Current Conditions at Sanborn Field

Wednesday Night: Rain. Low: 30

Thursday: Freezing rain transitioning to snow in the afternoon. High: 30

Thursday Night: Clearing. Low: 2

Friday: Clear. High: 33

Friday Night: Clear. Low: 22

 

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Discussion:

Buckle up Columbia: we are about to see a busy 24 hours weather-wise. The temperatures in the 60s will quickly fall through the next several hours, bottoming out in the middle 20s by Thursday afternoon. As the temperatures fall, precipitation will begin. It will start as rain Wednesday evening, we even can not rule out a rumble of thunder this evening. Rain will continue into early Thursday morning around daybreak when we begin to change over to freezing rain, which will create slick surfaces with ice accumulation up to a tenth of a inch. The precipitation will change over to sleet in the late morning with sleet amounts up to 1”. Finally, it changes over to all snow in the early afternoon topping off the accumulations with 2-4” of snow. The snow should end by sunset. After the wintry weather settles, we continue to see temperatures fall into the single digits by Friday morning, warming into the upper 30s by the afternoon with abundant sunshine.

- Meyer

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Forecasters: Heienickle, Meyer, Orr

Date Issued: 2/16/2022 5:00PM CST

Technical Discussion: 

 

Looking at current conditions, while temperatures remain in the upper 60s, clouds fill the sky with rain beginning to fall. The NAM and GFS are very comparable in their forecasted temperatures, both showing the high to be 59. Looking at a surface map from 18Z, both models highlight the low system located in the southwest well. Because of the lack of differentiation, a blend of the two models will be used for this forecast from the 12Z run. The largest question for this forecast remains on when temperatures will become cold enough to shift from rain to winter weather.

In the upper level, a positively tiled deep trough is seen in the west portion of the CONUS at the 250-mb level. Missouri sits in a strong jet streak to the right of the trough with 130-kt winds from the southwest. Divergence is seen at 250-mb beginning at 08Z Thursday, strongest values are seen around 15Z and stays over Columbia until 21Z. The trough continues to move to the Northeast, and strong southwesterly winds persist throughout the day. Thursday afternoon is when Missouri will sit at the southern center of the trough, but prominence in the trough's shape has decreased supporting a more zonal flow. 130-kt winds begin to shift clockwise entering into a northerly flow by Friday night. 

Circulation shown at 500-mb is minimal at the beginning of the forecast period, as Missouri sits on the right side of a trough moving east. Vorticity moves in from the southwest, with increasing circulation being seen by 21Z Thursday. This vorticity moves to the southeast though as the trough flattens out. Missouri remains clear Thursday night into Friday, with only a small wave of vorticity shown on the map at Friday at 21Z. 

 

Relative humidity, looking at 700-mb, increases drastically beginning at 00Z Thursday, strong values continue over Columbia until 00Z Friday, moving eastward slowly. These increased values follow a low pressure system moving over Missouri to the east. There is a small break in the increased RH values 09Z Thursday. After the system moves to the east, Missouri should remain dry entering into the weekend. 

 

At 850-mb, 50-kt winds from the southwest continue to increase temperatures in Columbia. Winds begin to decrease as a low pressure system moves to the north of Missouri. This low pressure system brings in a cold front, impacting Missouri with colder temperatures and northerly winds, beginning at 15Z Thursday. At this time, Missouri sits on the left side of a deep trough that is slowly moving to the east. Cold temperatures will stay in Columbia until 00Z Saturday when winds become more westerly. 

 

At the surface, Missouri received a lot of warm air advection throughout the day Wednesday, increasing temperatures and moisture to the region. Winds shift from southerly to northerly around 06Z Thursday, as cold air pushes through Missouri from the North. This boundary line remains over Missouri throughout the day Thursday; temperatures do not drop until 18Z. A high pressure system from the southwest moves over Missouri Friday morning, bringing some calm surface conditions after rainy 24 hours. Cold temperatures will continue throughout the forecasting period. 

 

Soundings from the 12Z run of the NAM show a saturated surface at the time of forecast, supporting the current overcast conditions. The greatest chances for rain begin at 09Z Thursday, temperatures at the surface remain above freezing for the majority of Wednesday night. Strong storms with an increased chance of thunder around 03Z Thursday. Around 12Z Thursday morning, the surface begins to cool to below freezing. Although soundings show a warm nose and a small dry layer during this time. Rain is likely to switch over to freezing rain between 12Z and 15Z. Winds at the surface move to a strong northerly flow and support the likelihood of winter precipitation. Later in the morning, freezing rain will transition to sleet. Snow will begin around 21Z that day. The atmosphere remains saturated until 03Z Friday. Overnight rain accumulation on Wednesday can be expected to reach over an inch. Snow values Thursday are predicted to reach 2-4 inches.

 

- Heienickle