Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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462 FXUS63 KDTX 091902 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 302 PM EDT Sun Jun 9 2024 .KEY MESSAGES... - Late day showers will mainly develop over The Thumb region with lighter rates further south and east. A rumble of thunder also possible. - Gusts peak near 30 mph late today before subsiding overnight. - 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. && .DISCUSSION... Southeast Michigan positioned late this afternoon within the broad cyclonic expanse of a closed low lifting into southern Quebec. Weak cold frontal passage underway marking the transition toward deeper layer northerly flow. Interludes of dcva within a perturbed mid level environment in combination with cold/moist air advection will offer a greater coverage of cloud cover going forward through tonight. Overall moisture quality is limited, but proving sufficient with a diurnal boost to provide some widely scattered showers. Depth to this convective activity marginal for thunder, but worthy of a mention noting an earlier strike over lake Huron. Greater probability will exist across the thumb going forward into the evening hours. The northwest gradient and cloud cover will help keep temps elevated slightly overnight. Readings bottom out in the upper 40s most locales. Cooler northerly flow entrenched throughout Monday as high amplitude troughing takes residence just to the east. Lingering early day cloud vacates as shallow moisture effectively mixes out with daytime heating. Despite the increasing insolation potential with time, existing thermal profile will ensure highs arrive a solid 10 degrees below average. The onshore trajectory will make eclipsing 60 degrees a struggle for areas right along the lake huron shoreline. Seasonable mid June environment returns Tuesday as the upper height field recovers modestly atop surface high pressure. Full insolation potential into an increasing mean thickness field supports a standard warming trend with temps back to average. Initial period of warm air advection emerges Tuesday night into Wednesday as a low amplitude wave glances across the northern great lakes. Moisture quality lacks to support highlighting anything outside of some increase in mid level cloud at this stage, while bringing an uptick in projected lows and highs as dewpoints inch upward. A meaningful increase in humidity occurs within the background of a well above average thermal field Thursday under strengthening southwest flow. Improving convective potential during the late week period given the underlying thermodynamics and energetic lower amplitude upper level westerly flow positioned north of prevalent southern conus ridging. && .MARINE... Pockets of afternoon showers vacate over the course of this evening as low pressure over Quebec finally dislodges eastward. While this will allow winds to weaken some, lingering gradient likely supports northerly gusts around 20kts through much of Monday (25kts possible through Monday morning over central Lake Huron) despite high pressure beginning to build overhead. Small craft advisories remain in effect around the Thumb as the wind shift brings higher wave action into the nearshore waters. Aforementioned high becomes fully established over the Great Lakes Monday night leading to a period of dry conditions and light wind through the midweek period. && .PREV DISCUSSION... Issued at 200 PM EDT Sun Jun 9 2024 AVIATION... Diurnal cloud response underway as a deep mixed-layer develops this afternoon. Not only does this support the expansion of high-based VFR cumulus, but 30+ knot flow within the low-levels will continue to mix down producing similar peak wind gusts. Winds generally hold from 260-280 degrees until a weak frontal boundary crosses from northwest to southeast over the next 3-4 hours. Some showers have accompanied the FROPA, but most of this activity should remain over The Thumb and points east of the terminals. Winds behind the front veer toward 310 degrees while maintaining some gustiness until this evening, but speeds should decline enough to hold below crosswind thresholds (for DTW). Clouds linger tonight as low-level cold advection helps to cool and moisten the column leading to lowering of cloud bases with time. A period of high-end MVFR ceilings remains possible after midnight. Low clouds mix out late Monday morning with weak energy aloft touching off a period of VFR mid and high clouds during the midday timeframe. For DTW/D21 Convection...Thunderstorms are not expected through the TAF period. DTW THRESHOLD PROBABILITIES... * Low in ceilings at or below 5000 feet this afternoon. * Low in exceeding crosswind threshold. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...Small Craft Advisory until 10 PM EDT this evening for LHZ422. Small Craft Advisory until 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 until 10 PM EDT this evening for LCZ460. Michigan waters of Lake Erie...Small Craft Advisory until 10 PM EDT this evening for LEZ444. && $$ DISCUSSION...MR MARINE.......KDK AVIATION.....KGK You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.