Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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310 FXUS63 KDTX 080734 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 334 AM EDT Sat Jun 8 2024 .KEY MESSAGES... - Dry to start the day with showers arriving mid to late afternoon and spreading across the area this evening. - A stray shower is possible on Sunday with a weak cold front leading to slightly below normal temperatures Monday. - Cool and dry early week conditions are followed by a warming trend back into the 80s by late week. && .DISCUSSION... Modest height rebounds are ongoing early this morning as a mid-level shortwave ridge squeezes in between the departing upper low moving into southern Quebec and the next wave emerging out of southern Manitoba/western Ontario. This is driving the localized high pressure and window of clear skies over Lower Michigan as subsidence maintains control through the morning. Clouds will quickly increase through the day as the next wave induces a pattern of moisture advection and isentropic ascent ahead of it. Early day sun and burgeoning southwest wind will boost temps to the upper 70s across the south, while lower 70s are expected for a high across the north where clouds will make an earlier arrival. Showers will spread in from the west after noon - first across the Tri-Cities and Thumb along an elevated warm front, then spreading south and east as fgen lights up along the weak surface reflection as it tracks through during the evening. Warm and stable mid-levels will prevent much if any instability from developing - less than 10 percent of 00z NBM and HREF members show >100 J/kg of SBCAPE - so thunderstorms are not expected. Showers will depart east during the late evening with overnight lows settling into the 50s. Rainfall amounts are forecast to be on the order of 1 to 3 tenths of an inch. Troughing will dominate local conditions on Sunday as an upper low deepens over eastern Canada and sends additional shortwave energy across the Great Lakes. A cold front will sink south across the area during the afternoon bringing increasing clouds and about a 10 to 20 percent chance of light showers given relatively shallow moisture and forcing. Temps ahead of the front will reach the mid to upper 70s for much of the area before the cold advection commences. Lower 70s will be more likely north of I-69. 850mb temps fall steadily toward the 3 to 7 C range by Monday morning, setting us up for a cool start to the work week. The upper troughing and cyclonic flow sticks around into Monday and may present another low chance for afternoon sprinkles/showers if enough moisture can hold in place, but have left out of the forecast for now. With the thermal trough also overhead, high temps will be limited to the low end of normal in the mid 60s to around 70. The trough finally releases to the east by Tuesday, allowing a ridge axis and surface high to build into the Great Lakes with sunny and milder conditions expected. A more zonal upper flow pattern takes shape Wednesday into the late week, with a much warmer air mass arriving from the west to bring highs back into the 80s. There look to be periodic chances for showers and storms during this period as several shortwaves pass over the region. && .MARINE... Weak area of low pressure swings into the southern Great Lakes today bringing widespread showers, particularly over the southern two- thirds of the region. Winds shift northwesterly following this system as deepening low pressure over western Quebec results in tightening of the local gradient. Wind gusts between 20-25kts likely over the bulk of the central Great Lakes throughout the day Sunday into Sunday night. Areas where overachievement with gusts potentially nearing 30kts are the Saginaw Bay due to the warmer waters and subsequent more unstable thermal profile, as well as northern Lake Huron given the favorable fetch. Lighter winds, less than 20kts, then arrive Monday as high pressure builds overhead. This high remains in place for the first of half of the work week. && .PREV DISCUSSION... Issued at 1140 PM EDT Fri Jun 7 2024 AVIATION... Generally tranquil aviation conditions will hold into early Saturday afternoon as weak sfc high pressure lingers over Se Mi. A mid level short wave will then drive light rain across Se Mi from late Sat aftn into the evening. Ceilings are expected to be VFR upon the arrival of this rain given ample low level dry air. Model guidance would suggest increasing chances for MVFR at least brief intervals of MVFR conditions Saturday evening. For DTW/D21 Convection...Very little instability is expected with the short wave Saturday aftn/evng, so thunderstorms are not expected. DTW THRESHOLD PROBABILITIES... * Low for ceilings aob 5000 feet Saturday afternoon. Moderate Saturday evening. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ DISCUSSION...TF MARINE.......KDK AVIATION.....SC You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.