textproduct: Grand Rapids

KEY MESSAGES

- Severe storm chances today

- Freezing Rain Wednesday Night and Thursday

DISCUSSION

Issued at 302 AM EDT Tue Mar 31 2026

- Severe storm chances today

A wave of low pressure trailing a cold front will impinge on Lower Michigan this afternoon and evening with a chance for strong to severe storms ahead of the front. The best chance will be across the southern half of the forecast area where instability is available and the CAMs show two rounds of convection occurring between 18Z and 00Z as the front pushes south. Both of them have the potential to grow upscale from cellular to linear as they move southeast.

The main threat will be hail in strong isolated updrafts or multicell clusters and severe wind gusts along bowing line segments. The storms will exit to the south as the front clears the forecast area by about 02Z. We will also have to watch for flooding issues if training of storms persists.

- Freezing Rain Wednesday Night and Thursday

Cold high pressure will build in for mid-week as Plains cyclogenesis gets underway with sfc low tracking through Wisconsin on Thursday. This will set up the northeast CWA for another icing event. At this point it looks like icing of a quarter inch is possible in Clare and Osceola Counties. Future trends in sfc low strength and path will be monitored closely.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 159 AM EDT Tue Mar 31 2026

Overview: Complex aviation forecast with multiple aviation concerns within the next 24 hours, including: ongoing low level wind shear (LLWS), multiple rounds of showers/storms - some of which could be strong/severe, MVFR to IFR ceilings and visibilities (esp. within stronger storms), and finally, a wind shift late in the period with a cold front.

Next 6 hours: Tried to hone in on shower/storm potential a bit more, specifically removing the mention for MKG given the current gap...as well as indicate a likely break after 08-10Z between this round and the next round towards mid to late AM. Believe LLWS will persist all sites through dawn (given strong 45-55kt low level jet)- despite rather breezy sfc winds out of the SW at 15-20kt and gusts 20-30kt. Confidence: LLWS & sfc winds - high, showers/storms and resultant ceilings/visibilities/flight cat - medium.

Rest of the period: Expect another round of convection to develop and/or move in from the W by mid to late morning, and continue into the afternoon. Some of this activity could be strong to severe, but will really depend on how details evolve through the morning. Models suggest lowering ceilings, esp. for MKG, but probably elsewhere, as well. However, confidence on specific timing and magnitude of ceiling and visibility drop is quite low. Again...will depend on specific convective trends, but probabilities for at least MVFR conditions are 50-70%, and chances for IFR conditions are 20-50%, highest at MKG. Expect showers and storms to dissipate from NW to SE late afternoon into early evening with the passage of a cold front. This front will turn winds from primarily SWrly during the day, to NWrly by mid to late evening. MVFR to IFR conditions are favored to continue behind the cold front. Confidence: Low to medium.

MARINE

Issued at 302 AM EDT Tue Mar 31 2026

Hazardous winds and waves for small craft are expected much of this week. The current SCA goes through 12Z Wednesday. There will be a possible lull on Wednesday. Winds and waves will pick up again Wednesday night and persist into the weekend,

GRR WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...Small Craft Advisory from 8 AM this morning to 8 AM EDT Wednesday for LMZ844>847.