976 FXUS63 KDTX 061743 AFDDTXArea Forecast Discussion National Weather Service Detroit/Pontiac MI 143 PM EDT Mon Oct 6 2025
.KEY MESSAGES...
- Showers and scattered thunderstorm tonight and overnight, with showers lingering into tomorrow afternoon.
- Much cooler conditions Tuesday through the end of the week.
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.AVIATION...
VFR conditions will prevail through the remainder of the daylight hours with scattered clouds at 5-10 kft. Southwest winds gusting to to 15-20 knots this afternoon will also ease towards 00Z this evening. Increasing moisture tonight ahead of a cold front will bring rain/thunderstorms chances along with lowering cigs/vsbys. MVFR to periodic IFR ceilings can be expected as precipitation rolls through. Showers and thunderstorms taper off from north to south, clearing east of the southern metro terminals by around 18Z tomorrow afternoon. A wind shift from southwesterly to northerly post front will occur at MBS after 06Z with eventual passage south of DTW by around 16-17Z tomorrow. Post frontal environment will also see ceilings lift back to VFR.
For DTW/D21 Convection...Thunderstorm activity late today/tonight stays north of DTW. There is then a low chance (30%) for thunderstorms to impact the airspace tomorrow morning as early as 07z, but more likely between 10z and 14z.
DTW THRESHOLD PROBABILITIES...
* Low for ceiling 5000 ft or less through this evening, increasing to high by early tomorrow morning.
* Low for thunderstorms tomorrow morning between 10z and 14z.
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.PREV DISCUSSION... Issued at 312 AM EDT Mon Oct 6 2025
DISCUSSION...
Southwest flow preceding a slow moving cold front has limited nocturnal cooling and will result in a seasonally mild temps at daybreak in the 60s. This will give way to another day of afternoon highs into the 80s as the southwest flow and daytime heating support a deep and well mixed boundary layer. Slight prefrontal moisture advection in the low to mid levels will result in a little more diurnal cloud cover this afternoon. Can not rule out some shallow late afternoon convection, likely limited on coverage and intensity by continued mid level capping.
Deep layer troughing moving across northern Ontario tonight into Tuesday will drive the cold front across the Great Lakes region. The deep layer front will largely remain parallel to the deep layer southwest flow across Lower Mi tonight into early Tuesday morning, resulting in a very slow moving frontal system. A veering of the low to mid level flow to the west- northwest will help force the front southeast of the forecast area on Tuesday. A region of high deep layer moisture is forecast to lift into the northern Ohio Valley tonight. There is still respectable model agreement indicating the northern edge of this moist plume will get transported into the frontal system. The placement of an upper jet streak(s) and small scale mid level short wave impulses will help sustain intervals of low to mid level frontogenesis tonight into Tuesday. There are several high res solution which indicate a more focused region of ascent arriving late this evening into the early portion of the overnight, targeting the northern half of the forecast area. There are even indications of a surface reflection along the cold front. Weak to possibly moderate elevated instability will support a respectable convective response. While the instability axis will shift southeast Tues morning, frontal forcing higher up the frontal slope will persist across at least the southern portions of the forecast area into Tues afternoon, warranting continued rain chances. The cold front, which will move through Se Mi overnight into Tuesday morning, will be characterized by a strong thermal gradient in the boundary layer, leading to much cooler post frontal temperatures on Tuesday.
Strong high pressure associated with a building mid level ridge over the upper midwest/Manitoba/nrn Ontario will expand across the Great Lakes region Tuesday night into Wednesday. North-northeast low level winds preceding this high will sustain decent cold and dry air advection into Wed afternoon, leading to seasonally cool temperatures. In fact, conditions will be favorable for some locations to experience frost Thurs night. As the high departs to the east, return flow will support a warming trend into next weekend, with forecast highs into the upper 60s/low 70s.
MARINE...
Low pressure tracking through northern Ontario this afternoon and into James Bay tonight will maintain south-southwest flow into tomorrow. Winds looks to be mostly in the 15 to 20 knot range, but a few gusts up to 25 knots will be possible over Lake Huron as cold front approaches. The continued progression of low pressure into Quebec will then push a strong cold front across the region late tomorrow into Tuesday morning. Wind direction will veer to the north after the passage of the front. Post frontal cold air advection will sustain breezy conditions across Lake Huron Tuesday as 850 MB temps fall into the low to mid single numbers. A period of wind gusts in the 25 to 30 knot range are expected before winds diminish on Wednesday as expansive high pressure arrives.
HYDROLOGY...
Rainfall probabilities across Southeast Michigan are quite high tonight through Tuesday morning as a deep layer frontal system slowly works its way across the area. Weak to possibly moderate instability will support a convective component to the rain. This and possibly narrow regions of enhanced frontal forcing suggest a wide range in total QPF amounts across Se Mi, with some areas possibly receiving under a tenth of an inch. This is also noted in QPF probabilities and various hi res model QPF output. 12 hour conditional convective probabilities indicate a 10 to 20% chance for 2 inches or more, while basin average precip totals are most likely to fall into the quarter to half inch range. In light of the recent dry conditions, flooding is not expected. Localized urban flooding may be of concern should a more persistent area of convection become established over the metro Detroit region. Confidence on this scenario is low at this time.
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.DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. &&
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AVIATION.....AA DISCUSSION...SC MARINE.......SF HYDROLOGY....SC
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NWS DTX Office Area Forecast Discussion