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
50
265 FXUS63 KGRR 081128 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 728 AM EDT Wed May 8 2024 .KEY MESSAGES... - Dry and mostly sunny today - Rain and chance thunderstorm tonight through Thursday - Showers on Saturday && .DISCUSSION... Issued at 350 AM EDT Wed May 8 2024 - Dry and mostly sunny today The upper-level shortwave trough and surface low associated with yesterday`s thunderstorms is scooting east toward New England today, while its former parent low over the Dakotas begins to fill and shear out. There will be a narrow zone of ridging with 500 mb height rises over our area along with drier air moving through, keeping us mostly sunny until clouds increase late in the evening. There should be only a moderate breeze from the west becoming northwest. - Rain and chance thunderstorm tonight through Thursday Remnants of the Dakota low phasing with a southward-moving positively tilted trough from northern Ontario are expected to develop a surface low across Illinois-Indiana-Ohio tonight. To its north will be a period of likely rain for much of the day Thursday across southern to central Lower Michigan. Some MUCAPE may be present in southern Michigan which could be enough for some rumbles of thunder. Some questions remain as to the northward extent of a soaking rainfall, and also rainfall totals. HREF member model mean rain totals suggest 0.5 to 1.0 inch rain totals are most likely (though much less near/north of US-10), however, 1.5 inch totals are possible in some spots. - Showers on Saturday Shortwave ridging should bring fair weather for Friday into Friday night but clouds will be moving in after midnight as a shortwave trough approaches, with rain moving back in for Saturday. This trough is less amplified than previous runs but some diurnal enhancement of the showers Saturday afternoon is still possible given the steep lapse rates. Isolated thunderstorms are possible and even some small hail with any deeper updrafts. Cool air in northerly flow on the back side of the sfc low results in low temperatures in the upper 30s to lower 40s Saturday night with scattered frost potential in the colder outlying areas. The trough moves east on Sunday but there is low confidence with forecast details next week, although there is model agreement on a longwave trough forming across the central/eastern CONUS by late in the week. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 728 AM EDT Wed May 8 2024 VFR conditions expected through tonight. West winds around 10 knots this morning will go northwest this afternoon then northeast overnight. && .MARINE... Issued at 350 AM EDT Wed May 8 2024 West winds becoming north later today are not expected to pose a hazard on Lake Michigan. East-northeast winds Thursday morning may gust over 20 knots Thursday morning. As winds become north later on Thursday, some larger waves may peel toward the shore from the stronger midlake wind field. Essentially, could be marginally hazardous for small craft on Thursday, not to mention the chance of lightning. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Ostuno/CAS AVIATION...Ostuno MARINE...CAS