textproduct: Detroit/Pontiac

KEY MESSAGES

- Mild today with any morning rain showers ending by afternoon.

- Above average temperatures will persist into the weekend.

- Strong cold front moving through Sunday afternoon brings a good chance of showers and a significant cool down for Monday.

DISCUSSION

Latest water vapor imagery shows a strong, compact shortwave on track to move southeast through Lake Huron this morning. This supports the Thumb region having the best chance for numerous rain showers, with only scattered PoPs (30-50%) elsewhere. Negative upper-level PV advection/subsidence this afternoon should lead to dry conditions; however, uncertainty remains regarding the extent of low clouds, given low-level moisture (surface dew points in the 40s) and incoming cold advection. Max temperatures in the mid- 60s could be derailed across the far south if low clouds develop faster than expected.

A strong upper-level ridge is centered over Arizona, with the jet stream tracking through the northern Great Lakes this weekend before shifting briefly south of the region early next week. Surface high pressure on Saturday will provide tranquil weather.

A strong cold front will track through southeast Michigan Sunday afternoon. A wave of low pressure riding along the front will attempt to delay its southward progress, adding uncertainty to the exact frontal position during the day. Meanwhile, strong northeast winds over Lake Huron will accelerate the frontal passage and enhance the temperature gradient. Expect a dramatic temperature contrast of 20-30 degrees from north to south across southeast Michigan by afternoon. Locations toward the southern border could reach the 60s, with an outside chance of 70+ degrees if the warmer solution (see 00z regional GEM model) materializes. Modest instability also presents a slight chance of thunderstorms near the southern Michigan border.

The post-frontal cold shot Sunday evening into Monday (850 MB temperatures dropping into the negative upper single digits) looks to be brief. Temperatures should recover to near or slightly above normal by mid-week.

MARINE

Gusty southeast wind precedes a compact clipper system that tracks across northern Lake Huron later this morning. Wind shifts to northwest in its wake this afternoon, around 10 to 15 kt, while rain/snow tapers off. High pressure then eases in late today into early Saturday with northerly wind generally aob 10 kt. A strong cold front sinks south across the region on Sunday with gusty northeast wind of 20 to 30 kt developing behind it. Probability for gales remains low, but Small Craft Advisories will likely be needed across southern Lake Huron due to wave heights around or above 4 feet. Expansive high pressure builds in behind the front on Monday, then the next cold front is expected on Tuesday.

PREV DISCUSSION

Issued at 1209 AM EDT Fri Mar 20 2026

AVIATION...

An upper level short wave and associated sfc low will track from Upper Mi early this morning into Se Mi and ern Ontario late this morning and early afternoon. Strengthening SW wind fields atop a shallow nighttime stable layer will remain supportive of low level wind shear during roughly the 08Z to 14Z time frame before daytime mixing transitions conditions to gusty winds at the surface. Ample dry air in the low levels will warrant low probabilities for rain showers this morning as the upper wave advances across the region, with ceilings remaining high (VFR) based. As the surface low and associated cold front depart southeast of the area this afternoon, shallow post frontal cold air and moisture advection will result in an expanding MVFR based stratus deck.

DTW THRESHOLD PROBABILITIES...

* Low in ceilings aob 5000 feet this morning. High this afternoon and tonight.

PREV DISCUSSION... Issued at 229 PM EDT Thu Mar 19 2026

Record breaking high amplitude ridge over the western United States will result in a northwest flow regime for the Great Lakes region Friday and this weekend. Generally looking at minor forecast concerns over the coming days with the most pertinent of challenges being the swings in the temperature forecast locally with the baroclinic zone wavering in vicinity of Southeast Michigan.

Quiet weather with a few breaks in the clouds early this evening as synoptic scale subsidence and surface high pressure pushes through the area. Upper level jet exit region spreads into the northern Great Lakes late tonight opening the door to midlevel warm advection. Favorable synoptic lift in combination with embedded shortwave energy will support a Clipper/area of surface low pressure tracking from the Straits at 12Z Fri to Toronto by 18Z. Warm midlevel air mass, 900mb temperatures of +12-13C, pushes across southern portions of the area supports an all rain forecast. Dry air and subsaturation in the lowest 9.0 kft agl yields lower confidence in rainfall amounts, less than a tenth. The forecast PoPs range from 60% likelies in the Thumb to 20 percent for much of Metro Detroit. Better support for rainfall exists across Ontario and perhaps the eastern cwa for a time between 12-18Z Friday. Highs are tricky with the surface cold front along the Irish Hills axis at 18z pushing southward through Metro Detroit during the afternoon.

The surface front is forecasted to backdoor southward clearing the region into portions of Iowa and Illinois Friday night. Big question is then what temperatures can moderate to on Saturday especially with expected cloud cover. Latest guidance was a little cooler for Saturday highs; but additional downward adjustments are likely needed especially locations adjacent to the Lakes.

Deep midlevel trough and change in orientation to upper level jet axis is expected to result in a frontal wave pushing through Lower Michigan Sunday. There is a converging of global model solutions for a frontal timing Sunday midday/afternoon. Very warm midlevel temperatures are again expected with 850mb temperatures of +16 or +17C. Post front precipitation may changeover to snow for a time but warm ground will likely limit much of impactful accumulation outside of the Thumb. PoPS for Sunday currently reside in the high chance, 40-55 percent range.

A large area of stable high pressure is anticipated for the beginning of the next work week. Cold nighttime temperatures are expected to warm into the 40s with full sunshine.

MARINE...

A weak ridge of high pressure takes brief residence through late today as a frontal boundary washes out overhead. Northwest wind becomes light this evening before organizing out of the southeast early Friday morning in response to a clipper system, reaching a peak around 15 to 20 kt. This system tracks across northern Lake Huron Friday morning, bringing a quick round of rain and snow overnight into the first half of Friday. Winds shift to north and northwest in its wake at around 10 to 15 kt, then weaken into Saturday as high pressure builds back in. A strong cold front sinks across the region on Sunday with gusty northeast wind of 20 to 30 kt developing behind it. Probability for gales remains low, but Small Craft Advisories will likely be needed across southern Lake Huron due to wave heights around or above 4 feet. Expansive high pressure builds in behind the front on Monday, then the next cold front is expected on Tuesday.

PREV DISCUSSION... Issued at 213 PM EDT Thu Mar 19 2026

DTX WATCHES/WARNINGS/ADVISORIES

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