Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 281131
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
731 AM EDT Tue Mar 28 2017

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 248 AM EDT Tue Mar 28 2017

One area of low pressure will track up the Ohio Valley today. This
system will produce mainly some cloud cover for Michigan. An area
of high pressure in the upper plains will track east tonight and
Wednesday scattering the clouds out. The temperature will end up
close to normal for this time of the year for today and Wednesday.
Another storm will ride up the Ohio Valley for Thursday. This one
will track closer to the region...and result in
precipitation...some of which could be mixed.

&&

.SHORT TERM...(Today through Thursday)
Issued at 248 AM EDT Tue Mar 28 2017

The main forecast challenge deals with the potential impacts with
the storm for Wednesday Night into Thursday.

Relatively quiet weather is forecasted through Wednesday. Starting
Wednesday night into Thursday...a low pressure system will track
up the Ohio Valley. Forecast soundings initially support snow. As
a result...most locations will feature at least a period of snow.
The new High Res Euro would warrant accumulations...especially
toward Mount Pleasant and Harrison. The GFS suggests a period of
snow ...then maybe freezing rain toward 00z Fri for that same
region. Will feature mainly a snow to rain scenario for most of
the region. Any period of snow Wednesday Night or Thursday am for
Grand Rapids and Lansing looks limited at this time...with this
system to be mostly a rain event. Impacts at this point look
limited with surface temperatures mostly above freezing...but this
system bears close monitoring in the coming days as there is some
potential for temperatures to end up cooler than currently
forecasted which would result in impacts.

.LONG TERM...(Thursday night through Monday)
Issued at 248 AM EDT Tue Mar 28 2017

The beginning and the end of the period will be the wettest parts of
the long term. Both the ecmwf and gfs are in pretty good agreement
showing low pressure moving across the Ohio Valley Thursday night
accompanies by an upper trough. Precipitation will mainly be rain.
However, given the cool feed of air from the northeast, the low
levels of the northeast cwa may get cold enough for a brief period
of freezing rain and/or sleet late Thursday night. This is a fairly
progressive system and won`t linger over the Great Lakes and high
pressure will quickly build into the state producing dry weather for
the weekend. Temperatures will climb into the mid to upper 50s by
the end of the weekend and early next week.

The next system early next week isn`t handled as well between the
models. It`s another southern stream system that gets booted east by
a northern stream wave. The resulting phasing isn`t real clean. As
such, model timing and track are not in good agreement. The main
theme, though, is that more rain is possible late Monday as the
system develops over the Arklatex and moves in a general northeast
direction.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 727 AM EDT Tue Mar 28 2017

Low clouds were expanding across Southwest Lower MI early this
morning. Based on the recent trends it looks like the TAF sites
will see IFR for much of the morning. The afternoon is forecasted
to feature a gradual rise in the cloud bases with VFR still
expected to arrive by evening. Patchy drizzle is possible early
this am...which could also reduce the visibility.

&&

.MARINE...
Issued at 248 AM EDT Tue Mar 28 2017

A relatively weak pressure gradient will be in place through
Wednesday. Thus no marine headlines are expected.


&&

.HYDROLOGY...
Issued at 320 PM EDT Mon Mar 27 2017

Most rivers have demonstrated within bank rises after rainfall over
the last 4 days. However, more elevated river levels at Ionia,
Hastings, Eagle, and Holt may be susceptible to additional rainfall
expected Thursday and Friday, possibly another 0.50"-1.00". This may
act to provide secondary river crests heading into the end of the
week and weekend, potentially higher than the current crests.

&&

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

$$

SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...04
AVIATION...MJS
HYDROLOGY...Hoving
MARINE...MJS


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