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
859 FXUS63 KMQT 061059 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 659 AM EDT Thu Jun 6 2024 .KEY MESSAGES... - Breezy with some showers today, and maybe a thunderstorm or two near Lake Michigan. A west to northwesterly gust up to 40 mph possible over the Keweenaw this afternoon. - Showery weather and much cooler conditions through the weekend under the influence of low pressure, then warming and drying early next week. && .SHORT TERM /THROUGH THIS AFTERNOON/... Issued at 234 AM EDT Thu Jun 6 2024 Outside of the last of the rain showers over the far east and far south central early this morning, the convection in relation to the secondary cold front moving through the area this past evening has now ceased. In its place, partly cloudy to mostly cloudy skies traverse the region as a low pressure sets up shop over northern Ontario. Given the recent rainfall and limited cloud cover overhead, lows this morning shouldn`t drop much more; expect lows around 50 to maybe the upper 40s in a few spots in the interior west, and the lower to mid 50s over the east where cloud coverage is projected to be more abundant during the pre-dawn hours. Moving into the daylight hours today, another shortwave rotating around the parent low over northern Ontario looks to move through the Upper Michigan. This will bring scattered showers across the area, particularly over the east where some lake breeze dynamics from Lake Michigan may increase lift locally enough to produce a thunderstorm or two. With mostly cloudy skies expected overhead to day due to the shortwave, instability for thunderstorm formation will be hard to come by. Therefore, expect any thunderstorm activity to be fairly limited to around the Lake Michigan shoreline. With cold air advection continuing across the area today, expect cooler temperatures, with highs only getting to around 60 in the north central and west and the mid 60s in the east and south central. Given the cold air advection, expect some breezy westerly winds today (despite the cloud cover), becoming northwesterly late this afternoon. The highest winds are expected in the Keweenaw, where we could get a stray gust or two up to 40 mph given the long fetch over Lake Superior. Expect the highest wind gusts during the mid to late afternoon hours, when the diurnal heating becomes maximized. Shower activity begins to diminish over the west half late this afternoon as the shortwave moves closer to the Straits. && .LONG TERM /TONIGHT THROUGH WEDNESDAY/... Issued at 426 AM EDT Thu Jun 6 2024 Building high latitude blockiness will peak this weekend as building mid-level ridging/positive height anomalies from eastern Canada thru n central Canada and across the Arctic Ocean, where the anomalies peak, merge with a building ridge over western N America. This has already forced trof development from s central Canada into the Great Lakes. This trof will persist into the weekend before evolving into a more general eastern N America trof as western N America ridge begins to shift e. The ridge will then deamplify and continue eastward under a temporary change to more progressive flow next week. This progression will bring the next shortwave trof to the Great Lakes in the midweek period. For Upper MI, this pattern evolution will support blo normal temps/cool conditions thru early next week. Then, the return of a more progressive flow regime will send temps up to around normal for Tue/Wed. Farther down the road, the last 24hrs of medium range ensemble guidance remains consistent in the flow evolution toward the end of the model runs. The signal is for building heights across the central and eastern U.S. in the June 15-20th period. This ties into the 00z June 5 ECWMF weeklies. So, we`re probably heading toward an overall warm/humid last half of June. As for pcpn over the next 7 days, the mid-level troffing thru the Great Lakes region will support showery weather at times thru the weekend. Overall, expect many areas to be dry much of the time as shra are likely to be mostly sct in coverage. With mid-level trof weakening and drifting e early next week, dry weather will return. Shortwave trof arriving midweek will bring the next chc of shra late Tue/Wed. Beginning tonight, shra will diminish in the wake of shortwave that passes across Upper MI this aftn/evening, but the shra won`t end. Best chc of shra lingering thru the night will be over the eastern fcst area. That area will actually be under some isentropic ascent as warmer air to the n advects toward the 850mb thermal troffing that will be set up from nw to se across Upper MI tonight. On Fri, center of mid-level low that is over the area today will be moving to southern Ontario. Weak shortwave ridging develops into western Upper MI between that low and another mid-level low over s central Canada. This suggests a drier day over western Upper MI. In fact, with models also showing a drier air mass advecting into the area, it may end up as a dry day. Will carry 20pct chc of shra early over nw Upper MI before moisture thins out. Otherwise, expect dry weather across the w on Fri. To the e, model trends are drier as well, but given closer proximity to the mid-level low with deeper moisture lingering, will continue a mention of shra, but mainly just for Luce County. High temps on Fri will be coolest over the e where more clouds and some shra are expected. Mid 50s to around 60F expected there. Low/mid 60s F expected to the w where there will be increasing breaks in the clouds. Closer to Lake Superior, temps will be in the 50s F under wnw flow off of the lake. Models have moved toward decent agreement in taking a shortwave that reaches British Columbia on Thu and driving it ese to the western Great Lakes during Sat. It will also pull some shortwave energy from the mid-level low over s central Canada to Lake Superior/Upper MI. This will work to expand the circulation/cyclonic flow of mid-level low to the e back to Lake Superior/Upper MI as well. While a more organized area of shra associated with the shortwave from British Columbia will mostly pass s of fcst area, daytime heating and cooling mid-levels (500mb temps fall from around -14C Fri evening to around -21C Sat aftn) will result in 100-500j/kg of MLCAPE building across across Upper MI, likely supporting sct/nmrs shra development for Sat aftn. Given the MLCAPE and cold pool aloft moving over the area, some thunder will be possible as well, particularly across the s half of Upper MI. With lower wetbulb zero heights of 5-7kft, there could be some small hail, especially if the higher end MLCAPE develops. Expect high temps generally in the 60s F, except for 50s F near Lake Superior in continued w to nw flow. On Sun, although model consistency isn`t great on exact details, most of the models hint at a shortwave/mid-level trough axis moving across the area in the Sat night/Sun time frame. Would expect at least isold shra from this feature, perhaps aided by weak isentropic ascent from the north as winds shifting from nw to n advect a pocket of warmer 850mb air into the area. North flow off Lake Superior will result in another day of 50s F temps near the lake while 60s F will be more common inland. 850mb temps fall back at least a couple of degrees from Sat, so Sun highs will be a little lower than Sat. On Mon, mid-level troffing shifts e with upstream ridge building toward the western Great Lakes. Thus, expect drier and warmer conditions on Mon with highs in the 60s to lwr 70s F, warmest toward the MI/WI stateline. Some lakeside locations along Lake Superior will not get out of the 50s F. As discussed earlier, next shortwave trof progresses e to the western Great Lakes midweek, bringing the next chc of shra late Tue into Wed. Shra may reach western Upper MI as early as Tue aftn. Dry weather will follow later Wed/Thu. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 658 AM EDT Thu Jun 6 2024 Expect conditions to drop to MVFR across the TAF sites this morning as a shortwave low moves through today. Expect to see some showers across the TAF sites, mainly during the morning hours over KIWD and KCMX. The showers end this afternoon from northwest to southeast as the shortwave leaves the area. Yet as it does so, expect cigs to degrade to 2 kft or less across the TAF sites and to remain that way throughout the rest of the TAF period. Other than the showers and deteriorating cigs, expect breezy conditions across the TAF sites today; I wouldn`t be surprised if KCMX overachieves and possibly gets to around 30 to 35 kts by this afternoon. Expect the breezy conditions to continue overnight at KCMX, and possibly KIWD and KSAW too as decent conditions for mixing in the lowest few thousand feet in the atmosphere continue through tonight; I`m thinking the breezy conditions will be more sporadic at KIWD and KSAW tonight as the lack of sunlight will make it harder for the stronger winds aloft to make it to the surface. && .MARINE... Issued at 426 AM EDT Thu Jun 6 2024 Across Lake Superior, steady W to WNW winds, generally at around 20kt with occasional gusts to 30kt, will set in from w to e today/tonight and then continue thru Fri. Highest gusts will be around and w of the Keweenaw today and then across the e half of Lake Superior tonight/Fri. A slight diminishing of winds will occur over the weekend with sustained speeds falling back to mostly around 15kt. However, passage of a sfc trof will bring a little uptick in winds for Sun across the e half of Lake Superior where NNW winds will be back closer to 20kt again. Sfc high pres ridge arrives on Mon, leading to winds falling to under 15kt. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...TAP LONG TERM...Rolfson AVIATION...TAP MARINE...Rolfson