Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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781 FXUS63 KDTX 090956 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 556 AM EDT Sun Jun 9 2024 .KEY MESSAGES... - Weak cold front brings possibility of a few stray showers this afternoon, mainly across the Thumb. - High pressure brings dry conditions for the first half of the week. - Cool on Monday followed by a warming trend back into the mid to upper 80s by latter half of the week. && .AVIATION... Lingering moisture trapped beneath a low inversion has resulted in areas of MVFR to IFR stratus early this morning. This will mix out early in the TAF period as the June sun quickly deepens the boundary layer. Winds out of the west shift to northwest today as a weak cold front eases south across the region. The cold advection and a tightening gradient will result in a deep mixed layer and wind speeds increasing this afternoon - peak gusts of 25 to 30 knots still look on track. Some mid-level clouds will accompany fropa but look to remain predominantly above 5000 ft through the evening. Winds subside this evening with increasing likelihood for MVFR ceilings to develop after midnight beneath a strengthening inversion. For DTW/D21 Convection...Thunderstorms are not expected through the TAF period. DTW THRESHOLD PROBABILITIES... * High in ceilings aob 5000 feet early this morning. Medium after midnight. && .PREV DISCUSSION... Issued at 350 AM EDT Sun Jun 9 2024 DISCUSSION... Subsidence inversion has developed in the wake of the cutoff mid/upper level low that will continue to drift east into Quebec today. Post rainfall moisture boost is trapped under this inversion supporting the development of low clouds. Expect lower clouds to gradually scatter out post sunrise. The central Great Lakes will be under northwest mid/upper level flow on the western side of the Canadian trough, which will usher in another disturbance this afternoon. Overall moisture will be lacking a bit, but just enough daytime instability should be able to support a few stray showers. Greatest PoPs (~20)% will be favored across the Thumb. The 850-925mb layer flow will ramp up to 30 knots or greater by this afternoon. Mixing depths are forecast to climb to nearly 10 kft for some locations with high low level lapse rates to 10 C/km. This should easily mix down wind gusts to 30 mph or greater with perhaps a few isolated gusts approaching 40 mph. The peak of these westerly wind gusts will fall between 11 am and 6 pm. Wind speeds will begin to decline this evening in the wake of a cold front while turning out of the northwest. This will usher in a cooler airmass tonight and bring overnight lows ranging from the mid/upper 40s to low 50s. Long northwest fetch across Lake Huron will maintain at least low precipitation chances in the form of sprinkles/light rain for the Lake Huron shorelines with continued mid-level shortwave support dropping out of Ontario early tonight. High amplitude ridging builds across the plains and Midwest with a surface high pressure spreading across the Great Lakes early to mid- week. This will bring dry weather for the bulk of this period. It will be a cool start to the work week though as temperatures of 4-6C at 850 mb settle across the region for Monday afternoon. The result will be a day of below normal temperatures with daytime highs down in the low to upper 60s for the bulk of southeast Michigan. We start to get some return flow on Tuesday as the ridge axis moves over the central Lakes. This will increase temperatures on Tuesday back into the 70s for daytime highs. This also marks the start of a warming trend that will carry into the late week as the ridge tracks eastward and progressive zonal flow ushers in much warmer air into the region from the west. Temperatures at 850 mb into the mid teens C will support highs approaching 90 degrees across metro Detroit by Thursday. Moisture transport increases Wednesday into late week bringing higher dewpoints more solidly into the 50s by Thursday. This sets the stage for the next chance for precipitation during the Thursday- Friday period as the west to East mid/upper level jet helps push a cold front into the Great Lakes. Timing uncertainty exists as activity will largely depend on how convection evolves upstream in the plains. MARINE... Friday`s low finishes vacating the area early this morning setting up northwesterly flow in its wake. Lingering, deepening low pressure over Quebec tightens the local gradient resulting in an uptick of winds early this afternoon into tonight with gusts generally topping out around 25kts. Potential exceptions remain northern Lake Huron (due to favorable fetch) and Saginaw Bay (due to warmer waters) where peak gusts could reach around 30kts this afternoon-evening. Small craft advisories are in effect for the Saginaw Bay and southern Great Lakes due to these wind gusts with the remainder of Thumb under advisories tonight into Monday as northerly winds push higher wave action into the nearshore waters. High pressure then builds over the Great Lakes Monday relaxing winds and supporting dry conditions for the first half of next work week. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...Small Craft Advisory from noon today to 10 PM EDT this evening for LHZ422. Small Craft Advisory from noon today to 4 PM EDT Monday for LHZ421. Small Craft Advisory from 2 AM to 10 PM EDT Monday for LHZ441>443. Lake St Clair...Small Craft Advisory from noon today to 10 PM EDT this evening for LCZ460. Michigan waters of Lake Erie...Small Craft Advisory from noon today to 10 PM EDT this evening for LEZ444. && $$ AVIATION.....TF DISCUSSION...AA MARINE.......KDK You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.