Area Forecast Discussion
Issued by NWS Grand Rapids, MI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KGRR 202327
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
627 PM EST Fri Jan 20 2017

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 326 PM EST Fri Jan 20 2017

Very mild conditions will stretch through the weekend with highs
ranging from the mid and upper 40s over central Michigan to well
into the 50s over southern Michigan. A couple waves of light rain
will affect the area early Saturday morning and once again Sunday.
Cooler air moves in at the beginning of next week with additional
chances for rain and snow, but temperatures will remain above
normal. A reinforcing shot of cold air is expected late next week,
bringing us back to reality with highs in the 30s.

&&

.UPDATE...
Issued at 452 PM EST Fri Jan 20 2017

Abundant low level moisture and light winds will result in fog
development this evening and overnight. Dense fog of one-quarter
mile or less could lead to hazardous driving conditions through
Saturday morning. Therefore, a dense fog advisory was issued.
Fog is expected to slowly dissipate through mid morning Saturday.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 326 PM EST Fri Jan 20 2017

Considering we are in the midst of a chaotic weather pattern the
next couple of days are relatively tame. The main theme incorporates
gloomy conditions, a bit of fog, chances for light rain and well
above normal temperatures.

The first of several waves will continue to push north through
Michigan this afternoon. The main surface low rotates over Lake
Huron, effectively bringing an end to most of the precipitation
over southwest Michigan. A sprinkle or widely scattered shower
cannot be ruled out, but we will trend drier through the evening.

Temperatures do not move much tonight, only falling off by about
5 degrees. Upper levels dry out, but we keep quite a bit of low
level moisture with dewpoint depressions of around 2F or less.
Winds also lighten up, which may give way to fog late tonight
into early Saturday. Fog could be locally dense, especially where
the ground is a bit cooler and some snowpack still exists.

Despite being well departed from the next upper level wave and
corresponding surface low over Minnesota, rain chances increase early
Saturday morning. Shortwave energy spokes around the eastern
periphery of the main low, bringing showers back into the area.
Precipitation develops and progresses south to north through the
state just before and around dawn. Much of the daylight hours
should be dry with just a few showers dotting the map.

Yet another system passes through the Ohio Valley late Sunday and
will likely throw additional rain our way as early as Sunday
morning, extending into Sunday afternoon.

.LONG TERM...(Monday through Friday)
Issued at 326 PM EST Fri Jan 20 2017

Kept chances for rain going Monday to the northeast as a deep
surface low moving up the east coast may introduce wrap around
precipitation with perhaps some enhancement off Lake Huron.
Precipitation amounts should be light.

A fairly deep surface low is expected to move northeast across the
forecast area Wednesday. The overall pattern is not conducive to
much additional deepening as the low approaches. However, the track
of the low will largely influence local precipitation type and this
will need to be watched.

Based on the current forecast track of the low, we expect a
rain/snow mix Tuesday night as precip enters the area, followed by
all rain much of Wednesday, followed by a gradual transition back to
snow Wednesday night when colder air surges in behind the departing
low. Precipitation amounts during the day particularly across the
southern forecast area could be curtailed by what looks like a
substantial dry slot. Behind this system, lake effect precipitation
will persist for the rest of the week predominantly in the form of
snow, although a mix is possible Thursday afternoon with highs
approaching the upper 30s to the south.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 622 PM EST Fri Jan 20 2017

Conditions have deteriorated this evening and indications are they
will continue to lower. Most sites in Southwest Lower MI are LIFR
already. There is not much change expected...except the
temperature will fall off a few degrees. This should support the
fog becoming thicker.

Looking upstream...the low clouds did break up in parts of MO and
southern IL late this afternoon. With a southwest flow developing
tonight and Saturday...it looks like the thick fog and low clouds
will break up here in Southwest Lower MI during the afternoon.

&&

.MARINE...
Issued at 326 PM EST Fri Jan 20 2017

There is little to no concern for marine interests with regard to
winds and waves. We remain below small craft guidelines through
at least Monday. Areas of fog are expected to develop late tonight
into early Sunday.


&&

.HYDROLOGY...
Issued at 326 PM EST Fri Jan 20 2017

The Grand River at Robinson Township has been falling to near flood
stage today. Runoff from rain earlier this week is being routed
downriver as the ice restrictions decrease. Most rivers are rising
due to the rain, but seem to have less notable ice impacts now.
Temperatures (and dew points) will be above 32 degrees through the
middle of next week, with highs at or above 50 possible Saturday and
Sunday. The remaining river ice should move out or melt, at which
time flooding at Robinson would likely alleviate. Low-land flooding
near riverbanks is occurring at multiple forecast points, but
impacts to property are minor.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Dense Fog Advisory until 10 AM EST Saturday for MIZ037>040-
     043>046-050>052-056>059-064>067-071>074.

LM...Dense Fog Advisory until 10 AM EST Saturday for LMZ844>849.

&&

$$

UPDATE...JAM
SYNOPSIS...JAM
SHORT TERM...JAM
LONG TERM...TJT
AVIATION...MJS
HYDROLOGY...63
MARINE...JAM



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.