338
FXUS63 KGRR 030616
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
216 AM EDT Fri Jul 3 2026
.KEY MESSAGES...
- Heat Risk Gradually Diminishes
- Chances for Storms Continue Through the Holiday Weekend
&&
.DISCUSSION...
Issued at 313 PM EDT Thu Jul 2 2026
- Heat Risk Gradually Diminishes
Subsidence and drying from this morning`s dying convective system
has left behind dew points in the mid 60s in central MI, while
closer to I-94, dew points are still in the mid 70s with heat
indexes around 100. With the exception of Ludington, it`s still
hot, but the somewhat drier air gives an opportunity to chisel
away at the Extreme Heat Warning along and north of a Muskegon to
Clare line. The remaining warning will turn over to a Heat
Advisory this evening through Friday morning as moderate to high
heat risk continues as the heat wave potentially stretches into a
fifth day in southern portions of Michigan. While some noticeable
humidity will remain, models are locked in on temperatures
trending closer to normal by early next week, given the weakening
of the SE US heat dome and a tendency for weak upper level
troughing over the Great Lakes.
- Chances for Storms Continue Through the Holiday Weekend
Unsettled weather continues with fairly low confidence in the
predictability of thunderstorms given weak forcing mainly driven
by upstream convective complexes and their associated induced
atmospheric waves. The drier air and strong cap present this
evening will keep the chance of storms very low, though can`t rule
out a shower popping up near Battle Creek or Jackson. The storm
complex in eastern Iowa will track toward west/southwest Michigan
for late this evening/tonight, though its intensity when it
arrives is very much in question. Any threat would primarily be
wind, as there will be weak cloud-layer shear but substantial
DCAPE.
The chances for additional storms remains for Friday
afternoon/evening, particularly in southern Michigan, followed by
scattered storms popping up through the remainder of the weekend
as a larger-scale weak upper level trough deepens over the Great
Lakes. A majority members of the ECE and GEFS are fairly bullish
on the precip chances through at least Saturday night.
&&
.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 216 AM EDT Fri Jul 3 2026
VFR weather is in place across most of the region at 06z. The
exception is in some very localized thunderstorm activity across
the Southern Great Lakes stretching from Northern Illinois into
Southern Lower Michigan. Isolated to scattered thunderstorms are
expected to continue across Southern Lower Michigan the rest of
the night impacting the I-94 TAF sites. The I-96 TAF sites will
likely remain north of the activity. A lull in the showers/storms
will likely occur during the morning hours of Friday after
sunrise. During the afternoon and evening we expect another round
of showers and storms to mainly affect the I-94 TAF sites between
roughly 20z and 03z. Winds will be southwest at 5-15 knots today
with some gusts to around 20 knots in the afternoon.
&&
.MARINE...
Issued at 313 PM EDT Thu Jul 2 2026
Mostly a lighter south/southwest flow over the lake has kept us
out of beach hazards today. Smaller zones of 15 knot winds over
the lake could build waves to 2 to 4 feet with a moderate swim
risk this afternoon between Muskegon and Ludington. Otherwise,
outside of any thunderstorms, a lighter wind regime through the
holiday weekend will keep wave hazards low.
There is a chance of scattered thunderstorms crossing the late
tonight and again later in the day Friday. Wind gusts and
lightning will be the main threats.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Heat Advisory until 8 PM EDT this evening for MIZ046-051-052-
056>059-064>067-071>074.
MARINE...None.
&&
$$
DISCUSSION...CAS
AVIATION...Duke
MARINE...CAS
NWS GRR Office Area Forecast Discussion
