After a long wait of waiting for spring weather and warmer temperatures, Iowan’s will finally be able to experience just that as highs make their return into the 60’s and 70’s for much of the state — at least for a short time. However, with this type of weather returning, we also have to look at what comes with it: severe weather.
An upper level trough will shift eastward into the Midwest on Friday with an associated area of low pressure centering itself over the Central Plains. Meanwhile, at the surface, a low pressure center will meander somewhere in east central Nebraska, likely just to the west of the Omaha area. A dry line will sit in the central Plains before being overtaken by a cold front, extending southward through the lower Mississippi Valley, with a warm front to the east of the low. These synoptic features will set the stage for a complicated forecast on Friday.
On Friday morning, some convection will likely be ongoing over areas north of Highway 20. Some of these storms may have some small hail or gusty winds, but organized severe weather is not anticipated. Ultimately, this convection and associated cloud sheet should be thin enough in nature to allow for daytime heating to brew elements, with dew points in the low-to-mid 60’s leading to CAPE values (instability) reaching 1500-2500 j/kg over western Iowa, which is more than enough at this time of year to get storms cooking. With deep-layer shear in place, initiation should begin near the triple-point in east central Nebraska around mid-afternoon in the form of discrete cells with large hail, damaging winds, and tornadoes all possible.
While storms will initially be discrete, they should band together and become more linear into the form of a QLCS as the night progresses. After sunset, much of the instability will wear off, and the hail and wind threat should not last long. However, it is important to note that the biggest concern with this event will be the tornado threat, primarily on the southeast side of the triple-point in southwest Iowa and near and along the warm front in central Iowa. It’s important to note that as these synoptic features change, the overall forecast placement will change. We should be able to get this finer-tuned details worked out over the next 24 hours.
Stay tuned to the Iowa Weather Network for the latest information!