Expires:No;;325829 FXUS63 KMQT 160804 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 404 AM EDT Mon Jun 16 2025 .KEY MESSAGES... - Strong or severe storms are possible (5-15% chance) this afternoon/evening across the west half of Upper Michigan. Damaging winds and large hail are the primary risks. - Greatest chances for rain and thunderstorms Tuesday night through Wednesday night are south and east. Scattered showers/storms possible Thursday across Upper Michigan. - Near normal temperatures this week trend above normal by late this coming weekend. && .SHORT TERM /THROUGH TONIGHT/... Issued at 403 AM EDT Mon Jun 16 2025 Early this morning, KMQT radar returns show light rain shower activity over western Lake Superior and the Keweenaw Peninsula with GOES-East Nighttime Microphysics RGB imagery showing a variety of cloud decks over the UP. METARs show some of these cloud decks as low as 2kft AGL (such as over the Keweenaw) though out east, cloud decks to around 5 and 6 kft are observed while high cirrus is also observed on satellite. RAP 500mb analysis shows these clouds and showers to be associated with the first in a pair of shortwaves upstream of the UP. This first shortwave is situated over the MN/WI line at 07Z and while SPC mesoanalysis shows these showers in a region of around 250 J/kg of MUCAPE, ample MUCIN is also present and is helping keep shower coverage and intensity limited this morning. CAMs generally show scattered to isolated light rain shower coverage/intensity this morning, so will continue to carry previous forecast's 15-30 percent PoPs. This ample cloud coverage is helping keep this morning's low temps elevated as well, with 07Z METARs still showing many locations in the 60s. Not expecting temperatures to fall much below the mid 50s for most as a result. 00Z HREF suite is unfortunately still spread in regards to the outlook of thunderstorms for the afternoon time period associated with the second upstream shortwave. Shortwave that is currently the cause of ongoing severe thunderstorms in the Dakotas will progress into Minnesota by the early afternoon hours. Ahead of the shortwave's arrival, CAMs do show some isolated convection as HREF mean SBCAPE grows to 400-800 J/kg and the cap eroding to virtually nothing. With rather nebulous forcing and sub-100 0-3km SRH that is just "ok", severe potential with any early afternoon storms is limited. The main potential for strong to severe convection will come with the shortwave-forced storms arriving from the west sometime after 00Z. The timing of the storms' arrival will come as diurnal instability is waning (though SRH climbs to 125-150), plus each of the CAMs has a different interpretation of how the MCS/line of storms evolves, when (if?) it arrives at the UP, and at what strength. Given the unknown upstream evolution of storms, the potential for early storm activity to convectively contaminate the atmosphere, and the timing relative to available instability, the SPC outlook remains Marginal (1 of 5) for the interior west with damaging wind and hail being the primary threats. The most likely solution may be one shared by the HRRR, NAM Nest, and climatology, that being a strong complex of storms tracking through northern WI and narrowly avoiding the UP. However, enough strong storm potential exists (especially over western Lake Superior) that we can't take our eye off the ball just yet. With any luck, the 12Z HREF will finally give the clarity that the previous two runs have not. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Issued at 230 PM EDT Sun Jun 15 2025 Weak, quasi-zonal flow Monday breaks down with the passage of Monday night's shortwave, resulting in weak ridging on both ends of the country and troughing across the Central Plains Tuesday. Various shortwaves are noted within this broad area of troughing as it slowly migrates eastward into and through the Great Lakes region to round out the end of the coming work week. Upper level ridging builds into the Central Plains Friday, which stretches into the Upper Great Lakes Friday night. This ridge looks to gradually result in an amplified trough/ridge pattern across CONUS through the weekend. This evolution provides almost daily chances of rain or thunderstorms for our forecast area this week and coming weekend. Beginning Tuesday, surface low and associated cold front tied to Monday evening's thunderstorm chances will continue to press northeast and east/southeast respectively, resulting in the slow end to precip across our forecast area through the day. How slowly looks dependent on how far the cold front makes it Monday night. A broad look at various CAMs suggests the front should make it into the west by early Tuesday morning, then exit to our east by early evening. Precip should follow this same pattern, with precip ending in the west by early afternoon and the east by early evening. Instability ahead of the front across the central and eastern third of the forecast area may be enough for some thunderstorms, but severe weather is not expected. Highs across the region span the 70s and low 80s, with the coolest conditions expected near Lake Superior. Dry conditions follow Tuesday night for most, although a stray shower or two can't be completely ruled out, mainly central and east. Overnight lows dip into the 50s to low 60s south-central. While the cold front presses eastward through the Great Lakes and midwest thereafter, multiple shortwaves within the eastward migrating trough will help to support various waves of precip along the boundary through Thursday night. For us, the best chances for showers or thunderstorms associated with these features will be the central and eastern portions of the forecast area. Similarly to Tuesday, severe weather isn't expected. Thursday afternoon and evening, daytime instability along with the last wave within the trough looks to swing through the Great Lakes. This may support more widespread showers and thunderstorms before conditions diminish with the setting sun. Daytime highs are expected to climb mostly into the 70s or low 80s while overnight lows settle into the high 40s to 50s. Friday and into the weekend, ridging presses into our forecast area. Guidance suggests another wave of showers/storms Friday night/Saturday. On Sunday, board area of low pressure across the Northern Plains may result in a warm front lifting through the region and widespread mid to upper 80s for daytime temperatures. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 130 AM EDT Mon Jun 16 2025 Low stratus has been able to spread across the UP earlier than previously expected; though satellite shows some breaks in the cloud cover, this should keep primarily MVFR ceilings in through the rest of the night and into Monday morning. Improvement to VFR is expected into the afternoon; however, chances for scattered thunderstorms return Monday afternoon and evening ahead of an approaching cold front. Thunderstorms become more likely at IWD and CMX from around 00-06Z, then at SAW after 06Z as the front moves through. && .MARINE... Issued at 320 PM EDT Sun Jun 15 2025 Light northerly winds of 15 kts or less this afternoon veer east across the lake this evening then south over the east half of the lake for Monday. Southerly winds Monday afternoon and evening increase to around 20 kts ahead of a passing cold front into Tuesday. This brings potential for some thunderstorms as early as Monday afternoon, but best shot for storms holds off until Monday night. There is a marginal risk for severe wind gusts to 34 kts and hail up to 1" over the far western waters (5% chance) Monday evening/night. In the wake of showers and storms Monday and Monday night, some fog development is likely with patchy dense fog <1mi possible over the west half of the lake 40-50% chance. West winds up to around 20 kts behind the cold front settle below 20 kts Tuesday night, remaining light and variable through Thursday. The next potential for 20-25 kts winds returns over the weekend. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...GS LONG TERM...JTP AVIATION...LC MARINE...Jablonski