840 FXUS63 KGRR 211747 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 147 PM EDT Thu May 21 2026 .KEY MESSAGES... - Periodic rain chances late Friday through Sunday - Mainly dry early next week with warming temperatures && .DISCUSSION... Issued at 304 AM EDT Thu May 21 2026 - Periodic rain chances late Friday through Sunday Upper ridging and high pressure at the surface are dominating the weather for the forecast area this morning. We do have high clouds based around 15k ft agl floating overhead preventing a mostly clear sky from being experience this morning. Some low clouds are also floating from east to west. The low and mid/high clouds are separated way too much for any precipitation to occur in the cloud and make it to the sfc. The mid clouds will hold through Friday also, before we see deeper moisture move in over the area ahead of the next system approaching the area. This will eventually lead to more widespread rain moving in by Friday night. This will be the result of a short wave that moves toward the area from the SW. The short wave itself is not that strong. However with it moving ahead of a stronger low to the NW, it will strengthen a bit. This will strengthen the sfc low, and strengthen the flow ahead of the low from the Gulf up into the area. This looks like a more widespread rain Friday night and Saturday morning, before it tapers off from SW to NE Saturday afternoon. Instability is quite weak, with not enough present to include a chance of storms at this time. The system will then move away from the area Saturday afternoon, allowing the rain to taper off temporarily. Showers and a few storms will move in for Sunday. These will be the result of the upper low over the Upper Midwest that will get dislodged, and will move through Sunday afternoon. Instability is once again not impressive, but may just barely be unstable enough to trigger a rumble of thunder during peak heating. - Mainly dry early next week with warming temperatures We will see a nearly zonal upper flow then set up for a couple of days in the wake of the Saturday system and Sunday short wave that moves through. This flow will not be conducive to good chances of rain, but it will not allow for completely dry conditions either. Monday and Tuesday will see some potential weak short waves embedded in the flow. These combined with peak heating and lake breeze boundaries could pop a shower off. The small chances of rain Monday and Tuesday afternoons should diminish for Wednesday and Thursday. This is because we see the strong ridge over the Western states get pushed east by a strong upper low over the Eastern Pacific. The rising heights from the ridge building will squash any convection that would try to develop, and also warm temperatures through the period. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 145 PM EDT Thu May 21 2026 VFR conditions will dominate the pattern for the next 24 hours. Some gust winds will continue with minor wind shifts through the afternoon. Winds will subside around sunset. There is a very weak jet aloft, around 30 to 35 kts overnight .However it is not strong enough to warrant LLWS in TAF. Winds will remain out of the east becoming gusty tomorrow morning. .MARINE... Issued at 304 AM EDT Thu May 21 2026 We are not expecting to need any marine headlines for the next few days. High pressure situated just north of the area has brought in offshore flow. This is expected to hold through at least Saturday. Winds will not be enough to justify a SCA for our area, and waves surely won`t with the offshore flow. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...NJJ AVIATION...Ceru MARINE...NJJ

NWS GRR Office Area Forecast Discussion