Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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081
FXUS63 KGRR 190725
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
325 AM EDT Thu Apr 19 2018

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

.SYNOPSIS...
Issued at 325 AM EDT Thu Apr 19 2018

A slow moving area of high pressure will drift into the Great Lakes
region today and tonight. The high will remain over our area through
the weekend. The high will bring dry and quiet conditions. Mainly
clear skies are expected the next several days. The next chance of
precipitation comes Tuesday night into Wednesday of next week so we
are looking at a prolonged period of dry weather. We are forecasting
a moderating trend in temperatures the next few days. Highs today
will top out in the 40s, warming the 50s for Friday and Saturday and
reaching near 60 on Sunday. Normal highs for this time of year are
in the upper 50s to around 60 degrees.

&&

.SHORT TERM...(Today through Saturday)
Issued at 325 AM EDT Thu Apr 19 2018

The first order of business was the Winter Weather Advisory
headline. We have dropped it with this forecast issuance as the
precipitation has ended and road temperatures remain near or above
freezing. Road temps range from just above freezing along U.S. 10 to
the middle 30s along I-94. Feel limited impacts will occur this
morning and therefore dropped the headline. Cannot rule out a few
slick spots though as air temps try to drop below freezing towards
sunrise below a clearing sky.

Otherwise, an uneventful short term period is expected with dry
weather and mainly clear skies. There is a period from Friday night
into Saturday when high cloud cover will increase. Skies will
generally be partly cloudy through this time frame. 300-500mb layer
RH values peak Saturday morning around 75 percent though. It may
even trend towards mostly cloudy Saturday morning with the high
cloud cover.

.LONG TERM...(Saturday night through Wednesday)
Issued at 325 AM EDT Thu Apr 19 2018

High pressure will maintain a stretch of dry and quiet weather into
Monday. Meanwhile, large upper low will amble across the country and
into the southeast U.S. early next week. This will precede a
northern stream trough pushing across the Great Lakes Tuesday into
Wednesday. A few previous model runs had scooped the southern low up
ahead of the northern stream trough, bringing it into the Great
Lakes on Tuesday. 19.00Z runs have backed off this scenario, keeping
these systems unphased. Will continue to monitor model trends, but
current forecast keeps Tuesday mostly dry before surface low
pressure and a cold front associated with the approaching upper
trough provides a chance for showers Tuesday night and Wednesday.

Temperatures look to finally reach near normal early next week, with
highs in the low 60s Sunday and Monday, and mid 60s Tuesday.
Temperatures will be cooler near Lake Michigan.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 137 AM EDT Thu Apr 19 2018

Snow associated with low pressure tracking across the Ohio Valley
will continue to affect southern terminals for the next few hours
before ending. At 530Z, back edge of snow had cleared GRR and was
about to clear LAN. Low-end MVFR to IFR conditions will persist at
AZO, BTL and JXN until 08-09Z before quickly transitioning to VFR.
VFR conditions will then persist through the remainder of the
night and all day Thursday, with forecast models indicating very
little moisture available for even cu formation after 12Z.

&&

.MARINE...
Issued at 325 AM EDT Thu Apr 19 2018

Small Craft Advisory remains in effect through midnight. Winds and
waves are on the increase, with Michigan City at the south end of
the lake, blowing at 25-30 knots. The Port Sheldon buoy has 2
footers as of 240am, but that will be on the increase as the waves
fill in along the shore. 4 to 7 footers will be common in the
nearshore waters today. Waves will subside quickly after dark as the
winds come down. A stretch of very quiet conditions is expected from
late tonight through Saturday night with high pressure centered over
the Great Lakes.

&&

.HYDROLOGY...
Issued at 140 PM EDT Wed Apr 18 2018

Lowland flooding near riverbanks will be ongoing over the next
several days as water from last weekend`s mixed precipitation event
moves through the river basins. About 0.2 inches of rain/snow are
expected tonight in the Grand and Kalamazoo basins. Since no heavy
rain events are anticipated through early next week, river levels
will gradually crest then subside. The exception may be the Muskegon
and Chippewa Rivers, which still have a fair amount of surface water
locked up as snow/sleet. That snowpack will gradually melt with
warmer temperatures this weekend, so flood concerns are limited
though river levels will remain elevated.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until midnight EDT tonight for LMZ844>849.

&&

$$

SYNOPSIS...Duke
SHORT TERM...Duke
LONG TERM...HLO
AVIATION...HLO
HYDROLOGY...CAS
MARINE...Duke



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