Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 160721
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
321 AM EDT Mon Oct 16 2017

LATEST UPDATE...
Synopsis/Short Term/Long Term/Marine

.SYNOPSIS...
Issued at 308 AM EDT Mon Oct 16 2017

An area of high pressure in the Middle Mississippi Valley will
build east today and into the Central Appalachians for tonight. As
a result the weather here in Michigan today  will feature
diminishing clouds and showers followed by a warming trend as we
go into Tuesday. Unseasonably mild weather will then prevail for
much of the week.

&&

.SHORT TERM...(Today through Wednesday)
Issued at 308 AM EDT Mon Oct 16 2017

The main challenge in the short term deals with the potential for
showers. I ended up increasing POPs this morning.

Satellite imagery shows abundant clouds across the CWA to start
the day. Additional clouds in WI are tracking east and are colder
than -15 deg C...thus some ice likely exists in those clouds. We
currently have light showers around the region...plus the airmass
is cold enough for lake enhanced moisture. Those clouds that are
in WI headed our way may keep the showers going here in wrn MI as
they pick up some of the lake moisture this morning. Thus I did
feature low POPs for the morning for much of the CWA...followed
by a dry afternoon and skies clearing out.

The pressure gradient tightens up tonight as warm air advection
strengthens. This will support moderating temperature as we go
through the remainder of the short term period. Well above normal
temperatures are likely to return to the region.



.LONG TERM...(Wednesday night through Sunday)
Issued at 308 AM EDT Mon Oct 16 2017

Fair wx will continue Wednesday night through Saturday. Temperatures
will continue to undergo a slow gradual moderating trend due to
continued south to sw flow warm air advection and an amplifying
upper level ridge over our region late in the week in conjunction
with moderating h8 temps.

High temperatures late in the week will easily reach the upper 60`s
to lower 70`s and could even reach well into the 70`s by
Friday/Saturday. This will be at least ten to fifteen degrees above
normal for this time of year.

A consensus of latest medium range guidance continues to suggest
that a weak cold front will bring the next chance for showers by
Sunday. Temperatures will be a little cooler behind that system for
early next week but should still average a little above normal for
this time of year.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1130 PM EDT Sun Oct 15 2017

Mainly vfr conditions will continue at all the terminals overnight
but brief reductions to mvfr are possible at our western terminals
(KMKG... KGRR and KAZO) due to low clouds and scattered showers.

Considerable diurnal cumulus clouds will develop late Monday
morning through the afternoon but conditions will remain vfr with
cloud bases around 4-5 kft agl. Skies will gradually clear Monday
evening.


&&

.MARINE...
Issued at 308 AM EDT Mon Oct 16 2017

The main change to the forecast was to drop the small craft
advisory for the northern half of the nsh area. The buoys show
that the winds and waves have diminished below criteria. We may
need to extend the headline for the region south of South Haven
this morning as the waves are only subsiding slowly.

Another small craft advisory headline will likely be needed for
tonight.

&&

.HYDROLOGY...
Issued at 327 PM EDT Sun Oct 15 2017

A widespread 1 to 3 inches fell across the majority of the area,
with the exception of Ludington to Clare. Greater totals of 3 to 5
inches were focused south of Holland-Lansing and west of Jackson.
Southern Van Buren, central Kalamazoo, and northern Calhoun counties
received a swath of 5 to 7 inches. Isolated amounts of 8 or 9 inches
fell around Decatur, Lawton, and west of Portage. And we`re not
talking about snow here.

The scope of this weekend`s rainfall in Southwest Michigan is
reminiscent of the tropical rains received on August 15-16, 2016.
However, the magnitude of the highest totals today is greater (the
highest totals in the 2016 event fell by South Bend). At the
Kalamazoo airport, greater than 6 inches fell, which is the greatest
2-day total (midnight-to-midnight) recorded there since the remnants
of Ike came through in September 2008.

This weekend`s rain fell over a longer duration than Aug 2016 and
had relatively dry preceding conditions, so flooding is not as bad
as it could have been. Nonetheless, a number of road closures
occurred due to flooding across Van Buren and Kalamazoo, a small dam
failed near Paw Paw (with little to no impact to the downstream
Maple Lake, which was drawn down 4 feet last week for the winter),
and no doubt some homes and businesses were affected as well. Some
river points in the Kalamazoo and Grand river basins have risen or
are expected to rise above bankfull, and reaching flood stage is not
anticipated (except for minor flooding occurring on the Portage
River near Vicksburg). With a dry week ahead, rivers will run their
course without further exacerbation.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until 8 AM EDT this morning for LMZ844>846.

&&

$$

SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...Laurens
AVIATION...Laurens
HYDROLOGY...CAS
MARINE...MJS



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