Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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440
FXUS63 KGRR 171145
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
645 AM EST Wed Jan 17 2018

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 245 AM EST Wed Jan 17 2018

High pressure will bring fair weather into the weekend. Low
pressure will move in by Sunday, with southerly winds bringing
warmer temperatures and some rain. The low will move by on Monday
with colder temperatures and some snow showers for Monday night.

&&

.SHORT TERM...(Today through Friday)
Issued at 245 AM EST Wed Jan 17 2018

No significant weather in the near term. Sfc ridging to our south
and northern stream clipper passing well to our north will mean
some breezy conditions with milder temperatures Thursday and
Friday. No precipitation is expected but we will have to watch for
low stratus clouds trapped under inversion as moisture advects in
from the south on Thursday and Friday. Temperatures should rise
above freezing Friday afternoon along with some clearing as
inversion is forecast to weaken by that time.

.LONG TERM...(Friday night through Tuesday)
Issued at 245 AM EST Wed Jan 17 2018

Much above normal temperatures are forecast Friday night through
Monday before returning to near normal by Tuesday. A strong low
pressure system will bring a good chance of precipitation from late
Sunday through Sunday night into Monday.

Strong sw flow warm air advection will continue Friday night through
the weekend. Dry wx is fcst Friday night through Saturday afternoon.
A warm front will bring an initial mix of light pcpn Saturday night
into Sunday morning with the high pressure to the north still
providing some low level cold air.

However any mixed pcpn should quickly transition to rain Sunday
given the strength of the warm air advection and moderating thermal
profiles. In fact high temperatures by Sunday and/or Monday could
flirt with the 50 degree mark in a few spots. We did not fcst temps
quite that mild given the lingering snow cover and extensive cloud
cover and pcpn forecast by then.

Persistent southerly flow off the gulf will result in increasing
moisture and the best chance for rain late Sunday night and Monday
as the strong low pressure system moves from the central Plains
states Sunday to the Great Lakes region Monday. Temperatures will
finally cool and return to near normal for this time of year by
Tuesday behind that system.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 645 AM EST Wed Jan 17 2018

VFR conditions expected to prevail today with ceilings around 4000
feet this morning. CLouds should be decreasing in the afternoon.
Winds will be west around 10 knots with gusts over 20 knots at
times.

&&

.HYDROLOGY...
Issued at 1230 PM EST Tue Jan 16 2018

The ice jam continues along the Muskegon River in Mecosta County.
Latest information from Emergency Management is that little rise has
been noted since impacts from the jam were reported Monday evening.
Little or no additional impacts have been reported. Previously
open waters have since frozen with ice chunks that have built in
on the back side of the jam, but seem to be stable. Given the
little noticeable changes, we could be seeing the peak, but it
does not rule out ice movement and further fluctuation. Residents
should continue to monitor levels and pay close attention to
latest updates that are provided.

Sites elsewhere are showing some affects as a result of river ice,
but seem to be stable. Minor fluctuations have been noted with
overall downward trends on rivers at or near bankfull. Only one
advisory remains in effect, but is likely to be dropped sometime
late this evening or overnight.

Colder temperatures will allow ice to continue to build over the
next couple of days. There is concern in the upcoming weekend and
into early next week as temperatures rise and precipitation
chances increase. We could see a repeat of last week with melting
snow and rainfall. In addition to weakening ice, runoff could
cause rivers to rise and lead to additional ice jams.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&

$$

SYNOPSIS...Ostuno
SHORT TERM...Ostuno
LONG TERM...Laurens
AVIATION...Ostuno
HYDROLOGY...JAM



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