Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
994 FXUS63 KDTX 101057 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 657 AM EDT Fri May 10 2024 .KEY MESSAGES... - Cooler temperatures (50s to low 60s) hold through Saturday before returning to at or above normal Sunday. - Shower and thunderstorm chances throughout much of Saturday with the passage of a compact low pressure system. Severe weather is not expected. - Another chance of showers and thunderstorms comes Monday as a cold front drops through the area. && .AVIATION... The remaining clouds associated with eastward exiting low pressure have stripped away from SE Mi early this morning. That leaves weak upper Midwest high pressure in place to move into the central Great Lakes today. A steady but light north wind brings in a cool air mass favorable for expansive high based cumulus development as daytime instability builds. This leads to a broken VFR ceiling above 5000 ft by afternoon through this evening. Wind backs SW tonight as the first sign of the next low pressure system moving in from central Canada. It brings a band of showers late tonight with a rumble of thunder possible. The surface system occludes overhead while supporting a field of MVFR ceiling through Saturday morning. These clouds lift into low end VFR with NW wind gusting near 20 knots upon passage of the front into the afternoon. For DTW/D21 Convection... A stray thunderstorm is possible within a band of showers inbound with the next low pressure system late tonight into Saturday morning. DTW THRESHOLD PROBABILITIES... * Low for ceiling 5000 feet or less this afternoon. * Low for an isolated thunderstorm late tonight and Saturday morning. && .PREV DISCUSSION... Issued at 305 AM EDT Fri May 10 2024 DISCUSSION... Cooler airmass (850mb temps around 2-3C) settles over the region today as a positively tilted upper trough swings overhead. Said active cold air advection will support the re-expansion of stratocu cloud cover by early afternoon as lower level lapse rates steepen. Given the airmass and more constrained diurnal insolation potential, highs will generally be held to the lower 60s. While this setup is favorable for the development of pockets of drizzle/light showers during peak heating, induced mid-level ridging, from departing Thursday low and approaching northern Ontario low, slides across southern lower MI over the course of the daylight hours today. Bulk of guidance is in agreement that these height rises should be sufficient to stifle most if not all precip chances through at least early evening hours. Height falls eventually arrive around/after sunset offering a low chance for spotty areas of light rain to crop up late evening-early tonight. Widespread showers arrive over SE MI early Saturday morning as the aforementioned Ontario shortwave swings into the central Great Lakes. Can`t rule out some rumbles of thunder or an isolated embedded thunderstorm as showers work through during the morning due to respectable forcing from the fairly robust parent vort max as well as a few hundred J/kg of elevated instability. A dry slot follows late morning/midday as the system undergoes occlusion however this is shortlived as the near stacked low tracks directly over the area Saturday afternoon favorably aligning with peak diurnal heating. As a result, scattered to numerous showers with isolated to scattered thunderstorms redevelop through the afternoon- evening timeframe. Saturday looking to be the coolest day of the forecast period as a reinforcing surge of Canadian air drops 850mb temps to around 0C capping highs in the upper 50s to around 60, though likely will feel cooler with the on-off rain through the day. Northern edge of surface high pressure centered over the mid- Mississippi river valley builds into southern lower MI Saturday night-Sunday as upper troughing vacates toward the Northeast. Lower level west-southwest return flow rapidly advects an above average airmass (850mb temps climb to or above 10C) back into the region likewise supporting above average highs in the upper 60s to mid 70s Sunday and Monday. Active patterns continues early next week as another upper trough drops into and lingers over the Great Lakes offering additional chances for showers and thunderstorms. MARINE... Drier conditions expected today with just some lingering shower activity possible this morning between Port Sanilac-western Lake Erie. Brief period of high pressure today ensures light northerly winds and minimal wave action. By Saturday, another glancing low pressure system supports widespread showers across the area along and behind a surface cold front. A shift to southwest winds ahead of the front will be short-lived with the frontal passage veering winds sharply back to the northwest by Saturday afternoon. High pressure returns for Sunday ahead of yet another low to bring widespread rainfall to the area on Monday. Wind and wave action hold below headline thresholds through early next week. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ AVIATION.....BT DISCUSSION...KDK MARINE.......MV You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.