819
FXUS63 KGRR 070710
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
310 AM EDT Tue Apr 7 2026
.KEY MESSAGES...
- Mainly dry and cool through Wednesday
- Rain Thursday; Rain and Snow Friday
- Dry Saturday, then increasing rain chances through Monday
&&
.DISCUSSION...
Issued at 310 AM EDT Tue Apr 7 2026
- Mainly dry and cool through Wednesday
The cold pool aloft and northern branch of the jet are steadily
moving ENE away from the area this morning. The anti-cyclonic flow
ahead of the incoming upper ridge is bringing strong subsidence to
the area. This will lead to diminishing lake effect low cloud cover
currently across Northern Lower as it tries dropping down over the
area. Temperatures will remain quite cold by early April standards
as the northerly flow is continuing to advect cold and dry air from
Canada.
The ridge overhead early Wednesday should bring plenty of clear
skies by then, with maybe some high clouds advecting in later
Wednesday out ahead of the next incoming system. The far NW corner
of the forecast may see a sprinkle being on the eastern edge of the
stronger warm air advection, but dry low levels will really limit
rain chances at the sfc. The return flow from the south will bring
much more seasonable temperatures Wednesday with highs well into the
50s.
- Rain Thursday; Rain and Snow Friday
We see an abnormally strong upper low currently over British
Columbia that will be dropping ESE toward the area by Wednesday
night. As this system approaches, there is a period late Wednesday
and Wednesday night where it is able to directly tap some good and
deep moisture in the lower levels from the Gulf. We will see this
precipitation in the form of rain as 850 mb temperatures will be up
around +6 to +8C, and the moist axis is aimed toward the area. As
time passes into Thursday, the low level flow becomes oriented more
from the Southern Appalachians, so the moisture is limited from that
point on Thursday.
Thunder chances for our area seem a bit too low at this time to
include a mention in the forecast. Sfc based and elevated LI`s are
all positive, so we will hold off for a thunder mention at this
time.
It seems that the front will mostly clear the area by Thursday
afternoon. This means that the moisture will be swept out, and we
could see some clearing take place Thursday mid-late afternoon as
high pressure builds in for a short period.
The front does not go far, as it drops only to Northern Indiana and
Ohio before stalling out as it becomes parallel to the upper flow.
It will be there for upper jet energy to act on it, and these
features phase on Friday. In addition to the strong dynamics, the
low level flow will be more favorable to draw moisture northward out
of the Gulf, and up and over the front.
There is good agreement and consensus on bringing additional
precipitation with this setup. There is a bit of uncertainty yet
with this period, as there is some disagreement on p-type. The flow
from the NE in the lower levels will feed cool and dry air over the
area just north of the front. Therefore, if the air is cool enough,
it would fall as some snow of the far northern periphery. This is
one thing we will need to continue to monitor.
- Dry Saturday, then increasing rain chances through Monday
Upper and sfc ridging will help to sweep the front and moisture well
out of the area by Saturday. The air will not be much cooler than
Friday when the cool air is advecting in from the NE.
We will see quite a change then take place by Sunday that the models
and ensembles have been handling well for the last few days. A long
wave trough will move over much of the Western U.S. by later
Saturday and Sunday. This will bring a deep S to SW flow aloft over
the area once again. Initially we may see the benefits of this being
a significant warm up for Sunday as 850 mb temps warm into the lower
teens C. The moist axis looks to stay west of the area for the day,
allowing for a warm and mostly dry Sunday.
This will change on Monday as the front inches closer, and the deep
moist axis moves overhead. It will stay warm, but the day will
likely be much more wet. This will be the beginning of yet another
wet period, similar to what we saw last week. This could be
concerning as area rivers and streams will not have had a chance to
totally recover from the high to flooding flows currently going on.
&&
.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 132 AM EDT Tue Apr 7 2026
We are expecting VFR conditions to dominate during this forecast
period. All of the terminals are starting with clear skies out of
the gate. There are some lower clouds based around 3-4k ft agl
across Northern Lower. These are lake effect clouds, and will try
to spread southward. Some of them will make it, but will also
dissipate a bit losing the source of Lake Superior as winds go
from the NNE. Will go mainly sct clouds in the forecast, but there
could be some times of broken. This should not be a big deal with
VFR expected either way.
Otherwise winds will diminish and go light this evening and
overnight with clear skies by then.
&&
.MARINE...
Issued at 310 AM EDT Tue Apr 7 2026
We will be issuing a Gale Watch for areas near Holland and northward
for late Wednesday and Wednesday night. The current Small Craft
Advisory remains in effect with no changes at this time.
We are at the tail end of the ongoing Small Craft Advisory. High
pressure is building in over the area, and the pressure gradient
between the departing low and the incoming high is just about past
the area.
Winds will start to increase on the backside of the sfc ridge later
Tuesday night and Wednesday. The core of wind with this event will
be late Wednesday and Wednesday night, which is when we have the
Gale Watch. Gales look likely for that, and we will likely need a
Small Craft Advisory leading up to the Gale event.
&&
.HYDROLOGY...
Issued at 251 PM EDT Mon Apr 6 2026
No significant rain is expected until Wednesday night and Thursday
when one quarter to half an inch is forecast across the Muskegon
Basin with lesser amounts to the south across the Grand and
Kalamazoo river basins. Until then, crests will continue moving
downstream across the rivers.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 8 AM EDT this morning for
LMZ844>849.
Gale Watch from Wednesday afternoon through late Wednesday
night for LMZ846>849.
&&
$$
DISCUSSION...NJJ
AVIATION...NJJ
MARINE...NJJ
HYDROLOGY...Ostuno
NWS GRR Office Area Forecast Discussion
