Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 281820

Area Forecast Discussion
National Weather Service Grand Rapids MI
220 PM EDT WED SEP 28 2016

Synopsis/Short Term/Long Term/Marine

Issued at 220 PM EDT Wed Sep 28 2016

A large area of low pressure will remain anchored over the Great
Lakes through much of the weekend. That will result in numerous
showers and high temperatures in the mid 60s.


.SHORT TERM...(This evening through Friday night)
Issued at 220 PM EDT Wed Sep 28 2016

There was little change to the going forecast. Short range models
continue to have a good handle on the progression...or lack
thereof...of the upper low as it tracks across Michigan and south to

Latest radar imagery shows an area of showers moving northwestward
from southeast Lower. This is in response to a short wave pivoting
around the upper low that`s anchored over indiana. We`re going to
see a few more waves rotate around the low as it moves slowly back
north toward the cwa by Saturday. Pops will remain high across the
southeast cwa through the period and decrease as you go toward the
northwest away from the upper low.

Not much change in temperature is expected either under this cloudy
environment. Highs in the mid 60s and lows in the mid 50s are

.LONG TERM...(Saturday through Wednesday)
Issued at 150 PM EDT Wed Sep 28 2016

The main issue today is when does the upper low move away far enough
to end the periods of rainfall. There is a decent amount of model
agreement on Sunday night being that time period when the rain
should finally end. There is an issue of heavy rainfall into at
least Saturday from the wrap around on the north side of the system,
feeding moisture from the Atlantic back into Michigan.
That will have to be watched but where the heaviest rain will be is
hard to say this far out in time.

Once that system gets out of the way we should see upper ridging
bring a dry period Monday into Wednesday. Then the next Pacific
system will bring the threat of rain back to the area later Wed into
at least Friday.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 150 PM EDT Wed Sep 28 2016

Really this is a complex forecast as we have to time in periods
of rain from shortwaves rotating around the upper low. VFR
conditions should largely remain at MKG as most of the rain
should be south of there and even if it does rain there later this
afternoon it should not be enough to cause deteriorating
conditions, VFR should continue. The I-94 TAF sites should see
the most persistent rain later this afternoon into Thursday. I
would expect IFR cigs/vsbys by Thursday morning for those TAF
sites. GRR and LAN are on the north edge and are the most
questionable. There is an area of rain rotating westward from the
Detroit area now and that should reach the GRR/LAN TAF sites by
21z or so. It should move out of there through by 00z or so and I
would expect it to be dry there most of the night before more rain
moves in by midday Thursday with at least MVFR there.


Issued at 220 PM EDT Wed Sep 28 2016

Issued a small craft advisory through Friday. The combination of
northeast winds 15 to 25 knots coupled with waves aoa 3 feet will
make the lake hazardous for small craft.


Issued at 140 PM EDT Tue Sep 27 2016

River levels are around normal for this time of year. Lake enhanced
rain showers are possible through Wednesday. Rain showers continue
to be possible into Sunday. Rainfall totals into the weekend will
range from a half inch up to an inch and a half. Rivers and streams
should remain below bankfull through the weekend.


.GRR Watches/Warnings/Advisories...
LM...Small Craft Advisory from 6 PM this evening to 6 PM EDT Friday
     for LMZ844>849.



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