textproduct: Detroit/Pontiac

KEY MESSAGES

- Chance (20-40%) for a light wintry mix overnight, including a low chance for freezing drizzle. Trace amounts of ice accumulation possible.

- Additional chances (30-50%) for rain showers Friday morning and afternoon.

- Warming trend into the weekend.

AVIATION

Low-level frontal boundary locked in the deep northwest flow across the central Lakes region will persist across the Southeast Michigan airspace for most of the forecast period. There is weak ascent up this frontal slope - leading to persistent MVFR/low VFR ceilings. Aside from some breaks in the lowest cloud deck across the Detroit terminal space, expect these clouds to linger and lower through the overnight hours. Enough moisture should gather along the boundary - especially across the northern sites to support some light fog and maybe some patchy freezing drizzle. Additionally, a weak impulse will roll through prior to daybreak - which could squeeze a brief flurry or freezing drizzle dose - albeit too low a chance to toss in the terminals. Improvement in ceilings will take place by midday as a little bit of near surface dry air washes in.

For DTW... expect variable ceiling heights this evening with mainly VFR conditions - but persistently around or below 5kft. A lower cloud deck is expected to crawl back in from the northwest overnight and through the fist portions of Thursday morning. there remains a brief window of forcing for very light precipitation - mainly around daybreak. Depending on the surface temperature - which will be hovering around 32F - this could be in the form of light drizzle or freezing drizzle.

DTW THRESHOLD PROBABILITIES...

* Medium in ceilings at or below 5000 feet this afternoon through tonight.

* Low for ptype Thursday morning being a mixed precipitation.

PREV DISCUSSION

Issued at 326 PM EDT Wed Mar 18 2026

DISCUSSION...

Passage of an elevated warm front have resulted in very light radar returns mainly as flurries to light snow showers with no accumulation. There have been some isolated reported of freezing mist/drizzle upstream as mid-level drying erodes moisture through the dgz. The chances of any freezing drizzle remains very limited across SE MI noting surface dew point depressions around 10 to 15F along with continued mid-level drying. Secondary contraction of the elevated boundary will bring a second chance for light precipitation overnight favored 3AM-10AM, mainly from I-94 south. With temperature right around the freezing mark and modeled soundings highlighting a modest wedge of above freezing temperatures in the low-levels, some low-end freezing drizzle chances will be possible. Given weaker forcing, precipitation rates will be poor, limiting any icing potential if freezing drizzle prevails. NBM 90th percentile (1 in 10 chance) for ice accumulation is capped out around trace amounts. The gradual warm air advection that takes place today into tomorrow morning will turn neutral by the afternoon, but will allow for highs to reach into the 40s for most locations, nearing or achieving 50+ through the southern Metro region down to the MI/OH border.

Renewed chances (30-50%) for precipitation arrives Friday morning into Friday afternoon with the arrival of a clipper system. Rising temperatures through the morning hours will bring high probabilities for rain as the main p-type with any precipitation. Reinvigoration of warm air advection in response to the clipper system will allow temperatures to rise in the 50s within the wake of the low, nearing 60s across the southern third of the cwa. H850 temperatures ranging between 8C-10C hold over SE MI through Saturday providing continued warmer temperatures with NBM showcasing highs ranging between 55-63 degrees. AIFS 2m temperature output is less bullish regarding temperatures highs Saturday potentially in response to any precipitation on Friday leading to overnight stratus development through Saturday morning under a strong low level inversion. However any mixing out in this potential scenario will mix temperatures in line with the outgoing forecast. A cold front is then projected to move across the Great Lakes on Sunday. Pending the timing of the front, warmer temperatures nearing 60 will be possible, most favorable near the state line, until precipitation and cold air advection drops temperatures back to below normal values by Monday.

MARINE...

An area of weak high pressure builds in tonight as low pressure tracks east across northern Ontario. This allows southerly wind to veer to westerly and diminish with time, becoming light and variable by late Thursday. Southerly winds then increase to around 15 knots Friday morning as a clipper system arrives over the northern lakes. Light snow is possible across northern Lake Huron, otherwise mainly light rain is favored as milder air works into the region. A weaker pressure pattern maintains relatively light and disorganized wind on Saturday. Strong high pressure spreads across the Midwest and Great Lakes Sunday into Monday, preceded by a strong cold front and northeast wind of 20 to 30 knots on Sunday. Probability for gales is low at this time, but Small Craft Advisories will likely be needed across southern Lake Huron due to waves around or above 4 feet.

PREV DISCUSSION... Issued at 638 AM EDT Wed Mar 18 2026

Anticyclonic influence to the east acts to suppress ascent associated with inbound mid-level height falls today. Although top- down saturation is currently underway, mid-level warm advection reinforces static stability from 3-12 kft AGL. Accordingly, models continue to trend lower with accumulating snow potential for today. Local decrease in PoPs is corroborated by meager upstream snow observation density, with only minor visibility reductions for the few sites that reported precipitation during the last several hours (over Minnesota and Wisconsin). Latest automated guidance refresh zeroed-out PoPs. To account for a few flakes at times, added in afternoon/evening flurry mention. Temperatures should be at or above freezing by the time flakes start to fall, therefore no accumulations expected, even if some localized overachievement on rates should occur. Still seasonably cold today with highs in the upper 30s. Becoming gusty this afternoon once shallow diurnal boundary-layer mixing taps into 25+ knot low-level flow. The weak disturbance will dislodge downstream ridging, allowing a secondary shortwave to transit the Great Lakes region late tonight into Thursday.

A speed max rolling downstream of a seasonably anomalous/amplified longwave ridge over western CONUS crosses into Southeast Michigan early Thursday morning. Thermodynamic profiles indicate precipitation type concerns, but favoring (liquid) rain. Given the narrow precipitation swath with this system, current trajectories focus most of the light QPF over the southwestern half of the CWA. Temperatures will start out in the upper 20s to lower 30s amidst insulating nocturnal cloud cover, therefore icing potential should be minimal/isolated for areas that sufficiently cool and reside further west, maximizing potential to freeze before temperatures quickly warm into the 40s shortly after sunrise. A glaze of morning icing is possible but not probable for the west-central counties. Liquid equivalent totals should only sum to a few hundredths by Thursday evening when the wave exits over Lake Erie.

Lower tropospheric ridging dampens as it slides over the state Thursday night into Friday. The next embedded wave ejects into the region Friday morning. Potential exists for showers as a perturbed wind field moves in overhead, but a very sharp low-level inversion layer prevents much of a wind (or precipitation) response. A warming trend will be well underway to close out the workweek with highs possibly exceeding 60F with greater proximity to the Michigan/Ohio border. This ensures any precipitation that does occur will be in the form of rain showers. Period of deeper saturation will be brief (if it materializes), then the mid and upper levels dry out quickly Friday evening. The aforementioned longwave ridge should flatten out and fold east over the weekend. Solution space remains mixed on the positioning of the more active periphery which will dictate any additional opportunities for showers. Sunday offers the best chance for some showers, along with a stronger wind field and a cold frontal passage veering winds northwesterly to bring about more seasonable temperatures by early next week.

MARINE...

Moderate southerly winds return today as return flow around departing high pressure kicks in, and low pressure tracks through northern Ontario Wednesday night, drawing a warm front north. Gusts of 25-30 knots are expected this afternoon over the over the open waters of Lake Huron, as 925 MB temperatures only rise to -6 to -7 C, leading to mixing depths up to that level.

Light winds return Thursday-Friday as a weak frontal boundary washes out on Thursday. A warm front will then arrive on Friday, bringing a better chance of precipitation.

Warm airmass (7-10 C at 850 MB) in place on Saturday favors winds aob 20 knots with limited mixing/stable low levels. Next cold front on track to move through Saturday evening, with good low level cold advection and gusty northerly winds for Saturday night. Once again, a period of wind gusts of 25 to 30 knots appear likely. The the unstable low level profiles and longer fetch will result in large waves building over the southern Lake Huron basin, with waves aoa 4 feet impacting the nearshore waters.

PREV DISCUSSION... Issued at 336 AM EDT Wed Mar 18 2026

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory until 10 PM EDT this evening for LHZ421-441- 442.

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