000 FXUS63 KGRR 231935 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 335 PM EDT Tue Apr 23 2024 .KEY MESSAGES... - Scattered Showers and Storms This Evening - Widespread Freezing Temperatures Wednesday Night - Showers and Thunderstorms Over the Weekend, Warmer && .DISCUSSION... Issued at 335 PM EDT Tue Apr 23 2024 - Scattered Showers and Storms This Evening Scattered diurnal showers and storms expected this evening underneath the cold pool and trough aloft should quickly fade toward midnight. However a few showers could linger past midnight in far eastern sections (Hwy 127) related to a secondary sfc trough rotating south through ern Lwr MI. Clearing skies follow from north to south on Wednesday as cold dry air mass pours in, with sunny skies emerging by early afternoon as sfc dew pts drop into the teens north and 20s south. - Widespread Freezing Temperatures Wednesday Night Guidance has been consistently showing high probabilities for sub freezing temperatures early Thursday morning as sfc high settles overhead with sfc dew pts of 15 to 20 in place. There are some questions regarding cloud cover with the potential for patches of mid and high level clouds floating through the northwest flow aloft. At this time those clouds do not look too extensive or thick and the timing is very late at night. Coldest temps in the mid 20s per NBM are expected to be over the nrn and ern portions of GRR CWFA with temps 29-32 anticipated near and south/west of GRR. Will post an areawide Freeze Watch now given the already high potential. - Showers and Thunderstorms Over the Weekend, Warmer Cold high pressure will bring more freezing temperatures on Friday morning, before moving east with return flow of warmer and moister air beginning Friday afternoon and continuing through the weekend. THe large scale pattern features persistent western CONUS troughing with rising heights to the east. Gulf inflow in the deep southwest flow across the east-central U.S. should help fuel an axis of potentially heavy rains across the greater Mississippi Valley and occasionally into Lower Michigan as surface lows track through the western Great Lakes. ALthough there are the usual timing issues with individual shortwave troughs, ensemble data indicates that the highest chances for rain/thunder appears to be Friday night and again during Sunday with a potential break in the rain coming early next week under shortwave ridging. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 124 PM EDT Tue Apr 23 2024 VFR conditions will continue this afternoon then an increasing chances of showers and some scattered thunderstorms will bring areas of MVFR around 00Z. THe thunderstorms could have localized hail and high winds but the threat is low and coverage is isolated. Ceilings around 1500 to 200 feet AGL is expected overnight with some slow clearing in Wednesday morning. Southwest wilds will gust to near 30 knots at times this afternoon. Winds will go northwest tonight and north by Wednesday morning with some gusts over 20 knots. && .MARINE... Issued at 335 PM EDT Tue Apr 23 2024 South-southwest winds to 30 kts will shift northerly tonight behind a passing cold front and could even briefly flirt with gales. Small Craft Advisory remains in effect through 8 PM Wednesday. Winds and waves subside quickly Wednesday night into Thursday as surface high pressure settles in, then winds increasing out of the southeast late Thursday night into Friday. Southerly flow should prevail over Lk MI through most of the upcoming weekend as a warmer/more humid air mass arrives. It`s quite possible the southerly winds will be strong enough to require small craft advisories, at least at times. Other marine threats over the weekend could include occasional thunderstorms and areas of fog as dew points above 50 arrive atop chilly water temps in the mid 40s. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Freeze Watch from late Wednesday night through Thursday morning for MIZ043>046-050>052-056>059-064>067-071>074. MARINE...Small Craft Advisory until 8 PM EDT Wednesday for LMZ844>849. && $$ DISCUSSION...Meade/Ostuno AVIATION...Ostuno MARINE...Meade

NWS GRR Office Area Forecast Discussion