918
FXUS63 KGRR 101901
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
301 PM EDT Fri Jul 10 2026
.KEY MESSAGES...
- Lingering Convection across the Southeast
- Upper High builds in early next week
- Storminess possible latter half of next week
&&
.DISCUSSION...
Issued at 300 PM EDT Fri Jul 10 2026
- Lingering Convection across the Southeast
Convergence along and ahead of a surface cold front, along with
diurnal peak heating and resulting instability, will yield
scattered thunderstorms across the southeast quarter of the
forecast area through early evening. Sfc-based CAPE around 1000
J/kg will persist in that area into the evening along with 25 to
30 knots of deep layer shear, so a few organized, persistent
updrafts are possible and some could produce localized downbursts
similar to those observed yesterday. Drier and cooler air advects
in later this evening, putting an end to the storms after sunset.
- Upper High builds in early next week
Drying and subsidence will rule over the weekend and into next
week. A heat dome over the PLains/Upper Midwest builds into Lower
Michigan, peaking on Tuesday before heights fall as upper
troughing amplifies across eastern Canada.
Although thermal profile forecast tools suggest mid 90s are
possible on Tuesday, the current forecast apparent temperatures
do not reach the local Heat Advisory criteria of 100F. This is
mainly due to forecast dew point temperatures not reaching 70
degrees. Recall that dew points were in the mid and upper 70s
during the hot weather at the beginning of the month. So this will
be a comparatively "dry heat".
- Storminess possible latter half of next week
The models have come into better agreement on the development of
a deep upper trough across eastern Canada next week. Heights fall
as the upper high retreats westward beginning Wednesday with
cooler temperatures along with the possibility of ridge-riding
convection Thursday and beyond.
&&
.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 124 PM EDT Fri Jul 10 2026
MVFR cigs are scattering out, with the last terminal (BTL)
reaching VFR around 18z. VFR conditions then continue through the
rest of the TAF period with one caveat. There is a 30% chance of
thunderstorms around the I-94 terminals through early evening, and
if one impacts a terminal a brief period of MVFR and lower
conditions is likely. Northerly winds to 3-8 knots today become
northeasterly for Saturday.
&&
.MARINE...
Issued at 300 PM EDT Fri Jul 10 2026
North winds will gust to near 20 knots this evening as high
pressure builds in and then decrease after midnight. Winds go more
northeast and offshore later tonight and Saturday generally less
than 15 knots. Wave action will be minimal until early next week
when southwest winds increase to near 20 knots.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...Ostuno
AVIATION...Thomas
MARINE...Ostuno
NWS GRR Office Area Forecast Discussion
