Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 260730
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
330 AM EDT Mon Jun 26 2017

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

.SYNOPSIS...
Issued at 330 AM EDT Mon Jun 26 2017

Another unseasonably chilly day is in store with highs only in the
60s and scattered rain showers. Temperatures will gradually moderate
after today, returning to closer to normal by mid to late week.
However the return of the warmer air will also result in showers
and thunderstorms with a risk of some stronger storms and locally
heavy rain.

&&

.SHORT TERM...(Today through Wednesday)
Issued at 330 AM EDT Mon Jun 26 2017

The last in a series of vorticity maxima/upper lows in the
anomalous northwest flow pattern arrives this afternoon. Expect
an increase in clouds and shower coverage as this feature drops
in, with thunder probabilities also creeping up by afternoon.

Since the shortwave arrival is coincident with peak heating, can`t
rule out a few isolated stronger cells today with strong gusty
winds and small hail. Freezing levels drop to 6500-7000 ft this
afternoon. The pattern is also supportive of cold air funnels as
the core of the cold air with H8 temps around 3C comes overhead
later today.

Shower coverage will decrease after sunset, then arrival of
surface ridging on Tuesday will lead to quieter weather
continuing into the first half of Wednesday. However the warm air
is quick to surge back in from the southwest later Wednesday as
low level jet cranks up to 50 kts over WI/IL in the afternoon.
Showers and tstms are likely north and west of GRR by late in the
day.


.LONG TERM...(Wednesday night through Sunday)
Issued at 330 AM EDT Mon Jun 26 2017

Active wx is anticipated mid to late week with potential for several
rounds of convection. A low pressure system will move east into the
upper midwest Wednesday night and bring the first round of showers
and storms.

Convection will develop on the nose of a strong 45-55 kt llj. This
in conjunction with increasing low level moisture and some weak to
moderate instability will set the stage for convective development.
Some strong to potentially severe storms are possible given this
synoptic setup and fairly strong deep layer shear.

Medium range guidance continues to show potential for a frontal
boundary to then stall out near our just south of our fcst area
Thursday through Thursday night. This would continue to focus
development of more showers and storms. Another low pressure system
will then move through our region Friday through Friday night and
bring more convection. A few showers may linger into Saturday before
a cooler and drier airmass advects in for later in the weekend.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1123 PM EDT Sun Jun 25 2017

Vfr conditions will continue at all the terminals overnight with
scattered light rain showers that should gradually taper off
overnight. West winds will increase considerably by mid to late
Monday morning and gust to around 25 kts from late morning through
the afternoon into early evening before subsiding.

Scattered showers are expected at all the terminals Monday
morning and afternoon. Isolated thunderstorms may also develop
Monday afternoon but there is not enough potential to warrant
mention in the terminal fcsts at this time. Conditions should be
mainly vfr Monday although brief reductions to mvfr are possible
in heavier showers.


&&

.MARINE...
Issued at 330 AM EDT Mon Jun 26 2017

Cold advection and cyclonic flow similar to a fall pattern will
result in hazardous winds and waves today into the evening.
Arrival of the upper low this afternoon and even colder air aloft
will also the support the possibility of a few tstms and waterspouts.


&&

.HYDROLOGY...
Issued at 330 AM EDT Mon Jun 26 2017

UPDATE: Sudden sharp rise noted on the Pine at Alma since last
evening has resulted in numerous road closures in Gratiot County.
The latest forecast has the River at Alma cresting around 9 feet
this morning before slowly receding.

Previous discussion: Rain heavy enough to affect river levels is
not expected until Wednesday afternoon at the earliest. This will
allow river levels to fall the next few days. We will enter a
potentially wet period from Wednesday afternoon into the weekend.

At this point it looks like heavy rain and thunderstorms will be
mostly likely Wednesday evening into Thursday morning and again
Friday morning into the evening. The combination of these two events
could produce amounts over 3 to 4 inches in some areas. We will
continue to monitor forecast trends over the next few days for
specifics on amounts and locations where the heavier rain is
expected.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement through this evening for MIZ037-043-050-
     056-064-071.

LM...Small Craft Advisory until midnight EDT tonight for LMZ844>849.

&&

$$

SYNOPSIS...Meade
SHORT TERM...Meade
LONG TERM...Laurens
AVIATION...Laurens
HYDROLOGY...Meade
MARINE...Meade


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