Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
307 FXUS63 KMQT 211753 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 153 PM EDT Fri Jun 21 2024 .KEY MESSAGES... - Widespread rain is likely tonight through Saturday. - The heaviest rainfall should stay south of the UP, but there is still a slight chance (5% chance) for locally heavy rain resulting in minor flooding impacts. && .SHORT TERM /TODAY/... Issued at 435 AM EDT Fri Jun 21 2024 Water vapor imagery/surface analysis this morning show Upper Michigan mainly under the influence of high pressure with this weekend`s weather making frontal boundary draped across the Lower Midwest. A few light radar returns have been tracking across the eastern portions of the forecast area early this morning, but little if any rain is reaching the ground with dry air in the lower levels. As the day progresses, though, rain and thunderstorm chances will increase from the southwest as weak WAA in association with the aforementioned frontal boundary spreads northward over Wisconsin. This will provide enough lift for some embedded thunderstorms within the rain showers, but limited instability will mitigate any threat of strong thunderstorms. Meanwhile, under mostly cloudy skies, today`s highs will top off in the upper 60s/low 70s inland (cooler near lakeshores). && .LONG TERM /TONIGHT THROUGH THURSDAY/... Issued at 422 AM EDT Fri Jun 21 2024 This weekend will be an active period as troughing currently over the western U.S. coast moves east through the Great Lakes. A brief dry period starts Sunday evening continuing through Monday, but another trough progressing east through Canada early next week brings a round of shower and storm chances for Monday night/Tuesday. A drier pattern then sets up for the rest of next week. The CPC`s 6- 10 day precipitation outlook reflects this extended forecast well with 40-50% chances for above normal precipitation for the entire UP. Showers continue tonight with the warm front stalled out over central WI, with the best chances over the southern UP. However, coverage of showers increase Saturday as a shortwave lifts out of the Rockies and a surface low deepens while tracking into the Upper Great Lakes. As the low moves northeast, the warm front lifts with it, reaching as far north as the northern end of Lake Michigan and northern WI; this is where the axis of heaviest rainfall is expected. Guidance over the past 24 hours has continued to trend more southward with this swath of heaviest, 2in or greater accumulations. This latest forecast continues to cut back on QPF across the UP, but this still will be a wet period for the area. Total QPF Friday through Saturday is around 0.5" in the Keweenaw, increasing southeastward to 1" across the southern UP with higher amounts to 2" possible across southern Menominee county. Also with this southward trend, the Keweenaw may not see any measurable precip until Saturday morning when the low lifts through the area. Meanwhile, though soundings and HREF guidance do show a few hundred j/kg of MUCAPE over the area, as well as anywhere from 35-50kts of deep layer shear depending on your model of choice, there is a pretty impressive cap in soundings. The SPC slight risk over our far southern zones therefore seems a bit ambitious, but regardless, will not rule out some rumbles of thunder. Another trough dives southeast over the area on Sunday, bringing an additional round of showers and possibly some thunder. However, model soundings are rather moisture-starved and instability remains fairly low, so showers should be light and strong storms are not expected. A brief dry period then follows through early next week as weak ridging and high pressure moves southeast over the area. The next round of showers and storms arrives late Monday night into Tuesday as another shortwave moving through Ontario drags a cold front through the area, but then ridding over the Great Lakes will once again bring in dry weather for the midweek period. As for temperatures, we will trend cooler than normal through the weekend with our rounds of rainfall, then we warm up early next week before the cold front ushers in cooler-than-average temperatures by Wednesday. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 153 PM EDT Fri Jun 21 2024 With a round of showers making their way eastward through the UP this afternoon, MVFR conditions are expected at IWD with CMX and SAW likely holding onto VFR until later this evening. This evening into tonight, conditions are expected to deteriorate down to IFR to LIFR as cigs lower and fog develops in the wake of showers; some guidance hints at periods of VLIFR cigs at SAW late tonight/early Saturday. With limited instability during this TAF period, mention of thunder was left out. That said, if any rumbles of thunder manages to materialize, the best chances are at IWD. Conditions will struggle to improve on Saturday as a low pressure moves into the Upper Great Lakes. && .MARINE... Issued at 422 AM EDT Fri Jun 21 2024 A stretch of light north to northeast winds mainly below 15 kts is expected through early Saturday with surface high pressure over Lake Superior. This high pressure weakens throughout the day today and a surface low lifts northeast through the Upper Lakes Saturday and Saturday night. This results in northeasterly winds to around 20 kts over the west half of the Lake during the day Saturday. Northwesterly winds behind the departing low should stay around or below 20 kts on Sunday. South winds return on Monday veering southwest Monday night and increasing to 20-25 kts ahead of another weak cold front by Tuesday afternoon. Winds fall below 20 kts again mid week. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...TDUD LONG TERM...LC AVIATION...Jablonski MARINE...LC