


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
331 FXUS63 KGRR 280550 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 150 AM EDT Sat Jun 28 2025 .KEY MESSAGES... - Strong to Severe Storms into this Evening - Cooler and Drier Saturday then Warmer and Wetter Sunday and Monday - Fair and Drier Tuesday through Thursday && .DISCUSSION... Issued at 253 PM EDT Fri Jun 27 2025 - Strong to Severe Storms into this Evening A line of strong storms that initiated along a horizontal roll circulation this afternoon is expected to continue propagating east and expand northeast through early evening before departing the eastern zones later this evening. Despite moving into and area of higher instability with CAPE of 1500 to 1800 j/kg, only modest strengthening is expected as deep layer shear is relatively weak and has so far precluded organized, sustained updrafts. Main threats will be isolated downburst winds over 60 mph and hail near 1 inch in diameter. - Cooler and Drier Saturday then Warmer and Wetter Sunday and Monday Cold front moving through overnight will usher in a welcome change of airmass with the oppressive 70 degree dew points dropping into the comfortable range of upper 50s to lower 50s dew points for Saturday and Saturday night. This will be a brief respite as return flow is already setting up ahead of a shortwave trough embedded in zonal flow moving from the Plains into the Great Lakes. Dew points surge back into the 70s by late Sunday into Monday with a cold front arriving by afternoon. Instability is sufficient for enhanced thunderstorm coverage but deep layer shear is once again limited, only around 20 to 25 knots, so storm mode may be of the pulse variety. - Fair and Drier Tuesday through Thursday Another cold front moves through Monday night and this will bring a longer stretch of comfortable temperatures and dew points lasting through Thursday. The long range indications are for shower/thunder chances on the 4th, but confidence remains low at this time. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 150 AM EDT Sat Jun 28 2025 Limited aviation concerns the next 24 hours with VFR weather in place at 06Z and VFR weather forecast through the TAF period. The only real threat to VFR weather in the TAF period is early this morning as some stratocumulus is being produced near and behind a cold front that stretches from near Lansing to Battle Creek at 06Z. The front will move to the east of the TAF sites in the next hour or two. Through 13Z there is a possibility some of these clouds could dip into the MVFR category, but the threat was too small to include at this time. Otherwise, with high pressure settling into the area we are expecting mainly clear skies and VFR conditions. Winds will be from the west both early this morning and through the day at 5 to 10 knots. Winds will become light and variable at 01Z this evening. && .MARINE... Issued at 157 PM EDT Fri Jun 27 2025 We`ll be watching showers and thunderstorms develop this afternoon mainly south of MKG as a cold front moves east. Waves will generally be around a foot through Sunday. However, north of MKG, waves will build to 2-3 feet by Sunday afternoon. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Ostuno AVIATION...Duke MARINE...04