Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 240545
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
145 AM EDT WED AUG 24 2016

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 330 PM EDT Tue Aug 23 2016

A low pressure system will bring showers and a few thunderstorms
Wednesday through Wednesday night into Thursday. Fair weather will
return Thursday night through Saturday. Another system will bring
another chance for showers and thunderstorms Sunday.

&&

.UPDATE...
Issued at 1025 PM EDT Tue Aug 23 2016

Have added low chance pops for showers after 09z for wrn sections
of the cwfa to cover the arrival of the sharp PWAT gradient and
higher theta-e air from the southwest. Current PWATS are near
0.75 inches and are progged to rise to near 2 inches Wednesday
morning. This moisture advection may generate a band of scattered
rain showers moving in after 5 am.

&&

.SHORT TERM...(This evening through Thursday night)
Issued at 330 PM EDT Tue Aug 23 2016

A low pressure system moving in tomorrow will bring showers and
a few thunderstorms. No severe weather is expected given weak
instability and lack of stronger forcing or wind fields with
height/shear.

Locally heavy rainfall is possible as low level moisture ramps up
with sfc dew points reaching the upper 60`s to lower 70`s and
precipitable water values up to around two inches. However
1000-850 mb moisture transport with this system does not look as
impressive as it did yesterday.

Some showers and perhaps isolated convection will linger into
Thursday. Most locations will only receive around a half an inch
to three quarters of an inch of rainfall tomorrow through
Thursday. Therefore hydro concerns are fairly minimal.

Dry wx will continue this evening with showers approaching from
the WSW by around daybreak tomorrow. A high pressure ridge will
build in from the west to bring fair weather beginning
Thursday evening.

.LONG TERM...(Friday through Tuesday)
Issued at 330 PM EDT Tue Aug 23 2016

Surface high pressure should provide dry weather from Friday through
Saturday. The upper flow is quasi zonal over the Great Lakes with an
upper ridge over the Southeast United States and shortwaves rippling
east along the U.S/Canadian border.

From Saturday night into early next week a shortwave trough is
forecast to slowly shift eastward through the northern Great Lakes.
At the surface, weak low pressure will traverse the area with an
influx of moisture from the south. Have low chance pops in the
forecast from Saturday Night through Tuesday. Certainly won`t be
raining all the time but the threat is there for a few
showers/storms each period. The best chances for precipitation look
to come from Saturday night through Sunday night.

Temperatures through the period look to be near seasonal normals.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 145 AM EDT Wed Aug 24 2016

We continue to expect quiet, VFR conditions through about 10-12z
this morning before conditions will deteriorate. High clouds are
currently over the area early this morning. We will see more mid
cloud cover move in through the early morning hours, with a few
light showers possible by 12z, especially west.

More widespread rain showers with some embedded thunder will
spread across the area through 17z this afternoon. MVFR conditions
are expected, with some pockets of IFR likely. The rain and lower
conditions will linger over the area through late afternoon/early
evening. Even as the rains move out, a MVFR cig looks to hold in
through the end of the fcst period.

&&

.MARINE...
Issued at 330 PM EDT Tue Aug 23 2016

A small craft advisory remains in effect through late Wednesday
night from South Haven north to Manistee where wave heights of 3
to 5 feet are expected through then. South to southwest winds of
15 to 25 kts may diminish somewhat late this evening and overnight
before ramping back up to around 20 to 25 kts Wednesday.


&&

.HYDROLOGY...
Issued at 330 PM EDT Tue Aug 23 2016

Fair and dry weather will continue this evening. A flood warning
remains in effect for the Portage River at Vicksburg where minor
flooding remains possible. However the river level is forecast to
continue to slowly fall to below flood stage by early Wednesday
afternoon.

The next system will bring potential for around a half to three
quarters of an inch of rainfall Wednesday through Thursday. This
rainfall could cause a small rise on the Portage River Thursday into
Friday.

&&

.GRR Watches/Warnings/Advisories...
MI...Beach Hazards Statement through late tonight for MIZ037-043-050-
     056-064.

LM...Small Craft Advisory until 2 AM EDT Thursday for LMZ845>849.

&&

$$

UPDATE...Meade
SYNOPSIS...Laurens
SHORT TERM...Laurens
LONG TERM...Duke
AVIATION...NJJ
HYDROLOGY...Laurens
MARINE...Laurens



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