Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 221922

Area Forecast Discussion
National Weather Service Grand Rapids MI
322 PM EDT Tue May 22 2018

Synopsis/Short Term/Long Term/Marine

Issued at 323 PM EDT Tue May 22 2018

The sky is expected to clear by early this evening. That will
allow extensive fog to develop overnight. Mostly clear skies and
warming temperatures are expected Wednesday and Thursday. Expect a
summer like weather pattern over the Memorial Day Weekend.
Thunderstorms are possible Saturday evening. Otherwise highs will
be well up into the 80s each day through Monday.


.SHORT TERM...(This evening through Thursday)
Issued at 323 PM EDT Tue May 22 2018

The only significant weather of concern is the fog areas of dense
fog I expect during the early to mid morning hours of Wednesday.
Once that fog is gone high pressure will provide light winds and
mostly clear skies

The upper trough that has allowed the system that brought a
soaking rain to the area yesterday into last night has moved east
and is being replaced by a large upper ridge. That upper ridge is
being built and forced east by a large Pacific systems moving
toward Alaska. That will also force the closed upper low out of
the SW CONUS. All of that ridge building forces a lot of
subsidence over Lower Michigan so I would expect mostly clear
skies and light wind Wednesday and Thursday. Temperatures will
warm each day. Highs should be close to 80 by Thursday afternoon.

.LONG TERM...(Thursday Night through Tuesday) Issued at 323 PM
EDT Tue May 22 2018

A pattern change to a more prolonged period of more summer-like
weather can be expected in the longer term portion of the forecast,
which includes the Memorial Holiday weekend. We can expect
persistent warmer temperatures along with a small chance of mainly
afternoon/evening storm chances.

We do not expect much rain before Saturday for most of the area. The
upper ridge building in behind the trough moving through today will
hold to our west and eventually over the area through Fri. This will
continue the dry weather and warmer temps that starts off in the
short term.

The chance of rain will start out on Saturday, with much of the area
seeing scattered coverage. Areas toward Clare may see a bit better
coverage as a short wave clips that area. The rest of the area will
see more humid conditions develop, and resulting instability as the
low level flow comes in from the Gulf and the developing tropical
system. Much of the day will be at least partly sunny with just a
few pop up showers/storms for inland areas.

Sunday through Tuesday will not see much change in the weather as
the upper air pattern will become a bit amplified and stagnant.
Upper low over the Great Basin, strong downstream upper ridge over
the Plains, and the tropical system near the Gulf, will all hold the
pattern in. This will continue the warm weather in the 80s for the
area with small afternoon/evening pop up storm chances each day.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 144 PM EDT Tue May 22 2018

Ceilings are improving from IFR to MVFR, visibilities have for the
most part improved to VFR. I expect skies to totally clear by late
afternoon. Clear skies and light winds, after the soaking rain
last night then having generally cloudy skies today will lead to
widespread fog Wednesday morning. This will be more of a problem
near the lakes shore were air cooled by the cold surface water of
Lake Michigan advects into the slightly milder and nearly
saturated air just inland. This will result in MKG, AZO and BTL
having LIFR fog toward morning. GRR and LAN may have an issue too
but at this point I was less confident so I have MVFR fog there.
All of the fog should lift and skies should be clear by early


Issued at 323 PM EDT Tue May 22 2018

The latest visible satellite images show the fog continues in the
near shore and the Muskegon web came as well as Michigan City show
the dense fog continues so I will leave the dense fog advisory as
is. It may have to extended.

Otherwise winds will be light so no need for small craft
advisories through Thursday.


Issued at 1234 PM EDT Tue May 22 2018

A half inch to over an inch of rain fell yesterday into today.
This will lead to some rises on area rivers. However, only minor
flooding should occur. We should remain dry until the weekend. This
will allow rivers to recover a bit before rainfall returns.


LM...Dense Fog Advisory until 5 PM EDT this afternoon for LMZ844>848.



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