Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 231647
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
1247 PM EDT Sat Mar 23 2024

.KEY MESSAGES...

- Winter returns for the weekend

- Warm, Windy and showery Monday into Tuesday

&&

.UPDATE...
Issued at 1150 AM EDT Sat Mar 23 2024

No weather concerns this afternoon as high pressure is entrenched
across the Great Lakes region. The high should become more
centered over the area by this evening, so partly to mostly sunny
and dry will be the theme. Some lake effect generated cumulus
clouds are about all we are dealing with today. We will see
generally scattered clouds, but some periods of broken clouds
cannot be ruled out. Highs will generally be in the middle 30s
with a north wind of 5 to 15 mph.

&&

.DISCUSSION...
Issued at 233 AM EDT Sat Mar 23 2024

- Winter returns for the weekend

In the wake of the winter storm cold northerly winds will continue
through most of the weekend. Light snow continues to fall early
this morning as a secondary front moves through the region spurred
on by the cold northerly flow. However, given that it is a very
cold air mass with little moisture present, expect only flurries.
 Otherwise cold and dry flow will continue today into Sunday. With
850mb temps of -12 and clearing skies expect highs to struggle
moving into the mid 30s and overnight lows into Sunday being in
the teens.
 Temperatures will rebound a little into Sunday with warm air
advection throughout the day. As a weak system builds into the
area Sunday night there will be a chance for light snow with only
light, if any, accumulations expected mainly along the US 10
corridor.

- Warm, Windy and showery Monday into Tuesday

A strengthening southerly low level jet lifts up into the CWA Monday
into Tuesday. The associated warm air advection will support well
above normal temperatures for the region.  Ensemble 2m temperatures
plots from the models show values reaching into the 50`s for both
Monday and Tuesday. Trends suggest slightly warmer temperatures for
Monday with increasing numbers of members showing values making a
run a 60 degrees for southern parts of the CWA.

The low level jet also advects in a very moist airmass from the
Gulf.  Ensemble PWAT values suggest values will top 0.80 inches
which is well above normal for this time of the year.  Mid level
heights fall here in MI Monday night into Tuesday as a wave tracks
north northeastward through the Plains and takes on a negative tilt
by Tuesday.  The associated surface cold front pushes through MI on
Tuesday.  This feature will tap into the moisture in place leading
to widespread showers.  Ensemble mean 24 hr qpf values are still
running around a half inch, but there is a decent amount of spread
amongst the members in all the models.  Thus we will need to monitor
trends, however hydro impacts appear unlikely at this time.

That low level jet will cause the surface winds to increase
considerably on Monday.  Ensemble gust values are supporting values
reaching into the 30 mph range and the GFS is showing a risk for 40
mph gusts.  We already have higher gusts in the forecast and will
maintain those values.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1247 PM EDT Sat Mar 23 2024

The low clouds that were left over from the system yesterday moved
out this morning leaving mostly clear skies for a brief period.
Now, fair weather cumulus clouds are developing, and will continue
to expand this afternoon. This is not a big concern since ceilings
will be VFR around 4-5k ft. Clouds will be more broken inland, and
more scattered at the lakeshore.

The clouds will dissipate this evening toward sunset, and winds
will go light. Was considering some fog potential with the
melting, clear skies and light winds. However, mid clouds will be
moving in overnight mitigating that threat a bit, along with a dry
air mass. The clouds will gradually thicken up on Sunday, and
lower a bit. They are expected to remain VFR no lower than 6k ft
agl through 18z Sunday and beyond.

&&

.MARINE...
Issued at 338 AM EDT Sat Mar 23 2024

Northerly winds will be continue and due to the overall weak
nature, we are not expecting the need for a marine headline
(Small Craft Adv or otherwise) through the day on Sunday.
 Latest CAMS due shows that winds, though off shore, will increase
Sunday night into Monday and an SCA will probably be needed. As
these winds increase the highest may reach gale status.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.

&&

$$

UPDATE...Duke
DISCUSSION...MJS/Ceru
AVIATION...NJJ
MARINE...Duke/Ceru


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