516
FXUS63 KGRR 070802
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
302 AM EST Sat Mar 7 2026
.KEY MESSAGES...
- Storms sweep through the area this morning
- Mid week system to bring rain
- Turning colder behind the mid week low with chances for snow
&&
.DISCUSSION...
Issued at 302 AM EST Sat Mar 7 2026
- Storms sweep through the area this morning
A cold front is sweeping east into portions of Western Wisconsin
and Eastern Iowa at 230am. Temperatures ahead of the cold front
in the warm sector over Illinois are in the middle 60s which is
obviously anomalous at this time of night in early March. The
warmth is being brought northward via a strong low level jet at
850mb on the order of 60 knots. The low level jet is forecast to
sweep east through Southwest Lower Michigan between 400am and
1000am. It is during that time frame where we expect storms to
sweep through. In terms of instability we certainly have enough
for convection as both the HRRR and the SPC mesoanalysis page
indicates 1000-1500 j/kg of MUCAPE to work with. Hodographs are
showing plenty of shear with 50 knots of deep layer shear (0-6km).
The bulk of that shear is in the 0-1km layer. So in the
CAPE/Shear balance both factors are well accounted for. Looking
at forecast soundings though there is a low level stable layer in
place, so not sure spin ups are much of a threat. Strong winds
and hail are certainly higher threats, although the stable layer
will aid to inhibit winds to the surface a bit. Given the strength
of the wind fields with adequate instability we will be
monitoring storms closely for all threats this morning. We are
still in a marginal threat for severe storms through 12z by the
SPC.
We will likely see another quarter to half inch of rain this
morning as the storms move through. This will add to rising river
levels. We issued a River Flood Warning for Sycamore Creek in
Holt. Not expecting many more warnings, but could be another one
or two depending on how things play out. We will be watching the
Red Cedar in East Lansing closely. Storm totals thus far have been
highest from the Grand River basin southward where 1-2+ inches of
rain has been fairly common.
- Mid week system to bring rain
A mid week system will move through the region bringing rain from
Tuesday afternoon into Wednesday. The GFS has a further south
track of the low (more along the MI/IN line) versus the ECMWF that
takes the low further north into the state. The differences in
track result in the GFS having more in the way of snow across
Central Lower Michigan whereas the ECMWF is mainly rain. At this
point feel the ECMWF is the way to go with more rain than snow.
That said, both models pull in colder air behind the system with
rain changing to snow before it ends. Only light accumulations of
snow are expected for the most part (an inch or less).
- Turning colder behind the mid week low with chances for snow
The colder air that is pulled in behind the Tuesday/Wednesday
system will linger into the end of the week when a clipper quickly
moves through the Great Lakes. This system has a chance to put
down a swath of snow but at this point the track is not certain.
The ECMWF is the further south bringing us better chances for
snow. We have time to keep an eye on this system and dial in the
track as we move forward.
Bottom line a bit of an up and down forecast with warmth to start
the 7 day period and colder air with snow towards the end of it. A
pretty typical scenario for early spring in the Great Lakes.
&&
.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1232 AM EST Sat Mar 7 2026
We are looking at more unsettled weather for much of the next 24
hours. We are in a relative break at press time as the widespread
showers/storms have moved east of the area for the time being.
There are a few light showers popping up, and could affect the
terminals, but the impacts should be minimal with VFR conditions
expected. Low level wind shear is present at all sites except KMKG
with 40-45 knots of wind 1-2k ft agl. KMKG is seeing these winds
making it to the sfc a bit, so have not included it there.
We do expect a line of showers and storms to begin moving over the
area from West to East after about 09-10z. This looks to be about
3-4 hours of showers/storms with IFR conditions likely with rain
and reduced visibilities under the heavier rain. There will be a
few more showers possible for a few hours after that until the
front moves through. Lower clouds will move in, and will hold on
even behind the front. Winds will be gusty from the SW ahead of
the front, and will switch to become from the WNW. These winds
will diminish toward or after sunset. Ceilings will slowly
improve, and will likely be MVFR by the end of this forecast
period.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...Duke
AVIATION...NJJ
NWS GRR Office Area Forecast Discussion
