Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 232026
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
326 PM EST Mon Jan 23 2017

LATEST UPDATE...
Synopsis/Short Term/Long Term/Marine

.SYNOPSIS...
Issued at 326 PM EST Mon Jan 23 2017

Areas of rain will continue to move through the region tonight, but
it will gradually diminish toward daybreak.  This will set the stage
for a mainly dry Tuesday as weak high pressure passes by.  Despite
the dry weather, rays of sun will be little, if any.

Our next weather system will already be moving across Iowa Tuesday
night and it will move across Central Lower Michigan Wednesday
afternoon. This will bring more rain to most of Southern Lower, with
a rain and snow mix across Central Lower Tuesday night and
Wednesday.  Then as the system departs it will drag colder air
across the region, and the rains in Southern Lower will also change
to snow Wednesday evening.

After temperatures mainly in the 40s Tuesday and Wednesday, we will
see a cool down for the second half of the week.  Expect mostly
upper 20s to mid 30s by then.  More snow should occur Thursday
and Friday.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 326 PM EST Mon Jan 23 2017

Rain continues to press westward this afternoon, reaching LAN as of
300 PM.  It will continue to back toward U.S. 131 by this evening.
The steadiest rains will occur this evening, with the rains
gradually letting up late tonight as the trough begins to move back
to the NE.  A few areas of light rain may linger toward U.S. 127
after daybreak Tuesday, but overall Tuesday will be a quiet day with
surface ridging passing through in the afternoon.  A peek or two of
the sun is possible toward the lakeshore and perhaps south of I-96,
but it will be fleeting.  Another day of highs of 40 to 45.

The break in the pcpn will be brief, with the next system already
pushing toward the Great Lakes Tuesday night.  The trend has been
for a slight farther southern track of the surface low.  It will
pass from roughly MKG to Saginaw Bay Wed afternoon.  Central Lower
will be north of the track and may struggle to see temps recover. So
expect we will see some snow there Tuesday night and Wednesday.
However it should also mix with rain at times.  So expect any accums
will remain minimal, general an inch or less, and perhaps up to two
inches in the higher terrain areas.

All rain expected across Southern Lower Tuesday night and Wednesday
morning.  But once the system passes, temps will tail off late
Wednesday afternoon and Wednesday night.  Expect all locations will
switch to snow from northwest to southeast late Wednesday afternoon
and through the evening.  This will be the deformation portion of
the system that looks to move through rather steadily. So again,
expected accums will be under an inch, or even trace amounts in some
areas.

.LONG TERM...(Thursday through Monday)
Issued at 326 PM EST Mon Jan 23 2017

Made some changes to Superblend in the extended. Bumped up POPs
significantly for Thursday through Sunday for lake effect snow and
lowered temperatures a degree or two.

West to northwest flow lake effect snow showers will be enhanced by
a couple shortwave troughs moving through. The first one is Thursday
night into Friday morning with inversion heights increasing to near
10 kft.

Snow showers should decrease by Friday night then pick up again on
Saturday with the passage of another trough which features a Lake
Superior connection and strong sfc convergence across the SW zones.
We could see a persistent band forming along the I-94 corridor
Saturday night into Sunday.

Lake effect snow should decrease by Monday as shortwave ridging
moves in ahead of a clipper and arctic front that arrives later in
the week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 100 PM EST Mon Jan 23 2017

IFR and LIFR conditions will continue through tonight then a
gradual improvement to MVFR will begin by Tuesday afternoon. Any
precipitation will be light and winds will be north below 10
knots.

&&

.MARINE...
Issued at 326 PM EST Mon Jan 23 2017

Some fog persists over the lake today, but this is expected to
gradually improve tonight as the winds come up.

We will likely need a small craft advisory by late Tuesday night
with the approach of the next system and the cold advection that
follows it into Wednesday and Wednesday night.

&&

.HYDROLOGY...
Issued at 1209 PM EST Mon Jan 23 2017

River levels are in the process of generally falling with the
recent lack of appreciable rainfall over the past few days and
with the ice having moved out with the warm temperatures.

River levels will likely stabilize or even rise a little with
more precipitation expected through Wednesday. No significant
rises are expected, and no major flooding is expected. We are
looking for up to around or just over half an inch with rain
tonight, and rain/snow Tue night/Wed. The precipitation could fall
as mostly snow up north, limiting immediate runoff into the
rivers.

Conditions will become colder at the end of the week and beyond.
Lake effect snow showers will become likely, with little to no runoff
expected after Thursday.

&&

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

$$

SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...Ostuno
AVIATION...Ostuno
HYDROLOGY...NJJ
MARINE...JK



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