FXUS63 KGRR 070131 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 931 PM EDT Sun Apr 6 2025 .KEY MESSAGES... - Brief Burst of Snow Monday Morning - Rain/Snow Chances Midweek && .UPDATE... Issued at 930 PM EDT Sun Apr 6 2025 No changes to the going forecast at this time but it should be noted that the new 00Z HRRR has backed off considerably on tomorrow morning's quick snow burst with the cold frontal passage. Will wait for complete 00Z guidance before considering any adjustments to pops, timing, and QPF/SnowAmts. Either way, little in the way of impacts expected. && .DISCUSSION... Issued at 335 PM EDT Sun Apr 6 2025 - Brief Burst of Snow Monday Morning A quick moving cold front will swing through Monday morning. Plenty of lift with this front with saturation reaching into the dendritic growth zone. This will bring a brief burst of snow across the area with amounts under an inch. With the warm surface temperatures not expecting snow to really stick, any accumulations would be limited to grassy surfaces. Visibilities though are expected to fall impacting portions of western and central Michigan for the morning commute. Some light lake effect snow may develop and bring additional light snow toward the US-10 corridor. Slightly higher snowfall accumulations are possible in Mason and Lake counties with amounts in the 1 to 2 inch range. - Rain/Snow Chances Midweek Positive vorticity advection moves in for Wednesday along with some convergence with the low level jet. This will bring a round of rain/snow showers through Thursday as a low pressure system passes us to the south. Temperatures look to warm enough where we see a transition to all rain Thursday afternoon before dry conditions return. && .AVIATION /00Z TAFS THROUGH 00Z TUESDAY/... Issued at 711 PM EDT Sun Apr 6 2025 Impacts to aviation will be minimal for the first 6-8 hours as lingering daytime cumulus and mid-level clouds exit the area. Tonight, a cold front will sweep across the area reaching near KLDM near 09z, KMKG by 11z, and continuing southeast through the morning. A 1-2 hour window of IFR snow showers and MVFR cigs is expected at each TAF site with this front, though the short-term models still vary by an hour or so on when these snow showers arrive. There may also be a brief 1-2 hour window of LLWS with the front due to the change in wind direction at the surface ahead of aloft. However with west to northwest gusts reaching 20-30 knots will preclude LLWS from the TAFs at this time given frequent gusts put all terminals below criteria. Cigs raise to VFR by 18z, though lake effect snow showers develop potentially bringing MVFR or lower conditions to any terminals if they directly impact one. Confidence in direct impacts is low so will stick with prevailing VFR. Gusty northwest winds also continue through the end of the TAF window. && .MARINE... Issued at 335 PM EDT Sun Apr 6 2025 A cold front will move through Monday morning with northwest winds gusting to 30 knots. A brief period of gales is possible Monday morning and early afternoon. Winds and waves will be slow to drop lower than Small Craft Advisory levels Monday night into Tuesday. && .HYDROLOGY... Issued at 335 PM EDT Sun Apr 6 2025 The Red Cedar at East Lansing is slowly falling as expected and is anticipated to drop below flood stage tonight. The Maple River at Maple Rapids has risen above flood stage and is forecast to remain at flood stage through Monday before falling. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Small Craft Advisory from 1 AM Monday to 8 AM EDT Tuesday for LMZ844>849. && $$ UPDATE...Meade DISCUSSION...RAH AVIATION...Thomas MARINE...RAH HYDROLOGY...RAH