Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 251930

Area Forecast Discussion
National Weather Service Grand Rapids MI
330 PM EDT Wed Apr 25 2018

Synopsis/Short Term/Marine/Hydro

Issued at 328 PM EDT Wed Apr 25 2018

High pressure will provide calm and quiet conditions overnight,
which will allow temperatures to fall into the low 30s for most
locations, and the upper 20s along and north of M-10. Dry and
warmer conditions can be expected tomorrow with high temperatures
warming into the low and mid 60s. A trough of low pressure moving
through the area will provide a few rain showers Thursday night
and Friday morning.


.DISCUSSION...(This evening through Tuesday)
Issued at 328 PM EDT Wed Apr 25 2018

Northerly flow with gusts to about 20 mph will persist into the
early evening, with clouds over the northern and eastern portions
of the forecast area gradually diminishing as drier air pushes
in. Upper ridge will build into the area tonight placing the
center of surface high pressure along the MI/IN/OH border. This
will let clear and calm conditions prevail overnight, and may
allow shallow patches of fog to fill in favored locations. Good
radiational cooling conditions and low dewpoints should help lows
drop into the low 30s for most locations, with upper 20s north of

Ridging will keep quiet and dry conditions over the area tomorrow,
with lighter winds. Highs should warm close to normal with
temperatures reaching the low/mid 60s. Temps will be a little
cooler near the lakeshore, where the lake breeze will move inland
during the afternoon.Upper trough now stretching through Central
Canada back into the Pacific Northwest will swing into Michigan
Thursday night, before several upper waves dive into the system
and form a closed low over the Great Lakes by Saturday morning.
Initial surface trough will pass through the western half of
Michigan Thursday evening through Friday morning. This will only
provide a quick shot of lift and moisture, which must first
overcome the antecedent dry airmass before any precipitation can
reach the ground. Held pops in the low chance category. Better
chance for precipitation looks to hold off until late
Friday/Friday evening as the strongest upper wave drops through
the Chicago area (per latest model consensus). This track will
largely keep precipitation south of I-96, which would fall as
rain. Temperatures will run cooler Friday and Saturday behind a
cold front and as the upper low sits overhead. Almost all of this
will fall as rain, but we could see a few flakes mix in Friday
night north of I-96.

High pressure will provide a nice warming trend Sunday through
Tuesday, with highs reaching the 70s for the first part of the
work week.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1258 PM EDT Wed Apr 25 2018

High confidence with VFR conditions continuing through the
afternoon as drier air works into the area behind a cold front.
North-northwest winds will gust to around 20 knots this afternoon
before subsiding this evening. Gusts may drop off a little before
00Z as the gradient starts to weaken. High pressure building into
Lower Michigan tonight will promote clear skies and nearly calm
winds. This could provide some light shallow fog tonight between
09-12Z, especially in favored locations. Confidence in formation
is low at this time, and will continue to look at new data and


Issued at 328 PM EDT Wed Apr 25 2018

Gusty north to northwest winds will continue through the evening,
keeping large waves of 4 to 7 feet over the nearshore waters. High
pressure building into the area tonight and early tomorrow will
allow winds and wave heights to diminish. Gusty winds developing
behind the next cold front late Thursday night into Friday may
cause hazardous conditions for small craft to redevelop.


Issued at 328 PM EDT Wed Apr 25 2018

Rivers are running near to above normal for late April. Only a
handful of locations remain above bankfull at this time. Local,
nuisance flooding may still be an issue for these particular
locations: Ionia, Eagle, Maple Rapids, Newaygo, and Evart. Looking
at the next 7 days, the next risk for rain comes late Thursday and
then again on Friday, but will have no impact on area rivers. Beyond
this, rain may return by the middle of next week but too early to
tell if this will have any impact on area rivers and streams.


LM...Small Craft Advisory until 8 PM EDT this evening for LMZ848-849.

     Small Craft Advisory until 2 AM EDT Thursday for LMZ844>847.



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