February 22, 2018

Warm Once Again

Current Conditions

Temperature: 30 °F
Dew Point: 12 °F
Winds: E 12 mph
Pressure: 1033.2 mb
Visibility: 10 miles

The weather has taken a turn for the warmer side today which means overcast skies from dawn until dusk. This morning the temperature was 6 °F and the dew point was 3 °F with winds NE at 4 mph. The wind direction is a first since I started my weather blog and is visualized in figure 1. 

Figure 1. Wind map from earth.nullschool.net. Notice the northeastern winds traveling over Wisconsin and the line crossing the southeastern United States. This line is the mixed front that moved over Eau Claire a few days ago.

  The rest of the day was overcast as well. By noon the temperature was up to 24 °F and winds were now ENE at 7 mph. As noted in the current conditions, the temperature did continue to climb up to 30
°F which is much appreciated this time of year. In figure 2 the water vapor satellite shows a small band of water vapor makings its way through the Midwest which is probably the source for the weather we're about to get.

Figure 2. Water vapor satellite image of the United States. Notice the stream of water vapor moving from Mexico to Wisconsin.

The water vapor trail shown in figure 2 is following the current path of the jet stream in figure 3. 

Figure 3. Jet stream map.

Finally, all of these images help explain the crazy weather about to hit the area that is partially described by the surface map in figure 4. 
 

Figure 4. Surface Map of the United States.

Before I proceed, I want to note that my previous forecast was correct: there was increased cloud cover and slightly warmer temperatures.

Returning to the surface map, right over the Eau Claire area is the boundary between heavy snow and freezing rain. These events are poised to strike either early tonight or into the early morning hours tomorrow. Although this might seem unfortunate, its nothing compare to what's coming on Saturday and maybe Sunday. A large snow event, possibly even snow thunder, will arrive from the south. This is created by what's called a bomb cyclone. Bomb cyclones are created rapidly and result in extreme weather events like snow thunder. This will not show up on the surface or radars until late Friday or early Saturday. So tomorrow there should be some snow on the ground from tonight and most of the day will be overcast with temperatures comparable to today. Of course, this is just the calm before the storm...