393
FXUS63 KGRR 061037
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
637 AM EDT Mon Apr 6 2026
.KEY MESSAGES...
- Brief periods of scattered light rain/snow showers through tonight
- Quiet with moderating temperatures mid-week
- Periods of rain late Wednesday through Friday
&&
.DISCUSSION...
Issued at 303 AM EDT Mon Apr 6 2026
- Brief periods of scattered light rain/snow showers through tonight
The coldest and most unsettled weather in the CONUS right now is
over the Great Lakes and far NE states. The responsible feature is a
long wave trough that extends over the aforementioned area. Over
this area is the northern branch of the jet with multiple short wave
impulses riding through it.
One of these impulses is moving through right now with a few areas
of light rain over the southern portion of the state, while some
rain or snow is ongoing over the northern section of the area.
Either way, this is not too impactful with sfc temps almost all
above freezing in the mid to upper 30s, and road sfc temps sitting
in the lower 40s. This will be short lived, and move out of the area
by daybreak.
The next wave will approach the area late this afternoon. Initially
ahead of the wave and associated sfc front will be a few
sprinkles/light rain showers. Then along and just behind the front,
a fairly robust narrow line of showers will try to drop through the
area. The best forcing will be further north, and the precipitation
will gradually diminish as it sinks south. There is just not much
moisture to work with. In addition, even though the air is cold, it
is not cold enough for lake effect/enhancement to do much.
- Quiet with moderating temperatures mid-week
The upper jet will finally lift NE of the area on Tuesday as the
upper ridge over the Pacific NW is pushed eastward by a strong low
coming out of the Gulf of Alaska. This ridge will bring drier
weather with no short waves and rising heights. Tuesday will start
off a bit below average with the colder air mass coming in behind
today`s cold front. 850 mb temperatures around -9C will support
highs likely only in the 30s.
The sfc ridge will slip east of the area by Wednesday. Return flow
in the lower levels will advect quite a bit of warmer air up over
the area. This warm up is shown well by the 850 mb temps as temps
warm to +7C by later Wed, an increase of around 16C from just 24
hours before.
Most areas should stay dry on Wednesday. There is a small chance
that the far NW section of the forecast area gets clipped by a warm
front and showers along it.
- Periods of rain late Wednesday through Friday
The better threat of rain initially will come in late Wednesday
night and Thursday. Thankfully this system does not look nearly as
wet as the systems from last week regarding rain amounts. Some of
the latest data indicates that the coverage of rain may diminish
some as the low level flow will initially be drawing some moisture
from the Gulf, and then becomes more from the south Appalachians
which would be a bit drier. Also, the passage of the front during
the coolest times of the day.
Thursday`s front stalls out just south of Michigan over IN and OH
late Thursday. Then we see additional short wave energy eject from
the newly formed upper low off of CA ride along this boundary, and
lift it back north over the area. This time, the flow more directly
from the Gulf will support better rain chances, especially for the
southern half of the area. Right now, the front looks to stay just
south of the area, with the warm sector staying south. That would be
where the better convective potential will be.
We see a fairly strong Canadian ridge then build in behind the wet
system from Thu-Fri. This should dry the area out efficiently, while
cooling us down once again. This will hold for late Fri through Sat,
with the next system potentially approaching late next Sunday.
&&
.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 637 AM EDT Mon Apr 6 2026
One area of light rain showers has moved through the area already
this morning, leaving partly to mostly cloudy skies at the
terminals. All sites are VFR to start out this forecast period.
Winds will start becoming gusty by mid-late morning.
We will see another batch of showers move in from NW to SE around
mid-late afternoon. These will start out as light rain showers
again, but they will then turn to snow showers with the intensity
increasing and freezing layer dropping. The snow showers are
likely to cause a drop in conditions to high end IFR. These will
be brief, and should clear out after 1-2 hours over any one
location.
A few light snow showers will remain possible, but they will be
scattered out quite a bit, and light in intensity. Winds will
remain gusty well into the evening, before dropping off toward
midnight EDT/04z.
&&
.MARINE...
Issued at 303 AM EDT Mon Apr 6 2026
The next marine headline event is poised to start later today, with
the Small Craft Advisory issued last evening for today and tonight
looking good. This event looks like a solid Advisory event with
winds to 30 knots expected from the North behind the front moving
through.
The next event after the one for later today will develop late
Tuesday night and last into Thursday night. That will encompass
increasing winds ahead of the next system, and stronger winds on the
backside. Small Craft Advisory conditions are expected, with Gales
possible.
&&
.HYDROLOGY...
Issued at 128 PM EDT Sun Apr 5 2026
Over a dozen river flood warnings are in effect for the next few
days as the crests on area rivers works downstream. Although light
rain is a possibility during the next couple of days, rain totals
will be less than a tenth of an inch and won`t significantly
impact the ongoing flooding. More rain later in the week may be a
bit heavier than what`s expected early this week, but will be
significantly less than the last few days.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory from 11 AM this morning to 8 AM EDT Tuesday
for LMZ844>849.
&&
$$
DISCUSSION...NJJ
AVIATION...NJJ
MARINE...NJJ
HYDROLOGY...04
NWS GRR Office Area Forecast Discussion
