The Mid-South will have two good rain chances over the next 10 days. The big question will be whether the 2nd of the two rains is a drought-denter or a drought-buster.
A split-flow pattern is observed over the central U.S. on Monday which will bring perhaps the last 85+ day of the year. The upper-level trough and vort max over the central Plains will weaken as it approaches the Mid-South by mid-week, but the SW flow ahead of the vort max will bring enough gulf moisture to wring out anywhere from 0.5 to 1.0 inches. With weakening dynamics, there is little to no risk of severe weather with this system but there will be some heavy downpours and gusty winds with thunderstorms.
The far more interesting storm is the deep-trough expected to develop over the Rockies this weekend. By Saturday, jet stream energy will dive into the Four Corners region and bring a major winter storm to the higher elevations. There has been great run-to-run variability with this storm, as model solutions range from an open wave that spawns a Northern Plains blizzard to a completely cut-off storm that sits over the Great Basin. The drought-busting solution of choice is the current 00Z GFS, which brings heavy warm-advection thunderstorms to the Mid-South on Sunday and continued heavy rain on Monday as the upper-level storm cuts off from the main flow. This type of system could easily bring 2-4″ of rain to the region and quickly end this short-term drought we are in. The main problem is that most of the other model solutions are not this generous with precipitation. The 06Z run cuts off the storm too far west and doesn’t bring any rain into the Mid-South until Tuesday when the system begins to weaken. The 18Z from Sunday is a much different looking storm that cuts off in the northern Rockies and moves into Saskatchewan. It will be interesting to see what the 12z run today looks like. The GFS ensembles show about as much variability as you could want. It will be interesting to see how this plays out.
