Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 160001
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
801 PM EDT Fri Sep 15 2017

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 259 PM EDT Fri Sep 15 2017

More nice late summer weather can be expected for much of the
weekend with above average temperatures expected. The weekend will
start out sunny, but clouds will increase on Sunday with a chance of
a storm developing in the afternoon and Sunday night.

Occasional chances of rain will remain through early next week as a
couple of systems move through. Temperatures will remain mild
through the period.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 259 PM EDT Fri Sep 15 2017

Our only real weather in the short term will be the going chance of
a few showers/storms in the Sunday/Sunday night time frame. Up until
then, above average temperatures and dry weather can be expected.

We should remain mainly clear through much of Sat night with only
some scattered cumulus the rest of this afternoon and Sat afternoon.
Upper heights are building and the upper ridge axis is almost right
over the area. This has prevented a few light showers over WI
earlier from making it here as they dissipated. We should see a
couple of degrees tacked on to today`s highs with h850 temps
increasing a tad.

The chance of rain will slowly increase on Sunday, with the best
chance coming late Sun afternoon and Sun evening. This chance is
still not expected to be very good, and many areas will likely miss
out on rain with this. The large scale forcing with the upper wave
and upper jet will remain well NNW of here, focusing the better
moisture transport there also. The only thing we have going for us
is that the front comes through during peak heating. Instability
looks to remain sufficient to mention thunder.

.LONG TERM...(Monday through Friday)
Issued at 259 PM EDT Fri Sep 15 2017

The only certainty with this forecast continues to be temperatures 5
degrees or more above normal through the long term. Though mostly
expected to be light, precipitation timing remains very different
between the mid range models. Therefore, at least a slight chance of
rain and/or thunderstorms is included for all of the long term,
except for Wednesday. The best chance for weather seems to be Monday
night into Tuesday, as a weak low moves along the cold front pulling
south of the area, and Friday afternoon and evening with another low
moving up a front laying across the region.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 801 PM EDT Fri Sep 15 2017

VFR weather is expected for the most part the next 24 hours. The
exception will be some fog tonight between 09z and 14z. We are not
expecting stratus, and the bulk of any fog that develops should be
MVFR (3-5SM). Some localized IFR or even lower is certainly
possible, but stronger winds aloft should keep the fog in check
tonight.

Otherwise, mainly clear skies are expected tonight with some
scattered to broken cumulus development on Saturday with bases
around 4,000ft. Winds will be light from the SSE tonight and from
the S at 5-10 knots on Saturday.

&&

.MARINE...
Issued at 259 PM EDT Fri Sep 15 2017

We will see winds pick up some for the weekend from the S/SW out
ahead of the incoming front late Sunday. Right now, winds and waves
look to stay just a little shy of Small Craft Advisory criteria.
Winds should then diminish a bit early next week with a weak
pressure gradient expected to be in place.


&&

.HYDROLOGY...
Issued at 1136 AM EDT Fri Sep 15 2017

Precipitation forecasts are mostly dry for the long term period,
which will continue to result in near/below normal river levels.
No hydro concerns exist in the foreseeable future.

&&

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

$$

SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...63
AVIATION...Duke
HYDROLOGY...JAM
MARINE...NJJ



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