Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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682 FXUS63 KDTX 210707 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 307 AM EDT Tue May 21 2024 .KEY MESSAGES... - There is a chance of showers and thunderstorms this afternoon. Potential exists for a line of strong to severe storms to arrive late tonight. Damaging wind is the greatest threat tonight. - Warm and muggy conditions with high temperatures in the mid to upper 80s continue through mid week until a cold front moves through the region Wednesday. - There is one more chance for showers/storms Wednesday before a cooler and less humid air mass follows the front for the late week period. && .DISCUSSION... Window of deeper layer stability set to emerge through at least the first half of the daylight period, as shortwave ridging briefly governs conditions within the immediate wake of an exiting MCV. Diabatic heating of resident warmth and humidity more typical of mid summer will gradually erode this stability through the day, augmented by renewed moisture advection fixated along a northward drifting frontal boundary. Ill-defined signal within the model spectrum regarding late day convective potential in an environment characterized as modestly unstable but generally lacking in larger scale forced ascent. Forecast will continue to highlight at least a lower probability of convective development, targeting a corridor within the M-59/I-69 region as localized areas of convergence or differential heating near the frontal zone and subsequent outflow/ lake breeze interaction offer the greatest potential. Plausible for a few stronger wind gusts to materialize as the degree of instability offers some water loaded updrafts, but lack of shear minimizes the opportunity for greater organization and a larger severe risk through the daylight hours. Highs today again landing solidly in the 80s. Attention tonight focused on behavior of convection expected to organize across the midwest later today. High magnitude forced ascent featured within the elongated height falls and cold front attendant to the parent upper Miss valley trough will effectively drive upscale growth of this activity with a progressive transition toward a linear mode. The local convective potential and prospective vigor with this inbound convective line remains highly conditional on retaining sufficient destabilization, acknowledging the arrival window within a less favorable period /05z-09z/. A familiar position locally, which often lends to the greater potential holding just to the west. General consensus of the hi res model solution space suggests a gradual weakening trend as the convective line transits lower Michigan. Strong winds become the main threat should a greater response arrive locally for the early morning hours. Trailing cold front arrives Wednesday. Frontal convergence remains weak as the boundary becomes parallel to the mean flow, but interaction with a moist boundary layer condition provides a limited window for convective development. Higher precip chance with eastward extent, with overall pace of the front relative to daytime destabilization dictating whether a more organized convective episode can manifest locally or remain to the east/southeast. Drying conditions with time through the latter half of the day. Less active pattern to finish the work week. High pressure arrives Thursday, beneath lower amplitude mid level west-southwest flow. Temperatures remain edged on the warmer side of average, but with notably lower humidity. Similar conditions hold into Friday as upper ridging migrates the region. && .MARINE... A front has stalled out across southern Michigan and will get pulled back north as a warm front today. The front will be associated with a strong low pressure system developing over the Plains that will lift up to western Lake Superior by this evening. The low will then send a cold front through the Great Lakes on Wednesday with showers and thunderstorms possible Tuesday night and Wednesday ahead of it. Conditions are expected to remain below Small Craft Advisory criteria tonight through Tuesday, though locally higher winds and waves will be possible within any thunderstorms. Winds increase out of the south to 20 to 30 knots ahead of the associated cold front Wednesday, then veer to the west Wednesday night into Thursday while remaining gusty to around 25 knots. Less humid air settles in for the late week as high pressure builds in. && .CLIMATE... Here are the record high temperatures for May 21-22: May 21st: Detroit 92 (set in 1977) Flint 93 (set in 1921) Saginaw/Tri-Cities 94 (set in 1977) May 22nd: Detroit 90 (set in 1994) Flint 91 (set in 1934) Saginaw/Tri-Cities 89 (set in 1992) Here are the record high low temperatures for May 21-22: May 21st: Detroit 71 (set in 2013) Flint 67 (set in 1934) Saginaw/Tri-Cities 66 (set in 2021) May 22nd: Detroit 67 (set in 1941) Flint 65 (set in 1977) Saginaw/Tri-Cities 68 (set in 1977) && .PREV DISCUSSION... Issued at 150 AM EDT Tue May 21 2024 AVIATION... Outside of a very sparse rain shower, rain chances have abated in the wake of a passing upper-level wave. Nighttime satellite highlights extensive coverage of low-level stratus that has developed in the wake of the wave, presently situated over west- central Michigan. hi-res model guidance highlights low-level stratus spreading inland, extending into KMBS and possibly into KFNT, where MVFR to IFR cigs will be possible. This stratus deck will further be reinforced from a strengthening low-level inversion, which would maintain coverage into the morning hours. Sunshine will lift and scour out any stratus development by the late morning. For this afternoon, diurnally heating will provide the chance for shower and thunderstorms development, but confidence remains very low regarding timing and coverage potential. KPTK to KFNT have some signal for development in model output, where a PROB30 has been introduced. For DTW/D21 Convection... Outside of a stray shower, generally dry conditions are expected overnight. The chance for a shower or storm will return this afternoon and evening, but confidence is very low regarding coverage and timing. DTW THRESHOLD PROBABILITIES... * Low this morning, low this afternoon and evening. * Low for aob 5000 feet this morning. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ DISCUSSION...MR MARINE.......MR CLIMATE......MR AVIATION.....AM You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.