The first major snow storm of the season is in the making and is
promising to bring hefty amounts of the white stuff to the US northern
tier states as well as Ontario, Canada.
Just two weeks into autumn, and the air masses coming out of the
north are now starting to be cold enough to change rain into snow.
On Thursday an area of low pressure with its counterclockwise
circulation was located over Wisconsin.
Just to the west of this low,
colder polar air from Alberta was being pulled into the US Rockies and
northern Plains. Ahead of this low, plenty of warm moist tropical air
has been moving north, keeping central and eastern cities warmer than
average.
Now that we have the colder air from the north in place meeting up
with the warmer moister air from the south, the science begins. Just
like with a hot air balloon wanting to rise, so does the warm air coming
in from the south when it encounters the colder air from the north.
Clouds begin to form and precipitation begins to fall. As the rain falls
through the cold polar air near the surface, it then changes to snow.
On Thursday, North Dakota will wake up to snow beginning to cover
what was left of their lawns, but this is only the beginning. Over the
next three days the amount of snow will be impressive.
The US states of Wyoming, Montana and Colorado could see a layering
of snow of up to 4cm, just enough to make the season’s first attempt at a
snowman. It is into Wisconsin and Ontario that the snow could reach
depths of up to 50cm.
While the season’s first snowfall will be a sight to see, it is going
to be quite dangerous as well. Over the next several days, temperatures
will climb into the single digits during the day, allowing for some of
the newly fallen snow to melt. Unfortunately, overnight, temperatures
will sink back down below freezing and any melted snow will refreeze,
making roads and surfaces very slippery.
Is this an indication of what’s to come? The private weather firm,
Accuweather, has just released a winter forecast for the region. It is
predicting that the winter across the northern part of the country will
see below-normal amounts of snow. If this prediction holds true, US
farming could again suffer next year from not enough water.
