Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 231929
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
330 PM EDT TUE AUG 23 2016

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

.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.

&&

.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 18Z TAFS through 18Z Wednesday morning)
Issued at 200 PM EDT Tue Aug 23 2016

Cumulus field will dissipate this evening with a mid and high deck
of clouds spreading in from the south overnight. Scattered to broken
cumulus clouds will have bases of 4000-5000ft. So, looking for VFR
conditions this evening and overnight. The gusty south winds will
diminish some after sunset. South winds of 10-20 knots this
afternoon will diminish to 5 to 10 knots overnight.

Clouds will lower and thicken late tonight and through the course of
Wednesday morning. At this point kept ceilings VFR, but there are
indications we may be dipping into the MVFR category after 12z.
Later forecasts may include lower ceilings. Showers and some
embedded thunderstorms are possible Wednesday morning and included
vicinity wording in the TAFs.

&&

.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 Wednesday night for MIZ037-
     043-050-056-064.

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

&&

$$

SYNOPSIS...Laurens
SHORT TERM...Laurens
LONG TERM...Duke
AVIATION...Duke
HYDROLOGY...Laurens
MARINE...Laurens



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