fairly dry and slightly warmer compared to normal over Alberta.
--Seasonable temperatures over Saskatchewan and Manitoba, but precipitation below-normal.
--Cold over northern Quebec.
--Slightly colder compared to normal around the Great Lakes, with near-normal precipitation.
--Colder than normal from the southern U.S. Plains to the Ohio Valley.
--Slightly cooler and wetter compared to normal over the northeastern U.S. and Maritimes.
--Milder pattern over southeastern Newfoundland with near-normal precipitation.

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