Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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177 FXUS63 KMQT 080857 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 457 AM EDT Wed May 8 2024 .KEY MESSAGES... - Rain showers this afternoon and tonight to bring half an inch to an inch of rainfall to the area. Thunder chances are low, but are most likely (15-30%) along the MI/WI state line. - Multiple passing low pressure systems will keep rain chances in the forecast into early next week along with thunderstorm chances both Sunday and Tuesday. && .SHORT TERM /THROUGH TONIGHT/... Issued at 242 PM EDT Tue May 7 2024 GOES-16 Day Cloud Phase imagery shows high cirrus over the eastern UP and east half of Lake Superior while a cumulus deck moves over the remainder of the region along with weakly convective shower activity along the MI/WI state line. RAP analysis shows a 984 mb low pressure over the ND/SD state line that is vertically stacked and not moving much over the past 3 hours. Rotating around the upper low are shortwaves that are supporting a now- occluded front which is pushing into the UP and causing the shower activity. CAMs show this shower activity overspreading the UP throughout the afternoon and evening. The QPF forecast has gone up a bit with the most recent run of the HREF, with the central UP now seeing slightly over 50% probabilities of an inch of rainfall compared to around 2/3 of an inch at the same probability the last couple of runs. Mean MUCAPE values are still meager, peaking at only around 100 J/kg along the MI/WI state line so the ~15% chance of thunderstorms remains the prevailing forecast along with no severe weather expected. RHs fell into the 20s and 30s ahead of the occluded front in the central and eastern UP this afternoon along with wind gusts around 25 mph, but with cirrus overrunning the region preventing RHs from falling further, expected reductions in wind with time, and the arrival of showers within the next 6 hours, fire weather concerns are low. && .LONG TERM /TONIGHT THROUGH TUESDAY/... Issued at 452 AM EDT Wed May 8 2024 Periodic rain chances will be common throughout the extended period as a series of low pressure systems pass through Upper Michigan. Initially though, the period will start in a bit of a lull as a Northern Plains closed mid-level low continues to slide southeastward while opening up and drifting around the Lower Midwest. Meanwhile, the associated surface low ahead of it will drift through the Ohio Valley. So, what this means for much of the UP is a dry forecast Wednesday night through Friday morning. Earlier model runs were originally taking more of a northern track with the aforementioned disturbance. But, the southern track has come to fruition, thus rain chances have been removed from the south and east from Thursday. And strengthening subsidence/ridging will keep the forecast dry through Friday morning. By Friday afternoon, mid-level ridging will begin to break down as the next shortwave dives southeast from northern Saskatchewan. With an uptick in isentropic ascent after Fri 18Z, rain showers will overspread the UP from west to east through the evening, quickly tapering off after Sat 06Z with loss of dynamics. In additiion, will briefly carry thunderstorm mention over the west-southwest portions of forecast area Friday evening with that sector falling under the left exit region of a weak upper level jet, but that is low to moderate confidence at this point. After some lingering 10-20% rain chances through Saturday afternoon (central and east) in association with departing shortwave, there will be a lull in activity Saturday night as brief ridging once again builds over the UP. Again though, the dry weather will be short-lived as focus turns to a series of systems traversing first northern Manitoba and then southern Saskatchewan/Manitoba. Showers and thunderstorms will accompany both systems on Sunday and again Tuesday. And, it is still a bit early, but instability and vigorous cold fronts could be enough to generate some strong thunderstorms both days. These will be targets of opportunity to monitor, especially Tuesday afternoon/evening as high temperatures climb into the low to mid 70s. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 125 AM EDT Wed May 8 2024 Main band of showers rotating back into the area from the east for the overnight with only SAW probably seeing steady rain from these showers. Expect conditions to lower to MVFR and then IFR overnight at SAW and IWD in showers as an upslope n-ne flow develops on the backside of the associated sfc low moving toward the Straits later tonight. CMX also has a good chance to see a period showers and MVFR cigs early overnight, but then expect CMX to improve to VFR late tonight (08Z or after) and continuing into Wednesday as a downslope ne flow develops there. Conditions will be slower to improve at IWD and SAW during the day on Wednesday under the n-ne wind onshore flow with improvement to MVFR by late morning and then to VFR in the afternoon. && .MARINE... Issued at 307 PM EDT Tue May 7 2024 Easterly winds diminish to below 20 knots tonight before becoming northeast and increasing to 30 knots on Wed into Wed night. North to northeast winds drop below 20 knots on Thu and stay that way into Sun. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Small Craft Advisory from 11 AM EDT /10 AM CDT/ this morning to 8 PM EDT /7 PM CDT/ this evening for LSZ240>242. Small Craft Advisory from 11 AM this morning to 5 PM EDT this afternoon for LSZ243-244. Lake Michigan... None. && $$ SHORT TERM...GS LONG TERM...TDUD AVIATION...Voss MARINE...07