022
FXUS63 KGRR 191816
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
216 PM EDT Tue May 19 2026
.KEY MESSAGES...
- Brief Window For Showers and Storms this Afternoon
- Dry and Cooler Wednesday into Thursday, Frost Possible
- Showers and Storms Return Friday into Saturday
&&
.DISCUSSION...
Issued at 216 PM EDT Tue May 19 2026
- Brief Window For Showers and Storms this Afternoon
Thunderstorms have developed east of a Kalamazoo to Lansing line.
It is in this area where surface based CAPE is highest (1500 to
2000 J/kg) with shear values around 35 knots. This is also in the
area of better moisture convergence. Downdraft CAPE values are
also around 1000 J/kg. With these factors strong to severe
thunderstorms are possible through 5pm with damaging winds as the
primary risk and small hail as the secondary. As we head into the
evening our instability and shear move east with dry conditions
moving in behind the cold front.
- Dry and Cooler Wednesday into Thursday, Frost Possible
High pressure builds in for Wednesday and Thursday with highs in the
mid 50s to 60s. Within this cooler air mass frost is possible
Wednesday night into Thursday morning mainly for inland and northern
portions of the forecast area. There is a 20 percent chance that
areas along and north of US-10 for temperatures at or below
freezing. If winds stay in the 5 to 15 mph range overnight, frost
would not be a concern.
- Showers and Storms Return Friday into Saturday
Low level moisture returns ahead of a shortwave trough expected to
move through Friday afternoon into Saturday morning. This will bring
another round of showers and storms to the area with drier
conditions trending for the rest of the weekend into next week.
There is decent agreement as seen in the cluster analysis with most
members keeping the area dry with temperatures warming up again into
next week.
&&
.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 138 PM EDT Tue May 19 2026
Shower and thunderstorm cells are developing in the vicinity of
JXN and pose a risk of microbursts with locally gusty winds around
40 knots over the next few hours before moving east toward Ann
Arbor and Detroit. Showers with a lesser chance of a thunderstorm
exist around AZO, BTL, and LAN for the next couple hours.
Otherwise, the weather of note for this forecast period includes
gusty southwest winds becoming northwest this evening, and also
areas of MVFR ceilings through Wed morning.
&&
.MARINE...
Issued at 216 PM EDT Tue May 19 2026
Winds and waves will gradually come down this evening with some
isolated Small Craft Advisory gusts through the overnight. If winds
trend lower the Small Craft Advisory could end earlier. A brief
period of northerly Small Craft Advisory winds and 4 foot waves is
possible Wednesday afternoon. Otherwise, easterly winds will keep
wave heights down through the remainder of the week.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 8 AM EDT Wednesday for LMZ844>849.
&&
$$
DISCUSSION...RAH
AVIATION...CAS
MARINE...RAH
NWS GRR Office Area Forecast Discussion
