Wednesday: Cloudy. Isolated showers through the early afternoon. High: 64
Wednesday Night: Clearing sky. Low: 32
Thursday: Sunny. High: 46
Thursday Night: Mostly clear. Low: 30
Friday: Building clouds in the morning. High: 48
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Forecasters: Kobielusz, Macko, Bongard
Date Issued: 11/17/21 10:00 AM CDT
The 06Z run of GFS20 was chosen for this forecast over the NAM40. Soundings and plumes were also consulted to determine cloud cover and consensus between model runs. Both the GFS and the NAM had an accurate portrayal of a low pressure system located in the southern Plains, but the NAM had the low being at a higher pressure than what was being observed. The GFS also had a higher consensus between model runs for temperatures and was closer to the current observed temperature.
Columbia is currently under the influence of a low magnitude meridional flow and an upper level jet core located in northern Missouri. There is weak upper level divergence throughout early afternoon today as light, isolated showers move out of Columbia. After the conclusion of these showers there is no divergence to be found until the late hours of the day on Friday. The magnitude of the meridional flow increases as we head into the overnight hours as a trough deepens over the central Plains and a closed low develops over southern Canada. By daybreak on Thursday the axis of said trough will move into central Missouri bringing along with it a jet core which will help to clear the sky. As the trough moves east, we will see a more zonal wind pattern on Friday.
There was no trace of vorticity throughout the forecast period in Columbia; however, there was a strong presence of vorticity in northern Missouri on Wednesday night, but this should not affect mid-Missouri. At the tail end of the forecast period on Friday night vorticity starts to build in the region. Future forecast shifts should take a look at this along with the increasing divergence aloft.
Moisture is prevalent this morning as the sky is overcast and passing showers are moving out of Columbia. This moisture will stick around until the winds shift to a northerly component in the afternoon on Wednesday and push the moisture to the southeast keeping us dry throughout Thursday. As a high pressure system develops in northern Arkansas on Thursday night and Friday, moisture will build back into Columbia as we will see a southerly component to our wind.
There will be a passage of a strong cold front late this morning or early this afternoon which is why our high temperature for the day was just after midnight. The fropa will shift our winds to a northerly component bringing us much colder Canadian air and will cause our temperatures to drop nearly 15 degrees from midnight. The rain associated with this front will be light and end in the early afternoon on Wednesday. Total rainfall accumulation will be less than 0.1”. Wednesday night we will fall under the influence of a LLJ which will help to clear the sky overnight into Thursday. Overnight on Thursday we start to see a shift in winds to the north-northwest as the high pressure system in northern Arkansas develops and by Friday we have south-southwest winds which will bring in more moisture and warmer air leaving us with an increasingly cloudy sky and warmer temperatures.