578 FXUS63 KDTX 131803 AFDDTXArea Forecast Discussion National Weather Service Detroit/Pontiac MI 203 PM EDT Sat Sep 13 2025
.KEY MESSAGES...
- Much above normal highs with continuing dry weather next week.
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.AVIATION...
Area of high pressure briefly disrupted by a trough passing over the region this morning. Overcast mid clouds filled the skies with only a few light showers. Skies have begun clearing resulting in more of a sct-bkn mid cloud deck. Some cu has begun to pop up across northern MI but is mainly above 6kft so shouldn`t result in any change in flight category. LIght winds and clear skies this time of year gives the potential for patchy fog development early Sunday morning. Guidance is not very supportive for fog though with only the NAM showing a good chance. All the other soundings are quite dry and surface winds are not persistent enough out of the east off the Lakes to increase boundary layer moisture. So will leave out of the tafs this forecast and assess temp/dewpoint trends heading into tonight.
For DTW/D21 Convection... Thunderstorms are not anticipated through the weekend.
THRESHOLD PROBABILITIES...
* None.
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.PREV DISCUSSION... Issued at 255 AM EDT Sat Sep 13 2025
DISCUSSION...
Regional radar shows the advertised ridge riding shortwave currently pushing through WI early this morning. This wave is set to drop southeast over far southern Lake Michigan due to the presence of an essentially stalled warm frontal boundary near the Mississippi river valley. Nocturnal low level jet remains confined along the Mississippi likewise as a result of stalled boundary leading to convection crossing into lower MI becoming detached from their primary forcing/moisture feed this morning. As a result of both the LLJ positioning and wave track well to our southwest, bulk of showers/storms are confined to the Chicagoland/northern IN area. Any rain locally comes from ongoing convection near Green Bay, however this activity will decay as it crosses lower MI as it pushes off the theta-e gradient that is fixed along the western shore of Lake Michigan. Additionally forecast soundings also depict a fairly dry lowest 10kft with dewpoint depressions around 10C even as showers arrive mid to late morning. End result is expected to be a mix of scattered light showers-drizzle-virga with minimal (if any) embedded thunder. While rain chances are lack luster, abundant accompanying cloud cover keeps high temps a few degrees cooler than yesterday, instead topping out in the upper 70s.
Deepening troughing over the western CONUS leads to a downstream amplification of ridging across the central CONUS to close out the weekend. Upper pattern attempts to develop into an omega block however troughing over the Southeast US is pinched off by the strengthening ridge instead looking to develop into a rex block pattern by Monday. Setup gradually weakens through the week though holds in place through midweek maintaining an extended period of dry weather and much above average high temperatures. Confidence remains high in afternoon temps pushing firmly into the 80s Sunday-Thursday (outside of lakeshore areas). Overnight lows hold on the cooler side as clearer night skies and light winds under high pressure promote efficient radiative cooling.
MARINE...
An upper low dives from Hudson Bay toward New England, carving through the existing upper level ridge over the Plains. Isolated shower potential will thus be possible today through this evening until a cold front settles across the northern Great Lakes overnight. Light SW winds persist today until the cold front shifts winds back to the east/northeast by Sunday morning. The ridge then slides east through early next week, combining with building surface high pressure over Ontario to return to dry and quiet marine conditions.
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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.....DRK DISCUSSION...KDK MARINE.......MV
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NWS DTX Office Area Forecast Discussion