We are currently in the return flow of a surface high pressure system with a weak cold front draped diagonally across central Illinois and Missouri. The strengthening upper level support will help to push the boundary through our area early Tuesday morning. The inflow of moisture is apparent, but not very significant. There is a nose of moisture extending into western Kentucky from the Gulf of Mexico.
The question is whether this precipitation will be of the frozen kind, and how much.
The GFS run above is showing the line of critical thickness (estimated freezing line) horizontally dividing Kentucky. Being situated near the freezing line makes determining the type of precipitation very tricky. Concerning the amount, both the NAM and GFS are concluding the precipitation at 12Z Tuesday, with the GFS calling for up to .09 inches and the NAM calling for up to .24 inches. I will stick to the lower end, since the frontal lifting and moisture inflow are moderate at best. The temperature difference on either side of the front is lacking, thus further reducing its chance of strengthening, especially at night. Right now, precipitation received is looking like rain, but I will continue to monitor and provide updates to precipitation type up to the frontal passage if needed.
After the frontal passage early Tuesday morning, a surface high pressure will settle into the region for the middle of the week bringing more of a return flow into Thursday.
Days at a glance:
Monday: High of 56, Low of 34, no precipitation
Tuesday: High of 43, Low of 22, .11 inches of rain
Wednesday: High of 49, Low of 25, no precipitation
Thursday: High of 55, Low of 32, no precipitation
Forecaster: Austin Boys