773
FXUS63 KGRR 142339
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
639 PM EST Sat Feb 14 2026
.KEY MESSAGES...
- Wintry mix and thunderstorms possible Wednesday
- More seasonable temperatures and precipitation return Friday
&&
.DISCUSSION...
Issued at 306 PM EST Sat Feb 14 2026
- Wintry mix and thunderstorms possible Wednesday
Wednesday is looking more and more like a dynamically potent day.
Precipitation starts as early as Tuesday night. A warm front is
expected to lift north across Lower MI coupled with a cyclonically
breaking upper wave that could provide significant upper diffluence
and inferred upper divergence. The sharp thermal gradient associated
with the warm front will offer a range of possible precipitation
types to the area.
Starting with far southern Lower MI...there is a strong consensus
among Machine Learning (ML) models regarding a chance for thunderstorms
Wednesday afternoon. The 14/00Z run of the GEFS ML model (produced
by the NSSL) indicates a greater than 40 percent chance of thunderstorms
over south-central and southeast Lower MI and a greater than 10 percent
chance of severe thunderstorms. A similar solution is presented
by both the CSU ML model and Weathernext2 (based on Google
DeepMind). This is not surprising given that MUCAPE approaching
1000 J per kg will be well juxtaposed with a belt of strong
westerlies. Thunderstorms are not yet explicitly mentioned in the
forecast, but expect that to change if current trends hold.
Moving farther north towards central Lower MI, including our
northern CWA...there is a signal for mixed precipitation, which may
include freezing rain (FZRA). Guidance such as NBM v5.0 and the
ECMWF ensemble gives about a 10 percent chance of accumulating a
couple hundredths of FZRA. That said, a FZRA ingredient that is
conspicuously absent is near-surface cold/dry advection from the
northeast, so a rain/snow mix seems a more plausible outcome, and
all rain is yet even more plausible based on forecast highs in the
50s to lower 60s for much of Lower Michigan Wednesday afternoon.
Finally, it should be noted that the evolution, position, and timing
of all the features mentioned above are subject to change with
subsequent guidance. It`s reasonable to assume that a fairly narrow
band of highly varied weather will occur somewhere in the region;
exactly where that is in relation to southwest Lower MI remains to
be seen.
- More seasonable temperatures and precipitation return Friday
After a very warm Wednesday and Thursday, another low originating
from the Rockies will bring precipitation to the area. As noted
before, this could be a rain/snow mix. Predictability is quite
poor due in part to dependence on how the mid week system evolves.
There is a range of solutions regarding the track of the surface
low relative to Lower Michigan, and this has bearing on precipitation
types and amounts. By late Friday, a minor incursion of colder
air will bring temperatures back down into the 30s and this will
last into Saturday.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 639 PM EST Sat Feb 14 2026
Main concern tonight remains fog redevelopment. Weak boundary
over central Lower MI (referenced earlier today and partly
responsible for last nights locally dense fog over central Lower
MI) remains intact /surprisingly/ per surface obs -- noting NE
flow from Saginaw Bay south toward LAN. Some areas north of said
boundary experienced cooler temps and at least some fog all day.
Will introduce MVFR fog at all TAF sites after 05-06Z, given
radiational cooling over snow pack, model soundings, and added
moisture from melting snow today. Given that remnants of
aforementioned surface boundary is now just south of LAN, will
also include risk for IFR fog at LAN between 08-12Z.
Any fog that forms will burn off within a few hours of sunrise
Sunday. Otherwise, meager pressure gradient will support light
and variable winds tonight, and light SW to W winds Sunday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...TJT
AVIATION...Smith
NWS GRR Office Area Forecast Discussion
