textproduct: Detroit/Pontiac

KEY MESSAGES

- Accumulating snowfall begins this evening with totals of a half inch to two inches by Sunday morning. Low confidence for localized higher amounts.

- Colder and drier on Sunday, followed by an extended warming trend during the upcoming workweek.

- The next opportunity for widespread precipitation occurs Tuesday with a wintry mix possible.

AVIATION

Band of light to moderate snow driven by midlevel frontogenesis will continue to impact Southeast Michigan this evening. Radar and surface observations support a period this evening of prevailing IFR snow with brief LIFR possible in the heaviest snowfall rates. The Detroit terminals appear to be impacted along the southern periphery of the band and included IFR to LIFR conditions. Much of the activity will push through by 4z with light snow then persisting until approximately 08z. Very strong signal for steep isentropic downglide and dry air advection between 09-12z. Should be steadily improving VFR conditions by late morning.

For DTW...The southern edge of the snow shield has been impacting the airfield. Included IFR to TEMPO LIFR this evening.

DTW THRESHOLD PROBABILITIES...

* High in ceilings aob 5000 feet this evening and overnight.

* High in precipitation type as snow this evening and overnight.

PREV DISCUSSION

Issued at 330 PM EST Sat Feb 28 2026

DISCUSSION...

Despite ongoing cold advection, a mostly sunny start to the day boosted temps well into the 40s across Metro Detroit and south, while 30s are prevalent elsewhere. The well advertised snow band is tracking across Lake Michigan with snow obs yet to be reported on the eastern shoreline. Very dry air has been in place across Lower MI, evidenced by a 35C+ dew point depression at 830mb/4200 ft AGL in the 12z DTX raob. Mid-level fgen and attendant ageostrophic response are ramping up this afternoon with a peak in forcing expected through mid evening, but much of this ascent will be used up to erode the dry sub-6000 ft layer. Model cross section analysis advertises modest, broad omega but with some intersection with lower static stability aloft. So transient weak banding is still in play, and a relatively abrupt onset to snow is expected over the next 2 to 4 hours as saturation is achieved.

Light snowfall causes temps to drop below freezing with minor accumulations through the evening, then rates diminish late evening as forcing peels east. Low-level moisture advection off Lake Huron may keep spottier rates going for parts of the area past midnight. Regional observations indicate the band is following the more southern model solution, with the highest QPF favored to set up between I-69 and I-94. Snow totals of 1 to 2" are most likely in this corridor and the Thumb with lower amounts elsewhere. Localized amounts of 3" still plausible if brief band contraction occurs, but this carries low confidence in occurrence and placement. Additional lake effect snow showers are possible in the eastern Thumb Sunday morning but otherwise high pressure will reintroduce dry air and help scatter clouds through the day. The thermal trough overhead keeps high temps in the 20s and lower 30s tomorrow.

High pressure passes east but maintains influence with dry conditions favored through Monday. Return flow begins to advect in a warmer air mass with a slight increase in daytime highs into the 30s. The next wave engages the frontal zone over the mid-Mississippi and Ohio Valleys Monday night to lift an area of precipitation northward into southern Lower MI on Tuesday. Thermal profiles during this period generally show a shallow sub-freezing sfc layer with a warm nose aloft, so light wintry mix will be possible if the precip arrives during the morning. Ensemble probabilities indicate roughly a 20 to 30% chance of a glaze and near 0% for 0.10" of ice.

A mild and active stretch is expected through the middle and end of next week as a strong Bermuda high induces a feed of Gulf warmth and moisture toward the southern Great Lakes. Several Pacific waves will track across the CONUS during this period, sending tongues of higher theta-e north with bouts of showers and even some thunderstorms. Model spread is high with regard to timing and placement of each system at this time but consensus supports the wetter pattern.

MARINE...

An upper level disturbance will bring light snow this evening. Steady low level cold advection through tomorrow morning as strong high pressure builds over the Central Great Lakes tomorrow afternoon. Subsequently, northwest winds around 20 this evening and tonight will decrease under 15 knots tomorrow and aob 10 knots by evening. As large high pressure moves off the East Coast early next week, strengthening southwest flow will bring milder air into the Great Lakes region. With the increase low level stability, it appears winds will just top out in the 25 to 30 knot range. A weak low tracking through the northern Ohio Valley mostly rain over Lake St. Clair and Lake Erie, with dry weather and light winds returning Wednesday morning, as high pressure briefly returns.

DTX WATCHES/WARNINGS/ADVISORIES

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