Area Forecast Discussion Issued by NWS Grand Rapids, MI
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000
FXUS63 KGRR 221932
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
332 PM EDT Fri Mar 22 2024
.KEY MESSAGES...
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- Snow Winds Down This Evening
- Dry Saturday
- Warm and Rainy, Then Dry Next Week-- End Changed Discussion --
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.DISCUSSION...
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Issued at 331 PM EDT Fri Mar 22 2024
- Snow Winds Down This Evening
A positive tilt mid level shortwave will progress eastward through
the Great Lakes region this evening. It will move off to the east
overnight and snow will come to an end. We trimmed back the
extent of the Winter Weather Advisory prior to 200pm. We will
leave what remains as is through midnight. So, the U.S. 10 and
I-94 rows have been removed.
Isentropic lift will continue in the advisory counties this
evening, especially the Ottawa to Clinton row and Allegan to
Ingham row. There is some decent mesoscale banding still occurring
within this zone, but widespread impacts are dwindling by the
hour. Another inch or two will occur in a few spots. The main item
for folks to keep in mind is temperatures will be falling through
the 20s this evening and overnight and meltwater from the snow
today will refreezing into slick spots. All of that said we may be
able to cancel the advisory early/before midnight.
- Dry Saturday
Dry weather is forecast for both Saturday and Saturday night as
surface high pressure moves through the region. Deep layer
moisture is not present and therefore we have high confidence in
dry conditions. Normal highs this time of year are in the upper
40s with normal lows right around 30. Highs on Saturday will be in
the lower to middle 30s which is 10 to 20 degrees below normals.
Nothing too atypical for this time of year though. Saturday night
we dip into the upper teens to middle 20s. These readings are 5
to 15 degrees below normal, but nothing we cannot handle.
- Warm and Rainy, Then Dry Next Week
Temperatures begin to warm Sunday as an 850mb thermal ridge moves
into the central Great Lakes. Cannot rule out an isolated warm air
advection based snow shower Sunday night up towards Ludington, but
chances are low (20-30 percent). Temperatures climb even more Monday
with highs in the 50s likely both Monday and Tuesday.
Dry conditions are expected Sunday into Monday (with the exception
of the aforementioned chance of snow showers towards Ludington)
before rain arrives late Monday and into Tuesday, which is a trend
for a later start compared to yesterday`s 12z guidance. The
widespread showers will be a result of ample forcing from a coupled
upper-level jet and numerous shortwaves, combined with the arrival
of deeper moisture. Forecast MUCAPE and LI values support little to
no thunder threat, so will keep it out of the forecast.
Deterministic and ensemble guidance paints around 0.5 inches of QPF
across lower Michigan providing a soaking rainfall with this system.
Rain winds down Wednesday morning as the low, forcing, and deeper
moisture pull away, and a cold front brings cooler air into the
region. Monday also looks to be breezy given an 850mb 40-50 knot low
level jet moving across the area. Numerous members of the EPS and
GEFS show 30-45 mph gusts during the day on Monday, dependent on how
deep we are able to mix.
Conditions then dry out later Wednesday through the end of the work
week as surface ridging and low level dry air come into place. Highs
in the 40s are expected Wednesday and Thursday as we remain under
longwave troughing.-- End Changed Discussion --
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.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 132 PM EDT Fri Mar 22 2024
Primary aviation concerns are through around 03z associated with
the current snowfall across the area. The primary band of IFR
visby snow has moved north from the I94 corridor and will
primarily impact MKG/LAN/GRR this afternoon. This band then
shifts southeast this evening, causing the I94 terminals to fall
back to low end MVFR to high end MVFR for a few hours before snow
exits. Conditions improve from northwest to southeast starting
around 00z. MKG returns to VFR behind the band while high
resolution model guidance has trended towards the moisture
remaining trapped under an inversion keeping MVFR stratus
overnight at all other sites. Signals for areas of fog and IFR
cloud cover exist south and east of KGRR associated with a few
hours of NE flow off of Saginaw Bay, but low confidence keeps IFR
restrictions out of the TAFs at this time. Condition then improve
to VFR for the rest of the terminals just after daybreak and
remain so through the rest of the TAF period. Southeast winds 7-12
knots shift to north at 5 knots or less overnight and strengthen
to around 10 knots again after daybreak Saturday.
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.MARINE...
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Issued at 331 PM EDT Fri Mar 22 2024
We are not expecting the need for a marine headline (Small Craft
Adv or otherwise) through the day on Sunday it appears. Winds from
the GFS using a BUFKIT overview at the southern buoy location
show values that are mainly sub advisory. There is a brief time
around daybreak on Saturday when winds increase to 20-25 knots.
These winds are off shore and at this time do not look to pose to
much of a threat in our nearshore water. High pressure looks to
keep things tame on the big lake from Saturday afternoon into
Sunday.
Once we get to Sunday evening winds being to ramp up out of the
south on the leading edge of a strong low moving through the
Western Great Lakes. South winds will be of sufficient force for
at least a SCA and most possibly a gale. At this time it looks
borderline for a gale but we have plenty of time before we need to
make decisions on that headline.-- End Changed Discussion --
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.GRR WATCHES/WARNINGS/ADVISORIES...
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MI...Winter Weather Advisory until midnight EDT tonight for
MIZ043>046-050>052-056>059-064>067.
MARINE...None.-- End Changed Discussion --
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DISCUSSION...Duke/Thomas
AVIATION...Thomas
MARINE...Duke