A very complex weather situation is already unfolding today as the remnants of a Mesoscale Convective System continue to fly eastward in our northern counties, where a Severe Thunderstorm Watch remains in effect until 6:00 a.m. this morning. The primary threat with this line of storms will be damaging winds to 70 MPH in the watch area. These storms, as noted, are somewhat the center point of discrepancies in our forecast below. How long these stay around, if they re-intensify, and what boundaries are left behind, are just a few of the issues that we have with the forecast for today.

It’s important to note that there are several situations that could play out today and models have no real pinpoint of what’s going to happen. Two of the major weather forecast models, the GFS and NAM, both have dew points to levels where they don’t make sense – in the upper 70s and low 80s. This is overly exaggerating many of the severe weather parameters that we use, so reliance on short term models, what’s happening now, and pure meteorological experience are factored into the forecast below.

Current expectations have storms across the north weakening and essentially leaving behind cooler temperatures and lots of cloud cover. This should leave a boundary somewhere over the northern one-fourth of the state. In theory, this should prevent any storm development in the northern part of our coverage area and keep it to the south. This, in interaction with a frontal passage to the south, should allow storms to begin forming after a strong cap erodes over central Iowa. It’s tough to pinpoint exactly where this will happen due to many of the features present, but current expectations will likely be between Waterloo and Creston.

These isolated cells will be capable of all threats of severe weather initially, including very large hail and damaging winds to 70 MPH. An isolated tornado also can’t be ruled out. These storms will move east-to-southeast across eastern Iowa and it is probable that it will form a squall line or bow echo across the east and transition to a primarily damaging wind threat. This threat would be enhanced overnight as a low level jet increases.

One uncertainty and possible situation with this is if the current MCS begins to re-intensify over the north and take a turn to the south. Therefore, damaging winds would be the primary threat over eastern Iowa. However, models have been pointing away from this option as of late and it is not as much of a concern.

Whatever happens, it would be a very good idea to keep an eye on the skies today. Stay tuned to the Iowa Weather Network for further updates!