134 FXUS63 KGRR 060454 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 1154 PM EST Thu Mar 5 2026 .KEY MESSAGES... - Fog Likely Tonight - Strong to Severe Storms Possible Friday Afternoon and Night - Above Normal Temperatures Through Mid Next Week - System Mid-Next Week May Bring Chances For Thunder and Snow && .DISCUSSION... Issued at 237 PM EST Thu Mar 5 2026 - Fog Likely Tonight Robust low-level moisture will keep cloud cover persistent through the rest of the day into tonight. It is likely, similar to this morning, that fog will form again overnight tonight. In addition, patchy drizzle is also possible. Fog could be locally dense at times, impacting the morning commute on Friday. - Strong to Severe Storms Possible Friday Afternoon and Night Attention then turns to the potential for two rounds of strong to severe thunderstorms. Round one will be Friday afternoon into the early evening, and round two will be early Saturday morning. Round 1: Friday Afternoon/Evening Strong low-level advection thanks to a 50-60 knot LLJ will drive a warm frontal boundary north across the area Friday afternoon. Latest high resolution model guidance suggests that convective development along the warm front in the form of one or more QLCSs/multicellular clusters is likely after 2-3pm Friday. The key forecast question for this round is will the warm sector reach far enough north for this convection to be surface based. If the strong advection can win out, potentially over 1000 joules of CAPE will support the chance for strong to severe thunderstorms. However, if the advection is not able to overcome the entrenched stable airmass, the severe threat will mainly remain south and west of the area, though isolated hail will be possible. Damaging winds to 60 mph and large hail to 1 inch are the most likely hazards. Given the strong low-level and deep layer shear and warm frontal boundary across the area, a brief weak tornado or two is possible if storms can become sufficiently surface based. The very moist ambient airmass also suggests heavy rain is possible in any thunderstorms. Any storms should clear the area by mid-evening. Round 2: Saturday Morning Round two will be pre-cold frontal convection expected to arrive after 2am Saturday in the form of one or more QLCSs/multicellular clusters. Guidance is split on how much instability persists to fuel potential strong to severe storms when storms arrive. If we can get severe storms, hail to 1 inch is the primary concern. If we can break through low-level stability damaging winds to 60 mph are possible. Cannot rule out rotating storms Saturday morning however hodographs become weak in the 1-3km range overnight keeping the risk low. Storms should clear the area to the east within an hour or two of daybreak Saturday. Once again, confidence is lower in severe potential with instability being the main complicating factor. If the instability does not materialize, this limits the severe threat. Heavy rain is once again also possible in any thunderstorms. - Above Normal Temperatures Through Mid Next Week Ensemble guidance suggests we are moving into a notably warmer pattern late this week into the first half of next week. Highs, normally in the upper 30s/low 40s, will be in the 50s and 60s the next several days. Can`t rule out temperatures approaching 70 at times across our southern forecast area. This will be associated with low-level warm advection ahead of our next system that arrives mid-week. - System Mid-Next Week May Bring Chances For Thunder and Snow Ensembles are in good agreement on a mid-level trough arriving mid- next week with a surface low developing out ahead of it. Depending on where the low-level baroclinic zone and associated warm sector sets up, the strong dynamics means we will have to watch for the potential of organized convection Tuesday. Behind the system, much colder air filters in as 850mb temps fall below zero. This will lead to rain mixing with or changing over to snow as the system departs Wednesday. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1154 PM EST Thu Mar 5 2026 Widespread LIFR conditions expected overnight into Friday morning. Showers and thunderstorms move in from the southwest during the late morning and any steady rain should result in conditions possibly improving to IFR by afternoon. Winds will be around 5 to 10 knots from the southeast overnight to south-southwest during the afternoon. && .CLIMATE... Issued at 237 PM EST Thu Mar 5 2026 Record High Temperatures... Friday March 6th... Grand Rapids... 68 (1983) Lansing... 65 (2009) Kalamazoo... 72 (1983) Battle Creek... 68 (1973) Holland... 72 (1983) Muskegon... 67 (1983) Saturday March 7th... Grand Rapids... 72 (2000) Lansing... 74 (2000) Kalamazoo... 76 (2000) Battle Creek... 76 (2000) Holland... 71 (2000) Muskegon... 64 (2000) Record Warm Lows... Saturday March 7th... Grand Rapids... 53 (2012) Lansing... 50 (2012) Kalamazoo... 50 (1983) Battle Creek... 51 (1973) Holland... 56 (2012) Muskegon... 50 (2012) && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Thomas AVIATION...Ostuno CLIMATE...Thomas

NWS GRR Office Area Forecast Discussion