


Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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405 FXUS63 KMQT 071111 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 711 AM EDT Mon Jul 7 2025 .KEY MESSAGES... - Cooler, more seasonable, temperatures return to the Upper Peninsula for the work week. - Rain showers and a few thunderstorms return Tuesday. && .SHORT TERM /THROUGH TUESDAY/... Issued at 343 AM EDT Mon Jul 7 2025 Early morning satellite imagery across the Upper Great Lakes reveals mostly clear skies under sprawling surface high pressure extending southward from James Bay atop Lake Superior. Observations across the UP have cooled to the upper 40s/low 50s. Some patchy fog may develop prior to sunrise, otherwise another quiet day is expected to kick off the work week as largely zonal flow aloft keeps sfc high pressure overhead. Winds are expected to remain light, under 10 kts, and generally out of the north save for direction changes influenced by afternoon lake breeze development. Look for high temperatures to peak in the 70s area wide with cooler conditions in the upper 60s along the Lake Superior shorelines. Seasonable lows follow tonight in the 50s, though incoming cloud cover in the west half may keep lows a tad higher near 60. Weak ridging/zonal flow aloft breaks down late into early Tuesday as a shortwave ejects eastward out of the Northern Plains, potentially providing two rounds of showers and thunderstorms. The first round, mainly driven by weak isentropic ascent, will enter the far west sometime Tuesday morning with individual CAM guidance varying on the exact timing. This first round continues east and largely peters out across the central UP. Confidence is lower on how the second round progresses along a cold front / lingering outflow boundaries, and CAMs struggle even more with where redevelopment will occur across the central third. Latest HREF guidance suggests meager diurnal instability (500-1000 j/kg of MUCAPE) building ahead of the second round sometime Tuesday afternoon and marginal shear ~25-35 knots, so cannot rule out some gusty thunderstorms. Additionally, no hydro concerns expected with PWATs only climbing as high as 1-1.3" and latest LREF guidance suggesting a 50-80% chance for QPF >0.25 in the west-central. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Issued at 343 AM EDT Mon Jul 7 2025 Following this passing shortwave, ensemble and deterministic guidance continue to show another trough digging into the Great Lakes Wednesday out ahead of a ridge extending from the Plains into central Canada. However, soundings are quite dry, so little more than lingering cloud cover is expected from this secondary trough. Afterwards, deterministic and ensemble guidance are in more agreement on the Plains ridge moving over our region Thursday, perhaps flattening some into Friday ahead of our next trough/frontal system moving out of the Canadian Rockies later Friday into the weekend. This would favor dry weather Thursday at least into early Friday before chances for showers/storms move back in next weekend. By Friday afternoon, deterministic and ensemble guidance show a couple of features (a weak shortwave moving out of the Central Plains and a deeper trough moving out of the Canadian Prairies) phasing over the Upper Midwest. PoPs work back into the area Friday with warm advection out ahead of the system, lingering into Saturday as the cold front sweeps through. Severe parameters are also lackluster with this next system, with just a few hundred j/kg of CAPE and around 20-30kts of bulk shear. Guidance diverges after Saturday, with some of the guidance showing the system becoming vertically stacked and meandering over the Great Lakes, and others a little more progressive. This will keep in at least some low-end chances for lingering showers/thunder into the end of the forecast period. Otherwise, look for temperatures to come in more or less seasonal through the coming week with highs ranging generally in the 70s and lows in the 50s. Thursday and Friday are looking like the warmest days of the week as temperatures in the interior peak in the lower 80s. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 711 AM EDT Mon Jul 7 2025 Under high pressure, VFR conditions with light and variable winds mainly out of the north. Lake breeze development and associated wind shifts should be expected this afternoon. Showers and a few thunderstorms may be knocking on the door of the far western U.P. by 12z Tuesday, but have opted to leave this for future TAF issuances. && .MARINE... Issued at 343 AM EDT Mon Jul 7 2025 Winds and waves will remain light, mainly from the north, today as sfc high pressure becomes planted overtop the lake. South winds develop early Tuesday ahead of a weak low pressure before veering NW behind a cold front Tuesday night. However, winds are not expected to top 15 kts. Showers and a few thunderstorms accompany the weak low`s passage Tuesday, which may caused gusty and erratic winds. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...BW LONG TERM...LC AVIATION...BW MARINE...BW