Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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532
FXUS63 KGRR 210830
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
330 AM EST Sat Jan 21 2017

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

.SYNOPSIS...
Issued at 330 AM EST Sat Jan 21 2017

Today will start out with dense fog and scattered rain shower but
the passage of a warm front late this morning should push the
showers and fog north of the area. It will also push our air
temperatures into the mid 50s near and south of I-96. However a
storm developing over Colorado this morning will track into the
Southern Plains Sunday and a trailing cold front from the northern
system will push through the area ending our brief warm spell.
Scattered showers are possible.

Sunday night into Monday there is some question as to how far
north that system gets but the current thinking it will get close
enough to bring us rain Sunday night into Monday. The next storm
coming trough, in the Wednesday time frame will bring winter back
to the area. This should be a rain to snow event and after that it
should be below freezing with periods of snow into the following
week.


&&

.SHORT TERM...(Today through Monday)
Issued at 330 AM EST Sat Jan 21 2017

There are several issue to deal with this morning. The first is
the fog adviosry and what to do with it. Next is the showers
around us...and what to do with that. The other issue is that
storm that for Monday, how close does it get to us?

First for the fog, after coordinating with IWX, I plan on killinjg
the adviosry south of I-96 but holding on to it north of that. We
have a warm front, which at 3 am was just south of I-96 as winds
are from the south near I-94 with temps in the mid 40s, while over
I-96 area winds are east and temperatures are in the 30s. There
is an area of showers are just north of the warm front but it is
moving northward. South of the warm front visibilities are over 5
miles. So it will lift north and kill the fog.

The system for Monday has been tracking more and more to the
norhtwest with each model run. I am thinking we will get rain from
this system.




.LONG TERM...(Monday night through Friday)
Issued at 330 AM EST Sat Jan 21 2017

A sfc/upper trough will bring extensive cloud cover and showers
Monday night before showers taper off Tuesday as upper ridging very
briefly builds in. Unsseasonably mild wx will continue Monday night
through midweek.

A fairly strong low pressure system will move northeast into the
Great Lakes region Tuesday night and Wednesday and bring potential
for mixed pcpn. A consensus of latest medium range guidance
continues to suggest a mix of pcpn at the onset of pcpn Tuesday
night followed by mainly rain for most of our fcst area Wednesday
with a rain/snow mix over our northern fcst area.

This system will need to be monitored closely as a low track a
little further south and earlier arrival of colder air would
potentially bring accumulating snow to a larger portion of our area.
Temperatures will finally cool to closer to normal for this time of
year behind that system for late in the week in a nw flow caa
pattern.

Scattered snow showers are also anticipated late in the week as an
upper trough settles over the Great Lakes region. H8 temps will also
likely be cold enough for some lake effect snow showers late in the
week as well.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1144 PM EST Fri Jan 20 2017

IFR/LIFR with some VLIFR will continue overnight through much of
Saturday morning due to areas of dense fog. Southwest flow will
develop Saturday so we expect low clouds and fog to dissipate and
break up from around midday through the afternoon. Conditions will
improve to MVFR Saturday afternoon and eventually VFR by late
afternoon/evening.


&&

.MARINE...
Issued at 330 AM EST Sat Jan 21 2017

No small craft avisory planned.

&&

.HYDROLOGY...
Issued at 326 PM EST Fri Jan 20 2017

The Grand River at Robinson Township has been falling to near flood
stage today. Runoff from rain earlier this week is being routed
downriver as the ice restrictions decrease. Most rivers are rising
due to the rain, but seem to have less notable ice impacts now.
Temperatures (and dew points) will be above 32 degrees through the
middle of next week, with highs at or above 50 possible Saturday and
Sunday. The remaining river ice should move out or melt, at which
time flooding at Robinson would likely alleviate. Low-land flooding
near riverbanks is occurring at multiple forecast points, but
impacts to property are minor.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Dense Fog Advisory until 10 AM EST this morning for MIZ037>040-
     043>046-050>052-056>059-064>067-071>074.

LM...Dense Fog Advisory until 10 AM EST this morning for LMZ844>849.

&&

$$

SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...Laurens
AVIATION...Laurens
HYDROLOGY...63
MARINE...WDM



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