We are expecting the possibility of severe thunderstorms come Friday evening and overnight. There are some precluding factors in their ignition, however. Any one of the factors, or a combination of them, may spare us of a long Friday evening and overnight. Here are a few of my thoughts going through my head when it comes to forecasting Friday’ severe weather potential–it gets complicated. I also hope this blog gives you a little insight as to how hard it is to forecast severe thunderstorms (can be a real beast…and bust).

Morning thunderstorms are expected on your Friday. The atmosphere is set for a few of these storms to produce some lower-end severe hail. Good news, widespread severe weather is not looking very likely out of this first bout. In fact, this first bout will likely produce clouds that could place a cooling-veil over Northeast Kansas for a good chunk of the day.

You need heat to drive severe thunderstorms. Friday morning clouds may help to limit heating come Friday afternoon. Less heat means less fuel for thunderstorms. However, if we clear out earlier, then the surmounting heat could actually increase later afternoon storm chances. In either regard, we are expecting enough heat to provide at least sufficient fuel for potential storms by late Friday afternoon.

Sometimes you can get warm air to build up a littler higher in the sky. What this does is it puts a “lid” on the atmosphere. If this lid is not broken, then storms do not form. A lid is expected to form on Friday. However, there is a flip-side to the lid (no pun intended).

To some degree, a lid actually lets the atmosphere boil. If the atmosphere boils underneath the lid, and the lid is popped, then explosive storms can occur. Either the heat building underneath the lid itself, or a kick, is needed to cause storms to explode.

If we have enough morning clouds on Friday, then the heat underneath the lid may not be enough in-and-of itself to pop the lid. So, that means we may need a “kick” to get storms to blow. We do have a strong kick coming in by late Friday afternoon and evening.

Right now we think enough heat will boil underneath Friday’s lid; that, provided a kick, could realize some pretty strong storms by Friday evening. Should storms kick, they will likely become severe. Large hail and gusty winds are the main threats, but enough twist near the ground could help fix broad thunderstorm rotation to the ground in the form of a few tornadoes.

Even though Friday’s situation is complicated already, I can throw another monkey-wrench into the mix–morning storms can actually help create additional kick for new storms. Now, I said that morning storms can produce clouds that keep things cooler (keeping storm chances down), but they also can help increase storm chances, too. Sure, clouds can clear out, but the cool imprint of morning storms often gets mixed about in the atmosphere, too. The cool imprint of morning storms can actually help to provide a kick for new storms by late afternoon. As weathermen/women, we are trained to look for the imprint of morning storms (usually via radar). We have to keep a close lookout for these features Friday, too.

In short, it’s complicated. All of these features/variables have to be watched very closely by the time we hit late Friday afternoon across the area. The hope is that we have morning storms that really cloud things over and keep us cooler than currently expected. The cooler temperatures, and a lid on the atmosphere, would be ideal at lowering severe thunderstorm chances come Friday evening and overnight. Let’s hope this is the case.

Best,

Alex