Early April Severe Weather Outbreak

A potentially major outbreak of severe weather could be in store from portions of the Plains into the Deep South early next week.  This probably could have been predicted months ago when I elected to leave Mississippi during severe weather season to present at the Association of American Geographers Annual Meeting in Los Angeles during this same time frame.  Nevertheless, here are some of my early thoughts on the developing situation.

A low pressure system and associated cold front forming in the lee of the Rockies on Sunday will begin to progress eastward Monday.  As this system progresses toward the east it will become the focus for severe weather for at least the early portions of the week.  Major model differences do exist right now with the most notable difference existing between the timing of the system between the GFS and ECMWF models, which are nearly a day apart on the timing of the front now.  The animation to the right shows the GFS model's progression of the 250 mb winds during its past four model runs.  The GFS has moved the trough further east over the past 24 hours and

tilted it more neutrally.  The ECMWF has the trough further to the west with more of a positive tilt in its two past runs, both shown to the right with the 00Z run from last night on top and the 12Z run from this morning on the bottom.  The timing differences here between the two models are rather vast and mean the difference between severe weather on Tuesday or Wednesday for some.  However, the GFS has a bias in pushing these systems through too quickly and thus it is the ECMWF model that should be given more weight.

These are the same thoughts the Storm Prediction Center has also abide by in issuing there latest Day 4-8 Convective Outlook, seen below and to the right.  An enhanced severe threat would be possible over a small portion of western Kansas on Monday, to the northeast of the surface low.  A larger threat area would exist on Tuesday over eastern Kansas, eastern Oklahoma, northeast Texas, western Arkansas, and western Missouri.  Wednesday the threat would move into portions of northern Louisiana, western

Mississippi, eastern Arkansas, southwest Missouri, western Tennessee, western Kentucky, and southern Illinois.  The threats over these three days will include all forms of severe weather with some large tornadoes possible, especially on Tuesday and Wednesday.  Unfortunately, until the GFS comes around toward a solution that is similar to that of the ECMWF, most of the products I am able to look at do not depict an event I believe will actually occur.  Therefore, I have created my own map showing where I believe the threats will be on Tuesday and Wednesday based on limited ECMWF guidance.  The orange outlined area is the area I believe could see CAPE values in excess of 1000 J/kg.  Meanwhile the green line represents the area that according to the ECMWF is at risk of precipitation during this time period.  As of right now, without knowing much more than this, the threat area could really be just about anywhere within this region, which I show in red shading.  However based on some other analysis, I have also tried to outline an area of where I think a greater likelihood of severe weather could occur, which I shaded in pink.  This is my preliminary outlook, I will update this sometime this weekend, especially if the GFS and ECMWF begin to converge on a more similar scenario.