948
FXUS63 KGRR 122318
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
718 PM EDT Thu Mar 12 2026
.KEY MESSAGES...
- Snowfall through Central Michigan Early Friday
- High Winds Across Southern Lower Michigan Tomorrow
- Significant Late Winter Storm Possible Sunday into Monday
&&
.DISCUSSION...
Issued at 259 PM EDT Thu Mar 12 2026
- Snowfall through Central Michigan Early Friday
Bottom Line Upfront: Have issued a Winter weather advisory for
most of the US 10 Corridor and extended it southward to include
Mecosta and Isabella counties.
The Alberta Clipper system remains on track with a deep low that
is still expected to move through northern Michigan. There is
still a question about how much snow will accumulate. However, The
strong gradient, QPF of upwards of 0.80, and a 2 to 3 KFT DGZ
should allow for inch per hour rates at times from 06Z until
around 15Z. Strong mixing and lapse rates through the DGZ will
help. Considering this is occuring in the pre dawn hours
expecting 4 to 6 inches with locally higher amounts possible north
of the US 10 corridor, especially in any higher elevations. Any
snow accumulations southward will be limited with at most an inch
closer to the I 96 corridor.
- High Winds Across Southern Lower Michigan Tomorrow
Models continue to show a highly anomalous gradient associated
with this low which will begin with strong southerly flow out
ahead of it. It will then sweep across southern Lower Michigan
tomorrow. Mid range models are in fair agreement with lapse rates
of over 9.0 C/km near the SFC in some locations which would mix
down 50 to 60 mph winds. Any precip loading will further add to
the winds. The upper level low is tracking through the Upper
Peninsula mid day tomorrow with downsloping winds and cold air
advection adding to the winds. Winds throughout the day will be
gusty, though there will be two peaks; the first on the onset as
the low moves into the area around 12Z and mid to late in the
afternoon with any amplification from a shortwave through the mid
levels. Winds will finally slacken mid to late Friday evening.
- Significant Late Winter Storm Possible Sunday into Monday
Sunday into Monday looks to potentially be one of the more
impactful events of the winter. There remains a lot of questions
but a swath of ice and significant snowfall is possible Sunday
into Monday. A large upper level low will track through the Great
Plains with strong warm air advection Sunday. That warm front will
bring a chance for storms Sunday afternoon. As the low lifts to
the east the cold air along with strong moisture advection will
pivot a swath of moisture across Lower Michigan with a wintry mix
of precipitation across the region. There could be a narrow band
of freezing rain Sunday night through Central Michigan with heavy
snow to the north. Models are beginning to narrow in on the threat
area, but there remains a focus of freezing rain and heavy snow
north of Muskegon to Mount Pleasant Sunday night into Monday.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 718 PM EDT Thu Mar 12 2026
The big story will be the wind with LLWS over 60 knots tonight
into Friday morning. Surface winds will also start gusting over 40
knots late tonight into Thursday with some gusts over 50 knots.
VFR conditions through 06Z then conditions will suddenly drop to
IFR/MVFR by 12Z as snow arrives from the west. Most of the snow
will be across central and northern Lower Michigan where IFR could
persist into the afternoon.
&&
.MARINE...
Issued at 259 PM EDT Thu Mar 12 2026
The marine section will have a gusty restart as a strong upper
level system will move through the region tomorrow. Winds will
increase and will amplify from the south with storm force winds
beginning late this evening. Winds will shift to the west on the
backside of the system tomorrow morning but will continue its
intensity through Friday. Waves will increase to 11 to 16 feet
through Friday, The winds will finally begin to slacken overnight
Friday into Saturday with waves subsiding Saturday morning.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...High Wind Warning from 2 AM to 8 PM EDT Friday for MIZ037-
043>046-050>052-056>059-064>067-071>074.
Winter Weather Advisory from 11 PM this evening to 2 PM EDT
Friday for MIZ038>040-045-046.
MARINE...Storm Warning from 11 PM this evening to 11 PM EDT Friday for
LMZ844>848.
Gale Warning from 11 PM this evening to 11 PM EDT Friday for
LMZ849.
&&
$$
DISCUSSION...Ceru
AVIATION...Ostuno
MARINE...Ceru
NWS GRR Office Area Forecast Discussion
