![National Oceanic and Atmospheric Administration](/build/images/header/noaa.d87e0251.png)
![National Weather Service](/build/images/header/nws.4e6585d8.png)
![United States Department of Commerce](/build/images/header/doc.b38ba91a.png)
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
943 FXUS63 KMQT 070700 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 300 AM EDT Sun Jul 7 2024 .KEY MESSAGES... - Scattered showers and thunderstorms over mainly the west half of Upper MI this afternoon. - Monday through at least Tuesday, daily chances of showers and thunderstorms, highest chances in the afternoons. - Drier weather expected for the last half of this week. Could see highs into the 90s by Friday/Saturday. && .SHORT TERM /THROUGH THIS AFTERNOON/... Issued at 258 AM EDT Sun Jul 7 2024 Water vapor imagery and RAP analysis show mid-level troffing over central N America. Within the trof, a well-defined shortwave is over western MN with additional shortwaves dropping se from the Canadian Prairies thru eastern MT/western Dakotas. In association with the MN shortwave, shra and some tsra extend from nw MN se thru eastern MN into IA. Closer to home, it`s been a quiet overnight under clear to partly cloudy skies and little to no wind. A few of the traditional interior cold spots are down to 50, but current temps mostly range from the mid 50s to lwr 60s F. Aforementioned shortwave over western MN will drift ne today and will be over ne MN/western Lake Superior by sunset. On this track, best forcing will shift over western Upper MI this aftn. Models indicate roughly 300-1000j/kg of MLCAPE will build today. Of the 00z models, the HRRR is around and blo the low end of that range. On the opposite end of the spectrum is the NAM which is often on the high side. It shows widespread 1000-1500j/kg building today. With deep layer shear on the order of 25-35kt, expect some storm organization, and if the NAM`s greater instability materializes, there would be a risk of an isold svr storm. Instability build up will be something to monitor during the morning into the aftn, but with expectation of lower instability per bulk of guidance, don`t currently anticipate any svr storms to develop this aftn. Some brief gusty winds/small hail is a possibility in addition to the brief hvy downpours that will accompany some of the storms. While some of the shra to the w and sw may brush the Ironwood vcnty mid morning, expect shra/tsra to begin to develop toward noon or early aftn and then quickly expand across roughly the w half of Upper MI, greatest coverage generally w of a L`anse to Iron River line. Lake breeze will try to develop and shift inland from Lake Superior into Alger/Luce counties. Should end up pinned along or very close to shore. The resulting convergence combined with building instability on the land advecting northward across the boundary on lower level southerly winds brings the potential of isold shra/tsra development e of Marquette toward Whitefish Pt (including the nearshore waters of Pictured Rocks National Lakeshore) as well during the aftn. These isold shra/tsra may end up mostly offshore unless the lake breeze can make a bit of inland progress. Expect high temps today to be mostly in the mid 70s to lwr 80s F. && .LONG TERM /SUNDAY THROUGH SATURDAY/... Issued at 324 PM EDT Sat Jul 6 2024 After a very progressive pattern kicked off this summer, a more blocky pattern has now emerged as 500mb ridging over western North America will only very slowly progress eastward with time throughout this forecast period. The consequence of this for the UP will be dealing with the low-amplitude shortwaves that spill southeast from the ridge. While none of these shortwaves on their own are going to be strong enough to force any surface low pressures deeper than about 1005mb per the 12Z GEFS, with the help of diurnal heating, chances of showers and thunderstorms will increase each afternoon. As the the northern arm of the ridging slowly moves off of the Canadian Rockies, signal is strong for high pressure to usher in a period of dry weather Wednesday night into the weekend for the longest dry stretch of the summer for the UP so far. Sunday morning, the next shortwave in line will be centered over Minnesota and approaching the UP from the west. Without much of a surface feature resolved in global ensembles, forcing will be fairly broad and unfocused, but HREF does show notable destabilization throughout the morning hours, with mean SBCAPE values climbing to near 750 J/kg by noon. Shear will not necessarily be abundant, and with the forcing being weaker and broad, severe thunderstorms are not expected, though a few stronger thunderstorms could bring frequent lightning and locally heavy rain to interrupt those wrapping up their weekend plans. Timing-wise, the HREF shows a line of showers approaching Ironwood perhaps as soon as 9AM Central but more likely closer to 11AM. Showers overspread the rest of the western half of the UP throughout the early afternoon with Alger/Delta counties and east not seeing much rainfall until around sunset. Monday`s PoPs look to be a similar pattern to Sunday`s, though for different reasons. The residual cloud cover from the previous day`s showers will keep SBCAPE closer to 500 than the 750 of the previous day per the 00Z LREF, but the 12Z GEFS shows a cluster of low pressure centers around 1005 mb, which is a bit stronger of a low pressure than the guidance of 24 hours ago. Stronger forcing but weaker instability should lead to a similar level of impacts as a few stronger thunderstorms are possible but should remain sub-severe. Tuesday and Wednesday, uncertainty begins to grow as global ensemble and deterministic models diverge in the handling of shortwave propagation as the 500mb ridge axis finally shifts out of British Columbia. Once showers cease Wednesday, the northern arm of the ridge will shift towards the Great Lakes and high pressure looks likely to keep precipitation out of the forecast Thursday into the weekend for what would be the longest dry period UP-wide since the beginning of the summer. One interesting thing to note will be the progression of Beryl as it makes landfall and turns northeast. The 06Z GEFS has a 20% chance of the remnants of Beryl coming within 200km of the UP, which depending on how much strength Beryl maintains, could introduce showers into the forecast again late in the week. The more likely impact would be in how long the high pressure resides over the UP and at what strength, so it will be worth keeping an eye on Beryl as it becomes better sampled by the upper air network. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 123 AM EDT Sun Jul 7 2024 VFR conditions will prevail at all TAF sites through the period. Calm conditions are expected for the rest of the night before a weak surface low moves into northern Minnesota today. This wave, along with diurnal instability, should result in scattered showers and thunderstorms developing around IWD in the early to mid-afternoon, where a PROB30 was placed during the window when tsra are most likely. Lower probability of tsra making it to CMX/SAW in the late afternoon and evening, so it was not included in the TAFs. && .MARINE... Issued at 324 PM EDT Sat Jul 6 2024 Light winds of 20 knots or less will continue across Lake Superior this weekend through next week as a cycle of weak shortwave lows followed by weak ridging continues across the Upper Great Lakes as high pressure continues to build over the western CONUS. That being said, a few of the disturbances will be strong enough to produce some thunderstorms across the lake from time-to-time over the next several days, namely over the western portions of the lake Sunday and over the east overnight into Monday, and in the nearshore waters Monday afternoon and evening. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...GS AVIATION...Thompson MARINE...GS