127
FXUS63 KGRR 191845
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
245 PM EDT Sun Apr 19 2026
.KEY MESSAGES...
- Freeze Warning Tonight
- Some Storminess by Friday
&&
.DISCUSSION...
Issued at 245 PM EDT Sun Apr 19 2026
- Freeze Warning Tonight
Sharp upper trough moving through today combined with sufficient
low to mid level moisture has resulted in convective updrafts
with scattered showers this afternoon. Lake shadow and high clouds
has prevented widespread deeper updrafts, lowering the potential
for ice pellet/graupel. Showers will diminish end this evening as
the trough axis moves east and with the loss of insolation.
Cold surface high builds in overnight with drying and subsidence
with winds decoupling after midnight. Radiational cooling
conditions become optimal by 12Z with the surface high progged to
be centered over southwest Lower Michigan. A hard freeze is
expected as temperatures will be below freezing for several
hours.
- Some Storminess by Friday
The surface high moves east by Tuesday with southerly flow
developing but the moisture return does not immediately result in
precipitation as shortwave ridging is expected during the middle
part of the week ahead of an upper low over the NW CONUS that
eventually moves into Upper Plains and Canada by the end of the
week. A cold front trailing a surface low moving into northern
Minnesota before it occludes and moves into Canada will
concentrate showers on Friday with the chance for thunderstorms
during the afternoon.
&&
.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 200 PM EDT Sun Apr 19 2026
VFR weather is expected through the 24 hour TAF period of 18Z
Sunday to 18Z Monday. Diurnal heating has resulted in fairly
widespread cumulus and altocumulus clouds this afternoon with
bases in the 4,000 to 8,000 foot range. These clouds will continue
to work through the area this afternoon and dissipate this evening
with the setting sun. We are expecting mainly clear skies tonight
and Monday morning. Scattered showers will work through the TAF
sites this afternoon, but these should not affect ceilings or
visibilities much at all as they will move through any one
location fairly quickly. Cannot rule out some small hail in the
deeper convective towers. At this point given the nature of the
showers, we have covered them with VCSH wording. Winds are gusty
at 18Z from the west sustained at 10-20 knots with gusts of 20-30
knots. Winds will decrease substantially as we approach and move
through sunset. Light winds are expected tonight.
&&
.MARINE...
Issued at 245 PM EDT Sun Apr 19 2026
High pressure brings tranquil conditions on Lake Michigan tonight
and Monday. The high will move east and southerly winds increase and
waves will build Monday night. A SCA will be needed from late
Monday through Tuesday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Freeze Warning from 11 PM this evening to 11 AM EDT Monday for
MIZ050>052-056>059-064>067-071>074.
MARINE...None.
&&
$$
DISCUSSION...Ostuno
AVIATION...Duke
MARINE...Ostuno
NWS GRR Office Area Forecast Discussion
