textproduct: Detroit/Pontiac

KEY MESSAGES

- Stretch of colder conditions will exist through Tuesday with temperatures remaining below normal during this time. Milder air returns for the mid to late week.

- Brief higher intensity bursts of snow showers will be possible tonight, with a dusting to half inch of accumulation on grassy surfaces in isolated areas. Northeastern Thumb has the potential to get clipped by lake effect bands off Huron and see an inch or two of accumulation by sunrise Tuesday.

- The next chances for rain arrive Thursday and likely persist through much of Friday.

DTW THRESHOLD PROBABILITIES

* High for ceiling at or below 5000 ft this evening. Low tonight and Tuesday morning. * Low for rain/pellet mix this evening through 02Z.

PREV DISCUSSION

Issued at 305 PM EDT Mon Apr 6 2026

DISCUSSION...

Mid-upper troughing continues to govern conditions locally allowing a couple of sheared shortwaves to track into the region. The second of these is beginning to arrive over lower MI this afternoon spurring the development scattered showers. Given wet bulb zero heights only sitting around 2kft and diurnal heating supporting sharp mid-level lapse rates, graupel is likely (and could be the predominant p-type) within the more robust convective cells. A few rumbles of thunder also possible with these cells given the weak instability and availability of ice within the cloud. Greatest shower coverage arrives this evening as a respectable cold front sweeps across the state. Forecast soundings advertise wet bulb zero heights further falling aob 1kft as cold advection ramps up which would allow some snow to mix in, particularly in the Thumb where columns are coolest. A good pop of NW wind is expected to occur along the cold front with 35-40mph gusts possible.

Stronger cold advection follows through tonight keeping winds breezy gusting 25-30mph as 850mb temps fall to -12 to -14C. Resultant wind chills reach lower teens to single digits F as overnight lows drop to the lower 20s. Magnitude of cold airmass is supportive of scattered lake effect flurries/light snow showers overnight into Tuesday morning. Most areas see little to no accumulation though isolated areas could pick up a dusting to half inch on grassy/evaluated surfaces. One exception is the northeastern Thumb who, seeing an early changeover to snow this evening and potential for Lake Huron lake effect bands to clip shore, could pick up an inch or two by sunrise Tuesday. Thermal troughing holds for the day Tuesday keeping temperatures much below average in the mid to upper 30s for most of the CWA- southern areas especially toward the Ohio border stand the best chance to reach 40.

High pressure shifts to our east Tuesday night ushering in milder southwesterly flow for the mid to late week period as 850mb temps return to the positive upper single digits C. Rain shower chances return by daytime Thursday as a broad northern Ontario low drags a cold front into lower MI. Mid-range model solutions continue to suggest this front slowing, potentially stalling, over southern lower MI late Thursday as parent troughing rapidly lifts into northern Quebec turning the frontal slope parallel to mean flow. A secondary trailing shortwave arrives over the Great Lakes Thursday night-Friday reinvigorating the remnant baroclinic zone and offering another period of widespread showers before the front finally clears southeast Friday night. With the recent heavier rain/flooding, especially over the northern half of the area, this potential for longer duration rainfall will be something to monitor. Further adjustments/refinements to the exact positioning of the frontal boundary and axis of heaviest rainfall to come in further forecast cycles.

MARINE...

Low pressure carves across Lake Huron this evening, dragging a cold front across the region and shifting winds to the northwest. A brief pop in wind gusts up to 35 knots will be possible late this evening immediately behind the front. Small Craft Advisories remain in effect as northwest gradient flow increases wave heights into Tuesday morning. High pressure fills in briefly Tuesday ahead of the next impactful low, which tracks across Ontario late in the week. This system brings a 60-70 knot low level jet into the Great Lakes region Wednesday night-Thursday morning, although forecast soundings depict a very stable boundary layer that prevents this magnitude of gusts from reaching the surface over the open waters. Nocturnal timing of the jet should also prevent overachievement of gusts along the land-lake interface. Expectation with this system is thus sustained southerly flow of 25 to 30 knots, and gusts in the 30 to 35 knot range. This system will also be responsible for numerous rounds of rain and possible thunderstorms late in the week as it draws a slow-moving cold front across the region.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory until 10 AM EDT Tuesday for LHZ421.

Small Craft Advisory until 4 AM EDT Tuesday for LHZ422.

Small Craft Advisory until 4 PM EDT Tuesday for LHZ441>443.

Lake St Clair...None. Michigan waters of Lake Erie...None.