Jeff Andresen | November 9, 2017
An active weather pattern continued across the Upper Midwest during the second half of October with the passage of a series of upper level troughs and low pressure systems.
This led to frequent rounds of precipitation and extended delays in fall harvest and other fieldwork activities.
An incursion of a seasonably cold Canadian-origin air mass late in the month behind one of the low pressure systems led to the first freeze of the fall season across most of central and southern Lower Michigan (only the extreme southwest and southeast corners of the state have yet to observe their first freeze so far this season).
For many areas, the first freeze was at least two weeks later than normal. The colder air also led to the first significant snowfalls of the season across much of the Upper and northern Lower Peninsulas during the last week of the month.
Precipitation for October ranged from less than 4 inches across eastern sections of Lower Michigan and the southern Upper Peninsula to more than 10 inches across southwestern sections the Lower Peninsula (up to 300 percent of normal).
In some southwestern areas of the state, this October will rank among the wettest on record. Amazingly, problems with flooding and excess water during the past few weeks were relatively localized and fewer in number than would normally be expected due to the prolonged and abnormal dryness during the late summer and early fall that preceded the rainfall.
Mean temperatures for the month were warmer than normal statewide, ranging from about 2 degrees F above normal across western sections of Upper Michigan to more than 6 degrees above normal in central Lower Michigan. These departures would have been even larger due to normal to below-normal temperatures during the last week of the month.
Current indications from medium-range forecast guidance are that the recent active and unsettled weather pattern across the Great Lakes region will continue for the next couple of weeks, likely leading to normal to below-normal mean temperatures and to normal to above-normal precipitation totals.
A significant portion of the precipitation will likely fall as snow, especially in northern sections of the state. And, given relatively warm lake water, to more rounds of lake-effect precipitation.
This pattern is reflected in the revised NOAA monthly outlook for November, which also generally calls for more the same.
Collectively, these outlooks suggest continued delays and problems with harvest operations during the next few weeks.
Further ahead, there is a hint of milder and drier weather. The NOAA 3-month outlooks for November through January call for increased odds of above-normal mean temperatures state- and region-wide. Precipitation totals for the same period are without forecast direction, with near equal chances of above, near, and below-normal totals.
Extension Agricultural Meteorologist
Michigan State University