293
FXUS63 KGRR 252310
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
710 PM EDT Thu Jun 25 2026
.KEY MESSAGES...
- Scattered afternoon/evening storms north
- Building heat
&&
.DISCUSSION...
Issued at 136 PM EDT Thu Jun 25 2026
- Scattered afternoon/evening storms north
Radar shows scattered convection as developed over the northern
cwa near US-10. We`ll continue to monitor for the potential for
isolated severe storms as there is sufficient instability,
moisture, but marginal shear values. These showers/storms will
dissipate after sunset.
- Building heat
The developing story across the Great Lakes will be the building
heat that will likely result in heat headlines next week.
A deepening upper trough over the northern Rockies will result in
a building ridge over the central US including the Great Lakes. H8
temperatures are expected to increase from 18C Monday to 24C late
Tuesday. That type of heat will send surface temperatures into
the lower to mid 90s for much of next week. Most models increase
dewpoints into the lower to mid 70s during the heat wave which
will make the air feel incredibly humid. The high heat and
humidity may result in scattered convection if the cap doesn`t
become too strong. Overall, though, we don`t anticipate much
precipitation next week due to short waves riding over the top of
the ridge well north of the cwa.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 710 PM EDT Thu Jun 25 2026
Other than some lingering Cu, mid to high clouds will dominate the
first 6-9 hours of the forecast period. Then, nocturnal cooling
and a light north-northeast flow off of Huron will lead to fog and
low cloud development. Primarily MVFR conditions are expected
though some IFR is possible, especially at KLAN (where a 10%
chance of LIFR also exists). Any low clouds and fog dissipate
Friday morning before diurnal Cu development occurs again Friday
afternoon. Wind gusts will taper near or shortly after sunset
tonight. A lake breeze is also expected at MKG and possibly AZO
supporting a period of westerly winds Friday afternoon, with
easterly flow otherwise dominant Friday.
&&
.MARINE...
Issued at 136 PM EDT Thu Jun 25 2026
A weak pressure gradient will limit marine issues as we move
toward the weekend. However, dewpoints in the 70s over cold water
may result in dense fog by the end of the weekend through much of
next week.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...04
AVIATION...Thomas
MARINE...04
NWS GRR Office Area Forecast Discussion
