Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Grand Rapids Michigan
811 PM EST Friday Feb 5 2016

Latest update...

issued at 254 PM EST Friday Feb 5 2016

A weak area of high pressure in Iowa will build east tonight
through Saturday. A southwest flow around this system will create
snow showers later tonight into Saturday morning mainly for west
central parts of lower Michigan. This flow will also support
warmer than normal temperatures into Sunday. A stronger low
pressure system arrives Sunday into Monday with rain or snow
showers. A cooling trend will arrive early next weak as this slow
moving system pushes east of the area.


Short term...(this evening through Sunday night)
issued at 254 PM EST Friday Feb 5 2016

At this time I do not see any significant impacts through the
period. The main limitation will be the warmer than normal
temperatures...which should act to support more in the way of wet
roads rather than snow covered through Sunday.

One weak 700 mb wave tracks eastward through northern lower Michigan
tonight into Saturday morning. The southwest flow out ahead of it
may support an increased potential for mainly snow showers up
around Ludington. Only chance or less probability of precipitation elsewhere.

A digging middle level wave approaches for Sunday into Sunday night.
Stronger low level warm air advection out ahead of it does
support above normal temperatures. Rain or snow showers will be
possible as a cold front pushes through mainly later Sunday. A dry
slot is shown to move in for Sunday night...and will likely limit
the risk for widespread precipitation. The deeper moisture will be
lagging west of the area Sunday night. If the overall system
speeds up...we could see steadier precipitation moving in later
Sunday night.

Long term...(monday through friday)
issued at 254 PM EST Friday Feb 5 2016

A strong clipper moving over lower Michigan Monday will draw down
some Arctic air from Canada. Confidence is increasing that we/ll see
several days of snow showers next week an accumulating snow is

Monday will probably be the least snowy day due to some warmer air
over the County Warning Area and the low overhead. Boundary layer winds won't be
conducive for lake effect snow but that will change by late Monday
night. Nevertheless...instability provided by the upper low overhead
will be enough to create light snow. Then the Arctic air moves in
beginning Tuesday. Several short waves will reinforce the cold air
over the Great Lakes. 800 mb temperatures from -8c Tuesday morning to -20c by
Wednesday morning. Inversion heights will fall from Tuesday through
Wednesday but the dgz will remain saturated. Given the high
instability over the lake we/ll See Lake effect snow showers from
late Tuesday through Friday. Overall...we boosted probability of precipitation way above
guidance to account for the overall snow potential.

Wednesday will be the coldest day when temperatures top out in the lower


Aviation...(for the 00z tafs through 00z Saturday evening)
issued at 811 PM EST Friday Feb 5 2016

A mix of MVFR and VFR conditions are in place across the area at
800pm. The trend should be towards more and more VFR through the
night as we are in between weak weather systems.

Towards morning...the wind will increase out of the
southwest...which should bring in another round of MVFR ceilings and
possibly some light snow again.

Forecast has conditions going VFR in all areas by 100am and then
going back to MVFR Saturday morning after 12z. At this
point...only have flurries mentioned with no restrictions to
visibility on Saturday. Recent events have been over-performing
however in regard to snow/ later forecasts may change


issued at 254 PM EST Friday Feb 5 2016

Overall trends are for weaker winds and lower waves later tonight.
Marginal setup for small craft conditions expected...and if trends
continue...we may not need headlines. Will not issue a Small Craft
Advisory at this time given the limited confidence.


issued at 1134 am EST Friday Feb 5 2016

The Grand River at Ionia and Maple River near Maple Rapids are the
only rivers currently out of their banks. Both are at or near
their crests and will slowly recede into next week. No other
rivers are expected to exceed bankfull at this time. Most river
channels are free of ice... but colder temperatures next week may
lead to ice redevelopment and thus we will have to watch for river
level fluctuations.


GRR watches/warnings/advisories...


short term...mjs
long term...04

National Weather Service Glossary of Abbreviations