Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 121804

Area Forecast Discussion
National Weather Service Grand Rapids MI
204 PM EDT Mon Mar 12 2018


Issued at 302 AM EDT Mon Mar 12 2018

Low pressure will move across Lower Michigan today bringing light
snow which will transition to snow showers near Lake Michigan
tonight and on Tuesday.


.SHORT TERM...(Today through Wednesday)
Issued at 302 AM EDT Mon Mar 12 2018

No significant changes to previous forecast. Expect an inch or
less of snow across most of the area with some areas of 2 inches
where heavier snow showers persist. Some diurnal enhancement is
possible this afternoon given steep lapse rates as upper low comes
through. Hi-res models show convective looking showery nature of
the snow this afternoon. Ground temps will be marginal and hold
down accums even in areas of heavier snow showers.

Synoptic snows transition to lake effect in NNW flow tonight and
Tuesday. Lake effect will slowly move inland as flow goes NW
Tuesday night before tapering off as inversion heights come down
by early Wednesday.

.LONG TERM...(Wednesday night through Sunday)
Issued at 302 AM EDT Mon Mar 12 2018

We`ll be on the western fringe of the deep upper trough from
Wednesday night through Friday night. The weather should be
basically dry except for isolated snow showers adjacent to the lake
shore. We should see quite a bit of sunshine over the weekend and
temperatures will be in the 50s thanks to the upper flow becoming
more zonal after the upper trough exit.

The ecmwf and gfs aren`t in good agreement late in the weekend. The
gfs shows a trough moving through and mixed light rain/snow falling,
while the ecmwf is generally dry. The Canadian takes a middle
solution. We have some low pops in the grids to reflect the
potential of precipitation, but confidence is low.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 204 PM EDT Mon Mar 12 2018

The more widespread snow of the morning has moved south and east
of the area as of 18z. This afternoon we are expecting more
showery precipitation in the form of rain and snow showers.
Ceilings will vary for a time between VFR and MVFR, but the trend
should be toward VFR ceilings from 20z through this evening.

Overnight, lake effect snow showers will occur towards Lake
Michigan with the TAF sites staying mainly VFR. We cannot rule out
some MVFR ceilings from time to time however. A more widespread
MVFR cloud deck should move into all of the TAF sites around 12z
which will continue through Tuesday morning.

Winds will remain from the northwest through the next 24 hours.
Gusty winds towards 20 knots can be expected through 23z today.


Issued at 1052 AM EDT Sun Mar 11 2018

Expected precipitation Monday into Tuesday will be light and
should not impact rivers. This will allow river levels to
continue falling.




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