A low pressure center is expected to move into northern Minnesota and southern Ontario from eastern North Dakota Saturday with a cold front extending into the Upper Mississippi Valley. Ahead of this front, moisture will again flood the area as it has several times this season with muggy dew points near 70°. Strong mid-level flow will also be prevalent over the area as broad forcing and height falls develops across the area. Deep atmospheric moisture mentioned earlier in addition to steep lapse rates will establish strong instability at the surface Saturday afternoon. This instability in combination with ample moisture, large-scale forcing, and plenty of shear will create an environment favorable for severe thunderstorms.

Several cells are expected to develop in the late afternoon hours in western Iowa and into Nebraska as the cold front pushes into the area. In the environment mentioned above, large hail and damaging winds will be the primary threats. An isolated tornado will also be possible, primarily near the surface low. By late evening, these cells should form into a multi-cellular line and likely a linear mode as things evolve. This will continue a threat for damaging winds through the late evening hours.

The Storm Prediction Center currently has an elevated risk of severe weather primarily for areas west of I-35 and north of I-80. An upgrade to enhanced isn’t out of the question for northwest/west central Iowa and eastern Nebraska due to the overall threat and confidence being higher there. However, confidence in a smaller and more concentrated area of severe weather is low. Nonetheless, don’t be fooled, as the threat for large hail, damaging winds, and tornadoes is still there, and we can say that with higher confidence than in earlier outlooks. Those in the western and central parts of this elevated risk will have the best overall chance while the far eastern parts will likely see mainly a damaging wind threat.

Stay tuned to the Iowa Weather Network for the latest information!