Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 121800
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
100 PM EST Thu Jan 12 2017

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 328 AM EST Thu Jan 12 2017

Colder air and light snow will move in today across central Lower
Michigan. Some icy conditions can be expected across southern
Lower Michigan with freezing rain making travel hazardous. High
pressure builds in for Friday and generally fair weather can be
expected into the weekend except for a chance of snow Friday
night.

&&

.UPDATE...
Issued at 620 AM EST Thu Jan 12 2017

After collaboration with surrounding WFOs, we will issue a
freezing rain advisory for the southern zones from 12Z to 18Z.
Radar shows area of FZRA moving through the Chicago area now and
the HRRR brings this across I-94 corridor and as far north as I-96
towards Lansing eventually, with a transition to sleet and snow
on the northern edge of the precip shield.

&&

.SHORT TERM...(Today through Saturday)
Issued at 328 AM EST Thu Jan 12 2017

Cold air currently moving into lower Michigan and the forecast
issue in the near term is for light snow today and again Friday
night.

For today...patchy freezing drizzle is expected early this morning
as the DGZ is unsaturated. Soundings show deeper moisture
upstream and this will be arriving the next few hours along with
some f-gen forcing, so we expect the mesoscale snow bands across
Iowa and southern Wisconsin to continue to advance into Lower
Michigan and persist into the afternoon. Some light accums are
expected across the northern half of the forecast area.

Sfc ridging building in for Friday but another area of f-gen
arrives Friday night and this one could put down a stripe of
light snow across the central or northern forecast area.
Superblend guidance was bumped up along with QPF for the 06Z to
12Z Saturday period.

.LONG TERM...(Saturday night through Wednesday)
Issued at 329 AM EST Thu Jan 12 2017

The first couple of days in the long term are quiet. The focus
then shifts to the system that is poised to moved through
the Midwest during the beginning of the work week.

Not changed much over the past 24 hours. The upper level trough over
the Western U.S. will give way to a closed low. The low tracks
through the Central Plains late Sunday into Monday bringing a brief
period of snow at the onset. Mild southerly flow then brings
temperatures well into the 30s and 40s, changing much of the precip
to rain late Monday morning into Tuesday. Some of the precipitation
in central Lower may mix snow late Tuesday. However, mid levels
seems far too warm to support much in the way of frozen precip.

Much cooler air is expected to move in later in the week, brining
near normal temperatures back to the region, while the pattern
continues to remain active.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 100 PM EST Thu Jan 12 2017

Low ceilings persist in the wake of a cold front that has moved
south of the area. The front stretches from northern Ohio to
southern Indiana at 18z. The precipitation has ended, but
widespread IFR lingers across southern Lower Michigan. MVFR
ceilings remain across central Lower Michigan.

As we move through the afternoon and evening hours, these lower
ceilings will move out to the southeast. VFR weather is expected
in all areas near or shortly after midnight. VFR conditions should
then continue into midday Friday.

Winds will be northwest through the next 24 hours, becoming a bit
gusty 10-20 knots, this evening.


&&

.MARINE...
Issued at 329 AM EST Thu Jan 12 2017

Winds and waves will build today and a small craft advisory will
be in effect from late this afternoon into Friday afternoon.


&&

.HYDROLOGY...
Issued at 330 PM EST Wed Jan 11 2017

Rivers are running above normal across the area due to rain, melting
snow and ice jams. The Looking Glass River at Eagle and the Grand
River at Comstock Park have warnings active, as they are expected to
reach flood stage. A watch is out on the Grand River at Robinson
Township due to ice jam potential. Multiple sites also have
advisories active. A period of colder than normal temperatures today
through the weekend may allow river ice to redevelop.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Freezing Rain Advisory until 1 PM EST this afternoon for MIZ059-
     065>067-071>074.

LM...Small Craft Advisory until 4 PM EST Friday for LMZ844>849.

&&

$$

UPDATE...Ostuno
SYNOPSIS...Ostuno
SHORT TERM...Ostuno
LONG TERM...JAM
AVIATION...Duke
HYDROLOGY...63
MARINE...Ostuno



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