FXUS63 KGRR 192353 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 753 PM EDT Sun May 19 2019 LATEST UPDATE... Aviation .SYNOPSIS... Issued at 330 PM EDT Sun May 19 2019 -Showers and thunderstorms ending this evening -Breezy and Chilly Monday; patchy frost possible Monday night north of I-96 -Rebounding temperatures for mid to late week with shower and thunderstorms potential returning. && .DISCUSSION...(This evening through next Sunday) Issued at 330 PM EDT Sun May 19 2019 Narrow window of potential svr tstms with damaging winds still exists between 4 PM and 9 PM this evening as mid level shortwave and sfc cold front come through the area. High shear/low cape environment with MLCapes only around 500 J/KG but 0-6 KM shear of 70-75 kts. A brief area of clearing is now spreading in from the west and upstream storm reports indicate a history of localized svr wind gusts around Milwaukee and Chicago. This scattered convection may temporarily weaken over the cold waters of the Lk MI but then re- intensify again once over land in wrn Lwr MI. Latest CAMs indicate a scattered to broken line of strong convection along the lakeshore at 21Z, reaching the LAN/JXN areas around 00Z. Poor mid level lapse rates of 5.5 to 6 C/KM are a limiting factor, but if line of storms can somehow congeal and develop a cold pool, the damaging wind threat will increase as the storms move east at nearly 50 kts early this evening. Storm threat ends after 9 PM then dry but breezy and turning cool tonight. Extensive low level cloudiness will pour in late tonight and early Monday behind the front, lingering much of tomorrow. Incoming sfc ridge should bring decreasing clouds mid to late afternoon as well as diminishing winds. Will need to consider a potential frost advisory for Monday night up north with light winds and clr skies under the sfc ridge. Warm front will start lifting back north late Tuesday night and Wednesday, bringing our next chance of showers and tstms. Thursday and Friday look like warm/humid days with the warm front probably to our north, but isolated diurnal showers or storms could still develop. The upcoming holiday weekend could feature periodic showers and tstms with the frontal boundary draped across the region. Daily high temps will be tricky since cool readings are likely north of the boundary with summerlike readings and humid conditions to the south. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 753 PM EDT Sun May 19 2019 Still a couple hours of showers and tstms for areas east of a AZO to LAN line this evening. Expect widespread MVFR and gusty winds near cells, with IFR vsbys possible in any heavier downpours. Otherwise VFR will prevail for several hours this evening behind/west of the departing convection. Widespread MVFR cigs and local IFR cigs overspreading the region from the west/northwest after 06Z tonight. MVFR cigs remaining in place much of Monday although improving to VFR from west to east in the mid to late afternoon. Gusty west winds to 25 kts tonight becoming northwest on Monday. && .MARINE... Issued at 330 PM EDT Sun May 19 2019 No change to the Small craft Advisory. Still concerned about some potential beach erosion tonight with westerly wind trajectory behind the cold front and 4-6 ft waves, but confidence not high enough to issue Lakeshore Flood Advisory. Winds and waves diminishing late Monday and especially Monday night. && .HYDROLOGY... Issued at 330 PM EDT Sun May 19 2019 Rainfall since the locally heavy rainfall Friday night has been limited in nature, with no real impacts for most areas. The exception to this has been at Vicksburg where the level has come up to near flood stage. Emergency Management and river observers indicate no threat to homes or people, so we have held off on headlines for now, and will continue to monitor. We are not expecting any significant amounts of rainfall this evening with the storms, or through the coming work week. There will be a couple of chances of rainfall, however these systems look progressive, and should not have all of the ingredients needed for heavy rain events. Flooding already occurring due to high Lake Michigan water levels may worsen a bit with stiff southwest to northwest winds tonight into Monday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...Small Craft Advisory until 5 PM EDT Monday for LMZ844>849. && $$ SYNOPSIS...Meade DISCUSSION...Meade AVIATION...Meade HYDROLOGY...NJJ MARINE...Meade