Area Forecast Discussion
Issued by NWS Gaylord, MI
Issued by NWS Gaylord, 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
579 FXUS63 KAPX 291508 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 1108 AM EDT Sat Jun 29 2024 .KEY MESSAGES... - A few severe storms possible this afternoon/evening. Winds/hail primary hazards. - Cooler/drier Sunday and chilly Monday morning. - More unsettled weather starting Tuesday with potential for another round of heavy rainfall. - Drying out for the Fourth of July? && .UPDATE... Issued at 1038 AM EDT Sat Jun 29 2024 Clouds and showers continue to work their way east this late morning with clearing to the west. Western portions of the UP are beginning to clear out and thus destabilizing via RAP Analysis. Thought is for portions of the area to clear into this afternoon allowing for enough destabilization and thus shower and thunderstorm chances along/ahead of a cold front. Environment is characterized by good speed shear and modest instability (lapse rates not very steep) most locations and thus strong winds and large hail will be the main threats with the strongest storms. Guidance in particular is hinting at the UP as a potential area of a stronger storm or two this afternoon. Activity should steadily diminish this evening and into the overnight. && .SHORT TERM /THROUGH TONIGHT/... Issued at 353 AM EDT Sat Jun 29 2024 Pattern/synopsis: 500mb mean troffing evolves eastward toward the northern Great Lakes. Two primary shortwaves are responsible for this; one rotates thru this morning, the 2nd toward evening. At the surface, 1001mb low pressure over Lk Superior will move eastward. A warm front crosses from w to e early today, with a cold front following from the nw late today. Showers continue to cross the region early this morning, especially in eastern upper and ne lower MI. There hasn`t been much lightning with this activity, though in the past hour a few CGs have been seen from Atlanta to Alpena. Warm/moist advection continues, and additional destabilization is occurring aloft. MuCape values of 100-200j/kg are present, but closer to 500j/kg or more over WI and northern IL. CAMs generally favor an additional round of showers with some embedded t-storms to develop toward 7-8am, from MBL and Leelanau Co up into eastern upper MI. The low level jet does weaken with time, so this round of convection will push gradually eastward, with coverage decreasing with time. By noon, sct showers and perhaps a t-storm will linger over ne lower and far eastern upper MI, with nw lower drying out seeing some partial sunshine break out (especially by early afternoon). Morning convection is not expected to be strong or severe, due to limited instability. However, the emerging partial sunshine will allow for destabilization to occur ahead of the cold front. By late afternoon, MlCape values will be near 1k j/kg, with 0-6km bulk shear of 40-50kt. This is a reasonable spot for some storm organization (though this is over land; instability will be lower over the big lakes). Surface winds will be veered to west, even ahead of the cold front, which will significantly limit convergence along the boundary. Those winds will be too strong for pure lake breezes, but onshore turning and localized convergence will still develop in some areas. Initial stronger convection could form in central upper MI by mid afternoon, and gradually grow upscale and expand se-ward. These storms will bring a severe wind and (perhaps) hail threat, across all of northern MI. Instability falls off behind the cold front, though there`s sufficient moisture for a few showers to linger. By late tonight, there might even be a touch of drizzle over eastern upper and northern lower MI. Max temps today from low-mid 70s north, to mid 80s far se. Lows tonight upper 40s to mid 50s. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 353 AM EDT Sat Jun 29 2024 Pattern Forecast: Weekend ends/new week starts with long wave troughing over eastern Canada extending into New England/Mid Atlantic/Great Lakes Sunday... with rising heights/short wave ridging into the Midwest and Great Lakes for Monday. Ridge axis forecast to slide into the lower Lakes Tuesday as the next Pacific-origin short wave trough crosses the Rockies and into the Plains. This should set up a baroclinic zone across the Great Lakes by midweek...and the potential for unsettled weather heading into the Fourth of July holiday. Unseasonably strong high pressure (~1028mb/+2 to +3 sigma standardized MSLP anomaly) builds into the Plains/Midwest for Sunday...providing Michigan with cooler northwest boundary layer flow while a secondary short wave trough pivots southeast across the state. Surface high will be over the upper Lakes by Monday morning...then shifts east Tuesday allowing for a return of warmer air (along with a northward moisture surge). Height falls are then expected to push a cold front into the region Wednesday...will have to see how far south it gets before becoming parallel to more zonal flow setting up across the Great Lakes Thursday. Primary Forecast Concerns: Cooler/drier Sunday and chilly Monday morning: A nice cool shot on the way for Sunday in the wake of today`s cold front passage... probably cold enough (below 8C at 925mb) to allow lake convection to augment early cloud cover. Clouds should eventually mix into a high Sc deck and thin out in the afternoon. High temperatures should be in the 60s...possibly around 70 near Saginaw Bay due to downsloping flow...but a solid 10-15 degrees below normal for the last weekend of June. Should be breezy as well given cold air advection and a decent pressure gradient with upstream surface high...gusts of 15 to 25 mph expected (and likely Small Craft Advisories within most nearshore zones). Should be good radiational cooling conditions for most areas Sunday night as winds drop off under clear skies...and with temperatures only starting in the 60s suspect some of the colder low lying spots could dip into the upper 30s overnight. Used a combination of the NBM 10th percentile and statistical guidance to adjust low temperatures Monday morning. More unsettled weather starting Tuesday with potential for another round of heavy rainfall: The return of warmer air may be accompanied by an impressive surge of deep layer moisture from the Gulf. This could set the stage for potentially more heavy rainfall Tuesday night into Wednesday. Current probabilities only hint at it for northern Lower and are more focused on Wisconsin (as well as the Day 5 Excessive Rainfall Outlook). But an idea to monitor heading into midweek. Drying out for the Fourth of July?: As of now looks promising...rain chances may not be too far to the south but for now see no compelling reason not to be optimistic about it. Temperatures should at least be seasonable (normal highs in the upper 70s-lower 80s)...doesn`t look brutally warm at this point. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 708 AM EDT Sat Jun 29 2024 Low pressure will cross Lk Superior and continue ne thru Saturday. This will drag a cold front across the area this afternoon and evening. Periodic showers continue early this morning, with precip coverage waning for a time by mid/late morning. Additional SHRA and perhaps TSRA swing in from the w and nw, between 21Z and 04Z. Cigs will lower to IFR or low-end MVFR this morning, then improve after sunrise. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Small Craft Advisory from 11 PM this evening to 8 PM EDT Sunday for LHZ347>349. Small Craft Advisory from 8 PM this evening to noon EDT Sunday for LMZ323-341-342-344>346. Small Craft Advisory from 8 PM this evening to 8 PM EDT Sunday for LSZ321. && $$ UPDATE... SHORT TERM...JZ LONG TERM...JPB AVIATION...JZ