Stormy Week Ahead...

Hello Again...

I have the time now I didn't think I would have, to dive deeper into forecast data and tell you how the next week will shake out.  As an aside, I am considering adding a second tab to this blog, with forecasts on one page and the detailed discussions on a separate tab.  Let me know what you think.  Also, as time progresses, I will be pushing more traffic toward Google + and Twitter as opposed to Facebook.  That is down the road a bit, but it's on the radar - no pun intended.  Now - let's look at the detail and extended forecast.

SUMMER WEATHER INGREDIENTS:  The next three days will see temperatures in the mid to upper 80's and a 90 or two is not at all out of the question, as I stated this morning.  Showers and thunderstorms, some possibly severe, are in the mix as well.  The upper air pattern is currently a trough/ridge setup, with troughing from the High Plains west, and ridging east of that.  Look at this.

This is a chart that shows various features at 500 millibars (about 18,000 feet up, where the jets play).  I marked it up some to help you see what I'm talking about.  The solid black lines measure how high you need to go (in meters) to get a 500 millibar pressure reading.  Forecasters and meteorologists use it to identify upper air features.  As I have said in prior posts, the higher the number, the warmer the air is.  588 is usually good for upper 80's or even low 90's here in the bottom three to five thousand feet of air where we spend most of our lives.  So we have warm air.

Now, looking at charts that show how the atmosphere is stacking up between 5 and 10 thousand feet up (850 and 700 mb), I see there's a river of winds on the order of about 40-50 MPH over the middle third of the US.  This is the low-level jet (LLJ).  It brings warm temperatures, but most important, moist air up from the south, typically off the Gulf of Mexico, but sometimes from the Pacific, off southern California and the west coast of Mexico.  Add the moisture to the already warm rising air, and we get clouds.  As the air rises, it cools off, and when it gets cold enough, the clouds condense out their moisture into water - rain.

Now, there's other things we need for severe thunderstorms, such as shear (winds changing direction with height), lifting (usually an upper disturbance or a bona fide surface feature like a low or frontal boundary).  I won't get too technical with those, but they're in the area, or will be for tomorrow and Tuesday.  The green arrows I used to approximate the wind direction connected to the LLJ are different than the jet stream winds, so you will have some shear and instability.

STORM CHANCES TOMORROW AND HUMP DAY:  These maps are from the Storm Prediction Center.  They show that tomorrow and Wednesday we have a chance at severe storms each day.  We'll watch that for you and refine the forecasts as the day today progresses...

Severe Weather Outlook, SPC days two and three - South Central Michigan is in play for both days!

Here's how the six day outlook stacks up:

Have a great day!