Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 270900
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
500 AM EDT Sun May 27 2018

LATEST UPDATE...
Update

.SYNOPSIS...
Issued at 306 AM EDT Sun May 27 2018

An area of high pressure will remain over the region into Monday.
This feature will act to keep the weather dry for most places.
Temperatures will end up very warm for this time of the year at
the weather pattern will remain nearly stationary into Tuesday.

&&

.UPDATE...
Issued at 457 AM EDT Sun May 27 2018

Models are struggling with the nocturnal convection to the
northeast of Big Rapids. This was occurring in the region of
deeper moisture convergence...which is shown to shift east early
this morning.  I did feature a chance for some storms early this
morning in the forecast for this region.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 306 AM EDT Sun May 27 2018

Patchy fog was developing at this time...mainly in areas that saw
some rain during the day. The visibility at Mt Pleasant was under
3 miles. This fog should dissipate fairly quickly after sunrise.

It will once again become rather unstable this
afternoon...especially inland. Any forcing remains weak through
the day...but a storm or two could form well inland...closer to Mt
Pleasant and possible down to Lansing. The deep layer shear will
be relatively weak. Thus the storms should be pulse in nature.
Odds are with the PWAT values falling off today...dry weather
should prevail.

Will feature dry weather on Monday for now. Most models support
the dry conditions...but the latest High Res Euro does generate a
few afternoon thunderstorms in the Mt Pleasant to Harrison region.
PWAT values are forecasted to start climbing...so will need to
monitor precipitation trends closely.

.LONG TERM...(Tuesday night through Saturday)
Issued at 306 AM EDT Sun May 27 2018

The main forecast concern in the long term is the moisture moving
north with what`s left from the tropical system. Both the gfs and
ecmwf have been in pretty good agreement with the movement of this
system for a few days and move it north from Alabama into southwest
Lower by Wednesday afternoon. Precipitable water values increase to
greater than 2 inches suggesting a really juicy airmass. However,
given the arrival of the low on the west side of the cwa and that
heavier precipitation is usually on the northwest side of the low,
it`s very possible that the heaviest precipitation will stay west of
the cwa over Lake Michigan. Both the ecmwf and gfs show that. Of
course, any movement of the track of the low to the east would
result in higher qpf over the cwa. Latest model trends don`t move
the low to the east side of the state and instead take it north to
the Straits. That type of track would likely mitigate the flood
threat.

We`ll start to dry out Thursday night and Friday and Saturday look
dry. Highs will be 75 to 80 through the period.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1155 PM EDT Sat May 26 2018

Regional radar shows decaying showers and thunderstorms across
Lower Michigan. This precipitation will dissipate prior to
reaching the taf sites. Only high clouds are expected during the
period. A brief period of fog is possible from 09z-12z.


&&

.MARINE...
Issued at 306 AM EDT Sun May 27 2018

Satellite imagery indicates fog over the nearshore zones. High res
models try to keep the fog in place through the day. Will maintain
the fog wording through the day and into tonight. Models forecast
the fog to diminish somewhat later tonight into Monday. Will
feature patchy fog for this period.


&&

.HYDROLOGY...
Issued at 319 PM EDT Sat May 26 2018

River stages continue falling. This trend will continue through the
holiday weekend. The next risk for basin wide, measurable rainfall
will hold off until the middle of next week when the remnants of
Alberto will likely move into the Great Lakes region. Projected
rainfall amounts may boost a few river sites out of their banks, but
flooding appears unlikely at this time given the progressive nature
of the system across the area. Trends will continue to be
monitored.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&

$$

UPDATE...MJS
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...04
AVIATION...04
HYDROLOGY...Hoving
MARINE...MJS


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