Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 191148

Area Forecast Discussion
National Weather Service Grand Rapids MI
748 AM EDT Wed Oct 19 2016


Issued at 330 AM EDT Wed Oct 19 2016

High pressure will provide dry and mild weather today, then low
pressure passing through Ohio Valley will bring some light rain late
tonight and Thursday. Colder air flowing in on north winds will lead
to a chilly period for Friday and Saturday, along with a few lake
effect rain showers along the Lake Michigan shoreline.


.SHORT TERM...(Today through Friday)
Issued at 330 AM EDT Wed Oct 19 2016

The bulk of the widespread/heavier rainfall with the Ohio Valley
system is forecast to stay to our south and east late tonight and
Thursday. However strong mid level FGEN forcing and right entrance
region upper jet divergence should promote some banded precipitation
over Michigan north of the main precip area.

Highest pops for rain are forecast southeast of an AZO-LAN line, but
pops/qpf may not line up as a neat/uniform NW-SE gradient as
currently depicted due to potential FGEN banding farther north. Dry
air below 7000 ft will probably delay initial onset of precip a bit.

Predominately northerly low level flow should keep most of the lake
effect rain showers offshore on Thursday night, with the exception
of the Ludington/Pentwater areas.

The flow is shown to back a bit more northwesterly on Friday which
should send lake induced showers into more communities west of
Highway 131. Even in the absence of showers on Friday, the upper
troughing and cool cyclonic flow should result in considerable
stratocumulus clouds over the bulk of the area.

In the near term, patches of dense ground fog early this morning
related to strong but shallow low level inversion will mix out by 9
or 10 am. Otherwise sunny to start today, followed by increasing
high clouds.

.LONG TERM...(Friday night through Tuesday)
Issued at 330 AM EDT Wed Oct 19 2016

Scattered north northwest flow lake effect rain showers are expected
across our lakeshore counties Friday night with deep low level
moisture in place and h8 temps at -2 to -4 C. It will be quite cool
across our area with low temps in the lower to middle 30`s, except
milder right along the Lake Michigan shoreline.

H8 temps will moderate gradually Saturday and a weak high pressure
ridge will build in to bring fair but continued cool weather. A low
pressure system will move ese across the northern Great Lakes region
Sunday and will bring scattered light rain showers to our northern
fcst area well north of I-96 Sunday.

Canadian high pressure will then build in to bring fair weather into
early next week. Temperatures will average around 5 to 10 degrees
above normal from Sunday through Tuesday.


.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 748 AM EDT Wed Oct 19 2016

Some IFR/LIFR fog/stratus will impact the area through mid
morning otherwise VFR conditions are expected today. Even as
areas of light rain move in tonight, the cigs should remain at
VFR levels with limited vsbys restrictions due to dry air below
7000 ft.


Issued at 330 AM EDT Wed Oct 19 2016

A tranquil period on the lake today/this evening before waves begin
to build again in increasing north flow late tonight and Thursday.
Waves will initially build to advisory criteria near Big and Little
Sable Points very late tonight then eventually impacting more of the
lakeshore Thursday into Friday. Lowest wave heights in north flow
regime will be between Grand Haven and Whitehall. May need to add a
chance of waterspouts for Thursday night and Friday as the colder
air arrives.


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.




LONG TERM...Laurens
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