Fairly strong Halloween storm with T-storms, wind and UP snow

There will be major weather changes throughout Michigan during the day and evening on Halloween. A strong, large-scale storm system will bring a series of thunderstorms, gusty winds and ultimately a sharp drop in temperature. There will even be some snow in the Upper Peninsula.

There's a reason some of the fall storm systems are called “November storms.” The low pressure centers, which indicate how strong a storm system is, become deeper in late fall. These deep storm systems generate a lot of wind. The storm system for Halloween isn't quite as strong as the famous November storms, but it will definitely be a severe storm.

The storm scenario calls for the low pressure center to move from the Plains to Wisconsin and around Leelanau County in northern Lower Michigan. This will keep all of Lower Michigan in the warm sector of the storm until 6-8 p.m. A strong cold front will bring a line of showers and thunderstorms across Lower Michigan during the middle of the day on Halloween. Cold fronts typically only produce a few hours of rain. The rain may be accompanied by lightning.

Here is the rain forecast in one-hour increments so you can track the progress of the storm system. You'll also see snow forming on the cold northwest side of the storm.

By evening, the cold front and thundershowers will move east and south of Michigan. Then there is an abrupt drop in temperature. The new air won't be particularly cold for this time of year, but will feel like a shock when it's over 30 degrees today and Wednesday and over 20 degrees at noon on Halloween.

The temperature forecast below clearly shows the cold front and rapid drop in temperature sweeping across Lower Michigan after 6 p.m. That means Ann Arbor, Detroit, Flint, Saginaw and Bay City probably won't get – or treat – cooler air until near the end of the trick. On the west side of Lower Michigan, temperatures will drop into the low 50s during trick-or-treating.

When we have a deep low pressure system, that always means strong winds. There will be gusts over 30 mph throughout the day on Halloween, with some gusts near 40 mph.

Here is the wind gust forecast for the afternoon. You can see that the entire state is covered in green and yellow colors, meaning gusts of over 30 miles per hour. The strongest afternoon gusts will extend from Grand Rapids north to Traverse City and Petoskey.

The cold northwest side of the storm will bring some snow to the western Upper Peninsula. While the weather forecast shows the maximum amount of snow at 15 to 30 centimeters, snowmelt will reduce this by half. Some areas may see three inches of snow on Halloween.

Halloween will definitely be windy all day and possibly thundery for a few hours.

Stay tuned here if there is a chance of a severe thunderstorm.