The Storm Prediction Center in Norman, OK upgraded most of North Iowa and South Minnesota to a "Slight" risk of severe weather on Monday, a level 2 / 5 in how the agency designates severe weather threats.
This comes following a weekend of cloudy, cool, and rainy conditions that allowed for the atmosphere to build up humidity. Warmer temperatures moving in on Monday, along with strong winds, will allow for more energy for storms to develop.
Monday's primary severe threat are damaging winds, large hail, and even the chance for a few tornadoes.
We are going to time out tomorrow's severe weather threat for you here. Keep in mind there is some uncertainty in when exactly all these fronts pass, so the timing could change a bit. Stay tuned to KIMT for all the latest as we track this severe weather threat.
- Setup Sunday night will allow for continued small showers and widespread clouds. A weak warm front is developing across Iowa.
- By Monday morning, the weak warm front is moving through. Winds will be out of the south. Some stronger showers and even small storms will occur, but these will not be severe. Cloud cover clears as the front passes.
NOTE: Any lack of rain/clouds at this time will allow for daytime sunlight to heat up the ground, and will INCREASE severe threat later! Opposite is also true. Look for temperatures above around 72 degrees on Monday to know if severe threat has increased.
- There will be some downtime in the hours following noon. However, another warm front - this one stronger and more defined - will be closing in from SW. Upper level winds will be kicking from WSW. With SSE winds at the surface, there's enough wind shear to sustain some supercells (spinning thunderstorms). A few tornadoes and occurrences of large hail possible. Heavy rain and wind likely. Again, the threat increases with more sunlight earlier in the day.
- (A CLOSER LOOK) Looking at the picture on the right, this computer model (NAM3K) is overdoing how widespread the rain is. Radar tomorrow around 5pm will likely be a few isolated supercells throughout the area. These will be the main severe threat, and have the potential to produce large hail and damaging wind along with tornadoes.
- By early Monday evening. A low level jet will develop across Iowa and southern Minnesota. These strong winds out of the south will push the warm front through. All of this promotes continued storm activity through early Tuesday morning. Storms here could be better organized because of the low level jet.
- (A CLOSER LOOK) By better organized, this means that some of then supercells could consolidate into larger bow segments, seen here between Winona and Decorah. With this, the threat for damaging wind increases. However, the tornado threat marginally decreases.
- By Tuesday morning, a cold front will push through bringing one last round of storms. These are likely not to be severe. The low level jet will be weakening, and the instability in the atmosphere will be mostly exhausted at this point.