Occluded Front

Since this warm trend continues, and I think everyone fully understands that we're above average and we're going to stay that way for the rest of the week. The one thing that will really influence our weather this week is the area of low pressure that's in the Ohio River Valley.

The fushia (pink-purple) line you see in the comma shape is the occluded front that's associated with this area of low pressure that's caused over a foot of snow in Kansas and several inches of rain elsewhere. While it may seem like this entire system is stationary, it's not. Occluded fronts have movement too. Let's take a second to talk about fronts to find out more about occlusions. First, frontal boundaries are usually attached to an area of low pressure - and normally there is a warm and cold front associated with a low. See the pictures below. Warm fronts bring in warm, moist air behind it and are relatively slow moving. Cold fronts bring dry, cold air behind them and are faster moving than warm fronts. Since cold fronts follow warm fronts and they are more rapidly paced, cold fronts occasionally catch up to warm fronts. When the cold front catches up, it forms an occlusion, where the cold front will "lift" the warm front up and over the cold air. Making the weather ahead of the occluded front feet like warm front weather - slightly warmer temperatures with rain shower. Behind the occluded front it feels more like cold front weather - cooler temperatures with rain showers and snow showers possible if the temperatures are cold enough.

This area of low pressure will push back towards the eastern side of the state, bringing clouds and slight chance of drizzle into our forecast tonight and into tomorrow morning, mainly to the east of I-29 and to the south of I-90. Again, just a slight chance of a sprinkle - not going to tip the buckets.

~KDLT Meteorologist Jesse Ritka