000
FXUS63 KGRR 251906
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
306 PM EDT Thu May 25 2017

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

.SYNOPSIS...
Issued at 306 PM EDT Thu May 25 2017

Mostly near normal to cooler than normal temperatures expected for
the next week. There will be a couple of shots for light rainfall
this weekend and again late next week...though no significant
impacts from weather are expected.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 306 PM EDT Thu May 25 2017

European and GFS models continue to show differences in the effects
on lower Michigan of a weak low moving through the Ohio Valley
Friday/Friday night. Tend to lean more toward drier solution of the
Euro than the wetter solution of the GFS as the Euro has been a bit
more consistent with precipitation placement. The European also
continues to keep the precipitation much closer to the low than the
GFS does and this seems to make a little more sense. For now have
kept chance pops in on Friday night...but confidence is
increasing in the possibility of removing these from the forecast.
Saturday looks fairly nice and is still on track to be the nicest
day of the weekend with temperatures in the mid to upper 70s.


.LONG TERM...(Sunday through Thursday)
Issued at 306 PM EDT Thu May 25 2017

The initial cold front/shortwave preceding our next upper low is
shown to move through the region on Sunday. Timing of this feature
is a bit unclear but if it slips through in the morning the
afternoon could turn out nice (especially in western sections) in
the wake of departing showers and tstms. Highs in the low to mid 70s
are expected on Sunday with the colder air mass still upstream.

On Memorial Day the next upper low/trough will be digging into the
region. Cold advection pattern and cyclonic flow may result in some
afternoon/early evening diurnal showers, although at this time it
looks like those would be mainly north of I-96 on the holiday.
Slightly cooler highs near 70 expected.

Confidence is high that Tuesday and Wednesday will be unseasonably
cool and breezy days with highs only 60-65. The upper trough will be
firmly entrenched over the Great Lakes Region with H8 temps only
around 2-5C. Shortwaves swinging through base of the longwave trough
will bring occasional rain showers.

The shower threat will end and temperatures will moderate Thursday
as the upper trough begins to lift out.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 143 PM EDT Thu May 25 2017

IFR cigs were persisting southeast of a line from AZO to LAN
early this afternoon while improvement to MVFR has taken place
elsewhere. While cigs are expected to slightly improve through
early evening, they are expected to lower again tonight.

Confidence is high that widespread IFR/LIFR will redevelop and
impact the area late tonight /06Z-12Z/, with gradual improvement
to MVFR/VFR following after 12Z Friday. Lingering isolated showers
this afternoon are not expected to have a significant impact on
visibilities and would be of brief duration.


&&

.MARINE...
Issued at 306 PM EDT Thu May 25 2017

Light winds and small waves are expected for the next few days. some
fog may be possible at times near shore...especially friday morning.

&&

.HYDROLOGY...
Issued at 158 PM EDT Thu May 25 2017

An active pattern will set up across the Central U.S. over the
holiday weekend. The heaviest rainfall is expected to stay south
of Lower Michigan, stretching from Texas, northeast through the
Ohio Valley. Lower Michigan seems to stay north of the heaviest
precipitation amounts. Any appreciable precipitation should
remain light and be rather short in duration.

Despite low risk for additional flooding, elevated river levels
over southern portions of Lower Michigan will remain sensitive to
heavier rainfall. Any deviation in the current forecast could
impact river levels. Anyone planning activity on/or near rivers
this weekend should pay attention to updated forecasts.

&&

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

$$

SYNOPSIS...Maczko
SHORT TERM...Maczko
LONG TERM...Meade
AVIATION...Meade
HYDROLOGY...JAM
MARINE...Maczko