29. Light snow chances today, arctic air coming Saturday.
A weak surface trough has been moving southeast this morning, the radar screenshot (to the right) shows some light snow associated with the trough. Echoes on radar have been weakening and falling apart, so NWS Duluth has reduced the forecast from "chance of light snow" to "flurries" across northern Wisconsin.
The strange radar beam pointing to the southeast is from the sun as it was rising above the horizon. The sun radiates many wavelengths of energy, one of which is the same microwave band that we use in weather radar.
Speaking of the sunrise...
My first picture (to the left) was taken at 7:48 from my living room sliding-patio door. The large trees in the yard to the left are Basswood, the large deciduous on the edge of the forest on the right is a Red Oak, with numerous Balsam, White Spruce, and Canadian Hemlock in the background.
As of this morning I measured 14.6" of snow on the ground. We had 1" of fluff yesterday from Lake Superior that produced 0.06" of liquid equivalent.
The sun this morning is nice, but changes are coming!
Today will bring some clouds and maybe a few snowflakes later in the day. Friday will bring some more light snow chances as warm air gets pumped up and a weak trough/clipper goes through the region. Accumulations will be very light and occur mainly in the afternoon.
Saturday is when things begin happening when a cold front blasts through. A couple inches of snow are possible but major snow is not expected. The map (to the right above) is from the HPC and shows the model's forecast map for 6:00 on Saturday morning. The tight pressure gradient over the Upper Midwest means strong winds from the northwest. Putting the cold in cold front.
This front is the leading edge of arctic air that has been bottled up in northern Canada, but it's making a break and spilling our way. Luckily it isn't bitter Siberian cold, nor will it stay here very long.
High temperatures on Saturday will occur at (or just after midnight) and then continue to fall through the day and into the evening. The chart (to the left) shows forecast temperatures at my location for the weekend. The dashed lines are average high and low.
Cold plus wind equals low windchills.
Winds Saturday afternoon could be gusting as high as 40 mph from the northwest, sustained in the lower 20s. Wind this strong, combined with afternoon temperatures around 5 degrees, produces windchills around -20 degrees. This windchill value can freeze exposed skin within 30 minutes.
Also, several inches of snow before the winds arrive would produce whiteout conditions. NWS Minneapolis is mentioning the possibility of a ground blizzard Saturday afternoon.
This picture (to the right) was also taken this morning, showing the blue sky above the garage.