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378
FXUS63 KGRR 240818
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
418 AM EDT Tue Apr 24 2018

LATEST UPDATE...
Marine

.SYNOPSIS...
Issued at 330 AM EDT Tue Apr 24 2018

Cooler temperatures can be expected the rest of the week,
although highs will still be near to only slightly below normal.

Weak low pressure over the Ohio Valley and a cold front
approaching from the northwest will bring clouds and scattered
showers today and tonight. High pressure will build back into the
region on Wednesday resulting in decreasing clouds and dry weather
which continues into Thursday.

Another chance of showers arrives late Thursday night and Friday
with a cold front which ushers in a cool air mass for the weekend.

&&

.SHORT TERM...(Today through Thursday)
Issued at 330 AM EDT Tue Apr 24 2018

Coverage of showers has been very limited so far and generally
just trace amounts of rain have been observed. This should
continue to be the case this morning due to dry air still hanging
around, although an uptick in coverage and intensity is possible
for a time this afternoon and evening due to the approach of a nrn
stream shortwave and a possible diurnal boost.

The best chance of a few heavier, more organized, rain showers
looks to develop in a narrow band along the sfc cold front late in
the afternoon from Gaylord/Alpena southwest to Big Rapids. This
band of showers will move southeast during the evening, then
gradually dissipate after dark. However the risk of showers will
linger until about 12Z Wednesday when the nrn stream trough axis
passes through.

We may see considerable diurnal cumulus development on Wednesday
due to a pocket of cold air aloft, especially near and east of
Highway 131. A lake shadow should provide mostly sunny skies at
the lakeshore, but brisk northwest winds off the chilly waters
should hold down temps, and some coastal communities may struggle
to reach 50 on Wednesday. Winds will be lighter on Thursday as the
sfc ridge comes overhead, and diurnal cu potential will be less.


.LONG TERM...(Thursday night through Monday)
Issued at 330 AM EDT Tue Apr 24 2018

A cold front will bring a chance of rain showers late Thursday night
into Friday. High temps Friday and Saturday will only reach the
lower to perhaps middle 50`s.

A high pressure ridge will build in from the northwest and bring
fair weather Sunday into early next week. High temps Sunday will
reach the upper 50`s to lower 60`s with ample sun with subsidence
under the ridge over MI by then.

A significant moderating trend of temps will occur early next week
as strong southwest flow warm air advection develops after departure
of the ridge. High temps by early next week will reach the 70`s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 1140 PM EDT Mon Apr 23 2018

VFR conditions will gradually deteriorate to MVFR overnight as
lower clouds move in and scattered light rain showers develop. The
combination of low clouds and scattered showers/drizzle will
result in MVFR to IFR cigs and visbys through the day Tuesday and
Tuesday evening. Wind speeds will be aob 10 kts through the next
24 hours and predominantly out of the east through Tuesday evening
before backing to the north northwest Tuesday night.

&&

.MARINE...
Issued at 418 AM EDT Tue Apr 24 2018

After coordination with APX/IWX/LOT, have issued Small Craft
Advisories for all marine zones. The advisory starts at 8 PM
tonight north of Whitehall and at 2 AM tonight for the rest of the
nearshore. A period of brisk northerly winds of 15 to 25 kts and 4
to 7 ft waves is expected, beginning tonight and continuing into
Wednesday evening.

&&

.HYDROLOGY...
Issued at 307 PM EDT Mon Apr 23 2018

Five Flood Advisories remain on the area rivers as of this morning.
River levels are cresting up north where snow melt from Northern and
Central Lower has allowed for some runoff. The snow has pretty much
entirely melted in the Muskegon basin, so river levels will start
coming down.

For all areas, rain is expected tonight into Wed. Basin averages
should be mostly under quarter of an inch, with everybody expected
to stay under half an inch. This over a period of time should not
cause any rises on the rivers this week.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory from 8 PM this evening to 8 PM EDT
     Wednesday for LMZ848-849.

     Small Craft Advisory from 2 AM Wednesday to 2 AM EDT Thursday
     for LMZ844>847.

&&

$$

SYNOPSIS...Meade
SHORT TERM...Meade
LONG TERM...Laurens
AVIATION...Laurens
HYDROLOGY...NJJ
MARINE...Meade