Cold temperatures will be the main concern for today. But that will change as we head into Wednesday. We will see another system that will be moving into the Missouri. This system will almost be like what we saw yesterday. Another chance for Ice southeast of hwy 63 and I-70. For the day of Wednesday humidity will start increasing as widespread snow starts to move in. This system will persist into Thursday leaving central Missouri with a possibility to see up to 2".
When determining model diagnostics the NAM/GFS are having a hard time grasping the current state of the atmosphere when compared to the SHREF and the RAP which were used for prognostics. So for this forecast the primary models used were the SHREF, RAP, and 06z GFS. The 06z GFS was on spot with current temperatures, and started to correlate with the SHREF moving into Wednesday, therefore was incorporated into this forecast. Update: the 12z GFS run came out which will be incorporated into this forecast as well.
Currently, the main story for today is cold temperatures. There is a strong high pressure system sitting over Iowa, which is pushing dry air and cold temperatures to the south. This high pressure system is giving central Missouri all the ingredients for unseasonable cold temperatures and cloudy skies. At 250-mb heights/winds, things are pretty zonal, we have the polar jet sitting right about Missouri. At 500-mb, the zonal trend continues, nothing in the way of areas of circulation. At 700-mb, there is not much vertical motion. At 850-mb winds are coming from the west. There appears to be a surface low sitting in southwest Missouri, that will continue to push north as the day goes on. That will help switch winds from the west to the south. Humidity levels will be decreasing through out the day, but we will have enough saturation in the lower levels of the atmosphere to remain cloudy. When looking at the 12z GFS sounding, there is backing with height which means that we are experiencing cold air advection. That is playing a role into our even colder temperatures today.
Going into tonight, we will see a possibility to see some snow showers/flurries after midnight. At 250-mb as the polar jet moves a jet streak is starting to form leaving central to northern Missouri in the right entrance region giving us some divergence. At 500-mb possible areas of circulation start to pick up. At 700-mb, on Wednesday at 00z vertical motion starts to make its way into Missouri. This vertical motion looks to be wide spread. Humidity will start increasing as winds will switch to the south. Warm air advection will start to come into play in the overnight hours. With wide spread omega and humidity, this system that will be moving in will most likely be wide spread. With unseasonable cold temperatures we will most likely see precipitation in the form of snow. But with warm air advection playing a part in this system, this could give Missouri the potential to see some ice. Southeast Missouri will most likely see any ice, but the majority of the counties in central Missouri will see snow.
Wednesday, this precipitation will continue regarding that it will be widespread. At possible times we could see some heavy snow showers, 12z GFS sounding at 33 hours out it showing saturation all the way from 300-mb down to the surface. Temperatures between 700-mb and 850-mb will start to warm since we have veering winds with heights. These temperatures are around 25 and 30 degrees Fahrenheit. They will get pretty close to the freezing line indicating possible ice.