textproduct: Detroit/Pontiac

KEY MESSAGES

- Warmer conditions Friday, with a chance of rain showers.

- Above average temperatures will persist into the weekend.

- Rain chances on Sunday with a rain snow mix possible in the Thumb.

AVIATION

As the clouds depart from one system, the next batch is already on the northwest horizon. While the incoming system nears, low-level wind shear will emerge late tonight across the entire airspace. Surface winds remain rather light through the night, but a southwest flow will surge to near 45-kts around 2-kft. This increased flow will then be tapped into during the post-sunrise hours - supporting gusts to around 25-kts at most locations. There will not be much near surface moisture with the main batch of forcing, so only expecting a few high based showers with the best chance occurring near MBS around daybreak. The accompanying cold front will sweep through during the early afternoon. Notable changes with the front will be MVFR clouds in the colder airmass washing in and winds flipping to northwest. Otherwise, speeds will quell within the first couple hours after the frontal passage.

DTW THRESHOLD PROBABILITIES...

* Medium confidence in ceilings at or below 5000 feet Friday afternoon and evening.

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.