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Area forecast discussion 
National Weather Service Grand Rapids Michigan
650 PM EST Wednesday Feb 10 2016

Latest update...

issued at 324 PM EST Wednesday Feb 10 2016

Cold air and lake effect snow showers will continue into Saturday.
A large polar high pressure system will move over Michigan on
Sunday diminishing the lake effect snow shower but it will
continue to be cold. A frontal system moving across the area
Monday will bring warmer temperatures with a chance of snow.


Short term...(this evening through Friday night)
issued at 324 PM EST Wednesday Feb 10 2016

No changes in the headlines for tonight or Thursday. The lake
effect snow showers will continue into Thursday afternoon. They
will slowly diminish in intensity Thursday as inversion heights
fall as does the moisture depth. The Arctic front coming through
on Friday will likely have a band of snow showers that will impact
the entire County Warning Area as it comes through. Then we go back to north
northwest flow lake effect Friday night as the coldest air of the
season moves in.

Last week in my discussions I questioned if the mjo being in
phase 4 to 5 (warm for the eastern United states) or the
stratospheric warming event (cold for lower michigan) moving into
the area from northern Asia would be able to trump the impact of
the mjo. Well...clearly with the coldest temperatures of the
winter this week...there is little question the stratospheric
warming event did indeed take precedence over the mjo for our

As for the lake effect event that is ongoing the sun has caused
the snow showers to become more cellular. Once the sun sets they
will become less so and be confined closer to the Lake Shore. It
is during the night we should see the largest accumulations from
what remains of this event. All the high resolution models show
strong lift in the dgz near the Lake Shore as the coldest air
moves into the area. There is little question in my mind we have
significant snowfall yet to see. Thus I keep the headlines as is.

Long term...(saturday through wednesday)
issued at 324 PM EST Wednesday Feb 10 2016

We continue to expect that the likely coldest air of the season will
affect the area on Saturday...before we see a moderation in temperatures
and a somewhat unsettled weather pattern take shape for next week.

We will have seen the Arctic front move through by the beginning of
the long term on Saturday morning. The models have compromised on
the low level flow pattern for Sat. It is looking like it will be
north-northwest and shifting to the north-northeast by Sat night. This occurs as low level
ridging builds in fairly quick and the upper jet lifting north of the
area. This will bring some lake effect to the Lakeshore on Sat...and
then shift it offshore Sat night. This scenario will support
clearing skies for Sat night and lows having a good chance of going
below zero.

We will then see temperatures gradually moderate beginning on sun and
continue at least into Thursday. The northern branch of the jet will flatten
out a bit once the upper low over the weekend kicks east. This will
bring a couple of troughs through the area. One looks to move in
starting late sun into Monday...and another looks to move in Tuesday night
into Wednesday. The timing on these smaller waves is a little problematic
as is usually the case with the expected pattern. For now we have
gone with precipitation chances from Sun night through Wednesday and moderating temperatures
into the 30s.

It appears the bigger system poised to the affect the southeast U.S. Early
next week should stay to our south as the southern stream digs fairly
strong...and with our zonal flow in place. We will watch the trends
with case it were to approach the area.


Aviation...(for the 00z tafs through 00z Thursday evening)
issued at 650 PM EST Wednesday Feb 10 2016

VFR weather is likely tonight and Thursday morning at the taf
sites as the snow showers become limited to mainly just the Lake
Michigan shoreline. Some briefly lower visibilities are possible at mkg
but the heavier snow showers should remain just west of the
terminal there tonight and Thursday morning.

On Thursday the clouds and snow showers should spread back inland
as the winds become more westerly in the afternoon. Most of the
taf sites should become MVFR as this occurs although some IFR
visibilities will also be possible... especially at mkg and azo.

Winds speeds will be lighter than they have been tonight and
Thursday... generally around 10 kts out of the northwest.


issued at 324 PM EST Wednesday Feb 10 2016

No changes needed to the marine headlines for this forecast package. The
small craft advisories will cover things well through Thursday morning
before winds and waves diminish.

The next set of headlines needed will likely come beginning for
Friday and last into Sat with the next surge of cold air.


issued at 1233 PM EST Wednesday Feb 10 2016

Downward trends continue on the Maple River with minimal concerns
for additional flooding in the near future.

Precipitation forecasts through the next 7 days account for less
than three-quarters of an inch along the Lakeshore and less than
half an inch inland. This translates to little or no concern with
precipitation type mostly consisting of snow.

Temperatures will stay well below freezing today through the
weekend...possibly reaching freezing by next Tuesday. Ice may
begin to develop once again over the weekend as overnight lows
bottom out in the single digits. These temperatures do not last
very long though...and the return to 30s next week may help
mitigate any ice jamming. It is the main focus going through
Saturday and Sunday. Otherwise...fairly quite river-wise.


GRR watches/warnings/advisories...
Michigan...Winter Storm Warning until 10 am EST Thursday for miz037-043-056-

Winter Weather Advisory until 10 am EST Thursday for miz038-050.

Lm...Small Craft Advisory until 1 PM EST Thursday for lmz844>849.



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

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