637
FXUS63 KGRR 240800
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
400 AM EDT Fri Apr 24 2026
.KEY MESSAGES...
- Showers and storms today
- Dry weekend then another chance for showers and storms on Monday
- Cooling off through the upcoming work week
&&
.DISCUSSION...
Issued at 400 AM EDT Fri Apr 24 2026
- Showers and storms today
Showers and storms remain in the forecast today. The precipitation
should be on the lighter side and a bit more scattered this
morning as the precipitation is coming in, in a decaying state.
The moisture push is healthy and so is the low level jet, so we
should see at least some precipitation this morning. Surface dew
points will rise to around 60F this morning with PWAT values
surging from 0.80 inches at 2AM to 1.3 inches at 11AM. The 850MB
LLJ this morning is a very respectable 30-40 knots. Instability
(MUCAPE) is weak, generally less than 500 j/kg this morning with
surface based LIs that are positive. So, while we should see
showers move into the forecast area this morning, there should not
be much in the way of thunder.
This afternoon, the moisture will be in place, but the 850MB jet
backs off to 25-30 knots. The 500mb mid level jet is also
decreasing in speed through the course of the day which in turn
keeps deep layer shear less than 25 knots. Bottom line we will see
showers move through the area today with thunderstorm chances
increasing this afternoon especially from Highway 131 to the east.
Threat for severe looks low despite an uptick in instability to
around 1,000 j/kg this afternoon in the east towards MOP, LAN and
JXN.
- Dry weekend then another chance for showers and storms on Monday
The weekend looks dry with surface ridging holding on in the wake
of the a cold frontal passage this afternoon and evening. Focus
then shifts to a low pressure system moving our direction from the
plains. The GFS is a little quicker bringing in some precipitation
Monday afternoon, whereas the ECWMF holds precipitation off until
Monday night. This is another surge of 60F dew points and PWAT
values that will be a bit higher than today`s system to around 1.5
inches. At this point timing does not look great for stronger
storms, coming through Monday night. Instability is not high with
MUCAPE values remaining below 1,000 j/kg. We have high pops (90
pct) on Monday night with the system moving east on Tuesday.
- Cooling off through the upcoming work week
The rest of next week will feature upper troughing and cooler
weather. Highs mid to late next week look to be back in the 50s,
which is slightly below normal for this time of year. We should be
mainly dry, but with an upper trough in place in the spring
diurnal showers are certainly possible.
&&
.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 213 AM EDT Fri Apr 24 2026
A cold front will press in from the west this morning and move
through Southwest Lower Michigan this afternoon and early evening.
Rain showers are expected this morning spreading in between 11Z
and 14Z. These showers should be light with conditions mainly
staying VFR. MKG and GRR have a chance at seeing some MVFR
ceilings move in for a time. This afternoon a chance for both
showers and thunderstorms exist with conditions mainly staying
VFR. Timing on the potential for storms will be roughly from 18Z
to 23Z for GRR and AZO to the east. Tonight ceilings will try to
lower into the MVFR category starting at LAN and JXN and working
westward. Winds will be from the south at 5-15 knots early this
morning increasing to 10-20 knots during the midday hours.
&&
.MARINE...
Issued at 400 AM EDT Fri Apr 24 2026
We are expecting conditions to remain below advisory levels
through the weekend. Winds this morning will be southerly and
likely remaining in the 10-20 knot range. This afternoon behind a
cold frontal passage which veer to the northwest and north.
Speeds should remain in the 10-20 knot range as well. North winds
will increase some Saturday afternoon and night which will likely
bump the waves up to 2-4 feet for a time.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...Duke
AVIATION...Duke
MARINE...Duke
NWS GRR Office Area Forecast Discussion