Tuesday, February 9, 2021

Tuesday Night -
 Cloudy. Slight chance for snow. Low: 12-16 
Wednesday - Cloudy. Flurries throughout the day. High: 16-20

Wednesday Night - 
Cloudy. Flurries continue. Low: 10-14

Thursday -
 Cloudy. Light to moderate snow ending in the evening. High: 16-20

Friday - 
Cloudy. High: 10-14

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Cold and snowy weather will persist throughout this week in Mid-Missouri. Abundant moisture in our area will keep our skies cloudy and the chances for snow flurries consistent. Temperatures will likely remain in the lower to mid teens throughout the duration of the week, so make sure to dress warm and keep those ice scrapers on hand. Thursday afternoon will bring us our highest probability of snow accumulation, with the evening seeing potentially dangerous wind chills. Lingering chances of flurries are expected to end by Friday, but clouds will stick around.


Forecaster: Clemons, Orr, Vochatzer
Issued: 5:00 PM CST 09 February 2021
Technical Discussion (The nerdy stuff we are discussing in class)

The current run of the GFS seems to be handling this system better than any of the other major models, so it was chosen to be the main model in this forecast. The NAM was briefly consulted to check for consensus, but was otherwise left unused. The GEFS and SREF plumes were consulted as well for determining temperatures, with GEFS being the primary model since SREF continuity struggled. Soundings from the GFS were also consulted to determine precipitation type and timing. 

The 250mb level of the 12z GFS has Columbia positioned under the right exit quadrant of the jet streak from 15z Wednesday to around 9z on Thursday. This positioning is something to pay attention to, since it could lead to a period of heavier snowfall if conditions in the lower levels continue to support it. Central Missouri will remain under the influence of the jet for the entirety of the forecasting period, but its biggest influence will be during this time. 

The 500mb map of vorticity continues to favor increased rates of snowfall Wednesday night up to Thursday evening. The vorticity moves out of the region on Friday, implying that there could be a break from snowfall at this time. At 700mb, the map of relative humidity also supports this notion. Missouri remains under relative humidity amounts of around 80% or higher until the abundant moisture is moved out of the area by a shift in upper level winds from south westerly to north westerly. This shift in winds is brief, however, and may soon return southerly for more precipitation chances in later forecast periods. 

At 850mb, the plot of winds shows even more support as to why our ongoing snow chances weaken by Friday. A strong LLJ from the southwest is bringing plenty of moisture from the Gulf of Mexico to fuel the snow events. However, by 0z Friday the LLJ is cut off, causing Mid-Missouri to lose its abundant moisture. This should bring a long awaited break from the on and off snow events over the course of this period. The 850mb plot of relative humidity also supports this, showing a significant drop in moisture over the region once the southerly flow is cut off. 

SREF and GEFS plumes were used to determine the temperatures for our forecast. Due to a lack of consensus in the SREF toward the end of the forecasting period, GEFS was the primary model used. GFS soundings gave a clear picture of the endless cloud cover over the course of our forecast. The sounding temperature profiles never make it above freezing, so no melting will occur, causing any precipitation to be snow. Long term model tendencies suggest this pattern will persist.

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