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Area forecast discussion
National Weather Service Grand Rapids Michigan
727 PM EDT Mon Jun 26 2017

Latest update...

issued at 322 PM EDT Mon Jun 26 2017

Another afternoon and evening of spotty showers and isolated storms
can be expected tonight as cool Canadian air continues to filter
across the area. Conditions will dry out overnight as the system
begins to pull out. A stray shower will be possible across eastern
areas Tuesday afternoon, but temperatures will warm a few degrees
compared to today.

An occasionally active weather pattern is looking more likely
beginning late Wednesday, and lasting at times through early next
week. Multiple waves of low pressure will move east through the
region at times. These waves will bring the threat of showers and
storms with dry periods in between.


Short term...(this evening through Wednesday night)
issued at 322 PM EDT Mon Jun 26 2017

One more round of spotty showers is now beginning to rotate into the
County warning forecast area this afternoon from the northwest as one more major wave moves through
the region. The shower chances will linger into the early overnight
period before the wave rotates out. A rumble of thunder will remain
possible as the cold pool aloft interacts with the diurnal heating
this afternoon.

Tuesday should end up mainly dry across the area, however a slight
chance of a rain shower was inserted into the forecast for the
eastern counties. The models have trended toward the cyclonic flow
aloft lingering a little longer. The eastern counties will be on the
wrn periphery of the upper low Tuesday afternoon. Temperatures will
be a few degrees warmer than yesterday with the core of the coolest
air moving east of the area.

We will see a break in the weather then from Tuesday evening through
Wednesday morning. Rain chances will then increase Wednesday
afternoon and especially Wednesday evening. There is a short wave
that is currently coming onshore off of the Pacific to the California/or
coast. This short wave will move along the nearly zonal flow that
will take place once the current low moves out. A 60 knot low level
jet is expected to bring a very moist surge to the area. This will
help develop showers/storms over the area Wed afternoon/evening.
Right now, the heavier pcpn looks to occur across the northern
portion of the area given the forecast track of the wave.

Heavy rain is a concern given the heavy rain that has fallen across
portions of central Michigan over the last week. There is a lot of
wind energy available also that could produce damaging winds. We
will continue to monitor the situation.

Long term...(thursday through monday)
issued at 322 PM EDT Mon Jun 26 2017

A low pressure system is expected to pass over Upper Michigan/Lake
Superior Thursday and drape a front across the region, bringing
showers and thunderstorms to lower Michigan Thursday into Friday.
Instability, moisture, and lift may all be present in sufficient
quantities to make severe weather possible.

Another low pressure system will then move from southwest to
northeast across lower Michigan Friday and Friday night, accompanied
by more rain and thunderstorms. If the focus of the heavy rain ends
up stretching across the area, we could see areal and river flooding
by the end of the week.

Temperatures will be around normal through the week. Normal highs
are around 80 degrees and normal lows are in the upper 50s.


Aviation...(for the 00z tafs through 00z Tuesday evening)
issued at 727 PM EDT Mon Jun 26 2017

Expect VFR conditions through Tuesday and for that matter most of
Wednesday at all of our taf sites.

We have a band of scattered showers moving away from our eastern
taf sites (lan and jxn) as I write this. However this is one more
band of showers (23z) from pln to tvc to grb that will rotate
through our taf sites in the 03z to 09z time frame. Since the sun
will have set by then I would think most of these showers will
have dissipated, even so here is enough dynamic forcing with the
upper level system that it is possible they would hold together.
Even so the visibility and ceiling will remain VFR. Once they move through
the sky should clear totally. Tomorrow is the last day under this
weather system so we will have one more day of afternoon cumulus/towering cumulus
and isolated rain showers. This will be more of an issue for the
eastern taf sited due to the west wind. I put vcsh in the forecast
for those sites for Tuesday afternoon. It should not be as windy
during the day tomorrow as the system will be moving out by then.

So periods of VFR cigs tonight into Tuesday with lighter winds


issued at 322 PM EDT Mon Jun 26 2017

The Small Craft Advisory and beach hazards statement look good and
will be maintained. We will see one more uptick in the winds and
waves this afternoon as one more wave moves by and cooler air surges
in. Conditions will start to improve tonight and settle down more on

We are looking at hazardous conditions likely returning to the
waters late Tuesday night and Wednesday as the next system
approaches the area. These will likely last at least through


issued at 1119 am EDT Mon Jun 26 2017

River levels are trying to return to normal across the region...with
the Chippewa river at Mt. Pleasant and Pine River at Alma above flood
stage. Scattered showers and thunderstorms...which will develop as
an upper low moves over the state this afternoon...are not expected
to produce the areal coverage or intensity of precipitation needed
to slow the falling of the stages. Therefore...expect river levels
to continue to fall steadily over the next 24 hours.

Another round of potentially heavy rainfall will occur later
Wednesday into Wednesday night. Deep moisture returns to the
region...and bands of heavy rainfall may occur across central
portions of lower Michigan. Rivers in Isabella and Gratiot
counties are especially vulnerable to excessive rainfall...and
significant rises would likely develop on the Pine and Chippewa
rivers should the heavy rainfall occur in these basins.


GRR watches/warnings/advisories...
Michigan...Beach hazards statement until midnight EDT tonight for miz037-

Lm...Small Craft Advisory until midnight EDT tonight for lmz844>849.



short term...njj

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