Over the last few days, operational models have been trending more and more towards solutions that show severe weather striking the area on Tuesday. The Storm Prediction Center has now changed its forecasted “slight risk” area for Tuesday from an area that was contained in the ArkLaTex to one that now extends well into Kentucky.
Early Tuesday morning, a positively-tilted trough will swing into the area, providing the necessary momentum to push a front that is currently stalled across the state back to the north again as a warm front. As it does so, most of Kentucky will be in the warm sector of the storm, allowing for a progressively destabilizing atmosphere to take hold in the region. Mositure will increase ahead of the storm’s trainling cold front, with forecasted dew points in the low 60s. An elongated area of vorticity and increased shear hint at a developing QLCS across Missouri, Arkansas and Illinois that will likely affect the Warren County area after dark. With bulk shear values of 40-60 knots, damaging winds ahead of bowing segments of the squall line are the most probable convective mode to impact the region.
The models are differing as to the timing of the arrival of the system. The 06z ECMWF and the latest run of the NAM are showing a slowing storm, while the 06z runs of the GFS and NAM show the main line affecting us just after sundown on Tuesday. Nonetheless, heavy rains and the downward transfer of high momentum winds will make for a stormy evening Tuesday, which could possibly last into Wednesday morning. The latest forecasted rainfall totals by the HPC show well over an inch of rain falling across the western half of the state, with isolated totals being greater than that.
The strong ridge off to our east that has provided for the warm weather and gusty conditions over the last few days will prevent any tornadic activity for our region. A relatively stable boundary layer will provide a hostile environment for the sustenance of any convective activity across the Ohio Valley.