Area Forecast Discussion
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, MI
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253 FXUS63 KGRR 261724 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 124 PM EDT Wed Jun 26 2024 .KEY MESSAGES... - Patchy Fog This Morning - Light Rain Late Morning to Early Afternoon - Showers and storms Friday/Saturday && .UPDATE... Issued at 1122 AM EDT Wed Jun 26 2024 Patchy fog has lifted and the approaching trough continues to stream moisture into the region. Cloudy skies have overspread lower Michigan with scattered showers trekking into southwest Michigan. Any rain will be light but expect it to move from the west to the north east. With a weak jet and a relatively stable atmosphere, more then just general thunderstorms is unlikely. && .DISCUSSION... Issued at 327 AM EDT Wed Jun 26 2024 - Patchy Fog This Morning Still quite a bit of low level moisture around with dewpoints hovering in the mid 60s to low 70s across the area. Shallow fog development still looks possible early this morning but cloud cover streaming in from the southwest will act to limit radiational cooling and extensive fog development. Patchy fog with visibilities down to 2-4 miles looks likely before sunrise, but wouldn`t expect widespread dense fog development at this time. - Light Rain Late Morning to Early Afternoon A northern stream shortwave and associated cold front will act as a trigger for a few showers late morning to early afternoon today. Afternoon instability builds with MLCAPE towards of a few hundred with decent deep layer shear supporting a few storms. Minimal mid-level lapse rates and no substantial low level jet winds will reduce the potential for anything beyond general thunderstorms. High pressure builds in on the backside of the departing trough leading to quickly clearing skies during the afternoon and evening. Conditons stay dry through Thursday. - Showers and storms Friday/Saturday A belt of fast westerlies persists across the northern CONUS through the late week and into next week. Shortwave troughs will bring a chance of rain late Friday into Saturday and again Monday night into Tuesday Surface high pressure center moves east with warm advection pattern developing by Friday morning. Moisture advection is also underway with rain chances increasing Friday afternoon and evening as moisture pools ahead of the advancing cold front. Model consensus still has the greatest chance for showers and storms late Friday night. A severe weather threat may be possible late Friday night into early Saturday as Lower Michigan is in the warm sector and model soundings show 30 to 35 knots of shear ahead of the cold front. The limiting factor is the persistence of convective inhibition Friday night into Saturday. Surface high builds in behind the front with fair weather for Sunday into Monday, then another chance of showers as the next shortwave trough approaches Monday night and Tuesday. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 123 PM EDT Wed Jun 26 2024 We expect VFR conditions to rule for this forecast period, with little to no impact for aviation interests. We have mostly mid and high level clouds over the area early this afternoon. There have been a few sprinkles coming out of this deck, but nothing of any consequence. The mid and high clouds will gradually clear out from NW to SE this afternoon. As the clearing takes place, winds could become a little gusty with better mixing taking place and a little wind aloft mixing down to the sfc. Skies will stay mostly clear tonight, with a light wind from the NNW. These conditions will continue through the end of the period on Thu at 18z. && .MARINE... Issued at 327 AM EDT Wed Jun 26 2024 Going to be monitoring marine and beach conditions closely today for our typical "Advancing Surface High" scenario. In these types of situations, northwest to north winds build while channeling and funneling down the lakeshore against the dune bluffs. Wind speeds also tend to overperform due to tight thermal packing on the lakeshore with the cooler waters next to the warmer land surface. This results in a tighter pressure gradient right along the lakeshore. Winds will build towards 20 to 25 knots with gusts towards 30 knots at times. Waves will build this morning into the afternoon, peaking near 3 to 5 feet this afternoon and evening at Big and Little Sable Points. We will want to monitor beaches south of Whitehall for wave development, but the curvature of the lakeshore may spare more southerly beaches from the worst of the waves. We will go with SCA and BHS for Mason and Oceana Counties, but will monitor wave forecast trends closely in case headlines need to be extended further south. The northerly winds will make beaches on the north sides of north piers particularly dangerous due to structural currents and turbulent wave action. This includes Sterns Park in Ludington and Mears State Park in Pentwater within the Beach Hazards Statement. Muskegon State Park, Holland State Park, and North Beach in South Haven will also need to be monitored closely today. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Beach Hazards Statement until 11 PM EDT this evening for MIZ037- 043. MARINE...Small Craft Advisory until 11 PM EDT this evening for LMZ848-849. && $$ UPDATE...Ceru DISCUSSION...Ostuno/Thielke AVIATION...njj MARINE...Ceru/Thielke