Winter Weather Advisory in effect on Wednesday, Feb. 17 from 12:00 AM until 6:00 PM CST.
Current conditions across mid-Missouri closely resemble a snow globe scene. Snowfall should end after lunchtime, but road impacts will likely linger into the evening commute. Cold temperatures and cloudy skies will stick around into the nighttime. A slow warm up will start tomorrow as a drier period begins as well. We could start to see the hint of sunshine tomorrow, but Friday will be our best bet for sunny skies.
The GFS was the primary model used for this forecast since it had the most accurate readings for current conditions. In addition to this, the potential snow accumulation was more plausible than in any other model output. The biggest challenge this forecasting period will come from potential snowfall and determining accumulations.
At the 250-mb level, the presence of an intense trough, courtesy of the polar vortex that has been impacting the area for the past week, is located just to our west. This trough continues to push eastward throughout the forecasting period. The trough brings southwesterly winds that help to pull moisture into the area, allowing for the snowfall chance for today. This trough will cross the region by 18Z Friday. Behind this trough passage, upper atmospheric wind flow becomes more zonal.
The 500-mb level winds greatly resembled what was seen at the 250-mb level. The vorticity readings at the 500-mb level shows circulation entering the area for Wednesday. This circulation, combined with the presence of moisture, will likely produce snowfall until 19Z Wednesday. The vort max is located to our south currently, but by 09Z Thursday, this vort max will push off to the southeast. This circulation would suggest the possibility for more snowfall, but in this case, the moisture needed for that snow is lacking.
The 700-mb map showed a nearly closed low pressure system over Kansas at 12Z Wednesday. This low will move through the northwestern portions of Missouri heading northeast. Low pressure will likely keep cloud cover steady over the area.
At the 850-mb level throughout the day Wednesday, winds will shift from the south to the north. The trough was not noticeable at this level.
At the surface level, easterly winds will shift to become northerly by 09Z Thursday. These northerly winds will keep cold air in the region for Thursday. By Friday, these winds will become more westerly, reducing the amount of cold air being drawn into the region.
The GEFS plumes were used to narrow down potential snowfall accumulations and temperatures. The GEFS plumes showed strong agreement in near 1 1/4" of snowfall with some isolated higher totals possible. The temperature guidance also showed steady agreement on the slow warming pattern that is expected as the polar vortex retreats back to the arctic.