The hot December is expected to continue, with temperatures anticipated to be substantially above average today and tomorrow.
The upper air pattern is characterized by almost zonal flow throughout the eastern two-thirds of the continental United States, with a deep trough of low pressure ready to drive into the country's western half today.
The surface indices show that high pressure has migrated eastward into the Ohio River Valley and that southerly flow has taken over the Midwest.
A deepening region of low pressure will form to the lee of the Rocky Mountains in reaction to the solid southern shortwave, and the pressure gradient will continue to rise today and Friday.
Expect breezy winds combined with hot temperatures (temperatures 15 to 20 degrees above normal) for the end of December. Columbia and Quincy are both expected to set new high-temperature records tomorrow.
This storm system will arrive significantly sooner by the most recent suite of model advice. It will track low pressure from northern Missouri and into west-central Illinois early Christmas morning, with the accompanying cold front crossing the CWA by midday.
This more sensible approach would reduce the possibility of record temperatures on Christmas Day, and in reality, it would result in a day defined by stable or slowly declining temperatures.
As this storm progresses through the region, we may also see a few sprinkles or light showers in northern Missouri and western Illinois.
Next week, a storm system moving over the Midwest will maintain temperatures at or above average while still providing several opportunities for rain across the region.
It is projected that high pressure will develop over the region Saturday night, resulting in milder but still above-average temperatures on Sunday.
According to forecasters, by Sunday evening, warm advection ahead of the next storm system will bring the possibility of rain to most of the region.
On Sunday night and Monday morning, this second area of low pressure follows a similar northern path as the previous one, with the cold front moving southward and resting south of the predicted region by Monday evening.
The likelihood of rain is increasing once again. Another disturbance sweeps into the Midwest on Monday night and Tuesday, bringing with it warm advection and a warm front.
The active weather pattern appears to be holding firm heading into the New Year, with some indication in the ensemble data that at least a piece of the cold air that has been building up in Canada will move south into the Midwest during the first week of January, according to the National Weather Service.