Current Conditions at Sanborn Field

Friday Night - Cloudy with chance of sprinkles in the evening. Low: 22-26


 
Saturday - Cloudy. High: 34-38.



 Saturday Night - Cloudy with snow starting near midnight. Low: 24 - 28.

 
Sunday - Snowfall continues through the afternoon. Total snowfall accumulation: 3-5 inches. Temperatures steadily fall though the day. High: 26-30.


Monday - Mostly Sunny. High: 14-18.

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Discussion:


Tonight we will experience some light sprinkles with general cloudy sky as a cold front brings in colder temperatures. Tomorrow cloudy skies remain with maximum temperatures  near freezing. Saturday night our next winter storm system approaches to us near midnight. The snow will persist though Sunday afternoon with snow accumulations of 3 to 5 inches. We should expect extremely cold temperatures well below freezing after the snow finishes. Lows Sunday night could reach below zero and wind chills between -10 to -15 degrees. Even though we will see the sun on Monday we will remain cold. However the temperatures will slowly increase through out next week.

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Forecasters: Johnston, Rojas, Sumrall, and Hirsch

Issued: 4:45 p.m., March 1, 2019

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


   The upper level trough axis starts positive over the western side of the country and as it moves eastward, becomes more neutral tilted. The system itself deepens on Sunday as it moves eastward, the center of the lower system goes from 511 dam to 496 dam in 24 hours.


We used a general model blend. The NAM has the winds shifting to the NW between 21Z Friday and 0Z Saturday and the GFS between 18Z Friday and 0Z Saturday. So we expect the cold front passage occur tonight between 21Z Friday and 0Z Saturday. After this frontal passage we expect CAA.

The main concern for our forecast will be the winter storm occuring Saturday night into Sunday afternoon. At 500 mb, a shortwave will cross the area on Sunday at 9Z, maximum vorticity associated with this short wave will leave MO by Sunday afternoon. The upper level trough axis starts positive over the western side of the country and as it moves eastward, becomes more neutral tilted. The system itself deepens on Sunday as it moves eastward, the center of the lower system goes from 511 to 496, at the 500 mb level, in 24 hours. GFS soundings shows the atmosphere getting moist from 775 mb to 250 mb at 0Z Sunday and the full atmosphere is saturated by 3Z. So we expect snow to to start after 0Z Sunday. The temperatures on the soundings are below freezing at the start of this storm and through out it. We did not see a warm nose during any time, so we expect the winter precipitation to be all snow. The 1000 - 500 mb thickness keeps the 540 line to our south through out this storm. On the GFS We expect the heaviest snow to occur between 3Z to 9Z on Sunday. This is due to high omega values between 650 mb to 350 mb on the 3Z GFS sounding and high omega values between 850 mb to 500 mb at 9Z. However the soundings show no CAPE during this storm so we do not expect any thunder. The sounding start to dry out at 15Z Sunday, so we expect the snow to end near that time. We expect a total snowfall accumulation between 3 - 5 inches.

Sunday Night and Monday we expect drier air and much below average temperatures. With the fresh snowpack on the ground we expect temperatures to trend colder. We could come close or tie Columbia low record of -2 degrees Sunday night. The concern for future forecasts will be if clouds or moisture will be present for Monday midday. We did not include it, because the GFS soundings did not a large enough area of saturation. However GFS soundings shows saturation at 12Z Monday at 900 mb and 15Z at 875 mb.