Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 261930
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
330 PM EDT Fri May 26 2017

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

.SYNOPSIS...
Issued at 330 PM EDT Fri May 26 2017

Showers and isolated thunder will move across areas mainly along and
south of I-96 tonight.  Some areas south of I-94 could pick up as
much as a half inch of rain. Then as we open up the holiday weekend,
Saturday will be dry and comfortable, with highs in the 70s. However
a more widespread area of showers and storms will arrive late
Saturday night, that will linger into Sunday evening.  All areas
should see a quarter to a half inch of rain in this period.

More widely scattered showers and storms will be possible Memorial
Day into Tuesday, before we dry for much of the rest of the week. We
will stay at or slightly below normal next week, with most daytime
highs in the upper 60s to mid 70s.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 330 PM EDT Fri May 26 2017

An MCS will slide east across Southern Lower MI tonight.  Then a
break from the rain will occur Saturday, for the best day of the
holiday weekend.  Then another period of showers and storms moves in
by late Saturday night and continues on and off Sunday and Sunday
evening.

.LONG TERM...(Monday through Friday)
Issued at 330 PM EDT Fri May 26 2017

MCS was located over North Central IL as of 19Z and is expected to
track east, then east southeast tonight.  The jet dynamics and best
instability remains to our south.  So only expect showers on the
north end of the MCS, with embedded thunder.  Much of the rain will
stay along and south of I-96, with only hit and miss pcpn north.  A
period of moderate to heavy will be possible along the I-94 corridor
where some areas may see up to a half inch of rain.  However any
severe risk will stay well to our south.  I removed lowered POPs
toward daybreak as most of the pcpn should be east after 09Z.

Weak surface high pressure and upper ridging builds back into the
region for Saturday.  Will keep the forecast dry, however their
appears to be a fair amount of lingering low level moisture,
especially south.  For that reason I have gone with more clouds on
Saturday, but still most areas should see partly sunny conditions
into the afternoon.  Trimmed max temps to hold in the 70s, and
staying in the lower 70s for the cloudier SE CWA.

More showers and storms arrive late Saturday night as the upper
ridge moves east and a short wave moves into the upper midwest. This
wave eventually becomes an upper low into Sunday night.  A surface
front and low pressure arrives around mid day, so this should spread
a fairly widespread area of pcpn across the area.  Maintaining the
likely POPs.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 150 PM EDT Fri May 26 2017

VFR conditions will prevail through the afternoon then an area of
showers and a few thunderstorms will be arriving around 00Z. This
will bring areas of MVFR across southern Lower Michigan generally
south of MKG to GRR to LAN. The rain should taper off and end
around midnight with MVFR and patchy IFR lingering into Saturday
morning from AZO to JXN.

&&

.MARINE...
Issued at 330 PM EDT Fri May 26 2017

Waves will be held to two feet or less through Sunday night.  This
leave the threat of thunder as the main concern for boaters this
holiday weekend.  Highest thunder chance will come late Saturday
night through Sunday afternoon.

&&

.HYDROLOGY...
Issued at 217 PM EDT Fri May 26 2017

River levels in the upper Grand and the Kalamazoo basins are
running above normal for late May while elsewhere the levels are
closer to normal. Rain totals generally under a half inch in
Southern Michigan Friday night, then across much of the area on
Sunday, will likely not be enough to produce flooding.

&&

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

$$

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


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