Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 250725

Area Forecast Discussion
National Weather Service Grand Rapids MI
325 AM EDT Tue Oct 25 2016

Synopsis/Short Term/Long Term/Marine

Issued at 325 AM EDT Tue Oct 25 2016

High pressure will provide one more day of fair and cool weather
today. Then rain arrives late tonight and persists through
Wednesday night as low pressure moves through. Some wet snow may
mix in north of Big Rapids and Mount Pleasant.


.SHORT TERM...(Today through Thursday)
Issued at 325 AM EDT Tue Oct 25 2016

Forecast issues are for thunder chances across the south and
precip type across the north as low pressure moves through Lower
Michigan beginning tonight.

Model soundings continue to show instability lacking, to the point
of keeping thunder out of the forecast for all zones. Total totals
never get about the mid 30s even across the far south.

GFS model soundings are about 1 degree C cooler than yesterday
and wet bulb zero heights are near the ground at CAD. Will have
mix with snow going across the northern tier, primarily on
Wednesday night as the low tracks east and cold advection begins.
Cannot rule out some light accums across the high ground of
Osceola County. Precip ends on Thursday with sfc ridging bringing
subsidence and drying.

.LONG TERM...(Thursday night through Monday)
Issued at 325 AM EDT Tue Oct 25 2016

We are looking at a somewhat unsettled weather pattern through much
of the long term. There will be multiple chances of some rain,
although it will not be raining all of the time.

We look to be drying out temporarily at the beginning of the long
term Thu night and early Friday. We will see the sfc front and
supporting upper wave slide east of the state. Ridging at the sfc
and aloft will build in over the area.

The dry period will not last long however, as high pressure moves
east of the area. The upper air pattern will be that of a
progressive one with short waves coming through every couple of days
from west to east. The cold front that will settle south of the area
Thu will make a return back north as a warm front ahead of an
incoming system coming into the central plains. Rain will be
possible Sat into Sun until the system finally moves out.

We will cycle through the situation once again. We will see another
break in the rain for late Sun and most of Mon with short wave
ridging building in. Rain chances will increase late Mon and more so
Mon night as another system comes out of the plains, and strengthens
the srly warm and moist flow out ahead of it.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 143 AM EDT Tue Oct 25 2016

Our main focus for the 06z fcsts is on lower cloud cover based
around 3-4k ft coming in today. Right now, it appears that nrn
areas will see some clouds come down early this morning, with
more coming in this afternoon which will get a diurnal boost.
These clouds will then dissipate/move out toward 00z tonight.

Winds will tend to be a bit variable through today, generally
remaining under 6 knots. They will tend a bit more easterly later
in the day and tonight.


Issued at 325 AM EDT Tue Oct 25 2016

Winds and waves will be on the increase on Wednesday as low
pressure moves across Lake Michigan. East winds will be possibly
reaching gales on Wednesday especially south of Grand Haven.


Issued at 330 PM EDT Mon Oct 24 2016

The upper half of the Grand River basin (Ionia and upstream
tributaries) is largely running above climatological normal for
streamflow in mid October. The upcoming Wed to Thu system is
expected to produce at least a half inch of precipitation across the
whole area, with some of the area possibly eclipsing an inch. While
not the most likely scenario at this time, ensemble river models
suggest hypothetical 1.25 inch totals across the upper half of the
Grand River basin would lead to above-bankfull rises at some of the
typically flood-prone river forecast points.




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