Area Forecast Discussion
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, MI
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841 FXUS63 KGRR 170533 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 133 AM EDT Fri May 17 2024 .KEY MESSAGES... - Scattered showers and storms tonight/early Friday - Dry and Mild Weekend - Active Weather to Start the Work-Week && .UPDATE... Issued at 955 PM EDT Thu May 16 2024 Evening showers and storms are now diminishing as diurnal instability declines. Any regeneration/redevelopment overnight remains most likely in the northern zones (US-10 corridor) due to proximity to the shortwave and associated lift moving through Wisconsin and into the U.P. However, last few hi-res model runs have backed off a bit on thunderstorm coverage after midnight tonight, so it`s possible it could end up being a pretty calm night overall. && .DISCUSSION... Issued at 328 PM EDT Thu May 16 2024 - Scattered showers and storms tonight/early Friday A shortwave and accompanying sfc frontal boundary track slowly east through the region tonight and Friday morning, but are generally weakening as they do so. Instability isn`t the greatest either especially since these features come through mostly during the diurnal minimum. Initially this evening scattered showers and storms will be associated with the incoming warm front and higher dew points, then overnight will be linked more to the nearing WI shortwave and cold/occluded front. HREF guidance suggests best coverage of rain will be during the overnight period especially east of Hwy 131. Will carry some lingering low (20-30 pct) pops Friday mainly near/east of U.S. 127 and near/south of I-94 since the sfc front stalls out and there is still some lingering sfc instability (SBCapes 500-1000 J/KG). Otherwise decreasing clouds and a warm Friday expected with highs in the upper 70s. May have to consider a risk of patchy fog Friday night in light wind/clear sky regime. - Dry and Mild Weekend High pressure moves into the region resulting in dry weather this weekend. An 850mb thermal ridge peaking at +12 to +14C moves overhead Saturday and Sunday resulting in high temperatures into the 80s with plenty of sunshine. - Active Weather to Start the Work-Week A deepening longwave trough will eject out of the Rockies at the start of the work week sending a series of shortwaves through the Great Lakes Region. This will result in an active weather pattern through the first half of the week with showers and storms possible. The first round of storms will move through Monday evening as a front sweeps through the area. Instability looks sufficient ahead of the front to support some showers and storms Monday evening, but the better chance appears to be Tuesday afternoon and evening. As a more potent shortwave moves overhead, a surface low will track through WI into the UP while a trailing cold front sweeps through the state. Instability will build throughout the day Tuesday ahead of the front while a 40 to 50 knot Low Level Jet noses into Michigan during the evening. Model guidance has yet to come into good agreement therefore confidence remains low, but Tuesday may be a day to monitor the the potential for strong to severe storms in the area. Temperatures will drop closer to normal (normal highs are around 70) Wednesday and Thursday following the passage of the front. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 127 AM EDT Fri May 17 2024 VFR conditions were noted across the terminals, but that will likely change as the overnight progresses. Short range models show a fairly strong signal for IFR cigs/vsbys to develop after 08z especially at MKG which may see some fog develop over the lake and advect inland. Current dewpoint depressions are in the 2-3 degree range and recent spotty rains may help to speed the development of some stratus. Conditions will improve during the late morning. && .MARINE... Issued at 955 PM EDT Thu May 16 2024 A few showers and storms are possible overnight mainly north of Grand Haven, but this is looking less likely than it did earlier. Meanwhile, what does look likely is the development of fog overnight. By daybreak, we could be looking at dense fog conditions that persist through late morning. Otherwise, light west winds continue. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ UPDATE...AMD DISCUSSION...Meade/Thielke AVIATION...04 MARINE...AMD