Area Forecast Discussion
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, 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
992 FXUS63 KGRR 300753 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 353 AM EDT Mon Sep 30 2024 .KEY MESSAGES... - Patchy fog possible this morning with Warm weather today - Chance of showers and storms Tuesday - Mostly Dry and Seasonal Mid to Late Week && .DISCUSSION... Issued at 352 AM EDT Mon Sep 30 2024 - Patchy fog possible this morning with Warm weather today Any lingering showers and most of the low clouds remains along the Michigan border. The dropping temperatures and low level moisture coupled with calm winds could allow for some patchy fog this morning, especially in and around Jackson. A positively tiled ridge will build over the region today. This will bring fair weather with max temperatures today expected to be in the upper 70s to low 80s which is 10 to 15 degrees above normal - Chance of showers and storms Tuesday The warm temps and fair weather will be short lived as an upper level system will swing a cold front through the region tomorrow. There is still a narrow band of moisture that will correspond with the cold front which could spark some thunderstorms Tuesday afternoon. Latest models continue to show a lack of moisture through the western portion of the state which makes instability questionable. As the front gets through the central lower peninsula the short wave amplifies and HREF is showing then around 500 to 1000 J/kg of CAPE. So while moisture remains limited through the western side of the state the eastern half should 1 to 1.25 inch PWATS. That anomalous moisture could aid in thunderstorm development Tuesday afternoon. So have trended upward in POPS with an thunderstorms west of US 131 and mainly along and east of the US 127 corridor. The front will cool temperatures and move through quickly exiting the region Tuesday night. - Mostly Dry and Seasonal Mid to Late Week A fairly uneventful mid to late week period expected with a zonal flow aloft dominating and the upper jet core remaining mostly to our north along the U.S./Canadian border. High temperatures will average near to above normal in the 65 to 75 degree range. Some patchy frost cannot be ruled out early Wed morning north of I-96 depending on the extent of clearing behind Tuesday`s cold front. A weak sfc frontal boundary is shown to come into the area on Thursday and stall out nearby into Friday. Upper jet entrance region dynamics may come into play as the swift Pacific jet temporarily buckles south into the Upper Midwest, but moisture looks to be lacking and only 20 pops seem justified at this time. A better cold front may enter the picture next Sunday which could support a better risk of showers. However cluster analysis that far out currently depicts considerable uncertainty as to whether or not upper troughing to support that front digs south into the region, and to what extent. Only 20-30 pops are justified at this time. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 149 AM EDT Mon Sep 30 2024 VFR conditions exist areawide at 06z but we expect new areas of low stratus to develop and expand overnight...especially toward 12Z Monday. Confidence is low as to the areal coverage/extent of the stratus and just how low the cigs/vsbys get, with highest potential of IFR/LIFR at LAN and JXN then decreasing west from there. MKG is expected to remain entirely VFR and GRR could go either way being right on the edge of it. Stratus gradually lifting Monday afternoon with most locations becoming VFR again after 18Z. && .MARINE... Issued at 352 AM EDT Mon Sep 30 2024 The trends continue to show an increase of winds behind the cold front Tuesday morning. Behind the front it looks like we will mix into the 20 to 30 knot range. Combine that with cold air advection and it`s looking like a small craft advisory is likely going to be needed for the region. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Meade/Ceru AVIATION...Meade MARINE...Ceru/MJS