FXUS63 KDTX 100340 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 1140 PM EDT Fri May 9 2025 .KEY MESSAGES... - Clear again tonight but not as cold. Weak cold front crosses daytime Saturday offering a slight chance for an isolated shower though the vast majority remain dry. - Much above average temperatures arrive Monday and persist through the week. Scattered shower/storm chances arrive midweek. && .AVIATION... An approaching cold front will slowly advance across Se Mi during the day Saturday. This front will have limited moisture availability which will result in mainly mid level clouds late tonight into Saturday, prevailing VFR. Some high based showers and/or virga is possible. As the front translates across Se Mi on Saturday, there will be a veering of the winds from WSW to NNW from mid morning into the early-mid afternoon, followed by an abrupt shift to the northeast late afternoon with a push of post frontal Lake Huron modified air. For DTW/D21 Convection... No thunderstorms are in the forecast tonight and Saturday. THRESHOLD PROBABILITIES... * None. && .PREV DISCUSSION... Issued at 234 PM EDT Fri May 9 2025 DISCUSSION... Region remains under the influence of fairly strong high pressure centered over the western Great Lakes. Active subsidence combined with an extremely dry resident airmass- 09.12Z KDTX RAOB sounding only shows a PW value of 0.17" (this is only a few hundreths from the daily climo minima), has kept skies cloud-free. This as aided in a healthy thermal recovery after the cold morning start with all of SE MI now sitting around 60. Ridge axis begin to cross the state tonight allowing the warmer upper Midwest airmass (850mb temps near 11C vs our local 1-2C currently in place) to fold into the area. While this warm advection remains largely elevated atop the nocturnal boundary layer, it in combination with late night arrival of mid/high cloud limits radiational cooling efficiency to prevent a repeat of last night's frost/freeze. Instead, lows are expected to only fall towards the lower 40s to upper 30s. Aforementioned clouds are associated with a weak cold front dropping out of northern Ontario that is set to cross SE MI daytime Saturday. Moisture pooling in advance pushes surface dewpoints into the mid- upper 40s which could offer a shot for an isolated shower with fropa. Overall potential for this are low given the front's detachment from the parent wave over the James Bay with model guidance gradually backing off on advertised coverage. Will maintain the running slight chance (15%) PoPs during the late morning- afternoon though do expect the vast majority of the area to remain dry. Main impact from the front is a north-south gradient in high temps with areas north of M-59 topping out in the 60s to lower 70s and areas south reaching the mid to upper 70s. Stronger high pressure then follows to close out the weekend as broad upper ridging develops across the central CONUS. This ridge slowly crosses the Great Lakes for the bulk of next week bringing much above normal temps with highs in the 70s to lower 80s. A southern stream mid-upper trough is progged to lift out of the Gulf coast and undercut the ridge midweek offering chances to see scattered showers and thunderstorms. MARINE... High pressure to bring dry weather through the weekend, with the exception of late tonight into tomorrow morning across northern Lake Huron, with a spotty shower possible along an elevated front. A cold front is then set to pass over the Great Lakes through tomorrow morning and afternoon, which will veer wind direction from southwest to north-northeast. Winds generally remain light behind the passage of the front, but more favorable fetch through the Saginaw Bay will bring some sustained wind potential near 20 knots. It is borderline at this time for both winds and waves, but a Small Craft Advisory may eventually be needed through the Saginaw Bay for tomorrow. Otherwise, high pressure is again reinforced tomorrow through Sunday, continuing dry weather and maintaining lighter winds to end the weekend. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ AVIATION.....SC DISCUSSION...KDK MARINE.......AM You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.