Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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915
FXUS63 KGRR 240728
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
328 AM EDT Thu Aug 24 2017

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

.SYNOPSIS...
Issued at 328 AM EDT Thu Aug 24 2017

Weak low pressure will bring a few showers this morning then fair
weather will return this afternoon and continue into next week as
high pressure dominates the weather across Michigan.

&&

.SHORT TERM...(Today through Saturday)
Issued at 328 AM EDT Thu Aug 24 2017

Fairly vigorous shortwave trough moving through this morning and
into the afternoon should bring a few showers. Left thunder out of
the forecast but an isolated storm cannot be ruled out as lapse
rates steepen. The trough axis moves through this afternoon and
showers should exit the southern zones during the afternoon.

Then flat ridging moves in on Friday and Saturday with fair
weather and temperatures slightly below normal.

.LONG TERM...(Saturday night through Wednesday)
Issued at 328 AM EDT Thu Aug 24 2017

An upper ridge should keep us dry into Saturday night and Sunday.
The pattern becomes more amplified into the first part of next week.
The models may struggle with this pattern change, so timing issues
exist through much of the first half of next week.  This includes
the possibility of some tropic influence from Harvey.

It appears a short wave will be moving into the Western Great Lakes
by Sunday, bringing a surface cold front and showers to SW MI by
Sunday night into Monday.  The short wave appears to develop into an
upper low near Chicago by Monday evening, as some tropical
interaction with Harvey is possible by then.  The upper low is then
only progged to reach to about Detroit by Tuesday night.  With this
regime, the Monday through Tuesday period should be the wettest,
with perhaps lighter rains lingering into Wednesday.

Temps will be fairly uniform much of the weekend and into the first
half of next week with daytime highs in the 70s each day.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1255 AM EDT Thu Aug 24 2017

VFR conditions are expected through much of the next 24 hours.
However a weak system will be reaching the region around daybreak.
This will mainly bring a short period of light rain, and could
have some isolated MVFR ceilings with it. Most likely area to see
the MVFR would be near Lake Michigan, where warm waters and cool
air could bring ceilings lower. Have a brief period MVFR at MKG in
the TAF toward daybreak. This MVFR could reach toward GRR, but
left it out of the TAF for now. Then expect the MVFR to mix out by
14Z, before it gets too far inland or much farther south.

After a 3 to 6 hour period of light rain, the system will be
through, with clearing skies by mid to late afternoon.


&&

.MARINE...
Issued at 328 AM EDT Thu Aug 24 2017

Winds and waves will be relatively light into the weekend. There
is a very slight chance of a thunderstorm and even an isolated
waterspout through early afternoon.

&&

.HYDROLOGY...
Issued at 1213 PM EDT Wed Aug 23 2017

Area rivers are around normal levels for the time of the year and
well below bankfull. The rivers have already recovered from the
recent rainfall. No significant precipitation is expected through
the weekend, so no river issues are expected.

&&

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

$$

SYNOPSIS...Ostuno
SHORT TERM...Ostuno
LONG TERM...JK
AVIATION...JK
HYDROLOGY...63
MARINE...Ostuno



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