387 FXUS63 KGRR 272332 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 732 PM EDT Fri Mar 27 2026 .KEY MESSAGES... - Cold Through Saturday; Snow Showers Tonight - Stormy Stretch Possible Monday Night Through Tuesday Night - Turning Cold Again Wednesday/Thursday; More Rain Possible Later && .DISCUSSION... Issued at 231 PM EDT Fri Mar 27 2026 - Cold Through Saturday; Snow Showers Tonight Deep N/NW flow over the Great Lakes has settled in and temperatures will stay well below seasonal norms through Saturday. RAP13 guidance is showing 850mb temps bottoming out near -15C in the 06z-12z Saturday time frame. Lows Saturday morning will dip into the upper teens to low 20s and highs will be in the upper 30s to low 40s. On the cusp of a reinforcing cold front sweeping through in the 00z-06z time frame tonight, snow showers will likely develop. Based on RAP13 guidance, there is a 1 to 2 hour period at any given location (mainly near/north of I-96) for a decent burst of snow given some significant lift (ie. -10 to -20 ubar/s) within the DGZ. Given this will happen after dark and with the antecedent cold temperatures in place, a few tenths of an inch of snow will be possible (locally > 0.5" near US 10) with brief impacts to travel not out of the question. - Stormy Stretch Possible Monday Night Through Tuesday Night Both ensemble and deterministic model guidance are centering in on the Monday night through Tuesday night period as the next opportunity for rain and likely some thunderstorms as well. By Monday, model guidance is in good agreement on a warm front lifting north through the region. While initially we stay dry as this occurs, by Monday night there will be a broad and intense LLJ with Gulf origins rapidly advecting moisture towards the Great Lakes. GFS/ECMWF guidance is indicating 50-60 kts. This occurs ahead of an approaching shortwave trough into the upper Midwest with an impressive mid level jet of 60-80 kts. Further up, the right entrance region of a 150 kt ULJ approaches Michigan. Synoptic support will certainly be there for organized convection Monday night into Tuesday night. A round of showers and thunderstorms is likely Monday night into Tuesday morning, with a combined ECE/GEFS/CMC ensemble probability of 80% for 0.25" or more and 50-60% for 0.50" or more. Depending on when morning activity moves out, some surface-based destabilization could occur Tuesday out ahead of a cold front that will likely sweep through Tuesday night or Wednesday morning. Given timing differences in model guidance at this range, there is uncertainty regarding this destabilization scenario. If it does occur, strong to severe thunderstorms could develop. NCAR`s AI-based NWP convective hazards forecasts indicate severe weather potential on Tuesday stretching from Missouri to Michigan. This is contingent on factors that are not able to be resolved this far out, so trends will need to be monitored. - Turning Cold Again Wednesday/Thursday; More Rain Possible Later The early spring temperature roller coaster looks to continue next week after reaching the 60s and 70s Monday into Tuesday and then dropping into the 40s Wednesday into Thursday. Adding to the return of crisp air will be a fairly steady N/NE breeze midweek making temperatures feel like the 30s during the day and colder at night. Ensemble guidance has varied solutions by late in the week but in general there is some support for another upper trough to swing through with low level moisture flux ahead of it, supporting perhaps another round of rain late in the week or weekend. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 728 PM EDT Fri Mar 27 2026 Radar shows light snow showers moving toward the region. Upstream obs suggest the southern extend of the precipitation is evaporating but visibilities have dropped to a mile or less over northeast WI. We`ve kept the prob30 group for the potential of 5sm -sn for a few hours this evening. Short range models indicate the length of snow will be 4-5 hours, but most likely north of the terminals. Generally VFR through the period. && .MARINE... Issued at 231 PM EDT Fri Mar 27 2026 Another period of hazardous conditions to small craft sets up tonight into Saturday morning as northwest flow increases. Waves are expected to build into the 3 to 5 foot range with some 6 footers possible. Waves subside by midday Saturday and early Saturday afternoon only to build again Saturday night into Sunday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Small Craft Advisory until 10 AM EDT Saturday for LMZ844>849. && $$ DISCUSSION...Hoving AVIATION...04 MARINE...Hoving

NWS GRR Office Area Forecast Discussion