Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 201118
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
618 AM EST Tue Nov 20 2018

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 230 AM EST Tue Nov 20 2018

Light snow showers and flurries will taper off early this
morning. Another clipper system will bring light snow showers
again tonight. High pressure will bring fair but continued cold
weather Wednesday through Thursday before temperatures undergo a
moderating trend Friday through the weekend with a chance for rain
showers this weekend.

&&

.DISCUSSION...(Today through next Monday)
Issued at 230 AM EST Tue Nov 20 2018

A few light snow showers and flurries will linger over our
southern fcst area for 2-3 more hours (mainly south of I-96)
early this morning before weak ridging briefly builds in to bring
tranquil wx today. However another clipper system will move in
from the northwest tonight and bring another round of light snow
showers.

A consensus of latest high res guidance continues to suggest that
light accumulations of less than an inch will occur tonight. The
relatively higher amounts of over a half an inch are most likely
to occur near to west of US-131 due to lake enhancement with
little to no accumulations over our eastern fcst area.

High pressure building southeast from Canada will bring fair but
cold wx Wednesday through Thursday. Temperatures will undergo a
gradual moderating trend beginning Friday as strong southerly flow
warm air advection develops on the back side of the departing
ridge.

Persistent southerly flow will also result in an increase in
moisture and some showers are forecast this weekend. A potentially
stronger low pressure system is likely to move across the lower
Great Lakes region late Sunday into Monday bringing potential for
more widespread rain. A colder airmass will advect in behind
that system early next week and cause pcpn to change over to snow
showers by late Monday/Tuesday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 615 AM EST Tue Nov 20 2018

Light snow showers will be around for part of today leading to
local impacts. Tonight a more widespread area of snow showers is
forecasted to move in. Confidence is high that we will see MVFR
conditions along with an increased risk for local IFR and lower
conditions. Gusty winds are expected tonight with some values over
20 knots near the lakeshore.



&&

.MARINE...
Issued at 230 AM EST Tue Nov 20 2018

Wave heights will remain hazardous to small craft this morning
before subsiding a bit briefly this afternoon. However winds and
waves will ramp back up tonight after the passage of another cold
front. Southwest winds to 20 to 30 kts are anticipated this
evening which will veer to the northwest overnight and remain up
around 20-30 kts after frontal passage.


&&

.HYDROLOGY...
Issued at 217 PM EST Mon Nov 19 2018

There are no hydrologic concerns through the end of the week. A
few rounds of light precipitation, mostly falling in the form of
snow, will affect the area through Wednesday. The first will be
this afternoon through tonight, with a few light showers lingering
near the lakeshore through early Tuesday. The second round will
occur Tuesday night into Wednesday morning. Thursday and most of
Friday look dry.

Longer range models then continue to show a wetter pattern setting
up Friday evening through early next week. Several rounds of
rainfall look to occur, although the timing from Saturday onward is
still uncertain as forecast models vary widely with the timing,
track, and strength of low pressure systems near the region. We will
continue to monitor potential rainfall amounts, but it does not look
like there will be flooding concerns.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until 5 PM EST Wednesday for LMZ844>849.

&&

$$

SYNOPSIS...Laurens
DISCUSSION...Laurens
AVIATION...MJS
HYDROLOGY...HLO
MARINE...Laurens


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