Monday, March 4, 2019

Monday Night - Clear skies remain. Breezy. Low: 8-12

Tuesday -
Mostly Sunny. High 24-28

Tuesday Night - Mostly Clear. Low: 10-14

Wednesday - Partly Cloudy. High: 36-40

Thursday - Cloudy with drizzle. High: 36-40

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Meteorological spring may have begun on Friday, but astronomical winter is not letting up anytime this forecast period. Columbia will see persistent clear skies today into tonight. Despite the ample sunlight, temperatures will be bitter, struggling to reach 20 degrees. On the bright side though, Tuesday will be Sunny. Moving into Wednesday, clouds will begin to appear as temperatures warm up, reaching into the upper 30s. Precipitation chances will return on Thursday with highs in the upper 30s.
Forecasters: Danaher, Brown, and Hirsch
Issued: 4:45 p.m., March 4, 2019

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

On the heels of an active Sunday comes a tranquil, albeit very cold, period to start the schoolweek. As a matter of fact, temperatures below 0F were recorded at both Sanborn field and KCOU. This cold air is largely the result of a large 500 hPa longwave trough digging into the eastern half of the CONUS. This setup has us behind the trough, putting us solidly in NW flow, which has allowed brutally cold arctic air to move well into the central CONUS. This trough will continue to dig in over the next 36-48 hours, keeping us firmly entrenched in NW flow and 20-30F below normal temperatures. 

Specifically for the period through late Tuesday afternoon, we will be largely devoid of any influence from the 250 hPa jet (the core is well to our south). The aforementioned longwave trough at 500 hPa will be in place across the great lakes, putting us in NW flow. Flow at 850 hPa will also be out of the NW, with temperatures in the -12 to 18C range. At the surface, Missouri will be under the influence of a strong high pressure center, with winds out of the NW. Because of this, very little moisture will be present in the column through Tuesday afternoon, so very little cloud cover, if any, can be expected during this period. Temperatures, as mentioned earlier, will be running 20-30F below average, but thankfully this morning's temperatures were the coldest we'll experience over the next few days.

Heading into Tuesday night and Wednesday, a 130-kt 250 hPa jet core will develop to our NE, putting us in the right entrance region of the jet. This will create some areas of divergence aloft. A vort max will be ejecting from the Rockies, but will still be over KS/NE by Wednesday. 850 hPa and sfc flow will change from NW to SW, leading to WAA and, consequently, warmer temperatures.

This is important as moisture will be available for the next small precipitation event on Thursday. According to 18Z GFS soundings for Thursday afternoon, a backing wind profile in the low levels can be clearly seen which means CAA is occurring. The precipitation type seems to be a mixture of light snow and rain in the morning, switching to mainly light rain in the afternoon. Since temperatures are below 32F on Thursday morning and begin to rise during the afternoon, this will lead to the precipitation switchover from frozen to liquid. The GEFS and SREF also point out we will get about 0.10-0.20 inches of rain. However, conditions for Thursday precipitation are subject to change and further shifts will need to pin down the nature of the precipitation.

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