


Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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555 FXUS63 KMQT 110550 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 150 AM EDT Fri Jul 11 2025 .KEY MESSAGES... - Isolated to scattered showers and thunderstorms are possible on Friday, mainly south central and far west in the late afternoon. - More showers and thunderstorms are expected Saturday. Some of these storms may produce strong winds and heavy downpours. - Seasonable temperatures persist in the Upper Peninsula for the work week. && .UPDATE... Issued at 1050 PM EDT Thu Jul 10 2025 Quiet weather has persisted this evening in the UP as mid level shortwave shra/tsra activity has remained outside the CWA. This slowly diminishing precip is N of a stationary boundary stretching along the S end of the Great Lakes basin out into the Central Plains. Tonight into Fri, this wave progresses ENE over Lake MI and Lower MI with the frontal boundary not lifting as N as previously expected, keeping precip outside the CWA until late in the day Fri when a secondary wave pivots more NE into the region. Only major adjustments to the going fcst was to remove PoPs through Fri morning and back off on PoPs later in the day, aligning more with the mean of available guidance for a slower onset...holding off until Fri evening/night. && .SHORT TERM /THROUGH FRIDAY NIGHT/... Issued at 122 PM EDT Thu Jul 10 2025 While high clouds streamed into the west, mostly clear skies were observed this morning in the east. Near 1130EDT, diurnal clouds began developing in Schoolcraft and Luce counties, but by then, temperatures had already warmed into the low 70s. In the west, where the high cloud cover has limited heating some, high 60s were still being observed then, but light downsloping winds helped other locations quickly warm into the mid 70s. Expecting additional heating through the afternoon, with most locations climbing into the upper 70s to low 80s. The cloud cover is associated with an upstream shortwave over southern Minnesota and a warm front draped southeast from there into Iowa. Other then the cloud cover, rain/storms associated with this feature will stay out of the forecast area this afternoon. CAMs highlight this precip flaring this afternoon over south-central Wisconsin and near Duluth, but diminishing this evening. Its possible some showers may scrape the far west, but probability appears to be rather low (<15%). Overall, expecting a mostly dry but mild night with temperatures dipping into the 60s west and 50s east. Late tonight into Friday, a warm front will lift into the Upper Great Lakes. Where exactly, will depend on where the front ends up today. While there does appear to be a weak trend among the CAMS of the boundary lifting close enough for showers to develop and move into Menominee County by 12z Friday, solutions presented by a majority of the other deterministic guidance suggests this activity would stay to the south. This impacts shower and thunderstorm potential through the day, as the more northern solutions of the RAP/HRRR would result in isolated showers/storms near Lake Michigan and eastern Upper Michigan by afternoon, while the more southern solutions keep the east dry. Upstream in Minnesota, convection developing along a cold front will press east toward our forecast area. Similarly to the precip in the east, there are timing questions on when precip will factor in for the west. Latest CAMS suggest diminishing showers/storms moving slowly the west after midnight, while some 0 and 6z medium range guidance holds precip together longer into the evening and overnight hours for the west half. Warmer temperatures are expected Friday thanks to the warmer airmass over the area. Expecting mostly low to mid 70s except upper 70s by Manistique. Mild overnight Friday night is also expected, with widespread 60s for lows. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Issued at 207 PM EDT Thu Jul 10 2025 Beginning Saturday, phasing split flow over the Upper Great Lakes with the passage of a cold front from west to east will result in showers and thunderstorms moving through the forecast area for a majority of the day. Increasing jet dynamics in the afternoon and evening, alongside deep layer shear of 35-45kts and MUCAPE growing potentially to 1000-1500j/kg should support upscale convective growth ahead of the front, posing a strong to severe thunderstorm risk. Location of this risk will depend on the rate of destabilization ahead of the front through the day. However, with 12z guidance leaning into the front pushing into the western counties near 12z, suspect shower and thunderstorm activity may begin early in the west, with strong to severe potential increasing by late morning and early afternoon interior west and central, then peaking in the mid afternoon and evening central and east. Mid-level lapse rates near 6C/km and DCAPE ~1000j/kg suggest mainly a severe wind risk, but should a stronger updraft get going, small hail can`t be ruled out. Shower and storms may have difficulty moving off the frontal boundary per MBE velocities, which with PWATs increasing to near 1.5 inches, the warm cloud layer increasing to 10-12k feet, and some guidance packages suggesting low corfidi vectors, heavy rain will be possible should backbuilding or training occur. Right now flash flood potential, per WPC, is marginal (5-14%), but deterministic guidance suggests potential of 1 to 2 inches of QPF will be possible for parts of central Upper Michigan. Shower and thunderstorms looks to exit east near midnight, with surface ridging building in afterwards. Should notable QPF occur Saturday with enough dry air afterwards to support clear skies overnight, overnight fog may develop. The surface high will dip southeastward through the day Sunday while maintaining ridging overhead. This keeps conditions mostly dry into Monday, although a secondary shortwave within the broad transiting trough may support an afternoon uptick in cloud cover, perhaps dinurally enhanced. In the past 24 hours, guidance on the next wave Monday into Monday night has trended more north, although some deterministic guidance solutions continue to resolve rain/storms. Further upstream, a deep trough and cold front moving through the Canadian Prairies and a shortwave lifting northeast from the Central Plains will shift toward Upper Michigan on Monday. 6z Euro suggest the two features may remain separate, while the GFS continues to suggest potential phasing overhead in the Tuesday and or Wednesday period. Given this uncertainty, confidence in the timing and position of when that batch of precip occurs is low. Daytime highs each day look to climb into the 70s to mid 80s. After next week`s cold front, daytime highs look to climb only into the upper 60s to near 70. Overnight lows are largely expected to be in the 50s and 60s, with potential for may interior locations to cool into the low to mid 40s behind next week`s front. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 149 AM EDT Fri Jul 11 2025 VFR conditions are expected at CMX/SAW through the duration of the 6Z TAF period while IWD likely lowers to MVFR early this morning for FG/BR development. SHRA/TSRA look to return late Fri afternoon/evening, continuing into Fri night at IWD/SAW. With precip onset timing near the end of the period and still some spread yet in guidance, opted to add a PROB30 group in at IWD, but left mention out at SAW for now. CMX likely holds dry until Sat. Otherwise light winds are expected with wind direction possibly impacted by a lake breeze this afternoon. && .MARINE... Issued at 155 PM EDT Thu Jul 10 2025 Winds generally remain around 15 kts or less into the weekend with the exception of some 15 to 20 kts over eastern portions of the lake. By Saturday though, 15 to 20 kt winds out of the southwest will become more widespread through Sunday before decreasing again late Monday. This will coincide with some disturbances moving through the Great Lakes Region over the weekend. With these disturbances, showers and thunderstorms will overspread the lake from west to east Friday through Saturday. Further out, additional shower and thunderstorm chances will accompany a Clipper system late Monday through Tuesday. Also of note, patchy fog could result in reduced visibilities across far western portions of the lake tonight. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ UPDATE...Jablonski SHORT TERM...JTP LONG TERM...JTP AVIATION...Jablonski MARINE...TDUD