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
830 FXUS63 KMQT 250901 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 501 AM EDT Tue Jun 25 2024 .KEY MESSAGES... -Non-severe thunderstorms push east through this morning. -Today will be a warm and windy day, with highs around 80 and wind gusts up to 30-40 mph in the west. -Pattern remains active, especially from late week into early next week, with yet more rounds of showers and storms && .SHORT TERM /THROUGH TONIGHT/... Issued at 500 AM EDT Tue Jun 25 2024 Thunderstorms are ongoing this morning throughout western and central Upper Michigan. A few of these storms have been producing hail, though the largest report thus far has been pea sized hail in Ironwood. Perhaps more perplexing has been the wind gusts, with storms on Isle Royale and the Keweenaw Peninsula gusting above 50 mph, though the wind threat has fallen significantly since the time storms initially passed through that area. These showers and thunderstorms are forecast to continue pushing east through the rest of the morning, with 00Z HREF hourly PoPs falling below 30% UP-wide by 14Z. As winds veer westerly behind the front, soundings show a 30+ kt jet at 850mb that can be mixed into, leading to a gusty day expected, especially over the west and particularly the Keweenaw. By 21Z, the HREF shows 70-100% chances of wind gusts over 30 mph over the west half and along Lake Superior in the east, with the Keweenaw showing 40-90% probabilities of gusts over 40 mph. It will also be a warm day, with MOS guidance showing wide swaths of the south-central UP reaching into the mid 80s for highs today, with the NBM showing about a 25% chance that the M-35 corridor from Escanaba to Menominee could touch 90 today. Overnight, clear skies will begin to cloud up some, though enough radiational cooling should occur to allow low temperatures to fall below 50 away from the Great Lakes. A very subtle 500mb shortwave will be pushing southeast from northwest Ontario, reaching the western UP by 12Z Wednesday. Just enough forcing and moisture will be present for slight-chance (15-30%) PoPs over the west half, though precipitation will be struggling against the near-1015 surface high pressure present at the time, so impacts of any showers will be light, if any. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Issued at 408 AM EDT Tue Jun 25 2024 Starting Wednesday, a northwest flow shortwave and associated cold front moves from the Northern Plains across the Upper Great Lakes. Most of the models show an inverted sfc trough inflection associated with the shortwave from northern WI along the U.P. border. Instability is limited at 200 j/kg or less so expect isolated to scattered showers Wednesday, probably focused mainly west and along the WI border where the inverted sfc trough axis is situated. Expect drying and clearing skies from the west and north behind the shortwave trough and cold front in the afternoon into early evening as highs peak mainly in the 60s. However, those near the eastern Lake Superior shores may stay in the 50s throughout the day. Weak high pressure ridging persists across the region from Wed night into at least Thu evening, dry weather prevails. Under clear skies and near calm winds, radiative cooling will drop Wed night lows into the 40s, coolest over the interior. Expect highs Thu generally in the lower to mid 70s. Meanwhile, a trough just east of the Pacific northwest will move onshore Wednesday night. This trough progresses east along the international border toward the Upper Great Lakes by Saturday morning with at least a couple of shortwaves embedded in it. This will support cyclogenesis in the northern Rockies Thursday night with the low ejecting east into northern Ontario Friday night/Saturday. WAA/isentropic ascent and theta-e advection ahead of the low will support showers and thunderstorms spreading into Upper Mi on Friday. The first of the shortwaves within the mid-level trough moves through Sat which pushes a cold front through the area Fri night into Sat. Increased instability noted along the cold front should increase chances for thunder as it moves through the area at this time. The second shortwave in the trough will send a secondary cold front and another round of showers across the area late Sat into early Sun along with a burst of gustier nw-n winds and colder temps. High pressure building in quickly behind the front will result in drier, albeit cooler conditions Sunday afternoon into Monday. Models advertise another shortwave and associated sfc low lifting off the Northern Rockies and tracking e across the Northern Plains and Canadian Prairies into the Upper Great Lakes for early next week. This feature will bring another round of showers/t-storms into the area for next Mon night into Tuesday. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 129 AM EDT Tue Jun 25 2024 VFR conditions will prevail early this period, followed by a rapid deterioration as a line of thunderstorms moves into Upper Michigan. Expecting most activity between 06Z and 11Z, with the greatest potential for severe winds, maybe some large hail, at KIWD early on in the event. Expect ceilings to fall to MVFR/IFR after the line moves through with some brief fog/mist developing before the sunrise. Tuesday, gusty winds are expected to develop as ceilings improve. Initial thoughts are KCMX could gust near 30kts from the west. LLWS will occur overnight at IWD and SAW. && .MARINE... Issued at 408 AM EDT Tue Jun 25 2024 Thunderstorms tracking across eastern Lake Superior along a cold frontal passage will bring somewhat gusty winds and lightning to mariners over the eastern lake early this morning. Winds will shift from southerly to westerly winds behind the cold front later this morning while gusting as high as 30 kts. Strongest winds are expected over the central portion of the lake as fcst soundings and model guidance suggest a (20-30%) potential for west gale gusts to 35 knots, especially at higher platform locations like Stannard Rock. This period of longer fetch and stronger winds will help waves build up to 4-6 feet this afternoon and evening north of the Keweenaw. Winds around 20-25 kts veer north tonight behind an additional cold front that drops south across the lake before tapering off below 20 kts Wednesday morning. With high pressure over the lake through Thursday, winds are expected to mainly remain below 20 kts. A weakening low pressure tracking through the Upper Great Lakes early this weekend will allow for s-se gusts near 20 kt Friday and 20-25 kt nw gusts behind a cold frontal passage Saturday before building high pressure returns Sunday and ushers in lighter winds. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...GS LONG TERM...Voss AVIATION...07 MARINE...Voss