Current Conditions at Sanborn Field
Monday Night: Clear. Low: 42
Tuesday: Light Rain. High: 49
Tuesday Night: Rain transitioning to sleet, then snow. Low: 19
Wednesday: Snow. High: 19
Wednesday Night: Heavy snow. Low: 13
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Discussion:
As we transition into February, Columbia sees its first major winter storm of the year. A low pressure system moving north of our area paired with dropping temperatures come together to create ideal conditions for several snow days. With southerly winds bringing in moisture, we are prepared to start the storm with rain beginning Tuesday morning. Our temperatures drop as the region sees a wind shift to the north, this causes the rain to transition to sleet Tuesday night around 9pm. Columbia reaches freezing point around midnight and snow will start to fall at this time and will continue falling until Thursday. Tuesday’s total snow accumulation is expected to be around 4” with Wednesday’s reaching 8”. Classes for Mizzou have already been shifted to Zoom on Wednesday and Thursday to accommodate for this weather. Prepare to stay indoors until Friday as road conditions will be less than ideal.
-Cochran
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Forecasters: McMullen, Cochran
Date Issued: 1/31/2022 5:00PM CST
Technical discussion:
For this forecasting period, the 12Z GFS model run was used. When compared to the NWS 18Z surface map, both the GFS and NAM matched closely. However, SREF plumes showed significantly more uncertainty with regards to snow totals and temperatures, so the GFS was chosen. GFS soundings were also used to forecast sky conditions and precipitation type.
The main problem of this forecast period is the significant winter weather event starting Tuesday morning and continuing through the rest of the period.
Starting with the 250-mb plot of heights, winds, and divergence, a small ridge is currently passing over the central CONUS, a jet streak having just passed through Missouri. Spotty divergence remains over our area until about 3Z Wednesday when a deep trough, associated with an LPS located in southern Nunavut, CA, begins to move through the western US. This trough, in addition to two combining jet streaks over central CONUS, is one of the driving forces of this winter weather. Upper level divergence and strong winds aloft aid in the production of rain and snow throughout the forecasting period.
Moving down to the 500-mb plot of heights and voriticity, no vorticity will affect Missouri until about 0Z Wednesday. At this time, circulation associated with the aforementioned trough begins to advance into our area. This circulation will remain in our area through the rest of the forecasting period and will contribute to the expected rain and precipitation.
Shifting our attention to the 700-mb plot of heights, winds, and relative humidity, Missouri is currently bone dry keeping our sky clear for the rest of today and tonight. That is, until a large swathe of moisture will coat Missouri and much of the Ohio River Valley from 12Z Tuesday through the remainder of the forecasting period. At first, this moisture will aid in rainfall production; however, this will change to sleet, then snow early Wednesday morning.
Looking at the 850-mb plot of heights, winds, and temperature, we currently have south-westerly flow in Missouri, which is helping to keep our temperatures unseasonable warm this afternoon. Around 3Z Wednesday, our winds will shift to the NE, bringing in mass amounts of cold air and causing our temperatures to plummet. This cold air mass is unyielding and will persist through our forecast period. Examining the 1000-500-mb plot of thickness and MLSP, we can see some WAA currently occurring, shown by solenoids, which also contributes to our current warmer temperatures. This warm air will quickly give way to the approaching cold air mass. The 540 line passes through Columbia at approximately 6Z Wednesday, marking the transition to snow Tuesday night.
As seen in GFS soundings and GEFS plumes, rain will begin about 12Z Tuesday. This rain will persist through about 3Z Wednesday, when cooling temperatures cause a shift to sleet, with a QPF of about 0.25". By 12Z Wednesday, snow will have begun. Total snowfall accumulation for our forecast period is expected to be about 7"-11". The heaviest snowfall rates are expected to occur Wednesday night.
Future forecasters should look for changes in snowfall accumulation model approximations.
-McMullen
