387
FXUS63 KGRR 272332
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
732 PM EDT Fri Mar 27 2026
.KEY MESSAGES...
- Cold Through Saturday; Snow Showers Tonight
- Stormy Stretch Possible Monday Night Through Tuesday Night
- Turning Cold Again Wednesday/Thursday; More Rain Possible Later
&&
.DISCUSSION...
Issued at 231 PM EDT Fri Mar 27 2026
- Cold Through Saturday; Snow Showers Tonight
Deep N/NW flow over the Great Lakes has settled in and temperatures
will stay well below seasonal norms through Saturday. RAP13 guidance
is showing 850mb temps bottoming out near -15C in the 06z-12z
Saturday time frame. Lows Saturday morning will dip into the upper
teens to low 20s and highs will be in the upper 30s to low 40s. On
the cusp of a reinforcing cold front sweeping through in the 00z-06z
time frame tonight, snow showers will likely develop. Based on RAP13
guidance, there is a 1 to 2 hour period at any given location
(mainly near/north of I-96) for a decent burst of snow given some
significant lift (ie. -10 to -20 ubar/s) within the DGZ. Given this
will happen after dark and with the antecedent cold temperatures in
place, a few tenths of an inch of snow will be possible (locally >
0.5" near US 10) with brief impacts to travel not out of the
question.
- Stormy Stretch Possible Monday Night Through Tuesday Night
Both ensemble and deterministic model guidance are centering in on
the Monday night through Tuesday night period as the next
opportunity for rain and likely some thunderstorms as well. By
Monday, model guidance is in good agreement on a warm front lifting
north through the region. While initially we stay dry as this
occurs, by Monday night there will be a broad and intense LLJ with
Gulf origins rapidly advecting moisture towards the Great Lakes.
GFS/ECMWF guidance is indicating 50-60 kts. This occurs ahead of an
approaching shortwave trough into the upper Midwest with an
impressive mid level jet of 60-80 kts. Further up, the right
entrance region of a 150 kt ULJ approaches Michigan. Synoptic
support will certainly be there for organized convection Monday
night into Tuesday night.
A round of showers and thunderstorms is likely Monday night into
Tuesday morning, with a combined ECE/GEFS/CMC ensemble probability
of 80% for 0.25" or more and 50-60% for 0.50" or more. Depending on
when morning activity moves out, some surface-based destabilization
could occur Tuesday out ahead of a cold front that will likely sweep
through Tuesday night or Wednesday morning. Given timing differences
in model guidance at this range, there is uncertainty regarding this
destabilization scenario. If it does occur, strong to severe
thunderstorms could develop. NCAR`s AI-based NWP convective hazards
forecasts indicate severe weather potential on Tuesday stretching
from Missouri to Michigan. This is contingent on factors that are
not able to be resolved this far out, so trends will need to be
monitored.
- Turning Cold Again Wednesday/Thursday; More Rain Possible Later
The early spring temperature roller coaster looks to continue next
week after reaching the 60s and 70s Monday into Tuesday and then
dropping into the 40s Wednesday into Thursday. Adding to the return
of crisp air will be a fairly steady N/NE breeze midweek making
temperatures feel like the 30s during the day and colder at night.
Ensemble guidance has varied solutions by late in the week but in
general there is some support for another upper trough to swing
through with low level moisture flux ahead of it, supporting perhaps
another round of rain late in the week or weekend.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 728 PM EDT Fri Mar 27 2026
Radar shows light snow showers moving toward the region. Upstream
obs suggest the southern extend of the precipitation is
evaporating but visibilities have dropped to a mile or less over
northeast WI. We`ve kept the prob30 group for the potential of
5sm -sn for a few hours this evening. Short range models indicate
the length of snow will be 4-5 hours, but most likely north of
the terminals. Generally VFR through the period.
&&
.MARINE...
Issued at 231 PM EDT Fri Mar 27 2026
Another period of hazardous conditions to small craft sets up
tonight into Saturday morning as northwest flow increases. Waves
are expected to build into the 3 to 5 foot range with some 6
footers possible. Waves subside by midday Saturday and early
Saturday afternoon only to build again Saturday night into Sunday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 10 AM EDT Saturday for LMZ844>849.
&&
$$
DISCUSSION...Hoving
AVIATION...04
MARINE...Hoving
NWS GRR Office Area Forecast Discussion
