Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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317 FXUS63 KDTX 041702 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 102 PM EDT Sat May 4 2024 .KEY MESSAGES... - Morning fog and low clouds give way to a warm Saturday with highs in the low to mid 70s. - Scattered showers and possible non-severe thunderstorms this evening through Sunday morning. && .AVIATION... Moisture will increase from south to north again this afternoon and evening as mid level wave ejects into the general area in advance of approaching frontal system. Expect a trend from lower VFR back to MVFR with a few showers possible with this moisture especially into evening. IFR/lower MVFR stratus still looks likely overnight as the moist southerly flow persists before frontal passage early Sunday morning. While this front looks pretty dry, a few showers will be possible with its passage. Ceilings will slowly erode/lift within west to northwest flow in its wake on Sunday (especially by aft). For DTW/D21 Convection...Southeasterly winds today will drive weak instability across the airspace after 21Z. Isolated thunderstorms are possible within this environment. Forecast probabilities suggest a 20 percent chance across the southern portions of the airspace. DTW THRESHOLD PROBABILITIES... * Low for thunderstorms late this afternoon into tonight. * Moderate for ceilings aob 5000 feet this afternoon, high by the overnight period into Sunday morning. && .PREV DISCUSSION... Issued at 307 AM EDT Sat May 4 2024 DISCUSSION... Despite the showers and clouds yesterday, high temperatures were able to sneak into the lower 70s across most areas. Extremely dry airmass noted with the 00z APX raob, and some of the mid level dry air has/will make inroads into southeast Michigan. However, cool northeast flow off Lake Huron and lingering low level moisture looks sufficient to saturate the low levels, and deep enough moisture (5+ kft layer) to potentially trigger stray light rain showers, especially toward the southern Michigan border, as some of the deeper moisture over Ohio attempts to work back north late in the day, ahead of a weak cold front moving through from the western Great Lakes tonight. With surface capes under 1000 J/kg today and the mid level dry slot, do not see EQL levels getting high enough to generate thunderstorms during the daytime, but a slight chance of non-severe storms appears warranted this evening/tonight with the modest height falls and the slightly negative showalter values tracking through. Stability will be on the increase 15-17Z Sunday as the front clears the State. Despite a fair amount of clouds today and the early morning fog, will allow high temperatures to reach into the mid 70s across most locations, based on the forecasted 925 MB temps of 17 C. Westerly confluent upper level flow Sunday night preceding an upper level ridge axis arriving early next week, supporting dry weather on Monday and likely during the daylight hours of Tuesday before a warm front brings widespread showers and possible thunderstorms Tuesday evening/night. MARINE... An area of high pressure centered over the region this morning is resulting in a weak gradient with light winds and waves across the region. Elevated dew points within the stable environment have resulted in areas of dense fog across Lake Huron and a Dense Fog Advisory is in effect until noon today. The gradient increases this afternoon as the high departs east, with wind organizing out of the southeast late today into tonight. A stalled front lifts north as a warm front tonight as a weak low moves from the upper Mississippi Valley into the northern Great Lakes. The system then sends a cold front through early on Sunday with a chance of showers and thunderstorms. Wind shifts to northwesterly behind the front Sunday afternoon, peaking at around 15 to 20 knots. High pressure then builds in to bring quiet marine conditions for Monday and much of Tuesday. The next warm front moves into the area late on Tuesday with stronger easterly flow developing ahead of it. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ AVIATION.....DG DISCUSSION...SF MARINE.......TF You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.