A series of weather disturbances moving along a nearly stationary frontal boundary stretching west to east across the Midwest region led to several rounds of rain and snow across much of Michigan April 27 through May 2 (four separate events in five days in some areas). More than 2 inches of rainfall was observed at some southern and central locations.
The precipitation saturated soils and brought most spring fieldwork activities to a standstill. The cool, wet weather was associated with a southwesterly jet stream pattern and active storm track that has persisted across the Midwest during much of the late winter and spring seasons so far.
Mean temperatures during April ranged from near normal across southern sections of the state to 3 degrees Fahrenheit or more below normal across the north. At the end of the month, seasonal base 50 degrees Fahrenheit growing degree day accumulations since March 1 ranged from less than 20 across far northern sections of the state to more than 100 across the southern third of the Lower Peninsula. This translates into overall degree day deficits from several days behind normal across the far south to more than two weeks across the north.
Precipitation for the month was above normal in all of the states except for sections of the central Lower Peninsula. Totals ranged from just under 3 inches in the central Lower Peninsula to more than 5 inches (and more than 200% of normal) across portions of Upper Michigan.
It is important to note that Michigan is not alone in regard to the recent wet weather (and spring fieldwork challenges), with much of the Lower 48 states from the Great Plains eastward to the Atlantic reporting heavier than normal rainfall totals.
As of the last week of April, only 13% of the USA was categorized by the U.S. Drought Monitor as abnormally dry or under some stage of drought conditions, which is the lowest such total for any week since the Drought Monitor began operations in 2000.
Most medium-range forecast guidance suggests a continuation of the southwesterly jet stream pattern mentioned above into the latter half of May. This would, in general, leave Michigan in between an area of cooler-than-normal weather to our west and warmer-than-normal weather to our south and east.