The Storm Prediction Center has outlooked a slight risk of severe weather for Saturday for about the entire state of Iowa. All modes of severe weather will be possible on Saturday, large hail, damaging winds and a few tornadoes. There are still some uncertainties with the models differing on where the bigger threat may go and those questions may be able to be answered in the next 24-36 hours, regarding instability, prior thunderstorms earlier in the day etc. In any case the main window of severe weather will be in the afternoon through the evening hours before the storms are likely to form into a squall line and racing east and northeastward into the western Great Lakes. Here is what SPC said in their outlook this morning,

GIVEN THE STRENGTH OF THE WARM SECTOR DEEP LAYER MEAN FLOW FIELDS/SHEAR AND FORCING FOR UPWARD VERTICAL MOTION…SEVERE POTENTIAL ON SATURDAY MAY ULTIMATELY BE HIGHER THAN CURRENTLY INDICATED BY THE SLIGHT RISK CATEGORICAL OUTLOOK. CONDITIONS MOST SUPPORTIVE OF THIS POTENTIAL STILL APPEAR MOST PROBABLE TO EVOLVE FROM PARTS OF EASTERN NEBRASKA AND KANSAS THROUGH CENTRAL AND NORTHERN MISSOURI…IOWA AND ADJACENT PORTIONS OF SOUTHERN MINNESOTA…SOUTHWEST WISCONSIN AND NORTHWESTERN ILLINOIS.

HOWEVER…UNCERTAINTY LINGERS CONCERNING THE DEGREE OF WARM SECTOR BOUNDARY LAYER DESTABILIZATION THAT MAY OCCUR…DUE TO THE POSSIBILITY OF CONSIDERABLE EARLY PERIOD CONVECTION WHICH MAY SLOW OR INHIBIT INSOLATION. COUPLED WITH THE AFOREMENTIONED MODEL VARIABILITY…TOO MUCH UNCERTAINTY STILL EXISTS FOR HIGHER SEVERE PROBABILITIES. BUT A SIGNIFICANT CONVECTIVE DAMAGING WIND EVENT APPEARS A POSSIBILITY. IT MAY NOT BE OUT OF THE QUESTION THAT CONDITIONS COULD BECOME FAVORABLE FOR TORNADIC SUPERCELLS.