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Area forecast discussion 
National Weather Service Grand Rapids Michigan
112 am EDT Friday Jul 3 2015

Latest update...

issued at 326 PM EDT Thursday Jul 2 2015

The weather looks rather quiet for most of the upcoming Holiday
weekend for lower Michigan. High pressure settling into the area
this afternoon will control the weather for most of the weekend.
Temperatures will be on the increase and will maximum out in the 80s for
most of the area most of the weekend. The only chance of rain will
be across interior portions of central lower Michigan on Saturday.
This chance will be associated with a weakening front that will
sink south into the area before washing out.

The next best chance of showers and storms will come next week late
on Monday and into Tuesday as a stronger front moves in.


Short term...(this evening through Saturday night)
issued at 326 PM EDT Thursday Jul 2 2015

The only challenge in the short term is determining precipitation chances for
Sat as a front that will be washing out moves overhead.

Some residual moisture from the low clouds this morning has
developed cumulus across the southern portion of the forecast area. This
cumulus is mixing out as drier air aloft is mixing down...and we
expect this to continue this evening.

We expect dry conditions through Friday night across the entire County warning forecast area.
We will see short wave ridging build across the area...supporting
high pressure at the surface moving overhead. A very dry air mass and
subsidence inversion will result in the dry conditions. Temperatures
will moderate as The Heights build.

The only chance of rain will come across the northern third inland portion
of the County warning forecast area during the day on Sat. A short wave trough will slide by
north of the area across the u.P. And tip of the mitt on Sat. An
associated front will try to drop in the area...but will be washing
out as the upper support moves away. Models are all indicating
isolated precipitation up north as the weakening front encounters some slight
diurnal instability. The shoreline will likely be stable enough with
a wind off of the lake to keep them dry.

We will dry out entirely then Sat night as the front dissipates and
as a longer wave upper ridge builds in from the W/NW. This will
reinforce the surface ridge over the area and remain into the long term.
With the front washing out...temperatures will only increase each day with
a good deal of sunshine and only warm air advection.

Long term...(sunday through thursday)
issued at 326 PM EDT Thursday Jul 2 2015

I am beginning to believe this coming week will likely be the
warmest week of the Summer so far (not hard to do given how cold it
has been). There is still the cold front that comes through with
thunderstorms late Monday night or early Tuesday but it is looking
like that front will not be as strong as I was thinking earlier
since the really cold air is delayed behind a second upper air
system that likely will not get to Michigan until beyond this
forecast period.

We still have our Rex block over the area near the Bering Sea and a
closed upper low that was off the West Coast which has moved inland
to southern British Columbia. It is that system that brings the cold
front through Tuesday. Here is the issue through...there is a
stronger system that dives south over the Canadian rockies Monday
into Tuesday. That digs the large upper trough... over most of
Canada (centered near Hudson bay) southwestward over western Canada.
That in turn increased the upper air heights over southeastern
Canada and most of the eastern and central United States. This in
turn weakens the front...stalling it just south of Michigan. The
real cold air being trapped north of the polar jet...which next week
will be near north of 50n. This will change later in the week or
early in following week as the western trough moves east...but until
then... we will have a more westerly flow at middle and upper levels.
In turn we get to have more Summer like temperatures.

The bottom line to this is the risk of severe storms seems lower to
ME early next week and the for the most part expect dry weather
(except for around 18 hours later Monday into early tuesday). I
increased the forecast highs to the middle 80s Sunday and Monday. I am
thinking we may see lower to middle 80s Tuesday through Thursday...but I
went convective yet there.


Aviation...(for the 06z tafs through 06z Friday night)
issued at 112 am EDT Friday Jul 3 2015

Conditions will remain VFR through the next 24 hours along with
a light east-northeast wind. Some high clouds will Grace the I-94 taf sites
at times.


issued at 326 PM EDT Thursday Jul 2 2015

We do not anticipate any marine headlines being needed for the
upcoming Holiday weekend. Some slight uptick in winds and waves
remains possible into early this evening as high pressure builds in
and a diurnal gradient develops. Winds will diminish this evening to
below 15 knots...and should remain at or below 15 knots through
Sunday. Next increase in wind looks to occur on Monday ahead of the
cold front that will be approaching at that time.

On another note...some upwelling has occurred at the shoreline with
the north-northeast winds over the last day. Some water temperatures have dropped to
near 40f along the shore per latest water observations from the
sites along the coast this morning and modis satellite imagery.


issued at 326 PM EDT Thursday Jul 2 2015

The Kalamazoo river near Comstock and New Richmond is falling below
bankfull this afternoon. The Grand River at Ionia and Sycamore Creek
near Holt are the only rivers that remain above bankfull... and
levels at both locations are falling. Aside from an isolated
thunderstorm on Independence day... weather will stay dry until the
next chance of thunderstorms Monday/Tuesday.


GRR watches/warnings/advisories...


short term...njj
long term...wdm

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