Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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147
FXUS63 KGRR 190451
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
1151 PM EST Sat Feb 18 2017

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 250 PM EST Sat Feb 18 2017

Above average temperatures will continue through much of this week
with a quick shot of light rain looking likely late Monday night
through midday Tuesday. More unsettled and possibly more winter-
like weather may return next weekend.

&&

.SHORT TERM...(This evening through Monday night)
Issued at 250 PM EST Sat Feb 18 2017

Dry and mild weather expected through Monday with little adjustment
to the previous forecast made this afternoon. A little fog is
possible tonight but it should remain very patchy and does not look
like it will be of much impact if any at all.

Otherwise...minor adjustments to the forecast Monday night where
timing of approaching cold front continues to be slower than
previously anticipated. Have moved the greater precipitation chances
toward the latter half of the night time period. Regardless..still
looks like a quick hitter with only light rain amounts generally
under one quarter of an inch by the time rain comes to an end Tuesday.

.LONG TERM...(Tuesday through Saturday)
Issued at 250 PM EST Sat Feb 18 2017

Extended period begins with northern stream sfc low tracking across
southern Canada with trailing front to focus band of rain moving
east and out of the forecast area by Friday evening. The blended
POPs were not changed for Tuesday, but slower timing of the
precip is possible per the consistently slower ECMWF.

Another low tracks across northern Lower Michigan late Wednesday but
any precip should be inconsequential and limited to the northern
forecast zones. A trailing front from this low lays out just south
of Lower Michigan on Thursday as Plains cyclogensis is underway.
Overrunning precip breaks out along and north of the front Thursday
night with the main low arriving Friday into Saturday

There still remains a lot of ensemble spread with the track and
intensity of the low, and run to run consistency of the operational
runs of the ECMWF and GFS have shown some large variations as can be
expected that far out in time. The general idea is that the sfc low
will track close to the forecast area with rain changing to snow at
some point Friday night into Saturday, followed by a few lake effect
snow showers later Saturday. There is also the possibility that this
low remains weaker than advertised, as happened in a similar
looking forecast scenario a couple weeks ago, where the sfc low did
not intensify until it had passed well east of Lower Michigan.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1151 PM EST Sat Feb 18 2017

VFR conditions will continue through the next 24 hours with just
some high cloudiness around. Vsbys will remain unrestricted,
however some isolated fog could occur around daybreak. WNW winds
will remain very light.

&&

.MARINE...
Issued at 250 PM EST Sat Feb 18 2017

Mostly quiet conditions over the next couple of days. Some afternoon
breeze could increase waves up to the 2 to 4 foot range at times
Sunday and again Monday, but overall waves should remain in the 1 to
3 foot range.


&&

.HYDROLOGY...
Issued at 250 PM EST Sat Feb 18 2017

Light rain late Monday night into early Tuesday is
expected...though this result in no hazardous hydrologic
concerns.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&

$$

SYNOPSIS...Maczko
SHORT TERM...Maczko
LONG TERM...Ostuno
AVIATION...JK
HYDROLOGY...Maczko
MARINE...Maczko



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