March 6, 2018

Snow and Sun

Current Conditions

Temperature: 24 °F

Dew Point: 16 °F

Winds: N 9 mph

Pressure: 1015.9 mb

Visibility: 10 miles

The weather today changed quite a bit from morning until night. This morning the temperature was 29 °F with winds NE at 16 mph. The skies were overcast and light snow with fog was prevalent. By the afternoon snow showers had intensified and the winds continued to gust out of the northeast. Visibility dropped to 2 miles. Early in the afternoon the clouds broke and some patches of sunlight were spotted around 3:00 PM. The temperature now is not much different from this morning but the wind direction has changed to a northerly direction. 

The surface map today shows the low pressure system moving towards the east coast and taking with it the precipitation (figure 1). 

Figure 1. Surface map of the United States.

The low pressure system to the east of Wisconsin was actually pretty interesting. Just over Ohio one can see the purple line denoting an occluded front. This means a cold front cut off the warm supply of air in the low pressure system. The frozen rain pellets that fell yesterday were a result of the super-cooled water droplets that resulted from this. As it moves east it will bring more rain and snow to the east coast. 

The wind map in figure 2 shows the northerly wind direction at the surface. 

Figure 2. Surface wind map of the United States. 

Previous Prediction

My prediction on the cloud cover and temperatures was correct, but I did not predict any snow. The snow was minimal though and only occurred in spurts. 

Prediction

For tomorrow, I predict slightly lower temperatures and clear skies resulting from the high pressure air mass moving into the Wisconsin area. This is visualized in figure 3. 

Figure 3. Forecast map for 3-7-2018.