660 FXUS63 KGRR 050539 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 139 AM EDT Sat Apr 5 2025 .KEY MESSAGES... - Rain tonight into early Saturday - Cold pattern next week; snow showers Monday - Temps rebounding late next week but showers return && .UPDATE... Issued at 1040 PM EDT Fri Apr 4 2025 Lowered POPs for the next few hours based on radar trends. HRRR and other CAMs show rain blossoming in an area of f-gen moving across Lower Michigan overnight while the heavier convective rains stay south of the forecast area, && .DISCUSSION... Issued at 337 PM EDT Fri Apr 4 2025 - Rain tonight into early Saturday Frontal zone lifts back north through the Ohio Valley region tonight but stays south of MI. Series of lows moving along the front and upper jet entrance region lift brings widespread rain back into the area with the possibility of one or more enhanced FGEN bands. Spread still remains in QPF solutions for this reason but the most likely scenario is for around one quarter to one half inch of rain south and east of GRR. There are still a few ensemble solutions suggesting an inch or more of QPF near I-94 which could lead to some nuisance flooding but since the front and main thunder risk stays to our south the probability of those higher amounts seems relatively low. Most of the rain pulls away by Noon Saturday but a few showers may linger into mid afternoon around JXN. - Cold pattern next week; snow showers Monday Big pattern change on the horizon as deep, moist southwest flow is replaced by northerly flow from almost the North Pole. Recent rainy pattern accordingly transitions to much below temperatures and even some snow. Coldest air will be overhead on Monday and Tuesday when deep longwave trough digs into the GrtLks Rgn and minus 15C H8 air swoops down. The arrival of the "Arctic" front on Monday triggers a band of robust snow showers which may even be followed by a period of NNW flow lake effect Monday night. Some accumulations of an inch or two are possible, with current guidance favoring areas northeast of GR where the best synoptic lift along the front is progged. - Temps rebounding late next week but showers return Aforementioned deep upper trough lifts out midweek and temperatures moderate to closer to normal vales by the end of the week. However additional/renewed troughing aloft is shown and that brings the threat of rain showers back to the region. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 139 AM EDT Sat Apr 5 2025 Low pressure is centered in the Ohio Valley along a frontal boundary tonight. Widespread shower and thunderstorm activity is located near the front off to our south. Southwest Lower Michigan TAF sites will be on the northern periphery of this system. Our impacts will be limited to some light rain and fog and lower ceilings. Conditions should be lowest/worst around 13Z this morning as IFR and potentially LIFR ceilings move through the area. So, we expect a downward trend in ceilings the remainder of the night, then slowly lifting through the day on Saturday with VFR once again at all TAF sites by 22Z. As for visibilities, we feel the heavier more substantial rain will be off to our south so we will likely trend to MVFR visibilities late tonight and into Saturday morning and then back to VFR. In general we are expecting slightly improved conditions as compared to the last set of TAFs. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ UPDATE...Ostuno DISCUSSION...Meade AVIATION...Duke