Tuesday, February 19, 2019

Current Conditions at Sanborn Field

Winter Weather Advisory is in effect from 5pm this evening until 6am Wednesday morning.

Tuesday Night - Snow, Freezing Rain, Rain. Cloudy. Accumulations of trace to 2". Low:30-34

Wednesday - Drizzle ending around noon. Cloudy. High: 37-41

Wednesday Night - Cloudy. Low: 23-27

Thursday - Mostly Sunny. High: 42-46

Friday - Mostly Sunny. High: 46-50

Thanks to IconArchive.com for the icons!

Various types of precipitation are possible for this evening into Wednesday morning.  The possibility of snow accumulations overnight range from a trace to 2in. The changeover from snow to freezing rain is possible around 3-5am, and ice accumulations are possible up to 0.10".  If you have the urge to travel, please be careful, take extra time, and allow road crews room to clear the roads.  By Wednesday morning the freezing rain will change over to a cold rain and possible drizzle as temperatures begin to rise toward upper 30s to lower 40s.  Precipitation should begin subsiding around 2pm.  Clouds do begin to break up overnight Wednesday. Thursday and Friday will have sunshine in store and highs in the mid to upper 40s Thursday and upper 40s to possibly lower 50s Friday.

Forecasters: Azzara, Munley, Brown and Hirsch
Issued: 5:00 p.m., February 18, 2019

Technical Discussion (The nerdy stuff we are discussing in class!)

Our main interest over this forecast period will be the accumulating snow that will move into the area as we go into the evening and overnight hours. The jet stream is flowing in excess of 160 kts today so there is enhanced divergence at the entrance of the jet. The veering wind around 850mb will help funnel moisture into the area and cause rapid precipitation development in a matter of a couple hours. Models seem to be in agreeance on when snow starts to enter Columbia which is around 03Z on Wednesday, once the atmosphere is fully saturated. The dryness at the surface is what is pushing the start of this event back, the atmosphere is currently saturating from the top down with a stubborn dry pocket at the surface.

By 03Z the GFS has moisture availability set to 100% for 300mb and all the way down to the surface so the confidence is fairly high for precip to occur by 03Z. However there is variance between the models over accumulation, the NAM is showing that the snow will accumulate faster than the GFS. The amounting accumulation from this system has been debated over the past week and seems to be lessening as the event approaches mid-Missouri. Currently the mean ensemble accumulation of snow is around an inch with a spread from a trace to two inches. I would say that the total snow from this system would tend to between a half an inch to an inch.

But, snow is not the only precipitation form that we are concerned about from this winter event. Around 10Z on Wednesday, temperatures raise back above freezing, causing the snow to turn into freezing rain, creating hectic road conditions for the morning commute. The freezing rain should turn into drizzle as we get more into above freezing temperatures which should be around 16Z. The atmosphere looks to finally dry up completely by 19Z and the rain should push out, with clouds starting to break up as we warm up to almost 40 for our high on Wednesday.

The rest of the forecast period will be dry and mild as a high pressure center situates itself over Missouri for the end of the work week with good amounts of sunshine to get us through the rest of the week. Winds will blowing from the south, aiding in more comfortable temperatures with highs nearing 50 on Friday, providing the opportunity to melt off any snow left on the ground.

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