After lots of snow over the weekend in Sturgeon Bay, Wisconsin, temperature forecasting can be a little tricky. The NWS discussion says "There should be enough winds and clouds tonight to hold off what would otherwise probably be a huge temperature drop due to the fresh deep snowcover. Quiet weather is expected Tuesday as high pressure ridges toward the region. Again trended a little colder than guidance for highs due to the snowcover." So let's predict Tuesday's low temperature for Sturgeon Bay and see how the snow cover, wind speed and cloudiness affect it. Sturgeon Bay is on the scenic Door Peninsula, near Green Bay.
Question: Why would you expect a "huge temperature drop" at night with fresh snow cover?
The NWS forecasters were right -- the clouds and windy conditions lasted all night in Sturgeon Bay and the temperature didn't get below 25 F, and it even increased to 26 F for a few hours.
Answer: With fresh snow cover, the temperature can drop very sharply at night under favorable conditions, because the snow layer prevents the heat stored in the ground (soil, etc.) from moderating the temperature decrease as much as it normally would.
|Tmin, deg F (error)