COLORADO – We get areas of low pressure to form around eastern Colorado through something called “Lee Cyclogenesis”.
Here’s how it works… We have an upper-level low set up over the mountains. As this low moves towards the lower elevations, like our plains, it has to expand to fill up the added space as the surface gets lower. That expansion forces the low to tighten up and become stronger. It’s similar to how a figure skater can increase their rate of spin by pulling in their arms.
This happens pretty frequently when we get storm systems. However, the increase in strength isn’t typically as intense as what we had Wednesday.
It becomes a “bombcyclone” when the pressure drops over 24 mb in 24 hours. The lower the pressure, the stronger the storm can be. We often talk about intense development like this in hurricanes and nor’easters.
The lowest pressure physically measured with this system was 970.4 mb in Lamar. That’s like the pressure of a Category 2 Hurricane. For comparison, the average March pressure in Lamar is 1016.9 mb. That’s a big difference, and one we never like to see.