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KEY MESSAGES

- Chances for showers and storms begin late today and linger into Tuesday. Primary threat is heavy rain, with marginal threats of large hail and damaging winds

- Slight chance for mixed precipitation north of the bridge tonight into Tuesday morning

- Next larger winter system approaches northern MI early Thursday, which will bring chances for widespread snow and mixed precipitation

DISCUSSION

Issued at 229 AM EDT Mon Mar 30 2026

Current radar reflectivities show some low to mid level moisture moving over eastern upper and near the straights this morning. No surface observations are showing precipitation reach the surface, and per the 00Z KAPX RAOB it is having to overcome a decent amount of drier air below it. To the southwest, satellite derived PWATs show gulf moisture surging northward.. with up to three quarters of an inch reaching as far north as central IL. In the mid to upper levels, fairly zonal flow exists over the CONUS today. Pacific moisture continues to stream in over the northern Rockies, settling over the northern US plains and southern CAN plains. These two moister streams will meet over the Great Lakes region tonight and into Tuesday.

At the surface, high pressure is seeping over Ontario CAN today and will turn winds to the northeast over most of northern MI. A lee side low over CO/NE will strengthen southerly flow over the Ohio river valley today, advecting the gulf moisture towards MI. Near surface convergence will be seen over northern lower, with lower level convergence over eastern upper late this evening. At the same time, helpful jet dynamics will move over norther MI (right entrance region). The first wave of widespread light to moderate rain will move over northern MI late this evening and into the night tonight. Times of freezing rain and freezing drizzle will be possible over eastern upper and parts of the northern Lk Huron coastal areas early Tuesday morning. Precipitation will lighten up during this time for most of northern MI, and should keep any accumulations of ice up to a couple hundredths of an inch.

Early on Tuesday, an upper shortwave will be passing over northern MN and Lk Superior. This will aid in a 1030 hPa surface high treking down the northern plains. This will deepen a surface cyclone over IA/IL/WI early Tuesday. Strengthen southwesterly winds ahead of this feature will surge the warm sector moisture ahead of it and allow for elevated instability of around 700 to above 1000 j/kg to reach up towards the tip of the mitt. The second wave of moderate rainfall will move across northern lower in the form of multicell showers and storms Tuesday morning. The primary threat with these storms will be heavy rain, with marginal threats for large hail and damaging winds. Heavy rain on top of the existing snow pack could result in areas of localized flooding in low spots and in hilly terrain. Most locations over northern lower should see up to a half inch of rainfall total from tonight through late Tuesday. A reasonable higher end amount for areas adjacent to Saginaw Bay (75th percentile QPF) is one and a half inches. With the current QPF in the forecast, the Manistee river near Sherman is forecasted to reach into Minor flood stage Tuesday and Wednesday. There is typically greater amounts of uncertainty in exact locations of where convective QPF falls. This uncertainty translates to the river forecast, as it is highly sensitive to if the QPF falls inside the river basin.

Tuesday evening, the surface low will exit and usher in colder temperatures. Brief light lake effect snow/freezing drizzle over parts of eastern upper and northern lower will be possible Tuesday night. With a 1034 hPa surface high over Ontario CAN, colder air near the surface is seen on Wednesday and Thursday. At the same time, an upper trough over the central Rockies will be influencing the next surface low residing over CO/OK/KS. Existing moisture to the south of MI (pushed there via the cold front Tuesday) will meet with more gulf moisture around the Ohio River valley. The larger surface low will move towards the Great lakes region once the upper trough exits the Rockies, beginning earl Thursday. East to northeast winds will persist sub freezing temperatures over parts of northern MI while moisture and warmer air aloft climb north up the state. It is still too early to nail down precipitation type, amounts, and location.. However signals continue to point to some parts of northern MI seeing times of mixed precipitation early Thursday into the day. As far as chances for impactful mixed precipitation; currently the majority of LREF ensembles keep accumulating ice at a trace or less for all areas besides M55 and south where the majority of ensembles keep accumulating ice at a tenth or less. Per ensembles, impactful ice remains a less likely outcome for northern MI however that could change as we get closer to the event as global models struggle with resolving smaller scale features that ultimately decide the details. Conceptually, ice somewhere over northern MI does seem to be a likely outcome (especailly during or just after the onset of precip) as colder surface air will already be anchored over the area and the surface low has an upper level feature to strengthen it. Moisture will already be existing as well. How the precipitation evolves during the day will determine amounts, and thus impacts.

Current guidance tracks the surface low through the southern part of MI late Thurs into Friday with the next system right on its heels. With the active pattern, uncertainty looms over what will happen this weekend.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 132 PM EDT Mon Mar 30 2026

VFR conditions will continue across northern Michigan through this afternoon/early evening with mid/high cloud overhead. Low cloud is expected to quickly fill in later this evening, dropping most areas down to IFR CIGs tonight -- and potentially LIFR across parts of northern Michigan Tuesday morning. Shower and isolated thunderstorm chances move in later this evening and tonight, especially across northern lower Michigan. Current confidence is too low at any given TAF site to be more specific than VCTS for potential thunderstorms at this time.

APX WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...None.