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
140 FXUS63 KGRR 231643 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 1243 PM EDT Thu May 23 2024 .KEY MESSAGES... - Potential for Storms Friday Evening / Night - Precipitation Ends on Saturday - Rain Likely in Sunday Through Tuesday Time Frame && .DISCUSSION... Issued at 337 AM EDT Thu May 23 2024 - Potential for Storms Friday Evening / Night Weather conditions stay quiet today under upper ridging. Into Friday morning an upper shortwave will pivot into the region from the Northern Plains. A corresponding surface low will travel from Minnesota into western Ontario with a trailing cold front sweeping through the midwest. Surface flow across southern Michigan turns southerly ahead of the cold front with dewpoints increasing into the mid 60s. Mid-level lapse rates don`t look overly impressive over lower Michigan, and there is still disagreement on instability Friday afternoon and evening. There does appear to be agreement on the higher instability developing over the far southwest corner of Lower Michigan which corresponds well with the SPC Day 2 outlook Slight Risk over southwest Michigan. Similar to the Tuesday storms, these storms will be easily trackable as they travel from Iowa through Illinois and into Indiana and southern Michigan throughout the day. The primary storm mode will be linear along the front with some bowing segments possible. Damaging wind gusts will be the primary hazard as the storms travel into southern Michigan. - Precipitation Ends on Saturday Morning showers and thunderstorms should come to an end in the midday hours of Saturday as a cold front progresses off to the east. Moisture is shunted to the east early in the day and there should be plenty of sun with dry conditions for many for most of the day. Dry weather will persist Saturday night and into Sunday. - Rain Likely in Sunday Through Tuesday Time Frame Model disparity exists in the Sunday through Tuesday time frame and really event into Wednesday. The uncertainty is in how an upper trough moving through the northern tier of the CONUS interacts with a trough in the mid levels over Canada. The ECWMF phases with the Canadian trough earlier which produces a deeper low earlier on (Sunday night into Monday) vs the GFS which is later with the stronger low (Tuesday into Tuesday night). Bottom line is the Sunday through Tuesday time frame looks unsettled with chances for rain throughout. Can`t rule out a few storms at times, but we are not looking at severe weather given a lack of strong instability. Cool, showery weather is more of what is expected. Our forecast has highs in the 60s for Monday through Wednesday. Could see the need to lower highs on Sunday as well, which are currently in the low to mid 70s. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1243 PM EDT Thu May 23 2024 Very high confidence in VFR through the TAF period. At present, FEW to SCT cirrus are crossing the state and will exit by late evening. A few cumulus are possible but given how dry we are it`s unlikely to see more than SCT at the terminals around 5-6kft. Skies clear out overnight and remain so after 12z until cirrus approach the western terminals (MKG/GRR/AZO) just before the end of the TAF window. The other item of note is winds. West-Southwest winds around 10 knots this afternoon fall below 5 knots tonight with a general shift to the east to southeast as a boundary slides through. Tomorrow morning through the end of the TAF window expect generally southeasterly winds of 5-10 knots. && .MARINE... Issued at 337 AM EDT Thu May 23 2024 Wave heights continue to fall today and into Friday with no marine concerns to note. Storms will be possible Friday afternoon and evening, then westerly winds build Saturday morning leading to waves increasing towards 3 to 4 feet. Winds and waves stay marginally below Small Craft hazards, but waves will be hazardous to any swimmers that are brave enough to venture into 50 to 60 degree water. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Duke/Thielke AVIATION...Thomas MARINE...Thielke