Area Forecast Discussion
Issued by NWS Grand Rapids, MI

Home | Current Version | Previous Version | Graphics & Text | 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 242308
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
608 PM EST Fri Nov 24 2017

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 330 PM EST Fri Nov 24 2017

A few passing rain showers will cross Southwest Michigan tonight as
a cold front comes through.  The best chance of seeing a rain
showers will be along and north of I-96.  A few snow flakes may mix
in Saturday morning toward Highway 10, then much of the
precipitation will exit by afternoon.  The rest of the weekend will
be dry with near normal temperatures.

Temperatures will stay near to slightly above normal next week with
most daily highs of 45 to 50.  However Tuesday should peak to highs
of 55 to 60.  There may rain showers Tuesday, and again Wednesday
night and Thursday.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 330 PM EST Fri Nov 24 2017

A band of scattered rain showers across Northern WI as of this
afternoon, will track SE and reach Central Lower tonight.  Otherwise
much of the short term will be quiet with near normal temps.

The rain was ahead of a cold front and mid level short wave that
will cross Lower Michigan late tonight. The band was rather narrow
and is expected to remain that way, with the best lift remaining
near the front.  The best moisture pooling is progged to pass across
Central Lower where higher POPs will be carried.  An abrupt decrease
in the moisture will cross areas south of I-96, and most of this
area should remain dry.  The front exits quickly, so most areas will
only see a passing showers, then dry by daybreak.

There will be some wrap around moisture that tracks across Central
Lower Saturday morning. A few showers may linger and should mix with
some snow prior to ending toward mid day.  Abundant low level
moisture behind the front should result in a cloudy day for the rest
of the area.

The pattern by Saturday night through Sunday night will be one of
northwest upper flow, with high pressure floating in late Saturday
night into Sunday.  Skies should begin to clear Saturday evening,
with all areas starting Sunday with mostly sunny skies.  Clouds
should increase again late Sunday afternoon as a system passes well
to our NE.  These clouds should be exiting again toward daybreak
Monday.

.LONG TERM...(Monday through Friday)
Issued at 330 PM EST Fri Nov 24 2017

The long term period starts off with warm air advection developing
on Monday. There is a shallow cooler airmass shown below 850 mb...so
some uncertainty as to  how warm it actually gets on Monday.  The
NAM also suggests the shallow cooler airmass will be saturated.  If
we end up with low clouds...the forecasted highs will end up much
lower than we have in the forecast.  I will keep the theme of
temperature values climbing to above normal values.

Deeper warm air advection develops Monday night and lasts into
Tuesday.  Thus well above normal temperatures look likely for
Tuesday.  A cold front tracks through later on Tuesday.  At this
time the probability of seeing measurable precipitation looks low as
moisture will be lacking and the main forcing stays up in Ontario.

There is a trend toward tracking the next storm system further north
with time Wednesday night into Thursday.  On previous runs it
appeared that storm could miss us off to the south...but the recent
runs say otherwise.  We will need to monitor the temperatures at the
onset...as north of Big Rapids...sub freezing temperatures may
occur.  Thus a risk for local impacts exists. Some snow could mix in
toward the end of the event as colder air starts to filter back in
on Thursday or Thursday night.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 607 PM EST Fri Nov 24 2017

Currently we have solid VFR across all of our TAF sites and that
should continue till around 06z. Then a cold front will quickly
move from northwest to southeast across our TAF sites and bring
cigs to around 1500 ft agl with a period of sprinkles or light
rain (1 to 2 hours at any one location). After the light rain ends
cigs will lower to IFR (09z). Once the surface cold comes in, a
about 6 hours behind the actual surface front we will have several
hours of light rain or drizzle with MVFR or IFR conditions with
gusty winds. This will last through the afternoon. Any clearing
would be after midnight (Sunday morning).

&&

.MARINE...
Issued at 330 PM EST Fri Nov 24 2017

Gale warning has been verifying this afternoon north of Whitehall,
but not south of there.  The peak in the wind was happening this
afternoon, so will cancel the gales to the south of the Sable Points.

Winds will pivot to the northwest behind a front late tonight and
remain fairly brisk.  So will take the gales down south of
Whitehall, but replace it with a small craft advisory that will run
through Sunday.  It seems likely we will need to expand it in time
beyond Sunday.


&&

.HYDROLOGY...
Issued at 330 PM EST Fri Nov 24 2017

All river flood advisories have been discontinued as of Friday
afternoon. Water levels on area creeks, rivers, and streams will
continue to fall through early next week. Light rain showers or
drizzle are expected tonight and Saturday in association with a cold
frontal passage. Rain amounts should remain below a tenth of an
inch. No hydrologic concerns are anticipated through the middle of
next week as no significant precipitation is expected.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Gale Warning until 10 PM EST this evening for LMZ848-849.

     Small Craft Advisory until 7 PM EST Sunday for LMZ844>847.

&&

$$

SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...MJS
AVIATION...WDM
HYDROLOGY...HLO
MARINE...JK


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