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fxus63 kgrr 261900 
afdgrr

Area forecast discussion
National Weather Service Grand Rapids Michigan
300 PM EDT Wed Jun 26 2019

Latest update...
synopsis/discussion/marine

Synopsis...
issued at 300 PM EDT Wed Jun 26 2019

- warm and unsettled weather pattern setting up beginning Thursday,
and lasting into next week

- chances of showers and storms most days, but much of the time
will be dry

- timing and tracks of storms quite uncertain

&&

Discussion...(this evening through next wednesday)
issued at 300 PM EDT Wed Jun 26 2019

Our main focus of the forecast of the next few days will be on the
track and timing of thunderstorm complex activity that could
occasionally move through the area. The details are quite complex as
each round of storms helps to dictate where subsequent rounds will
move.

We believe that there is a good chance most areas will remain dry
through the first portion of Thursday. The better moisture and
instability has pushed south of the area, with the front that pushed
south through the area last night. We have been left with a drier
air mass with ridging helping to limit the vertical extent of any
diurnal clouds. The solid instability axis looks like it is far
enough SW, that anything that tries to ride the instability gradient
would stay out of our area. What looks to be the possible caveat,
is there is some thought that a weak wave may ride along the front
to our south, and try to bring a chance of some rain to the far
southern area.

The better chance of showers and storms will gradually increase
through the day on Thursday, with Thursday night/Friday morning
being the best chance for now. This is the result of the instability
axis/upper ridge/developing ring of fire pushing up into the area.
The models seem to be keying in on a wave that will fire convection
over the northern plains later today, and will ride the periphery of
the ridge. It seems that the instability will build over our area by
the time it makes it this far east, and has a decent shot of
affecting the area. If it were to hit the area, it looks like wind
would be the biggest threat as the cold pool rides the instability
axis. Wind fields do not look exceptionally favorable with the
strongest mid level winds north.

Depending on how exactly the late Thu/early Fri complex evolves,
will be where any subsequent complexes would ride. The upper ridge
will start building more toward the area, which would try to push
the instability back toward the area if it sinks south with the
first complex. There does look to be one more wave that could pass
through sometime on Saturday. The details and timing of this is too
difficult at this point to pin down.

There is a chance that we could see a break in the storm activity
sometime Sunday, into Monday. This would occur if the upper ridge
builds a bit, and moves almost overhead. Forecast soundings indicate
that we would be quite unstable, but likely be quite capped with a
warm layer aloft between 5-10k ft. We would also be quite dry in
much of the column.

We could get into a active pattern again early next week with more
thunderstorm complexes possible. The strong cap that is expected to
be overhead Sunday into Monday, will be eroded a bit as the upper
ridge gets flattened a bit by the upper low across Canada. The lack
of a cap would allow any short wave to fire convection fairly
easily, which will be possible with the upper jet being closer to
the area.

&&

Aviation...(for the 18z tafs through 18z Thursday afternoon)
issued at 130 PM EDT Wed Jun 26 2019

We are expecting a high chance of little to no impacts for this
forecast cycle. VFR conditions should dominate.

Skies are mostly clear this afternoon, with only thin cirrus at
25k feet overhead, and maybe a few cumulus clouds trying to
develop. This should continue to be the case through the remainder
of the day, with the cirrus clouds maybe thickening up tonight.
Fog potential is not zero, especially with a lighter wind. It
seems though that the low level moisture is limited enough,
combined with shortest nights of the year, that should limit the
fog.

More of the same through 18z Thu. Winds will pick up a bit from
the south, with southwest near the Lakeshore due to the lake
breeze.

More impactful weather looks to hold off until well after the end
of this forecast period, toward Thursday evening when a potential
line of storms comes through.



&&

Marine...
issued at 300 PM EDT Wed Jun 26 2019

Conditions over the next few days will be controlled more by
possible rounds of storms, rather than typical low pressure systems.
There are no major systems that are forecast to drive up the winds
and waves over the next few days. What will affect the conditions
will be occasional complexes of storms that look possible to move
through the area. There may be a increase in the wind from
immediately ahead of, to behind any round of storms that move
through. This pattern will persist on and off likely into early next
week.

&&

Hydrology...
issued at 130 PM EDT Wed Jun 26 2019

The river systems in our area continue a slow recovery from the
heavy rain last week. Each time we get these smaller rounds of
showers and thunderstorms through the area acts to re-soak the
sponge (the ground) and slow down The Drop in water levels. The
overall trend continues to be downward, with the crest working
through the lower sections of the Grand River (grand rapids to grand
haven) the most stubborn in showing only very small drops in water
level so far.

Sunny and warm conditions today will help the matter, but the threat
of multiple rounds of rain moves back in by Thursday
afternoon/evening. At this time it looks like rain totals will
generally be less than one-half inch, but this will again prolong
the higher water levels we're currently seeing around much of the
area.

Heading into this weekend, the overall weather pattern remains
unchanged, and could feature rounds of thunderstorms every day or
two. While widespread river flooding is not expected, this
continuing wet pattern will make it hard for the rivers to drop even
to the average levels for this time of year.

&&

GRR watches/warnings/advisories...
Michigan...none.
Lm...none.
&&

$$

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