textproduct: Detroit/Pontiac

KEY MESSAGES

- Dry weather tonight and Wednesday. Areas of fog late tonight and Wednesday morning.

- Showers increase coverage late Wednesday night and continue Thursday.

- A warming trend is on schedule this week with temperatures around 50 Wednesday and Thursday, 50s to near 60 Friday, and well into the 60s Saturday. Expect colder readings near the Huron and Erie shorelines.

- Showers become likely again Friday and Saturday with a chance of thunderstorms as a front moves across the region.

AVIATION

Light winds continue across Southeast Michigan early this morning. The clearing skies have supported expansion of fog into the Detroit airspace from the remnant low cloud and fog layer anchored to the west end of Lake Erie. Expecting visibilities to continue to drop for the next several hours and persist well into the daylight hours - before improving abruptly by midday. Farther north, where more drying has occurred near the surface, fog development will be limited. Deeper moisture from the next system will start arriving Wednesday evening in the form of low clouds and some patchy drizzle or a few showers.

For DTW...Pesky low clouds are drying up only to be replaced by fog expanding in from the south. Expecting the fog to thicken and deepen due to contributions from the Lake Erie marine layer - possibly dropping to 1/2SM with vertical visibility restrictions - especially in the 10z-15z time window. Another period low ceilings and visibility restrictions is anticipated Wednesday night into Thursday.

DTW THRESHOLD PROBABILITIES...

* High for ceilings at or below 5000 ft Wednesday morning.

* Medium for ceilings and visibilities below 200 ft and 1/2SM in fog Wednesday morning 10z-15z

PREV DISCUSSION

Issued at 313 PM EST Tue Mar 3 2026

DISCUSSION...

The sheared mid level wave is exiting eastward after producing a stray sprinkle and patchy drizzle toward the Ohio border. Dry air in the 850-700 mb layer was otherwise a formidable limiting factor on the northern fringe of the Ohio valley frontal zone.

Passage of the mid level wave leads to farther south consolidation of the Ohio valley frontal zone tonight, and slight reinforcement of surface high pressure over Lower Mi by Wednesday morning. This promotes a decreasing cloud trend this evening and a favorable fog setup late tonight through early morning. Clear sky and light wind allow accelerated radiational cooling after midnight leading to areas of fog as temperatures approach lows in the mid to upper 20s. Locations farther south and east are favored for greater coverage/density due to shoreline proximity and/or higher observations of surface Td this afternoon. Lingering surface high pressure then helps dry weather hold with at least partly sunny skies through the bulk of the afternoon. The corresponding temperature boost makes guidance readings in the upper 40s to lower 50s reachable, although with cooler conditions near the Huron/Erie shorelines due to light east wind.

The next low pressure system latches on to the Ohio valley front and brings our next round of precipitation Wednesday night and Thursday. This is the southern stream system in split flow aloft currently exiting the Four Corners into the southern Plains today on a mid MS valley track Wednesday night. The 500 mb circulation gains some strength in model depictions while on a transition from positive to more neutral tilt and as deep SW flow intensifies out ahead of the system. This activates strong moisture transport through the mid levels of the leading frontal zone and into Lower Mi late Wednesday night and Thursday morning. Later onset farther north gives time for temperatures to rise above freezing leaving just a brief mention of light freezing rain in a small area of northern Bay and Huron counties. Otherwise, it's an all rain scenario for the rest of SE Mi until the system moves eastward Thursday evening.

The peak of this week's warming trend arrives Friday and Saturday, more so Saturday as the next low pressure system tracks through the Midwest and northern Great Lakes. Friday, the surface low is still too far south to help the Ohio valley warm front overcome Great Lakes opposition to northward movement into Lower Mi. Slower timing and the likelihood of rain showers suggests leaning the forecast toward the cooler 50s end of the guidance range. A temperature surge well into the 60s is more likely Saturday as the surface low reaches Upper Mi and the warm sector more fully spreads over Lower Mi. This is also the day carrying the best thunderstorm prospects as the trailing cold front moves across the region during the day. Longer range model solutions and associated temperatures guidance indicate just slightly cooler air with a stray shower Sunday.

MARINE...

A ridge of high pressure maintains a weak pressure gradient over the Great Lakes tonight into Wednesday, with generally light and variable winds. Dry weather continues apart from some light showers near Lake Erie this afternoon. Low pressure tracking along a frontal boundary into the southern Great Lakes on Thursday brings the next window for widespread showers as well as increasing east-northeast wind over Lake Huron to 15 to 20 kt. Drier conditions with weaker wind on Friday, then another low tracks into the Great Lakes Friday night into Saturday to bring showers, thunderstorms, and stronger southerly flow.

DTX WATCHES/WARNINGS/ADVISORIES

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