Here’s a quick look at some of the changes to winter storm forecasts. These changes occurred as newer weather data arrived during the night.
The changes are subtle and point to more heavy snow for a slightly larger area in Lower Michigan.
The first change is a slightly colder idea across all models. The location of the snow-to-freezing rain line provides the best indication of temperature change. Yesterday, it was expected that this snow-to-freezing rain line would extend across southeast Lower Michigan, near Ann Arbor and Detroit.
The models’ overnight runs have moved the snow-to-freezing rain line about 20 miles southeast. This means more snow and less/no freezing rain in Ann Arbor and most of Detroit. It still appears that the south side of Detroit and Monroe may experience a brief period of freezing rain mixed with snow.
Otherwise, it’s all snow for the rest of us in Michigan.
This slightly colder solution results in changes to the winter storm watch overnight. Each National Weather Service office in Lower Michigan (Detroit, Grand Rapids, and Gaylord) has added a few counties to the winter storm watch list.
This is the layout of the winter storm watch as of 4:30 a.m. today, February 11, 2025.
The winter storm watch was expanded to include four counties in far southeast Lower Michigan: Washtenaw, Wayne, Lenawee, and Monroe. The National Weather Service in Detroit did this due to less mixed precipitation and more snow.
The winter storm watch covers a period of heavy winter precipitation from 1 p.m. Wednesday to 7 a.m. Thursday. This means Ann Arbor, Detroit, and Monroe are now under a winter storm watch, with 4 to 7 inches of snow expected and only a light glaze of freezing rain.
The National Weather Service in Grand Rapids has also added Calhoun and Jackson counties to the winter storm watch list. This was also done due to the slightly colder thought, which added an inch or two to the snow forecast. Jackson and Battle Creek are now under a winter storm watch with 5 to 7 inches of snow expected by 7 a.m. Thursday.
The National Weather Service in Gaylord has added some counties along the northeast shoreline to the winter storm watch. These counties were added because the colder weather forecast will result in some Lake Huron enhancement with a northeast wind.
During storms like this, Lake Huron counties receive a few inches more snow than the inland counties of northeast Lower Michigan. Alpena, Alcona, Ogemaw, Iosco, Gladwin, and Arenac counties have been placed under a winter storm watch, with snowfall expected to range from 4 to 8 inches by Thursday morning.
This still appears to be a 5 to 8-inch snowstorm from Grand Rapids to Mount Pleasant to Bay City and southward. Grand Rapids may be on the northern edge of the 5 inch or more snowfall, putting it on the lighter side of the spectrum.
The National Weather Service in Grand Rapids provided one final thought early this morning. In their discussion at 2:30 a.m., they write: “Overall thinking remains the same that widespread 4-7 inch snowfall is expected with a FGEN driven band of 7-12 inches is likely to develop, favored south of a Mount Pleasant to Grand Rapids line.”
An FGEN band indicates that a frontogenetical band of snow may form. This is a narrow, 10-mile-wide band of heavier snow formed at precisely the right time on the north side of a snowstorm. We often see this in mature winter storms. They mention an area extending from just south of Grand Rapids to just south of Mount Pleasant.
My thoughts on this are that one foot of snow is extremely difficult to obtain in Michigan, despite being such a snowy state. It does happen, but it is rare. This possible FGEN heavy snow band could cause a few areas to top out at 9 to 10 inches of snow.
In general, most of us will shovel a solid 5 to 7 inches on Thursday morning.
The snow began Wednesday afternoon, became heavier Wednesday night, and ended around sunrise Thursday.
