770
FXUS63 KGRR 101730
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
130 PM EDT Sat Oct 10 2026
.KEY MESSAGES...
- Breezy and warm today into Sunday
- Warm weather through Monday; remnants of Isaias shift east
- Pattern change Tues; strong system through latter half of week
&&
.DISCUSSION...
Issued at 253 AM EDT Sat Oct 10 2026
- Breezy and warm today into Sunday
Warm air advection showers continue to bring light rain early this
morning through central lower Michigan. A ridge of high pressure
will build over the Great Lakes and southern Canada today as warm
air advection continues to stream into the area. As the warm air
mixes out the inversion, expect gusty winds, upwards of 25 mph,
this afternoon.
850 mb temps of +15C will mix down bringing temps upwards of 15
to 20 degrees above normal, peaking in the upper 70s to
potentially the low 80s.
- Warm weather daytime Monday; remnants of Isaias shift east
The warming trend will continue through Monday. Sunday temps will
be slightly cooler due to the cloudy skies from the fringes from
the remnants of Isaias.
Ensembles continue to shows Isaias track shift to the southeast,
with it moving through the Mid Atlantic early Monday.
Part of the reason this is occuring is due to a positively tilted
ridge that will continue warm air advection that will keep max
temperatures 10 to 20 degrees above normal through daytime Monday
- Pattern change Tues; strong system through latter half of week
Models are showing a flattening of the ridge Monday night into
Tuesday with a more zonal upper level flow. Mid to low level low
pressure will move through Michigan into Tuesday with a strong
moisture boundary extending from New York, through the Great Lakes
and into the Upper Mid West. The best moisture late Monday into
Tuesday will remain to the north. However, can`t rule out some
scattered showers Monday night into Tuesday, especially as a
deepening trough swings through daytime Tuesday. There should be
enough instability for a chance of storms with this system. EC
ensembles continue to show strong anomalous moisture Monday night
into Tuesday with PWATS of 1.25 to 1.5 inches over the Lower
peninsula.
Expect a more tumultuous pattern through the latter half of next
week. There is some question on timing of the incoming system.
Some of the ensembles vary on where the upper level pattern will
be. Latest EC trends have backed off on how deep the moisture
advects into MI. Though there is a tilted trough that could bring
a strong frontal pattern through the end of the week. All that
said, there is the potential for showers and storms through the
latter half of the week, with the potential for a severe weather
event given the strong flow, copious moisture and warm air out
ahead of the system.
&&
.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 126 PM EDT Sat Oct 10 2026
Cloud cover will continue to thicken as the remnants of the
tropical system move north toward the Ohio Valley. A LLJ passing
to the north early tonight may result in some LLWS. Otherwise,
ceilings will continue to fall to MVFR for most terminals and to
IFR at BTL and JXN as precipitation gets closer. Light rain is
also possible at JXN after 14z.
&&
.MARINE...
Issued at 253 AM EDT Sat Oct 10 2026
Strong southerly flow will ramp up through Saturday. A small craft
advisory will be in effect from Holland and to the north where the
best winds and waves will be. The winds will be stronger aloft due
to the warm air advection. The gradient will then weaken tonight
as Isaias moves through the Ohio Valley and treks through the Mid
Atlantic.
The next headline event should occur Monday due to the increasing
gradient ahead of the next incoming cold front. A pattern change
will allow much of the upcoming week to be windy, especially
through the second half of the week due to an incoming low
pressure system.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 5 AM EDT Sunday for LMZ846>849.
&&
$$
DISCUSSION...Ceru
AVIATION...04
MARINE...Ceru
NWS GRR Office Area Forecast Discussion
