Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 271720
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
120 PM EDT Wed Mar 27 2024

.KEY MESSAGES...

- Cloudy and cooler today, sunshine Thursday

- Multiple Chances For Precipitation Through Mid Next Week

&&

.UPDATE...
Issued at 1027 AM EDT Wed Mar 27 2024

Cold cyclonic flow off Lk MI is supporting some flurries this
morning so have added that to the fcst through 18Z, which is when
weak omega in the cloud deck goes away. Best chance for late day
clearing is along and south of the I-94 corridor per latest low
level RH progs although breaks/thinning possible elsewhere too as
drier upstream air arrives.

&&

.DISCUSSION...
Issued at 225 AM EDT Wed Mar 27 2024

- Cloudy and cooler today, sunshine Thursday

Latest IR loop shows abundant stratocu covering the LP. However,
some clearing was noted over northwest WI and that clearing will
eventually make into the cwa late this afternoon.

Low pressure that pushed a cold front through the cwa yesterday is
now north of Lake Superior and high pressure will nose in from the
south today. Bufkit RH progs show clouds thinning and scattering
out after 20z today, which should lead to a little sunshine before
the day is out.

H8 temps are chilly...near -12c today, so we`ll see highs below
normal...only 35 to 40. As skies clear tonight, temperatures will
fall into the mid to upper 20s. The upper trough axis will swing
through tonight take the core of the colder air with it tomorrow.
Highs tomorrow will still be below normal, around 40, but a bit
warmer than today.

- Multiple Chances For Precipitation Through Mid Next Week

The long term portion of the forecast starts out dry as surface and
upper-level ridging and low-level dry air are in place for Friday.
The first chance of precipitation is expected to center on Saturday
morning as a surface low and associated warm frontal boundary tracks
across the southern third of the state. A few rumbles of thunder are
possible near I94 Saturday morning as 850mb LIs go slightly
negative, while a low chance of snow or freezing rain exists near
US10 due to a Canadian high pressure system brings cooler air in.
Highest QPF, presently looking to be in the 0.25-0.5 inch range,
focuses on the southern half of the CWA with lesser amounts north.
Thermal ridging puts highs into the 50s Friday into Sunday.

A brief period of surface and upper-level ridging then keeps the day
on Sunday dry before the next system arrives Monday morning into
Tuesday. Cluster analysis shows considerable uncertainty remains
with the amplitude and tilt of the expected mid-level wave across
the Central Great Lakes early next week, affecting the strength and
track of the surface low, and extent of temperature advection (to
add a bit of context, there is 10C of spread in the 850mb temps 25th-
75th percentile). A bit of snow mixing in across Central Michigan
can`t be ruled out if solutions trend towards the cooler side of the
envelope but this scenario is unlikely at present. Overall, rain is
likely with this system, with some details still needing to be
ironed out (not uncommon in the day 5-6 timeframe).

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 120 PM EDT Wed Mar 27 2024

MVFR cloud deck sticks round to start off the afternoon but clouds
are expected to lift into VFR near or before 00z this evening. VFR
ceilings erode overnight then clouds remain scattered into
Thursday afternoon. Westerly winds across the area will weaken
towards 5 knots overnight then will build back to 10 to 15 knots
gusting to 20 to 25 knots near mid- day.

&&

.MARINE...
Issued at 225 AM EDT Wed Mar 27 2024

No changes to the Small Craft Advisory which remains in effect
through tonight. Brisk west winds will keep waves high today.
However, high pressure will build into the region from the south
and winds will diminish tonight.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 8 AM EDT Thursday for LMZ844>849.

&&

$$

UPDATE...Meade
DISCUSSION...04/Thomas
AVIATION...Thielke
MARINE...04


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