textproduct: Detroit/Pontiac

KEY MESSAGES

- A High Wind Warning remains in effect for all of Southeast Michigan until 10 pm for gusts of 50 to 60 mph.

- Another round of accumulating snowfall arrives Saturday night into Sunday, changing over to rain showers by Sunday afternoon with some light icing possible during the transition, followed by some embedded thundershowers overnight.

- A bit cooler Monday, then turning significantly colder Tuesday, with additional opportunities for rain, snow, and gusty winds.

UPDATE

The first surge of strong winds has already produced wind gusts of 40-60 MPH. The 12z DTX sounding indicated strong winds aloft, 58 knots at 850 MB and 43 knots at the 925 MB level. This intense, negative tilted storm system will continue to move through the Central Great Lakes this afternoon.

As boundary layer depths increase and low level lapse rates steepen, should see some notable capes of 30-60 J/kg. Atlhough the bulk of this instability resides below the DGZ, enhanced wind gusts are still expected this afternoon within any convective elements. Upstream observations remain very impressive, providing high confidence of 55-60 mph gusts (trending westerly), with potential to hit 65 mph in localized spots late today. The only mitigating factor is the sub 990 MB low over northeast Wisconsin will be slowly filling in/weakening. None-the-less, the high wind warning through the evening hours looks to be in good shape, and unfortunately, power outages will expand in coverage throughout the day.

Will allow the winter weather advisory to expire across northern tier of counties. While some snow was observed on the untreated/less traveled roads, temperatures are currently at or slightly above freezing. Temps will continue to rise during the day, into the 40s for most places.

PREV DISCUSSION

Issued at 713 AM EDT Fri Mar 13 2026

AVIATION...

Strong low pressure system will continue the track across the Great Lakes today passing over northern lower Michigan this afternoon. Good ascent ahead of this system is producing snow showers that are moving across all terminals this morning resulting in MVFR ceilings and down to IFR visibility. There may be periods of moderate to heavier snowfall mainly focused north of PTK leading to some snowfall accumulation. Brief period of drying may help ceilings lift to borderline MVFR/VFR this afternoon with most of the area seeing a transition to rain/snow or all rain during the afternoon. A very strong low level jet to 60+ knots will be swinging around the south side of the low. Deep mixing combined with the very strong low level wind field will bring the highest wind potential with gusts to 40-45 knots or greater for all terminals by early afternoon as winds shift from southwest to west. Gust approaching 50 knots or perhaps achieving it will be possible across the southern metro terminals today. Winds gradually ease while shifting out of the northwest late this evening and into early tomorrow morning.

For DTW...The most probable window for light snow will be through 14Z. Warmer surface temperatures, should keep accumulations under an inch and confined mainly to grassy surfaces before a transition to rain/snow or all rain this afternoon. West-southwest winds will strengthen rapidly after 15Z, with frequent gusts in the 40 to 50 knot range expected through the afternoon. There will be a slight wind direction shift to the west late this afternoon into the evening hours with northwest winds for bulk of the tonight period. The west wind shift will lead to crosswind thresholds concerns.

DTW THRESHOLD PROBABILITIES...

* High for ceilings at or below 5000 feet today and tonight.

* Moderate in precip type as all snow this morning. Low this afternoon.

* Moderate to high in crosswind thresholds being exceeded afternoon and evening.

PREV DISCUSSION... Issued at 358 AM EDT Fri Mar 13 2026

DISCUSSION...

987 mb low pressure currently located just south of Duluth will track ESE into northern Lower Michigan by this afternoon. Ahead of the system, accumulating snowfall will spread across much of Southeast Michigan, then change over to rain showers during the afternoon once warmer air fills in. The highest accumulations (2-4 inch range) are expected along/north of M-46, therefore a Winter Weather Advisory is in effect through Friday morning. Meanwhile, a High Wind Warning is also in effect to address intense pressure gradient constriction, resulting in peak prevailing winds near 30 mph and gusts up to 60 mph.

Regarding this morning's snowfall, accumulating snow is fast approaching the Tri-Cities, and will spread across the rest of the northern half of the forecast area over the next several hours. Temperatures remained well below freezing last evening and through the overnight hours which supports accumulations at onset. System relative perspectives illustrate an axis of steep isentropic ascent within the mid-levels. This is powering the upstream flanking arc of snowfall which includes segmentation of reflectivity returns in excess of 30 dBZ. The initial rounds of snow will be moderate to briefly heavy given the overlap of strong UVVs and the vertical expansion of a saturated DGZ. As the core of the system approaches, QPF will be maximized as snowfall becomes more widespread with the peak of the event roughly occurring between 12Z and 15Z. Local probabilistic ensemble data indicates potential for snowfall rates to briefly approach an inch per hour with SLRs AOB 15-1. This burst of snow will be responsible for the bulk of accumulations, and largely target areas along/north of M-46. As mentioned earlier, expected snowfall range is 2-4 inches, but locally higher totals approaching 5 inches cannot be ruled out for the far northern portion of Midland and Bay Counties. Further south, totals drop-off with 1-3 inches from M-59 to I-69, while snowfall should largely hold below 1 inch south of M-59. Robust warm advection arrives by this afternoon, leading to a changeover from snow to rain. Precipitation becomes increasingly scattered with time during the afternoon hours as the dry slot punches in from the southwest.

Also of concern, the highly ageostrophic negatively tilted shortwave trough effectuates the translation of a powerful low-level wind field. As of 0542Z, KFSD WSR-88D VWP data sampled 118 knot winds at 4 kft AGL and 60 knot winds at 1 kft AGL. Deterministic progs indicate an 850 mb jet of 60-70 knots moving overhead by 12Z this morning. The nocturnal inversion wears off between 09Z and 11Z, with neutral stability profiles lingering until closer to 13Z or 14Z. Low- level lapse rates eventually steepen which quickly activates turbulent mixing. Gusts should be strongest during the mid-morning hours during the passage of the strongest wind field, but remain elevated through the rest of the afternoon, increasing again into the early evening time-frame. The back edge of the system offers a renewed spike in lower column winds, which should drive one last uptick until ridging starts to build in from the west. Note that forecast soundings indicate well-mixed profiles for most of tonight keeping conditions blustery after the High Wind Warning is set to expire (10 PM).

Anticyclonic configuration draws seasonably cool air back into the region with drier and much less windy conditions Saturday.

Active pattern returns Saturday night into Sunday with another dynamic system set to affect much of the Great Lakes region. Fortunately, Southeast Michigan should reside to the southeast of the heaviest snowfall/banding which could bring over 2 feet of snow for portions of northern Lower and the UP. An elongated isentropic ramp will drive moist adiabatic ascent and snow generation across Lower Michigan after 06Z Sunday. Accumulations are still highly track dependent as the system's VortMax resides well off to the west, barely reaching the lee-side of The Rockies by 12Z Sunday. The speed at which this wave amplifies is impressive, as the base of the mid level trough digs from Seattle to the CO/NM border in 24 hours. Ultimately, consensus guidance is very broad with local snowfall totals ranging from a half inch in the south to around 6 inches in along the far northern edge of the forecast area. No headlines are needed at this time given the anticipated run-to-run adjustments in QPF placement, but a more southeasterly track would favor a rise in forecast snow amounts. As with today's system, a warm front lifts in leading to a transition from snow to rain. Should accumulating snow develop, especially across the southern half of the forecast area, a period of light freezing rain is possible Sunday morning until the warm front makes deep northward inroads. Another possibility is that the environment struggles to favorably evolve thermodynamically, limiting the availability of IN. Outgoing forecast features highs reaching the 60s by Sunday evening.

The actual surface low crosses through Monday as the PV anomaly reorients and quickly stretches from the Tennessee Valley northward into Hudson Bay. This delivers another blast of cold air and increasingly wintry conditions. Aggressive cold advection, and a transition from rain back to snow, with perhaps some thunder, combines for renewed gustiness. Flash freeze concerns could arise Monday night as 850 mb temperatures crash 25C over 12 hours, from 8 AM to 8 PM. Much colder air lingers Tuesday with lake effect banding reaching Metro Detroit given the cyclonic northwest flow, and Lake Superior-Michigan connection.

MARINE...

A seasonably strong low pressure system moves across northern lower Michigan and central Lake Huron this morning. This system has produced a strong pressure gradient along with a strong low-level jet along the southern flank, which will result in a rapid uptick in wind speeds and gusts through this morning. Periods of sustained winds to gales and gusts to high-end gales will be likely with this today , along with sustained periods of snow, heavy at times, especially across central and northern Lake Huron. The stronger wind gust potential is expected to be co-located with the aforementioned low level jet across Lake Erie, possibly extending up through Lake St. Clair, where some isolated gusts up towards storm force will be possible. Confidence at this time remains low regarding. For central Lake Huron, a brief lull in gales will be possible directly under the low pressure system as it passes central Lake Huron in the late morning and early afternoon, however, cold air fills in in the wake of the departing low which will sustain favorable mixing depths and quickly bring returning gale potential leading into tomorrow morning. Overall, a Gale Warning remain in effect for all of the eastern Great Lakes. High pressure fills in for the later part of the day Saturday and will quickly diminish wind speeds.

A second strong low pressure system is looking likely to impact the southern Great Lakes Sunday into Monday. This will bring increasing chances to see another round of gales across the Great Lakes, along with winter weather. Prolonged heavy snow will be possible across northern or central Lake Huron, pending the final track of the system.

DTX WATCHES/WARNINGS/ADVISORIES

MI...Winter Weather Advisory until 11 AM EDT this morning for MIZ047>049- 053>055.

High Wind Warning until 10 PM EDT this evening for MIZ047>049- 053>055-060>063-068>070-075-076-082-083.

Lake Huron...Gale Warning until 4 AM EDT Saturday for LHZ361>363-421-422-441>443- 462>464.

Lake St Clair...Gale Warning until 4 AM EDT Saturday for LCZ460.

Michigan waters of Lake Erie...Gale Warning until 4 AM EDT Saturday for LEZ444.

Low Water Advisory until 4 AM EDT Saturday for LEZ444.