Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 151144
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
644 AM EST Sun Jan 15 2017

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 308 AM EST Sun Jan 15 2017

High pressure centered over the region will continue to control
the weather through tonight. Seasonably cold temperatures are
forecasted. For Monday into Tuesday an area of low pressure will
track out of Texas and through the western Great Lakes region.
This system will generate a wintry mix of precipitation for the
area...that will transition to all rain. High pressure then builds
in behind this system for the middle part of the week.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 308 AM EST Sun Jan 15 2017

The trend is toward more freezing rain...mainly for Monday night
into Tuesday morning. Currently it looks like this will evolve
into an advisory event. We are still several periods away from
this potential event...and no headlines will be issued at this
time.

Models show the soundings saturating later Monday into Monday
evening. The onset could feature a mix of precipitation types. We
are still looking at temperatures climbing above freezing for most
locations on Monday...so impacts may initially be limited. As the
precipitation becomes steadier...the low level temperatures cool
off with areas to the north and east of a Muskegon to Lansing line
likely to go below freezing. The new High Res Euro does support a
period of snow for some of these counties...that will transition
to freezing rain. Impacts could increase as the temperatures drop
off a few degrees and freezing rain increases. Currently the winds
speeds look relatively low...which may lessen the impacts
somewhat. At this time it looks like up to a quarter inch of ice
could accumulate...which would easily lead to some impacts.

.LONG TERM...(Tuesday night through Saturday)
Issued at 308 AM EST Sun Jan 15 2017

An upper trough should remain over the Eastern U.S. into mid week.
This should keep us showery and cool.  Most of the pcpn appears to
be rain, but some snow could mix in.  It looks like we dry out
later Wednesday as weak surface ridging arrives.

Then upper ridging builds across the area and the surface winds
become southerly by Thursday, signaling a warm up.  H8 temps climb
from around 0C on Wed to +7C Thu night and Fri.  The ECMWF wants to
temporarily break down the upper ridge with a short wave Friday
night, which could bring some rain, otherwise this warmup should
come with fairly quiet weather.  The ridge appears to reestablish
itself into the weekend with temps remaining well above normal in
the upper 40s to around 50.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 641 AM EST Sun Jan 15 2017

Close monitoring of the conditions today will be needed. A small
risk exists for sub IFR clouds to develop today. We currently have
higher level clouds in place...which have acted to limit this
risk. However they will likely scatter out later on. It is not
that common for low clouds to form as the sun goes higher in the
sky...so I did not include these low conditions...but some
computer models are attempting to do that.

&&

.MARINE...
Issued at 308 AM EST Sun Jan 15 2017

The pressure gradient will remain weak through tonight...keeping
winds mostly under 15 knots. The waves will also remain low. While
a low pressure system will be approaching the area on Monday the
winds are not forecasted to increase much. Plus with an offshore
flow developing...wave heights will remain limited. No headlines
are planned at this time.


&&

.HYDROLOGY...
Issued at 122 PM EST Sat Jan 14 2017

Rivers are running above normal across the area due to rain, melted
snow and ice jams. The Grand River at Robinson Township has an
active warning for minor flooding. Multiple sites also have active
advisories. A period of colder than normal temperatures through the
weekend may allow river ice to thicken. Next week looks warmer than
normal with highs possibly reaching the 50s. This could melt the
river ice and allow the rivers to flush out.

&&

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

$$

SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...JK
AVIATION...MJS
HYDROLOGY...63
MARINE...MJS


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