Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 271806
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
206 PM EDT MON JUN 27 2016

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 252 AM EDT Mon Jun 27 2016

A cold front will track southward through the region today
and tonight. A cooler airmass will then filter in from central
Canada. After another warm day today...below normal temperatures
are expected into the middle part of the week. As for rainfall
the cold frontal passage is expected to be dry for most locations.
A few showers could develop Tuesday...but any rainfall should be
brief.

&&

.UPDATE...
Issued at 1102 AM EDT Mon Jun 27 2016

Minor updates to ongoing forecast. Main concern for the next 12
hours is precipitation potential across northern zones. Current
forecast has low chances and that seems reasonable given latest
output from mesoscale models.

&&

.SHORT TERM...(Today through Wednesday)
Issued at 252 AM EDT Mon Jun 27 2016

The main challenge deals with the rainfall potential in the short
term.

We will need to monitor the risk for possible thunderstorm
development today. I noticed some instability showing up in the
models...and the HRRR RUC was developing some showers during the
day...especially around Ludington. Forecast soundings do suggest a
slight warm layer up around 700 mb...so no thunder. I ended up
adding a small chance for showers to the northwest counties this
afternoon. We may need to expand these showers depending on how
the pattern evolves.

Another risk for showers exists for Tuesday. Any should be few and
far between. Soundings show a shallow convective layer under 650
mb. Thus...with a cool airmass in place...any heating should fill
in with clouds and perhaps a few light showers...mostly away from
the lakeshore.

The low level thermal trough arrives for Tuesday evening. With
diminishing winds and clearing skies...it should be a decent
radiational cooling night. Perhaps some locations like Leota in
Clare county may make a run at the 30s for overnight lows.

.LONG TERM...(Wednesday night through Sunday)
Issued at 252 AM EDT Mon Jun 27 2016

The long term will be fairly quiet with only one real opportunity
for pcpn. High pressure over the Great Lakes will drift east
Wednesday night and a cold front will approach from the west. A
strong short that is depicted on both the ecmwf and gfs will swing
across northern Lower Michigan Thursday night and/or Friday but not
before pushing the cold front through the cwa Thursday. So, there
looks to be a 36 hour window in which we may see a few showers
and/or storms. Instability is highest Friday and so we`ll include
the mention of thunder then.

The weekend looks dry as high pressure will move over the Great
Lakes. Comfortable temperatures are expected during this time with
lows in the 50s and highs 75-80.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 205 PM EDT Mon Jun 27 2016

VFR weather prevails at all TAF sites at 18Z with gusty westerly
winds. VFR weather will continue into this evening and for much of
tonight. The winds will diminish to below 10 knots after 01Z.
Clouds seen on satellite imagery across the northern Great Lakes
will progress south this afternoon and evening and overspread the
area shortly after dark. VFR ceilings are expected through about
10Z with MVFR ceilings pushing into the I-96 TAF sites of KMKG,
KGRR and KLAN around 12Z. These ceilings will then lift through
the course of Tuesday morning. By 18z on Tuesday expecting all
sites to be VFR once again. Winds will increase to 10-15 knots out
of the north after daybreak on Tuesday.


&&

.MARINE...
Issued at 1102 AM EDT Mon Jun 27 2016

After coordination with surrounding offices, have hoisted a Small
Craft Advisory and Beach Hazard statement for late tonight into
late Tuesday night. Expect to see waves from 3 to 5 feet develop
in the Pentwater to Manistee area late this evening...spreading
south tomorrow...and ending from north to south Tuesday evening.
Waves from 4 to 6 feet may occur across the South Haven to St.
Joseph area tomorrow afternoon and early evening.


&&

.HYDROLOGY...
Issued at 238 PM EDT Sun Jun 26 2016

Widespread 0.75 to isolated 2 inches of rain fell between
Muskegon, Big Rapids, and Manistee on Sunday morning, with lesser
amounts to the southeast. The soil and rivers have more than
enough capacity to absorb this moisture. Other than a chance of
storms in southern Michigan Sunday afternoon then a chance of
precip late Thursday into Friday, the week is looking rather dry.

&&

.GRR Watches/Warnings/Advisories...
MI...Beach Hazards Statement from Tuesday morning through late
     Tuesday night for MIZ037-043-050-056-064-071.

LM...Small Craft Advisory from 10 PM this evening to 8 PM EDT Tuesday
     for LMZ848-849.

     Small Craft Advisory from 2 AM Tuesday to 2 AM EDT Wednesday for
     LMZ844>847.

&&

$$

UPDATE...MWS
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...04
AVIATION...Duke
HYDROLOGY...CAS
MARINE...MWS



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