Tornado risk tomorrow potentially higher than any time yet this year

I've been reading a lot of posts from people who are scared, and I want to begin by addressing those people. I make posts like this not to incite panic but to keep people ahead of the game on what's going on.  I do not want them to become a source of anxiety for anyone.  Please remember that your chances of being hurt in a severe weather event is low, especially if you take precautionary/preparedness actions in lieu of a severe weather risk. A little fear is a good thing, but it is probably more dangerous to one's health to be driven to an anxiety attack over this type of situation.  Above all else, I engage in this hobby because I love storms, and snow, and rain, and sunshine, and everything that makes this state as naturally beautiful as it is.  At the same time, I want to inform and educate those who are interested in what makes the atmosphere tick, and learn more myself at the same time.  If I ever feel like I'm doing more harm than good, expect this page to disappear overnight.

Posts like this one in particular are not meant to alarm anyone to the point of panic, but to help people prepare.  There is no reason to fear even the worst severe weather event any more than taking a drive down I-75, provided that you keep a plan of action on what to do if things go wrong.

Now, let's get to the outlook.

Latest model guidance is suggesting that the vigorous upper level disturbance to our west and associated negatively tilted surface low will push a cold front through Michigan tomorrow afternoon or evening.  This cold front will be robust and cause occlusion within the warm sector, meaning upward forcing will be very, very high, and updrafts should be robust.  Depending on the timing, moderate to extreme instability may be in place in some parts of Michigan when this occurs.

The general NWS consensus as of right now is hinging on around 1000-2000j/kg of CAPE, which is about par for the course for the average severe weather event.  NWS DTX is suggesting less - perhaps 500-1000j/kg - in place over SE Michigan.  The NAM4KM model, however, suggests that a great deal more - up to 3000j/kg - may be in place in some areas.  If that kind of instability manages to combine with the types of winds that are forecast to be in place in the upper atmosphere tomorrow, we could be looking at a much higher end event.  The deepening low is also causing low-level and surface winds to pick up, which adds an entirely different (rotational) dynamic to storms that may form.

Earlier in the week I talked about things that could make this go boom or bust.  I'm going to add to/refresh that list now, and talk about simple, non-technical things to watch for tomorrow that would indicate signs of big trouble:

• A bright, sunny mid day - How much instability is in place and where is going to be the key to just how big storms will grow tomorrow.  Needless to say, if it's bright and sunny in the late morning and early afternoon, it's going to contribute to this factor quite a it.  This is especially true in SE Michigan where instability is currently forecast to be low.  SE Michigan and the Thumb area tend to be where the storms "move to" on these types of days, and the instability factor will likely determine whether they dissipate or intensify as they enter these areas

• Moderate to strong surface winds - Pay close attention to which way the wind is blowing tomorrow and at what speed.  If a strong southeast wind begins to develop, this is a sign of bad things to come.

• Lack of early day convection - This one can have big potential to put a squash on things but also has big potential to be deceiving.  The more rain that cools things off in the morning, the less robust thunderstorms should be in the afternoon.  However, just because it rains in your area doesn't mean you won't see severe weather.  It may cause it to be -less- severe than it otherwise could be, but June 22nd should be enough of a lesson that early day rain/storms do not always kill off the risk.

MODEL GUIDANCE

The last few model runs are painting a picture that sits somewhere between concerning and grim. The NAM4KM model is far and away the most nasty looking right now, while the Rapid Refresh and its high-resolution counterpart aren't predicting quite as ugly conditions, at least initially; their forecast are still cause for concern, but the NAM4KM just takes things to a different level.

I've talked about the supercell composite index enough times that most people probably realize what it means by now - the darker the red, the better the conditions are for supercell thunderstorms to develop.  While those colors are foreboding, that isn't what has me most concerned.  Take a look at this loop:

This is the model's forecast for "1 hour maximum updraft helicity".  Let's discuss what that means. The updraft is the key to a severe thunderstorm.  The stronger the updraft, the longer the thunderstorm lives, and the more severe it becomes.  The other side to this coin is that an updraft that rotates can connect with wind shear on the ground, and spawn a tornado.  This parameter essentially forecasts just how much potential to rotate an updraft has in a one hour time frame; it literally predicts rotating updrafts, and can be a great indicator of tornado risk.  Wherever you see colors in that image, the model is predicting the presence of a rotating updraft.  The stronger the color, the more powerful the rotation, and the better the likelihood of a tornado.

Needless to say, those markings concern me a lot, especially when you take into consideration how accurate this model has been over the summer. The colors don't necessary indicate strong or violent tornadoes being possible yet, but they do indicate a fairly robust general tornado risk.

Tomorrow is likely going to be an active afternoon/evening.  I don't know just how severe an event we're looking at just yet.  Right now, it's sitting on the fence between Jekyll and Hyde.  The key is to be warning aware tomorrow.  Watches will likely also be issued, which should provide some indication of how intense storms that form will be.  Don't allow a day like tomorrow to paralyze you. So far, the chance of this plunging into the high end of the spectrum remains modest.  Simply stay forecast aware, keep your TVs and radios on, and turn an eye to the sky every now and then.