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
277 FXUS63 KMQT 161731 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 131 PM EDT Tue Jul 16 2024 .KEY MESSAGES... - ~20% chance of showers and isolated thunderstorms this afternoon. (Mainly central U.P.) - A 20% to 40% chance for scattered light showers on Wednesday. - Cooler and drier for midweek with the arrival of high pressure. - Next chances for showers and maybe some thunder return on Saturday. && .SHORT TERM /TODAY/... Issued at 436 AM EDT Tue Jul 16 2024 Cold and dry advection has overspread Upper Michigan early this morning with water vapor imagery/RAP analysis showing yesterday`s cold front now east of the forecast area. Clear skies have allowed temperatures to cool into the upper 50s at this time across interior west and central portions of the area with generally low 60s over the remainder of the UP. By daybreak, the cold spots across the interior west could dip into the low 50s. For the remainder of the day, expect mainly dry conditions with a return to seasonable high temperatures in the 70s. The only deviation from this could be the development of afternoon showers (isolated thunderstorms) during the peak heating of the day as shortwave energy rotates around an upper trough centered over northern Ontario. && .LONG TERM /TONIGHT THROUGH MONDAY/... Issued at 443 AM EDT Tue Jul 16 2024 Starting tonight, the mid level trough over northern Ontario pivots over the Upper Great Lakes. With the associated PVA, northwest upslope flow, and a reinforcing cold front dropping sough late tonight into Wednesday morning, light showers/sprinkles are expected to touch off in the west after midnight. Temps turn cooler tonight with upper 40s to 50s, warmer by the lakeshores. As the trough continues over the area and the front pushes south through Wednesday morning, precip expands southwest across the UP. Afternoon highs will be cool in the 60s to low 70s. With high pressure building in from the west and PVA diminishing, dry weather returns from west to east. That said, the broken stratocumulus deck looks to lasting well into the afternoon and possibly the evening hours. Mixing behind the cold front will result in light northwest winds with gusts expected up to 20 mph. Model soundings and the 7/16 0Z HREF indicate a 30-50% chance for gusts up to 25 mph in the Keweenaw and eastern UP. The cooler pattern holds through Wednesday night as high pressure and a drier airmass builds in. In turn, subsidence increases, winds tapper off, and radiative cooling under clear skies brings temps down into the 40s with low 50s near the lakeshores. High pressure continues to shift east-southeast over the Great Lakes through the rest of the week into next weekend, yielding more seasonable temps with plenty of sunshine. Also during this period, the mid level ridge over the western CONUS amplifies, deepening the trough over northern Ontario/Quebec. A shortwave trough dropping south across the Upper Great Lakes Friday night into Saturday brings a cold front with it for Saturday, supporting the next chances for showers and thunder. This also likely brings a brief period of cooler temps, especially near Lake Superior. From there, ensemble guidance continues to indicate that another high pressure pressure builds back in from northwestern Canada as the amplified ridge eventually gives way late next week and shifts eastward across the CONUS. This means that outside any additional shortwaves, precip will be largely driven by diurnal heating or lake breeze convergence moving into next week. Temps look to return to normal moving into next week. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 130 PM EDT Tue Jul 16 2024 VFR prevails at all TAF sites through tonight under mainly light northwesterly winds except for some gusty conditions at CMX. A few -SHRA may impact SAW this afternoon, but chances of precipitation are only around 25%. Overnight, a shortwave swinging through from the north will bring more 15-25% chances of rain but over 50% chance of cigs falling to MVFR at all sites. && .MARINE... Issued at 443 AM EDT Tue Jul 16 2024 West to northwest winds are generally expected to remain below 20 kts through this evening. Northwest winds increase to 20-25 kts late tonight, holding into Wednesday as a cold front pushes south across the lake; the strongest winds are expected over the central zones (LSZ263-266) of the lake. During this period, waves build up to 3-5 ft over the east half of the lake, particularly in the waters between Marquette, Grand Marais, and Stannard Rock. With high pressure building in from the west on Wednesday and continuing east-southeast over the Great Lakes into this weekend, winds are expected to remain below 20 kts into next week. A cold front moving southward from Ontario will yield a wind shift to the north for Saturday/Sunday, otherwise winds will be predominantly from a west and southwest direction though the forecast period. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...TDUD LONG TERM...Jablonski AVIATION...GS MARINE...Jablonski