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
192 FXUS63 KMQT 261906 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 306 PM EDT Wed Jun 26 2024 .KEY MESSAGES... - Cool late June night tonight. -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 306 PM EDT Wed Jun 26 2024 Water vapor imagery and RAP analysis show mid-level ridging over the Rockies and troffing over eastern Canada into the adjacent U.S., resulting in nw flow into the Great Lakes. Shortwave that was over southern Saskatchewan 24hrs ago is over northern Lower MI. Shra associated with this feature spread across Upper MI this morning, but diminished dramatically while doing so. Heaviest rainfall occurred over portions of the Keweenaw, CMX received 0.48 inches. Where sun dominated the morning, shra have developed in ne WI, and some of these -shra are affecting portions of southern Menominee County. In the wake of the shortwave, it has been a cool aftn with considerable low cloudiness across the w and n central. Clouds are slowly lifting and showing some signs of scattering out, but cloud cover extends across the lake into ne MN/and northern Ontario where cloud cover is taking on a decidedly more diurnal cellular look. Current temps range only from the low/mid 50s w and n to the upper 60s F s central where more sun has occurred today. Expect some thinning out of clouds for the rest of the aftn. Despite the more cellular look of the clouds upstream of the lake, the considerable coverage suggests that these clouds are not likely to completely dissipate tonight, leading to increased uncertainty in min temps. With center of high pres shifting se to northern MN/nw WI by sunrise, winds will become light to calm. Precipitable water also falls to 50-60pct of normal, aiding radiational cooling potential. Leaned toward the lower side of avbl guidance, which puts min temps down into the upper 30s F at traditional cold spots interior w. Given the cloud cover uncertainty and wet soils that dampen radiational cooling, seems highly unlikely that it would be even colder to support patchy frost development. If more cloudiness hangs on tonight, min temps will easily be at least 5 degrees higher. Otherwise, expect min temps tonight to range thru the 40s F. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 252 AM EDT Wed Jun 26 2024 The pattern will remain fairly active and progressive through the extended fcst period as a couple of Pacific-based shortwave troughs traverse the northern tier of the CONUS and bring more rounds of showers and t-storms to the Upper Great Lakes mainly in the Friday- Saturday night and Monday night into Wednesday time periods. Starting Thursday, a weak high pressure ridge persists across the region into much of Thu night as dry weather prevails. Weak pressure gradient and light winds will result in lake breezes during the day on Thursday. Expect highs generally in the lower 70s, except a touch cooler in the mid to upper 60s near the Great Lakes shores. Look for lows Thu night in the lower to mid 50s, except for some cooler upper 40s readings over the eastern interior. Friday and Saturday, a mid-level trough/closed low just off the Pacific Northwest coast as noted on satellite imagery early this morning will move onshore later this morning. This trough will support cyclogenesis in the lee of the Northern Rockies Thursday night with the sfc low ejecting east into the Dakotas and along the international border/northern MN Friday and into the Upper Great Lakes on Saturday. WAA/isentropic ascent and theta-e advection ahead of the low will support showers and thunderstorms spreading into Upper Mi on Friday. The initial shortwave embedded within the mid- level trough will move into the region Saturday while pushing a cold front through the area Friday night into Saturday. Increased instability noted ahead and along the cold front should increase chances for thunder as it passes through the area at this time. A second shortwave moving through the trough axis will send a secondary cold front across the area late Sat into early Sun perhaps triggering some isolated to scattered light showers 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 then advertise another mid-level trough moving in off the West Coast which again will promote lee-side cyclogenesis over the Northern Rockies early next week. The associated sfc low is fcst to lift northeast through the Northern Rockies into Manitoba and northern Ontario Mon night into Tuesday as it propels a cold front across the Upper Great Lakes on Tuesday. Ahead of and along this front another round of showers/t-storms is expected next Mon night into Tuesday. The passage of another shortwave and secondary cold front from this system could bring more light showers into the area on Wednesday. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 145 PM EDT Wed Jun 26 2024 A stratus deck, IFR cigs, that developed during the morning at IWD/CMX/SAW has lifted to MVFR recently. Expect MVFR cigs to gradually lift to VFR BKN clouds at 3500ft over the next 2-4hrs at all terminals. VFR will then continue for the remainder of the fcst period. && .MARINE... Issued at 252 AM EDT Wed Jun 26 2024 Winds have switched northerly early this morning at 15-20 kts behind a cold front dropping south across the lake but will taper off below 15 kts during the day today. 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 20-25 kt Friday over mainly the east half ahead of the front and then nw gusts 20-25 kt behind the cold frontal passage on Saturday before building high pressure returns Sunday and ushers in lighter winds into Monday. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...Voss AVIATION...Rolfson MARINE...Voss