007
FXUS63 KGRR 170703
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
303 AM EDT Tue Mar 17 2026
.KEY MESSAGES...
- Snow winding down today
- Light burst of Snow Wednesday morning
&&
.DISCUSSION...
Issued at 303 AM EDT Tue Mar 17 2026
- Snow winding down today
17/00Z HREF guidance suggests a secondary lower tropospheric trough
best resolved around 700 mb is swinging across western Lower MI at
this time. This feature is well corroborated by regional VWPs. We
have seen a slight decrease in lake effect snow intensity and
coverage in the last hour indicating that inversion heights
(currently around 7 kft AGL deep per the KGRR VWP) are in the
process of decreasing in response to subsidence behind the trough.
Water vapor imagery supports this notion with mid-level subsidence
just beginning to pivot across Lower MI in the wake of the trough.
We will see a continued decrease in snow today, probably wrapping up
by afternoon when near surface pressure ridging takes hold.
- Light burst of Snow Wednesday morning
We will have to watch for the possibility of minor travel impacts
Wednesday morning as an area of WAA/isentropic ascent could bring a
quick burst of snow. Accumulations at this time expected to be less
than an inch for roughly the western half of the forecast area but
temperatures will be below freezing and untreated roads may be
slippery.
&&
.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 158 AM EDT Tue Mar 17 2026
MKG/AZO: There is a 30-50 percent chance of temporary IFR
visibility restrictions mainly before 09Z this morning. Lower
chances of MVFR visibility restrictions mainly between 09Z and
15Z.
GRR/LAN/BTL: Greater than 80 percent chance of visibility and
ceiling restrictions remaining above fuel-alternates through 00Z
tonight. However, a very brief (15-30 minutes) period of MVFR
conditions may be experienced if lake effect snow bands pass over
the terminals.
JXN: 90 percent chance of remaining above fuel alternates through
the period, although ceilings around 3000 ft AGL should be
persistent today.
&&
.MARINE...
Issued at 303 AM EDT Tue Mar 17 2026
Coastal marine stations now reporting peak gusts below 35 knots,
so this is the cue to cancel our Gale warning and replace it with
a Small Craft Advisory (SCA) valid through this evening. For now,
kept the heavy freezing spray warning going until noon, but this
almost certainly can be cancelled prior to that.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Winter Weather Advisory until 11 AM EDT this morning for
MIZ037>039-043-044-050-056-064-071-072.
MARINE...Small Craft Advisory until 8 PM EDT this evening for LMZ844>849.
Heavy Freezing Spray Warning until noon EDT today for LMZ844>849.
&&
$$
DISCUSSION...TJT/Ostuno
AVIATION...TJT
MARINE...TJT
NWS GRR Office Area Forecast Discussion
