Another widespread rain with thunderstorms is expected to fall across Michigan Sunday into Monday. Northern Michigan has received several inches of rain this week and is highlighted as a potential flash flood area.
While most of us should only get another very useful shower Sunday night and Monday, the weather setup has the ability to produce rain streaks of three inches to four inches. Flash flooding is possible in northern Michigan. Southern Michigan was very dry from this week’s rain, and soils in southern Michigan can still take several inches of rain before flash flooding.
Source: National Weather Service – Gaylord, MI
I see four ingredients lining up to make up to four inches of rain possible in the rain total for Monday night.
First, we will have very abundant water vapor in the air over Michigan. These tiny invisible drops are what eventually join together to form a raindrop. Imagine a sponge full of water but not dripping. When you squeeze the sponge, the water drains out. We will have a sponge charged in the air.
Next, a cold front will move almost directly south across Lower Michigan. This movement is important because this type of movement usually has a slower speed of movement compared to a cold front moving west to east across Michigan. A slower speed means storms can last longer.
The third is the possibility of “train echoes”. Train echoes are individual storm cells that move from west to east over the same place, like train cars traveling on the same tracks. In a train echo situation, you can have three or four half-hour storms pass through the same place. With each storm dropping half an inch to an inch of rain, four bursts of this magnitude really add up.
Finally we will look at the time of storms. This is very important. Peak heat in the afternoon and evening makes storms strongest at this time of day. There is also a secondary peak of instability an hour either side of sunrise.
So we will likely see a train of storms moving east and gradually moving south. Storms will be strongest in the early morning and late afternoon/evening and then weaken in the late morning and early afternoon. This whole scenario will go from Saturday night in the UP to Monday night in the southern end of Lower Michigan.
Here’s a rain forecast showing six-hour periods of total rain.
Rain forecast for six hours Saturday night through Tuesday morning.
Here is a total rainfall forecast. You can expect the strongest storms to drop two to three times the general rainfall forecast.
Total rainfall forecast through Tuesday from the NOAA Weather Prediction Center
Overall, you can see that we can all look forward to another nice rain, and this should eliminate any soil dryness for our landscapes and farmers’ crops.
The National Weather Service says two to three inches of rain could produce flash flooding in the UP and northern Lower Michigan, where up to three inches of rain fell earlier this week. Stay tuned for updates as the weather system approaches Michigan.