Current Conditions at Sanborn Field

Winter Weather Advisory until February 25, 12:00 AM CST

Thursday Night: Clouds clearing through the night. Low: 15

Friday: Scattered clouds in the afternoon. High: 32

Friday Night: Clear. Low: 17

Saturday: Increasing cloud cover throughout the day. High: 40

Saturday Night: Partly cloudy. Low: 24

 

Thanks to IconArchive.com for the icons! 

====================================================================

Discussion:

    A Winter Weather Advisory remains in effect until 12 a.m. Friday for potential light ice and snow. Accumulations will be negligible but frigid temperatures and icy roads will spell out harsh conditions for the evening. Temperatures will also likely dwell below freezing through Friday even as sunshine returns, though the weekend promises a steady warmup. Highs will rebound to above average for more spring-like conditions; with the spring equinox only a month away, a respite from the winter chill may be on the horizon.

- Splater

=================================================================

Forecasters: Noblitt, Splater, Vochatzer

Date Issued: 2/24/2022 5:00PM CST

Technical Discussion: 

     For our forecasting period, we compared the 18Z surface analysis from the NWS to the MSLP plots in both the GFS20 and NAM40. Both models followed fairly similarly to the analyzed map, solidly placing two highs on both sides of the Great Lakes as well as the low over Colorado. When comparing the plumes, both the GEFS and SREF were close to the recorded temperature, with the most recent SREF runs running slightly warmer and the mean GEFS running slightly cooler. Due to the close proximity of the models’ outputs, both the GFS20 and NAM40 were utilized for this forecasting period. The NBM was also included to help with temperature forecasting, and GFS and NAM soundings were utilized for cloud cover.    

    Beginning with the 300mb plot of heights, winds, and divergence, a large jet streak rests across the eastern half of the CONUS, extending northeast from Texas into the North Atlantic-Appalachian region. A shortwave trough will begin to push eastward into the jet streak, increasing the speed of the winds over Missouri at this level around 150 knots late Thursday evening. This will bring some divergence over northern Missouri. After the trough passes to our northeast, the jet streak still resides over much of the CONUS, with wind speeds setting over the Mid-Mississippi Valley to around 100 knots. This jet streak remains over our region until very early morning Sunday when a positively-tilted trough slides in from the northwest.

    Observing our 500mb plot of heights, winds, and vorticity, a large area of circulation can be seen moving across the Mid-Mississippi Valley as a LPS over southern South Dakota transitions northeast, forcing the shortwave trough across Missouri Thursday night. Following this passage, zonal flow remains in effect for our region until early Sunday morning, when the positively tilted trough forces its way into Missouri, bringing another large area of circulation before quickly continuing to our east.

    Following this up with the 700mb plot of heights, winds, omega, and relative humidity, a large band of saturation associated with the Low over South Dakota will move across northern Missouri Thursday night. However, little to no lift can be seen from the omega values, indicating the possibility of clearing clouds despite the saturation. This saturation travels on late Thursday night, leaving the sky over the Columbia region unsaturated until Friday evening. A large batch of saturation, residing with a LPS over the Rockies, begins to move toward the Mississippi River during this time. This moisture continues to travel across Missouri through the end of the forecast. Some lift can be seen in the omega values corresponding to the passage, indicating the chance of building cloud cover Saturday.

    Finishing up with the 850mb plot of heights, winds, temperature, and dewpoint, we can see a surface Low residing over Kansas City. Despite this forming southeastern winds for our region, a blanket of cold air extends far enough to our south that we will receive very little warming. This low swiftly moves northeast, exiting Missouri late Thursday evening. A westerly into northwesterly shift of our winds helps to keep our temperatures cool Friday. However, a surface High moving from Oklahoma into Arkansas will see our winds shift back to the west and into the southwest. The change in our winds is short-lived however, as the positively tilted trough snaps our winds back to the northwest for the remainder of the forecasting period. Looking at the surface plot of MSLP and 1000mb-500mb thickness, some very strong CAA can be anticipated over Thursday night into midday Friday. Little advection can be expected for the remainder of the forecast due to the lack of solid solenoids.

    Soundings indicated increasing and decreasing cloud cover throughout the forecasting period, however due to the lack of significant saturation near the surface or aloft no precipitation is anticipated after Thursday night, with only trace amounts expected.

    Future forecasters should keep a close eye on the LPS moving in from the Rockies Saturday.

 

- Noblitt