Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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435 FXUS63 KDTX 252012 CCA AFDDTX Area Forecast Discussion...CORRECTED National Weather Service Detroit/Pontiac MI 412 PM EDT Tue Jun 25 2024 .KEY MESSAGES... - Breezy southwest to west wind persists through this afternoon with gusts of around 30 mph. - The greater chance for the next round of showers and possibly thunderstorms will be Wednesday with severe weather not expected at this time. - Cooler and less humid air moves back into the area by Wednesday night and lasts through early Friday. - Showers and thunderstorms return Friday night into Saturday. && .DISCUSSION... The early afternoon gusty winds associated with a wake low behind the morning MCS should slowly begin to fall through the remainder of the afternoon as conditions stabilize. Deep westerly flow will continue to draw in slightly better lower level moisture, which will support increasing daytime instability. However, the arrival of warmer temperatures aloft are expected to keep a cap on any additional development through the remainder of the afternoon. The rain cooled airmass and clouds have tempered daytime highs down slightly, especially across the south where clouds and back have lingered into the early afternoon. Though we still have managed to quickly climb into the lower 80s at some locations. Some hi-res models want to trigger off some precip along a weak prefrontal weak trough later this afternoon, mainly north of I-69. The cap should still in place and should keep any potential activity in check. Another round of showers and thunderstorms are then expected to develop downstream with the increasing low level jet and development of a surface low. The strongest activity is expected to hold south of Michigan, but could see activity that develops and moves along the southern border or possibly up to the I-94 corridor of Lower Michigan during the evening. Confidence is not high with this activity developing, especially up towards I-94. If it does, a strong thunderstorm would be possible, but will be losing instability with time into the tonight. By late morning/early afternoon tomorrow, the influence of the northern stream shortwave trough and cold front will increase lift across southeast Michigan in tandem with inbound low from the southwest and bring greater coverage of showers and thunderstorms. Meager mid level lapse rates and weak forcing with the lack of stronger lower level jet winds will preclude any severe mention at this time. However, MLCAPes of a few hundred J/kg look possible with good deep layer shear will support at least a general thunderstorm potential. Once the cold front sweeps through on Wednesday high pressure quickly builds across the region resulting in drier weather conditions for Thursday into Friday. A cooler airmass marked by 850 mb temperatures down to around 6-8C will help temperatures cool down more into the low/mid 70s outside of the urban heat island of Detroit that may be more in the upper 70s. Greater moisture advection returns on Friday as southwest flow increases ahead of the inbound trough sweeping across the plains. Greater consensus among models points towards Friday night into Saturday as the arrival time for showers and thunderstorms ahead of a cold front. High pressure and ridging aloft brings dry conditions to close out the weekend into early next week. && .MARINE... Breezy conditions in the wake of the morning line of thunderstorms gradually diminish over the course of the evening. There remains a low chance ( ~20-30%) for a few showers or non-severe storms to develop late this evening/tonight as a weak front sags through the region- potential generally favored for waters south of Port Austin. An upper level trough settles over the Great Lakes Wednesday as upper Midwest surface high pressure begins to builds toward the central lakes. Result is seasonably cooler, modest northerly flow for Wednesday and Thursday with the only chances for storms confined to the Ohio Valley, perhaps just clipping the far southern Great Lakes. Otherwise, the surface high drifts over the region through Friday before the next low arrives Friday night-Saturday. && .PREV DISCUSSION... Issued at 204 PM EDT Tue Jun 25 2024 AVIATION... Strong subsidence in the wake of the morning convection has cleared most of the cloud cover in the lowest 10 kft leading to primarily VFR, as well as gusty southwest winds, that will both persist through the afternoon. A SCT to BKN cloud deck based mainly between 3 and 5 kft may develop this afternoon as mid-level moisture attempts to work back in. Additional convection appears unlikely this evening into tonight even as a weak cold front sinks south into the area. There will be a chance for vsby reduction in fog/mist late tonight into early Wednesday morning, especially south of M-59, as winds become weak and moisture pools along the front - however confidence is too low to include at this time given expectation for a good amount of mid and high clouds. Chances for showers and possibly a thunderstorm then increase mid morning tomorrow as the stalled front helps trigger scattered convection in the area. For DTW/D21 Convection...Thunderstorms are not likely this evening into tonight. Chances for showers and possibly a few rumbles of thunder then increase after 14Z Wednesday. DTW THRESHOLD PROBABILITIES... * Medium for ceilings aob 5kft this evening, low overnight, then medium Wednesday morning. * Low for thunderstorms through Wednesday. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...Small Craft Advisory until 10 PM EDT this evening for LHZ421-422- 441>443. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ DISCUSSION...AA MARINE.......KDK AVIATION.....TF You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.