Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 181742

Area Forecast Discussion
National Weather Service Grand Rapids MI
142 PM EDT Tue Oct 18 2016


Issued at 328 AM EDT Tue Oct 18 2016

A few showers are expected today as a cold front pushes southeast
through the state. Most locations will remain dry however as the
chance for rain is small. It will remain mild today as the front
will not pass through the bulk of the area until late afternoon.
Highs from I-96 southward will be in the middle 70s. A mainly clear
and dry night is expected tonight with high pressure situated
nearby. Wednesday into Thursday a low will slide through the Ohio
Valley which will spread rain into Lower Michigan. The best chances
for rain look to be across Southern Lower Michigan from Battle Creek
to Detroit. Wednesday night into Thursday is when we will see the
best chances for rain. A cooler air mass will gradually filter into
the state this week with highs by Friday only forecast to top out in
the lower 50s.


.SHORT TERM...(Today through Thursday)
Issued at 328 AM EDT Tue Oct 18 2016

Forecast items of note in the short term are the chances for showers
today and threat for showers once again Wednesday night into

First off though is the windy conditions presently occurring across
Southwest Lower Michigan. The core of the wind is overhead now and
will pivot east of our area between 12z and 18z. So, it will remain
breezy past daybreak, but we are expecting winds to ease up hour by
hour from now through midday.

The cold front is situated from Northern Lake Michigan southwest
across Central Wisconsin into Iowa at 300am. The front is forecast
to traverse the GRR CWA between 800am and 500pm, exiting the JXN
area around 500pm. A few showers cannot be ruled out as the front
sags south, but drier air advecting in from the west will likely
preclude much in the way of activity. Deeper moisture really tails
off this morning. Have 20-30 pct chances for a light shower today,
but thinking most areas will remain dry. CAPE values although
elevated at 800am around 1000 j/kg quickly drop to below 200 j/kg by
1100am so no thunder mention in the forecast.

A quiet period is expected tonight and Wednesday with high pressure
situated over the Southern Great Lakes. Lows tonight in the 40s and
highs on Wednesday in the 60s.

Wednesday night and Thursday a low is forecast to be lifting
northeast through the Ohio Valley. Some light rain is expected to
spread into southern portions of the state. Both the ECMWF and the
GFS show rain into our area. The 12z ECMWF ensembles bring the low
much farther north than tonight`s 00z operational runs, to near CLE.
If this verifies it will likely be even wetter than forecast. As it
stands now have 40-50 pct chances for rain in the southeast CWA.
Highs on Thursday will be cooler still, in the upper 50s to around

.LONG TERM...(Thursday night through Monday)
Issued at 328 AM EDT Tue Oct 18 2016

A much cooler airmass will continue to move in Thursday night
through Friday with brisk northwest winds on the back side of the
departing low pressure system east of the Great Lakes region. A few
showers will linger Thursday night into Friday with lake
enhanced/lake effect showers as well as h8 temps fall to around -2 C

Scattered lake effect/lake enhanced showers may linger into early
Saturday before high pressure builds in. We kept a dry forecast
going for Sunday and Monday but forecast confidence that far out is
lower given larger medium range guidance discrepancies. Temperatures
will average rather close to normal for this time of year through
the long range forecast period.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 137 PM EDT Tue Oct 18 2016

A cold front was tracking eastward through the TAF sites this
afternoon. A narrow line of showers may develop along it as it
pushes through KLAN...KJXN...KAZO and KBTL in the next 3 hrs. A
brief period of MVFR cloud cover may occur behind the front...but
overall a diminishing trend to the cloud cover is forecasted from
about mid afternoon...on. The gusty winds will also decrease and
veer slightly behind the front this afternoon. Gusts over 25 knots
are still possible for the next 1 to 3 hrs as the front pushes


Issued at 328 AM EDT Tue Oct 18 2016

Winds are still gusting to 25-30 knots at the marine sites as of
300am. Most of our nearshore buoys have been pulled for the season,
but mid lake buoys are indicating 6-7 footers. Higher waves are
likely occurring in our nearshore waters given a southwest fetch.
The small craft advisory still looks good through 400pm. It will
take the bulk of the day for the waves to settle down after the wind
eases up. Expecting a big drop off in wind between 700am and 1100am
as the strongest winds shift east of our area.

Winds of 10 knots or less are expected from this afternoon through
Thursday morning with high pressure situated near the area.


Issued at 1149 AM EDT Tue Oct 18 2016

Although rivers continue to run well above normal, most sites have
leveled off and have begun a downward trend. No flooding is

Today`s frontal boundary will come through mostly dry. The main
question then shifts to the potential for rainfall with the
midweek system passing through the Ohio Valley. The latest update
of the GFS continues to plot the northern most edge of the
rainfall across southern sections of the CWA, mainly I-96 and
south. Heavier precipitation is likely to stay south of Lower
Michigan, but minor river rises cannot be ruled out along and
south of I-94.


LM...Small Craft Advisory until 4 PM EDT this afternoon for



LONG TERM...Laurens
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