Newaygo, Michigan Weather Forecast Discussion

739
FXUS63 KGRR 211921
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
321 PM EDT Sun Sep 21 2025
.KEY MESSAGES...
- Showers and storms possible tonight into early Monday
- Chances for showers and storms continues through the week
&&
.DISCUSSION...
Issued at 309 PM EDT Sun Sep 21 2025
- Showers and storms possible tonight into early Monday
Precipitation bands continue to exit the region with a lull in
the weather this afternoon. Predominately cloudy skies remain over
the area which has tempered diurnal heating. There are some
breaks in the clouds and looking at latest satellite there will
be some more cloud reduction with drier air aloft moving onshore
over the next few hours. If there is enough heating, it could
provide enough lift and decrease stability enough for storm
development. There remains copious amounts of low level moisture
due to last night`s rainfall.
The low level jet streak that previous discussions mentioned, is
currently progged southward. So the best shear and CAPE values
have trended southward. Latest model soundings for Grand Rapids
do show a brief period of 900 to 1100 J/kg CAPE, from 6 PM to 9
PM.
Soundings this afternoon and evening for Kalamazoo, Battle Creek and
Jackson are upwards of 1000 to 1300 J/KG. Given this environment,
SPC has cut back the marginal risk for severe storms to south of
the I 96 corridor. Main concern with any storms will be damaging
winds and heavy rainfall. QPF remains decent, though PWATS remain
much lower than yesterday. Around a half an inch to an inch QPF is
possible with higher amounts in and around thunderstorms.
Stronger shortwave should still arrive overnight which will fuel
any carryover of activity and allow for showers and storms to
linger into Monday morning. With the arrival of the shortwave,
winds will shift to the west.
- Chances for showers and storms continues through the week
A large upper level low will dominate the weather pattern this
week. That low will move through the upper Midwest Monday bringing
a streak of moisture across southern Canada that will extend
southwest through Michigan and through the eastern Great Plains.
Given that mid to low level moisture and upper air instability
from the wave, daytime showers and storms will be possible through
Tuesday.
That wave will dig southward with the latest models showing it
becoming a closed low. That low should propagate eastward through
midweek. There is some differentiation on the path of the low.
Latest trends show it moving through Michigan Wednesday night into
Thursday. Given the position and track of the low, that should
provide another round of widespread showers and storms Thursday
afternoon. Given track and timing of the trough, it should exit
the region late in the week. with drier air into next weekend.
Temperature trends this week remain around, to just above, normal.
So expect low to mid 70s for daytime highs with lows along US 10
corridor in the upper 40s to low 50s and the 50s to low 60s
elsewhere.
&&
.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 148 PM EDT Sun Sep 21 2025
Dialed back the thunderstorm probabilities this afternoon as this
morning`s models have trended down on coverage of precipitation,
plus instability may not build sufficiently for lightning until
around or after 22 Z. Some further refinement to timing a
thunderstorm at each aerodrome will probably be needed, but
generally there is a small chance of a thunderstorm popping up any
time between 22 Z and 07 Z. Other challenges include ceilings
below 2,000 feet presently in a few locations, which should mix
away by mid afternoon. Ceilings below 2,000 feet may return Monday
morning.
&&
.MARINE...
Issued at 309 PM EDT Sun Sep 21 2025
Generally 1 to 3 ft waves anticipated the next couple days with
southwest winds on Monday and north winds on Tuesday. Northeast
winds may strengthen Wednesday to Wed Night as a relatively deep low
pressure system from the middle Miss. River valley slowly moves
toward the southern Great Lakes, though not certain if the winds
will be a hazard to small craft.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...Ceru
AVIATION...CAS
MARINE...CAS

NWS GRR Office Area Forecast Discussion