Temperatures will continue to increase as we go into the weekend due to winds coming from the Southwest that push the cold air out of Columbia. Friday sees a lack of moisture in the atmosphere leaving us with mild weather and sunny skies. A low pressure system will bring in moisture and clouds Saturday. Clouds will continue to build until Sunday when precipitation is likely. With our temperatures increasing we may see a rain/snow mix which won't result in many road delays. These conditions are expected to continue into Monday.
GFS was the main model used for this forecast based on its recent accuracy in concurrence with station plot readings. The NAM had a much poorer handling on current conditions thus was not considered as highly. GEFS and SREF were used for temperature and precipitation type. The main focus for this forecast is upward trending temperatures and a wintry mix of precipitation moving in on Sunday.
Currently, the trough that has been influencing our recent weather trends still dominates the beginning of this forecast period. This trough begins to move out of the area on Friday, resulting in more zonal flow over the Midwest. This will help keep mild conditions throughout the weekend until Sunday. At the 250-mb level, Columbia resides in the left exit region of the jet, resulting in convergence aloft which aids in the mild conditions we will experience.
The atmosphere will remain mostly dry in the upper levels, with some saturation occurring near the surface up to the 700-mb level. The band of circulation that moves through the area on Friday night into Saturday will provide some UVM that can cause some low-level cloud cover. We can also expect the temperature trend to slowly increase throughout the forecast period as a result of a veering wind profile seen at multiple times in GFS soundings.
Going into Sunday, conditions are expected to derail from the previous weather trend due to an early-developed low moving across the upper Mississippi Valley. As a result, we will have an influx moisture in the lower levels of the atmosphere, which will be coupled with strong upper-level circulation in the area. The NAM and GFS soundings both depict saturation near the surface that rests right along the 0-degree Celsius isotherm up to about the 850-mb level. This allows for the chance of a rain/snow mix occurring for most of the day on Sunday.