672
FXUS63 KGRR 231050
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
650 AM EDT Sat May 23 2026
.KEY MESSAGES...
- Rain focused on this morning; A few showers/storms Sunday
- Warmer with non-zero rain chances Monday through Wednesday
- Seasonable and dry for the end of next week
&&
.DISCUSSION...
Issued at 246 AM EDT Sat May 23 2026
- Rain focused on this morning; A few showers/storms Sunday
The rain has steadily advanced north to around the I-96 corridor as
of 2 am this morning. This is only the beginning with rain extending
down to near the Ohio River Valley with the sfc low around there.
The low will track steadily into Southern Ontario this afternoon. As
it does, the backside of the rain will advance in from the west, and
move east of the area by early evening. The rain will not move much
further north with the dry flow from the NE eating away at the
leading edge. As the rain ends this afternoon, plenty of low level
moisture will hold in, possibly keeping some mist/drizzle in a bit
longer. Then fog is likely tonight with the very moist lower levels
and winds dropping off.
Early Sunday morning around sunrise, we will see a line of a few
showers approach the area from the west. These are associated with
the long wave low that shows up well on Water Vapor imagery over
North Dakota this morning. This low will be making a run east, and
will help the rain chances. There could be a few rumbles of thunder
later morning and afternoon as we see some diurnal heating bump the
instability up in addition to the cooling mid levels.
- Warmer with non-zero rain chances Monday through Wednesday
We see the upper air pattern evolve to more of a zonal flow for
Monday and Tuesday behind the departing upper low. Deep moisture
gets swept out, so most areas will be dry. A weak short wave is seen
coming through Monday afternoon and evening. It is expected to not
do much, other than maybe enhance the chance for a shower/storm
along the Lake Huron shoreline where the light westerly wind
converges with the easterly lake breeze. This should all stay east
of our forecast area. Tuesday looks dry everywhere as the upper
ridge sharpens up a bit and pushes closer to the area.
Once again, Wednesday should be mostly dry for most areas. However
we have a couple of weak features that will bring very small rain
chances.
The first feature is a weak short wave trying to lift to the NE
from the Plains. This wave tries to also bring some better moisture
around, of which most of it should stay just south. We also have a
back door cold front poised to move through with the way the upper
ridge is building over the area. These two features should not meet
over Lower Michigan, so that should limit rain chances to around 20-
30% based on ensemble members showing light or no rain.
- Seasonable and dry for the end of next week
The back door cold front is expected to clear southward through the
area by Thursday. This will usher in cooler and much drier air from
the NE. The upper ridge and a building sfc ridge will then dominate
the weather over the state Thursday and beyond. Temperatures will be
near average levels with almost no rain chances.
&&
.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 650 AM EDT Sat May 23 2026
Rain has now arrived at all terminals. IFR is in place along the
I-94 terminals with MVFR to VFR further north. The northern
terminals will see the IFR move in within the first few hours this
morning. IFR is then expected to rule the rest of the period. Rain
ends this afternoon from West to East, but low level moisture gets
trapped in. Then tonight as temps cool and winds go light, low
clouds will lower and fog will develop with the moist air mass in
place.
&&
.MARINE...
Issued at 246 AM EDT Sat May 23 2026
As we thought, there were a few gusts that touched the wind criteria
of a SCA yesterday and last evening. Not quite frequent enough to
need a headline with offshore flow and small waves. The offshore
will continue today, and will diminish as the pressure gradient
weakens.
After this morning, we will be entering a much quieter pattern with
no bigger systems on the horizon. That translates to weaker winds,
and no headlines likely for the next week.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...NJJ
AVIATION...NJJ
MARINE...NJJ
NWS GRR Office Area Forecast Discussion
