Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 241657

Area Forecast Discussion
National Weather Service Grand Rapids MI
1257 PM EDT Fri Mar 24 2017


Issued at 328 AM EDT Fri Mar 24 2017

It will be a wet weekend across Michigan as a front will stall
across northern Lower Michigan today and then slowly meander south
on Saturday. Periods of rain will continue into early next week as
low pressure approaches from the southwest.


Issued at 1023 AM EDT Fri Mar 24 2017

We have freshened up the forecast this morning to account for the
latest cloud and rain trends. The few rain showers that were in
place over the nrn counties earlier this morning have weakened
and moved out of the area. This has occurred as one of the sfc
fronts has moved well north of the area for the time being. It
appears there is another warm front that is near I-96 that
separates the real warm air down south from the moderate air mass
across the north.

These fronts will migrate closer together this afternoon as the
high across Canada pushes the nrn front south, and as the system
to our SW tries to push the warm front north. This will result in
rain dropping south into the nrn counties. Down south, there could
be a couple of showers/storms that pop in the instability. These
are expected to be later this afternoon with quite limited

We still expect highs along I-94 will approach or exceed 70
degrees. Temps up north will warm for a couple of hours before the
nrn front and clouds/rain will stop the warming and drop temps


.SHORT TERM...(Today through Sunday)
Issued at 328 AM EDT Fri Mar 24 2017

POPs and temperatures are the challenge in the near term as a
stalled front across northern Lower today sinks south tonight and
on Saturday. Expect afternoon maxes today to have a wide range,
from the upper 60s across the far south to the upper 40s across
the far north.

High res models show potential for some scattered showers
persisting across central zones this morning in an area of
continued isentropic ascent. POPs for this morning were shaded
south a bit to account for this. The afternoon should be dry
across much of the forecast area with some breaks in the overcast,
especially across the south under the crest of the upper ridge.

POPs increase again tonight and Saturday as the front sinks south
which also brings in shallow colder air with maxes restricted to
the 40s most places on Saturday. Sfc low is occluded and filling
as it approaches from the southwest on Sunday, but Lower Michigan
remains in an area of upper level divergence and coverage of
showers should continue to be extensive through much of Saturday
night and Sunday.

.LONG TERM...(Sunday night through Thursday)
Issued at 328 AM EDT Fri Mar 24 2017

The wx pattern will remain showery and unsettled Sunday night
through Monday. A trough of low pressure will continue to bring
showers Sunday night into Monday. A low pressure system over the
Arklatex region early Monday will also move northeast and bring more
showers Monday night into early Tuesday.

Dry weather will finally return late Tuesday through Wednesday as a
high pressure ridge builds in from the north. Temperatures will
average above to much above normal through Tuesday before returning
to closer to normal for this time of year for mid to late week.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1257 PM EDT Fri Mar 24 2017

I expect solid VFR conditions into late afternoon at all taf
sites. However, it increasingly is looking like the current two
frontal pattern over our area will merge into a signal front near
I-94 by this evening. Several runs of the HRRR and RAP model and
the latest run of the NAM shows a convective band developing near
I-94 by 00z that will remain nearly stationary till at least 03z.
The NAM12 thunderstorm probability increases to near 80 pct in a
narrow band along I-94 this evening (near 0 prob along i-96 at the
same time). The general over-running rain pattern for all of the
tafs does not really set in until 09z or so. Once started the rain
should continue into midday Saturday.

Ceilings will become IFR behind the front so the I-96 taf sites
will go IFR at least 3 hours before the I-94 ones do. I expect all
areas to be IFR in rain, drizzle and fog most of the morning


Issued at 1023 AM EDT Fri Mar 24 2017

We have issued a Small Craft Advisory for areas south of Grand
Haven through 00z tonight. Winds have come up to 25 knots and
waves will be around 3-5 feet in the warm sector.

We are looking at another advisory possible for Saturday with the
decent NE gradient dropping down. Waves will not be as bad with it
being an offshore flow.


Issued at 1241 PM EDT Fri Mar 24 2017

A wet pattern will continue through much of the next seven days
with multiple rain events taking place. Rainfall totals over the
next week will generally be in the 0.75 to 1.50 inch range. This
will result in rises on area rivers with some area rivers reaching
bankfull starting late this weekend and continuing at bankfull
potentially through the end of next week. Significant river
flooding is not anticipated with the amount of rainfall that is
expected over the next week.


LM...Small Craft Advisory until 8 PM EDT this evening for LMZ844>846.



LONG TERM...Laurens
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