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05 December 2007

Dec 4th snowfall.

Less snow fell at my house than I hoped :(

As the first clipper moved through the region, lake-effect snow plumes streamed off Lake Superior. Western Lake
Superior water temperatures are still hovering between 38 and 40 degrees, with northeast winds bringing cold air (in the 20s) across that warm water, several snow bands developed. One major snow band sat over Duluth and dumped 16.8 inches of snow!! Another band sat near Ashland and produced 9.5 inches there. Areas outside of these two major bands received variable amounts.

I measured 4 fluffy inches, which produced a water equivalent of 0.22" of liquid. This results in a snow-to-liquid ratio of 18:1, that's pretty light stuff!

Since NWS Duluth hasn't drawn up a map yet, but they did compile a list, I created the map above. I'm less familiar with locations in Minnesota, so I wouldn't bet my life on the accuracy of
the points, but it gives a general impression of how much snow fell. The higher amounts are in the screenshot to the left, those above 5 inches I posted.

Yesterday's numbers:


Temps: 16.9 / 21.3
Dpts: 16-18 then falling
Barometer:
30.30 down to 30.01 "Hg
Winds: light, gusting to 10 mph from N or NE
Windchills:
not an issue
Precip: 4 inches snow (0.22" liquid)

Cooler temperatures today

Behind this clipper temps have dropped. Today's high temp occurred at midnight, 16.9 degrees. Since then the mercury slid to 8.3 around 8:00 and has recovered only to 10 degrees during the afternoon hours. Forecast low temperatures fall to below zero for the entire region. High pressure 1031 mb (30.45 "Hg) slides across the region, bringing arctic air into the area. The map (down to the right) shows forecast low temps tonight. With new snow, clear skies, light winds, and arctic air, radiational cooling may force temps to drop even lower.

Clipper # 2

The next clipper approaches the Upper Midwest on Thursday night. 1 to 3 inches look reasonable with that system, maybe up to 4 inches near the Twin Ports, but the system doesn't have as much moisture to work with as the last system.

Currently at 15:10:

Temp: 9.2
Dp: 2
Barometer: 30.25 "Hg
Wind: 3 mph from the WNW
Windchill: 3.5
Sky: light cirrus, mostly sunny

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