Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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072 FXUS63 KDTX 300759 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 359 AM EDT Tue Apr 30 2024 .KEY MESSAGES... - Dry and slightly cooler today. - Well above normal temperatures persist through the week. - Mostly dry frontal passage on Wednesday with a better chance of precipitation arriving early Friday morning. && .DISCUSSION... The cold front moving through Michigan early this morning will usher in a drier airmass with the 1.25 inch PWAT from the 00Z DTX RAOB yesterday dropping to around a half inch by this afternoon. This will bring a gradual decrease in cloud cover from west to east throughout the morning. Cold advection will not be that strong with 850 mb temperatures only falling a few degrees at 850 mb to 3-6 C by 18Z. The lack of colder air and the clearing skies should allow the improving insolation to achieve daytime highs into mid/upper 60s to low 70s. Lower level westerly flow tops out around 25 knots in the post frontal environment with afternoon mixing yielding a west wind of 10 to 15 mph. Shortwave ridge will quickly pass over the region this evening and tonight with mostly clear skies. Overnight lows dip into the 40s for most of the CWA outside of the Detroit metro areas. A shortwave at the nose of the upper jet will be driven out of the central Plains and through the northern Great Lakes on Wednesday while dragging a weak cold front through Michigan. Warm advection ahead of the front for the afternoon will lead to an increase in daytime high temperatures returning to the mid/upper 70s. Frontal passage timing will be during the day, but overall lack of moisture leans toward a mostly dry frontal passage. The main result will be an increase in clouds. The better precipitation chances will be tied closer to the low off to the north. Lower level dewpoints do increase into the mid 50s, so wouldn`t be surprised if an isolated shower or two is able to develop along the front. Confidence is too low to have mention of PoPs at this time. Ridging begins building over the Great Lakes Wednesday night with a warm and dry airmass residing across Michigan through much of Thursday. Well above normal temperatures will persist into the late week period with daytime highs in the 70s common. Another mid level circulation is set to pivot across the northern plains and through the upper Midwest on Friday. Strong lower level jet will help drive better moisture into the region ahead of larger scale ascent associated with the cold front. Timing the onset of precipitation leans toward late Thursday night/Friday morning as models have trended a little faster with the frontal passage. This would likely prevent much instability for being able to develop before arrival of precipitation and limiting a more robust convective response. Lowered PoPs in the Friday night time frame given this quicker frontal passage trend. Limited cold air advection behind this front keeps warm temperatures in the forecast to start the weekend. && .MARINE... With lighter winds early this morning and still some elevated surface dew pts > than water temps, areas of fog will likely be around Lake Huron through the morning hours as wind gusts reside mainly below 20 knots throughout the day. Another low pressure system looks to be tracking through Minnesota and then into Lake Superior on Wednesday, with the cold front swinging through the Central Great Lakes. Moisture looks lagging, and the front appears to be weakening in the process. Thus, showers and moderate winds will be hard to come by, with another surface ridge then arriving Thursday morning. && .PREV DISCUSSION... Issued at 1142 PM EDT Mon Apr 29 2024 AVIATION... The back edge of the light showers will be east of metro Detroit around TAF issuance. Some thinning of the mid/high cloud deck overhead may open the door to some low clouds and/or fog development. This will be most probable at the metro Detroit TAFs where evening rainfall has contributed to increased boundary layer moisture. A weak cold front will then move across Se Mi in the 06Z to 09Z time frame. A gradual wind shift to the west will occur with the passage of this front. Subtle post frontal dry air advection should erode any low clouds/fog toward daybreak. DIurnal heating and some remnant low level moisture will contribute to a scattered to broken diurnal cu field Tues afternoon. For DTW/D21 Convection...The risk of lingering convection has ended across the airspace. No thunderstorms are expected through the TAF period. DTW THRESHOLD PROBABILITIES... * Moderate in ceilings aob 5000 feet tonight. Low on Tuesday. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ DISCUSSION...AA MARINE.......SF AVIATION.....SC You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.