Wednesday Night: Increasing Clouds. Low: 43°F
Thursday: Partly Cloudy. High: 49°F
Thursday Night: Clear. Low: 35°F
Friday: Cloudy, Wintry Mix. High: 31°F
Friday Night: Clouds clearing out. Low: 22°F
=================================================================================
General Discussion:
Expect the return of winter this week, Tigers! Temperatures will begin to dip starting tomorrow and continue to fall throughout the week leading up to Friday. Be prepared for cold conditions as you head to Fridays classes, as a wintry mix is expected during the day. So, be prepared to ditch your shorts for now and grab your winter coat!
-Cargill
=================================================================================
Forecasters: Cargill, Chirpich, Robinson
Date Issued: 02/14/2024 5:00PM CST
Technical Discussion:
The NAM and GFS were both taken into consideration for this forecast discussion. A shortwave modeled at 300mb is projected to move through Missouri tonight, as the polar jet dips down into the CWA. With this, a steep temperature drop can be expected down into the 40s from today’s high of 63°F. A weak jet streak is modeled in tandem with the jet stream, as well as very little divergence aloft, throughout the forecast period. However, these winds pick up as the polar jet and the subtropical jet begin to couple on Friday at about 12z. This coupled jet streak continues to build in power as it exits the CWA right at the end of the forecast period.
The very same shortwave can be observed at 500mb. With it comes a very extreme smoothed differential vorticity advection, as well as some weaker vorticity. Otherwise a few vorticity maximums are modeled to move through Missouri on Friday at 18z. The driving force of all this significant vorticity is a large low pressure system currently moving eastward through Southern Canada as well as a positively tilted trough. The latter of which seems to be bringing some vorticity into the Midwest as it exits the CONUS, right through the CWA at the end of the forecast period.
Despite all of this, there is very little moisture associated with the shortwave, so no unsettled weather can be expected tonight, save some clouds. However, significant moisture is modeled to move into the CWA around Friday 09z. In combination with the vorticity that is modeled around this time as well, some sort of weather event is expected. Considering, the strong CAA that is modeled to move into the area at 850mb around Friday 18z, some sort of winter precipitation is a safe prediction.
Considering that the strong CAA at 850mb is aligned with 700mb, and the shape that is modeled in, it is safe to assume a cold front is what is causing the cold temperatures. This cold front could be attached to the low pressure system mentioned before that is stationed in Canada. At the surface, in tandem with the 700mb and 850mb CAA, the 540 line is modeled to shift as far south as Arkansas. This puts Missouri behind the 540 line, meaning that winter precipitation is likely on Friday. Soundings show above 0°F at the surface and the temperature and dew point line very moist as well as staying inside the DGZ. Considering all of this, wintry mix is the most likely winter precipitation-type. Future forecasters should watch this 540 line, as it does not seem to retreat back to the north until Sunday.
-Cargill