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Area forecast discussion 
National Weather Service Grand Rapids Michigan
733 PM EDT Friday Apr 17 2015

Latest update...

issued at 325 PM EDT Friday Apr 17 2015

A weak cold front comes through the area Saturday morning but this
will do little more than shift the winds to the east and cool the
high temperature into middle to upper 60s. Meanwhile a developing
storm from the Southern Plains will move into the Great Lakes
Sunday. Rain will overspread the area from south to north during
the afternoon and it will be breezy too. There is a slight chance
of thunderstorms or two south and west of Battle Creek during the

Cooler weather will follow for all of next week with frequent
showers. There is a real chance for some wet snow to mix in with
the showers Tuesday night into Thursday morning. Highs will be
much cooler next week... mostly from the middle 40s to middle 50s.


Short term...(this evening through Sunday night)
issued at 325 PM EDT Friday Apr 17 2015

The main issue for this forecast is the storm system that moves
through the area Sunday into Sunday night. This will bring strong
winds a risk of elevated thunderstorms near and south of
Interstate 94 west of Battle Creek during Sunday evening and
between an half inch and an inch of rain.

The models are all in good agreement on the storm system Sunday
into Sunday night. A digging northern stream jet core interplay
with a strong southern stream jet core (120 knots) creating a
negative tilt upper wave that closes off into deep slow moving
upper low over the Great Lakes. With the precipitable water
reaching 1.5 to 2.0 Standard deviations from normal...Sunday
evening and 50 to 60 knot low level jet feeding the system in
combination with an impressive trowal....not to mention the mixing
ratio near 700 mb increases from 1 g/kg to around 6 g/kg... and
the fgen is very impressive from 850 to 700 mb...there is little
question we will see rain over the entire County Warning Area. It will mostly be
from late afternoon into middle evening. Winds will be strong and
gusty too... 15 to 25 miles per hour with gust near 35 more than possible.
There is some elevated instability but it is marginal.

A weak cold front comes through the area Saturday morning but the
air will be to dry for more than some middle clouds and that will be
limited too. Mostly another warm day yet as the colder air moves
in Saturday night.

Long term...(monday through friday)
issued at 325 PM EDT Friday Apr 17 2015

Rain showers will linger Monday with the surface low pressure system
still in place over the northern Great Lakes region and as an upper
level low drifts slowly east our region. The weather pattern for the rest
of next week will be unseasonably cool and unsettled with the upper
level low and trough over the Great Lakes region.

Scattered rain showers are anticipated given this synoptic pattern.
Thermal profiles and wbz heights also suggest that precipitation will mix
with or change over to wet snow at times next week. Some light snow
accumulations are possible Tuesday through midweek mainly across
relatively higher elevations of our northern forecast area.

Temperatures will average fairly close to normal into Monday before
much cooler air moves in Tuesday through Friday when temperatures
will average at least 10 to 15 degrees below normal.


Aviation...(for the 00z tafs through 00z Saturday evening)
issued at 733 PM EDT Friday Apr 17 2015

Very high confidence for VFR through Saturday evening. Winds will
increase and shift to out of the northeast shortly after 12z
Saturday with a cold front dropping into the area. Winds will
shift to out of the east going into Saturday night. No ceilings are
expected...but there could be at least scattered clouds near the
kazo and kbtl terminals Saturday afternoon.


issued at 325 PM EDT Friday Apr 17 2015

We will likely need a Small Craft Advisory Sunday and Sunday night
but we will deal with that on a later shift.


Fire weather...
issued at 325 PM EDT Friday Apr 17 2015

While I do not think we will reach red flag conditions Saturday
east winds of 10 to 20 miles per hour...minimum relative humidity values near 25 percent and
temperatures near 70...there is some concern for isolated wild


issued at 1119 am EDT Friday Apr 17 2015

No river flood advisories are in effect at this time. Improvement
is expected to continue as dry conditions will hold strong today
through Saturday.

Thoughts on the next round of moisture are consistent with the
previous Hydro update (4/16). A decent soaking rain is expected to
move in Sunday with off/on wet weather possible through the
middle of next week. Much of the moisture should fall late in the
weekend and early into the new work week. This could result in minor
upticks for rivers. The lack of convective activity...or high end
heavier rainfall...keeps ME somewhat conservative on any rises
that would otherwise be more concerning.


GRR watches/warnings/advisories...


short term...wdm
long term...Laurens
fire weather...wdm

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