372
FXUS63 KGRR 040005
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
805 PM EDT Sun May 3 2026
.KEY MESSAGES...
- Marginal Risk Severe on Monday
- Cool with Frost/Freeze Potential This Week
&&
.DISCUSSION...
Issued at 250 PM EDT Sun May 3 2026
- Marginal Risk Severe on Monday
Southwest flow with modest moisture return and elevated instability
ahead of an advancing cold front is expected to touch off
scattered showers and thunderstorms late Monday afternoon and
evening. Deep layer shear of 35 knots will aid the cause. Any
sustained updrafts could produce hail and strong winds are also a
threat given DCAPE resulting from evaporation of precip in a dry
adiabatic sub cloud layer. The threat diminishes after midnight
as the cold front moves through.
- Cool with Frost/Freeze Potential This Week
The front stalls across the Ohio Valley with a surface low
tracking northeast along the front. At this point it looks like
the precip shield stays east of Lower Michigan. Frost/Freeze
conditions will return for Tuesday and Wednesday nights
Showers are possible on Thursday afternoon and evening as a
shortwave trough and vorticity maximum moves though and model
soundings show wet-bulb zero heights not far off the surface
across the northern zones, so graupel or wet snow is possible
there. Frost/Freeze potential lingers into next weekend and beyond
as a cold northwest flow regime continues.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 805 PM EDT Sun May 3 2026
VFR is expected tonight into much of Monday with patches of clouds
at or above 6,000 feet scattering out this evening. Gusty winds
will diminish tonight as temperatures near the ground cool off,
though about 20 to 30 knots of LLWS will be present in its place
until 06 or 08 Z. Gusty winds are again expected with daytime
heating on Monday. Scattered showers or thunderstorms may develop
late in the day and will pose a microburst / surface gust / wind
shear threat given how well mixed and dry the lower atmosphere
will be beneath the cloud bases.
&&
.MARINE...
Issued at 250 PM EDT Sun May 3 2026
No changes to the SCA. There will be a brief lull tonight then
another SCA will be needed for Monday into Monday night.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until midnight EDT tonight for LMZ844>849.
&&
$$
DISCUSSION...Ostuno
AVIATION...CAS
MARINE...Ostuno
NWS GRR Office Area Forecast Discussion
