Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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394 FXUS63 KDTX 070807 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 407 AM EDT Fri Jun 7 2024 .KEY MESSAGES... - Breezy today with westerly wind gusts of 25 to 35 mph and high temperatures topping out around 70 degrees. Scattered showers mainly across the Thumb. - Showers are likely (50-70%) to spread across the area Saturday afternoon into Saturday evening. - Cool conditions early next week are followed by a warming trend back into the 80s by late in the week. && .DISCUSSION... Moist cyclonic flow around the upper low tracking across Georgian Bay maintains a breezy, unsettled almost fall-like forecast today. Isolated to scattered showers will develop through the day, likely most pervasive over the Thumb where moisture depth and stream of PV aloft will align favorably. 850mb thermal trough will be directly overhead at 5 to 6 C, limiting high temps to the upper 60s to around 70, roughly 1 sigma below normal for June 7. Meanwhile, a belt of 20 to 30 kt wind within the boundary layer will result in another breezy day with gusts in the 25 to 30 mph range during the afternoon. Any higher gusts to around 35 mph will be most likely along/south of I-94. Winds then begin to subside during the evening as surface heating/mixing tapers off. The upper low moves off into southern Quebec tonight, allowing a shortwave ridge to build into the Great Lakes through early Saturday. This quickly crests overhead by midday, sending a warm front into the area during the afternoon as low-level wind shifts from the southwest. At the same time, the next upper low begins to sink south across Lake Superior with difluent flow ahead of it forming a weak frontal low over the Midwest that moves in during the evening. The resultant fgen will bring an area of showers that spreads southeastward across the area from the late afternoon through the evening. Models across the board offer very little instability with this setup given weak lapse rates in part from strong mid-level capping. The best chance for any thunderstorms would be within the warm sector south of M-59, if capping is weaker and surface dew points are high enough to overcome the lapse rates. Otherwise, just expect around a quarter inch of rainfall from the showers before they move out overnight. Added a slight chance of light showers on Sunday, mainly north of I- 96, as a lobe of PV and mid-level moisture sink across the region while the aforementioned upper low tracks southeast across Georgian Bay into Quebec. Additional shortwaves rotate around the low Sunday night into Monday, driving a cold front south across the region. This brings a cool start to the week with high pressure then beginning to build in from the west as the resident low-amplitude trough over eastern North America begins to amplify over New England. The high pressure maintains quiet conditions through Tuesday but is quickly followed by the next trough and opportunity for showers by Wednesday. A substantial warm-up is likely by the late week with zonal flow helping advect a warm Plains air mass eastward. && .MARINE... Cooler air has filtered into the Central Great Lakes this morning, leading to low level profiles a bit closer to neutral. Overall, winds above the surface look slightly weaker compared to yesterday, and thus expecting winds to mostly hold in the 20-25 knot range today. Lake Erie stands the best chance of exceeding 25 knots due to the warmer water temperatures. Lighter winds (10-20 knots) arrive over the weekend before high pressure center settles overhead on Tuesday and brings light and variable winds. && .PREV DISCUSSION... Issued at 1147 PM EDT Thu Jun 6 2024 AVIATION... An upper low anchored across the northern Great Lakes will continue to influence the forecast through the TAF period. Intervals of mid/high clouds will give way to diurnally enhanced VFR based clouds by Friday afternoon. The onset of nighttime cooling has reduced wind speeds. A persistent westerly gradient will hold wind speeds of 8 to 12 knots through the night. The growth of the daytime mixed layer will again support increased gustiness to the winds Friday afternoon. Mixing depths are not expected to be as high as today, which should keep peak afternoon wind gusts around 25 knots. For DTW/D21 Convection...Thunderstorms are not expected. DTW THRESHOLD PROBABILITIES... * Moderate for ceiling 5000 ft or less Friday. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...Small Craft Advisory from 8 AM this morning to 8 PM EDT this evening for LEZ444. && $$ DISCUSSION...TF MARINE.......SF AVIATION.....SC You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.