Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 231224
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
824 AM EDT Fri Jun 23 2017

LATEST UPDATE...
Hydro

.SYNOPSIS...
Issued at 330 AM EDT Fri Jun 23 2017

A cold front will push south through the area this morning bringing
rounds of showers and thunderstorms. Cooler and less humid air will
filter in behind the front this evening and tonight. Lows tonight
will dip into the upper 50s with highs on Saturday only making it to
around 70 degrees. The cooler conditions will persist into Sunday as
well with highs around 70 once again. After a dry night tonight,
small chances for showers and a scattered thunderstorm return to the
forecast for the weekend.

&&

.SHORT TERM...(Today through Sunday)
Issued at 330 AM EDT Fri Jun 23 2017

We will be dropping the areal flood watch with this forecast
issuance as the heavier rain is winding down across Central Lower
Michigan. This area is covered by Flood Advisories and Flood
Warnings at this time. South of that area, we are expecting more
transient showers and storms as the cold front is finally on the
move south. The front stalled across Central Lower Michigan earlier
in the night resulting in rainfall totals in excess of 5 inches
across portions of Isabella County. Showers and storms will work
south into the I-96 corridor before day break and move south of I-94
around noon. Skies will turn partly cloudy this afternoon as deep
layer RH values below 50 percent late this afternoon and evening.

A quiet night tonight will be followed by a return to more unsettled
weather this weekend. Not expecting a washout, but diurnal
instability will build each afternoon with a chance for showers and
a few storms both Saturday and Sunday. The upper pattern will
feature northwest flow with embedded shortwaves working through the
area.

.LONG TERM...(Sunday night through Thursday)
Issued at 330 AM EDT Fri Jun 23 2017

The long term period starts off with a mid to upper level trough
over the Great Lakes Region.  Models are in decent agreement in
tracking it slowly east Sunday night into Tuesday.  The latest GFS
is quicker with this features departure.  So it looks unsettled with
the cold core system overhead and relatively warmer lakes around.

Mid level heights rise steadily into Wednesday as warm air advection
strengthens.  Will need to monitor the risk for showers and
thunderstorms as the warm front lifts north.

Another mid level low/trough drops out of the Canadian Prairies for
Thursday resulting in height falls for MI. We could see
thunderstorms developing by the end of the period.

I did warm up temperatures slightly during the warm air advection
period as we commonly see values that end up higher than forecasted
in those regimes this far out.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 758 AM EDT Fri Jun 23 2017

Cold front is progressing to the south this morning and should be
south of the TAF sites by 15z. Showers and a few thunderstorms
will remain possible through that time as well. MVFR and IFR
ceilings are prevalent this morning, but they will lift during the
late morning and midday hours. VFR weather is expected this
afternoon and tonight.


&&

.MARINE...
Issued at 330 AM EDT Fri Jun 23 2017

Some borderline small craft advisory conditions are possible this
morning as the low level jet is situated over the southern half of
Lake Michigan. The Port Sheldon buoy is at 3.6 feet at the present
time while winds at the MKG ASOS are gusting to 25 knots. Feel these
winds and waves will be short lived this morning and will not issue
a SCA. Winds and waves should remain below criteria tonight and
tonight, with addition borderline SCA conditions Saturday into
Sunday.


&&

.HYDROLOGY...
Issued at 824 AM EDT Fri Jun 23 2017

3 to 7 inches of rain fell overnight in much of Isabella,
Mecosta, Clare, and Osceola counties (greatest amounts in
Isabella). Areal/road flooding is ongoing though the exact impacts
are still being assessed. The bulk of the rain fell in the
Chippewa, Muskegon, and part of the Pine River basins. River flood
headlines will be needed at Mount Pleasant, Croton, Alma, and
Evart. Fortunately the heavy rain is moving out of the area this
morning.

&&

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

$$

SYNOPSIS...Duke
SHORT TERM...Duke
LONG TERM...MJS
AVIATION...Duke
HYDROLOGY...CAS
MARINE...Duke



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