Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/14/22

Area Forecast Discussion

National Weather Service Green Bay WI

 542 PM CST Sun Nov 13 2022

Updated aviation portion for 00Z TAF issuance

.SHORT TERM...Tonight and Monday
Issued at 254 PM CST Sun Nov 13 2022

The latest RAP analysis and satellite/radar imagery show polar
high pressure centered over the Mississippi Valley early this
afternoon. Although northerly flow has weakened, thermal troughing
combined with minor low level instability has led to a diurnal
uptick in strato cu and light snow showers/flurries. The most
persistent snow showers should occur near the U.P. border over far
northeast WI to the northern tip of the Door Peninsula. Don`t
think will see any accums larger than a dusting for the rest of
the afternoon in these areas. Looking upstream, the next storm
system is developing over the northwest Plains and poised to move
into the region Monday afternoon. Snow accum potential and timing
with this system are the main forecast concerns.

Tonight...Surface high pressure will move across the area. As the
high settles over the area, north flow will become light and
variable by the end of the evening, which should result in the
end of any linger snow showers or flurries into far northern WI.
A period of partial clearing remains possible tonight, but an
influx of mid and high clouds should prevent temps from tanking.
Will still trim back on temps in the cold spots where some snow
may be on ground. Lows ranging from the middle teens over Vilas
county to the middle 20s near Lake Michigan.

Monday...Cloud bases will continue to lower as a shortwave
trough/PV anomaly moves into the region during the afternoon.
Pockets of mid-level dry air look to hang around during the
morning, so think light snow will hold off until deep saturation
spreads across north-central to far northeast Wisconsin during the
afternoon. Snow may reach upwards of 1/2" to 1" by the end of the
afternoon over north-central WI, which could impact the evening
commute. Winds turn onshore over northeast WI in the afternoon,
which also could lead to lake enhanced bands moving into the Door
Peninsula. Would be more concerned if 1000-850mb wind speeds were
higher than 5 kts. Highs on Monday to range from near 30 in the
north to upper 30s over east-central WI.

.LONG TERM...Monday Night Through Sunday
Issued at 254 PM CST Sun Nov 13 2022

The extended period will see fairly static conditions through the
middle of the work week, dominated by a 500mb ridge off of the
West Coast and a strong upper trough that extends over the Great
Lakes and into the Central Plains. This pattern will keep cold and
below normal air flowing into the region and will bring even
colder air in for next weekend.

Precipitation-wise, the trough overhead will keep shortwaves
rotating through the area Tuesday morning through Thursday, which
will likely keep scattered snow showers going across the region.
The main concern for this time period will be the potential for a
lake enhanced band to set itself up sometime Tuesday through
Wednesday morning as easterly to northeasterly winds will be in
place during this portion of the forecast. If this occurs, will
likely need to bump up the currently forecast snow totals.
Overall, expect at least an inch or two across most of the area
for this extended period of snowfall, with a few locally higher
areas near Lake Michigan.

By Thursday, the initial system should be winding down, which
should bring a brief break everywhere but the far north sometime
near the end of the week. Unfortunately for the far north, with
the ridge not breaking down until after the upcoming weekend, lake
effect seems likely to continue. Finally, there are some hints
that another shortwave will swing through the region sometime at
the end of the week, but the timing on this is still unclear.
&&

.AVIATION...for 00Z TAF Issuance
Issued at 534 PM CST Sun Nov 13 2022

Scattered light precipitation over north central WI and northern
Door County should end this evening as high pressure moves into
the region. VFR stratocumulus will likely prevail into the
overnight hours, but when it erodes late tonight, mid/high clouds
will be overspreading the region. Clouds will thicken and lower
again on Monday, as an upper level disturbance approaches. Light
snow and MVFR conditions should develop in the mid to late
afternoon at the RHI/AUW/CWA TAF sites, with a few flurries
arriving at the eastern TAF sites late in the afternoon.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM.....MPC
LONG TERM......Uhlmann
AVIATION.......Kieckbusch



Area Forecast Discussion

National Weather Service Marquette MI

 1023 PM EST Sun Nov 13 2022

.UPDATE...
Issued at 1023 PM EST SUN NOV 13 2022

Challenging fcst setting up overnight into Mon morning with regard
to LES. Occasional +shsn have been streaming onshore in far eastern
Marquette County and far western Alger County since late aftn. Would
not be surprised if there have been some 4-7 inch accumulations
since late aftn roughly along the county line btwn Skandia/Carlshend
and Eben Junction/Trenary. While the somewhat organized banding of
earlier has diminished, there are still +shsn in eastern Marquette
County and far western Alger County. Sfc obs near the Marquette
County shoreline show land breeze developing, so this may be
responsible for the more disorganized appearance recently as the low-
level convergence that supported the loosely organized banding is
breaking down. New convergence on the developing land breeze should
eventually lead to heavier snow showers organizing more so over the
lake, just offshore. KMQT VWP also shows light northerly winds to
about 7kft diminishing, now under 10kt. That also explains the now
very disorganized appearance of ongoing shsn. To the w, KMQT radar
has also been showing returns in far northern Ontonagon County from
around Mass City northward. So, there has likely been several inches
of snow accumulation in that area this evening as well. More
recently, mdt/hvy shsn have also been developing just e of Copper
Harbor.

Not sure how the land breeze convergence will play out overnight.
Some of the 12z CAMS indicated that the strengthening land breeze
convergence just offshore during the night would slip back onshore
in Marquette/western Alger County late night/Mon morning. CAMS that
did show that now keep convergence/+shsn just offshore. However, wrf-
arw still clips northern Marquette County to the n of the city of
Marquette. Hourly HRRR runs have been supportive of heavier snow
also brushing areas farther s from the city of Marquette to Shot Pt.
Given the model trends, will hold off on an advy overnight/Mon
morning. LES trends per radar and sfc ob wind trends will need to be
closely monitored overnight to determine if developing +SHSN on land
breeze convergence will slip onshore for the morning commute from
Big Bay to Marquette toward Au Train. As gradient winds become ese
Mon morning, the land breeze convergent snow band will likely push
toward the Houghton area. Will be something to monitor for Mon
morning/early aftn.

Ongoing mdt/hvy shsn in far northern Ontonagon County will move
offshore in the next few hrs as land breeze develops/strengthens.
The heavier snow developing near Copper Harbor may shift sw into
more of Keweenaw County based on model consensus of low-level wind
fields, leading to a few inches of fluff for some locations there.
&&

.SHORT TERM...(Through early this evening)
Issued at 306 PM EST SUN NOV 13 2022

LES is slowly winding down, as evidenced on radar and satellite
imagery. There are more gaps appearing in reflectivity as well as
with the cloud cover, but again, emphasis is on the word slow. The
colder air has definitely arrived, with 850mb temps in the
negative mid-teens Celsius range. Dendrites/plates have taken
over today, and SLRs have raised themselves up quite a bit as
compared to yesterday. In other words, much bigger flakes with
much fluffier textures today, persisting into this evening. Accums
are, as expected, to not be as robust as the last 24 to 36 hours,
although locally, amounts could still quickly accumulate,
impacting motorists. Nrly winds continue, but their magnitudes
are on a downward trajectory, with a slight veering in the far W
by the end of this forecast period. Temps have generally gotten
close to or already topped out for their highs today, in the mid
20s inland to around the freezing mark along lakeshores and in the
south-central.

.LONG TERM...(Monday night through Sunday)
Issued at 336 PM EST SUN NOV 13 2022

Models and ensembles advertise anomalously strong ridging centered
over the Gulf of Alaska which will promote broad downstream
troughing over the central CONUS and Great Lakes region through next
week. This pattern will continue the below normal temperatures along
with periods of lake effect snow over Upper Mi. Lake effect snow
looks to be light through much of the week, although there appears
to be a potential for moderate to heavy LES into at least the
western counties late week into the weekend as a series of
shortwaves usher in colder Arctic air while providing additional
opportunities for LES enhancement.

Tonight, broad sfc ridging and a weakening wind field should bring
an end to LES propagating well inland, but that said, CAMs indicate
that strengthening land breezes could lead to a LES convergence band
or series of mesolows from near Munising west through Marquette to
Big Bay and Houghton/Calumet. Models have been latching on to this
idea for several days now so there is higher forecast confidence
that these LES features will develop, but uncertainly still exists
in exactly where and how much snow they will yield. Most likely snow
accumulation will be on the order of an inch or two for most of the
aforementioned sites with locally higher amounts possible.

Monday into Monday night, the prevailing winds take on a more east-
southeast component by Mon afternoon. With 850 mb temps of -9C to
-11C LES bands will become mainly focused over the Keweenaw and into
south central portions of the U.P. Forcing from a shortwave moving
in from southern MN/northwest WI could also provide enhancement to
the LES into Mon evening while bringing a dusting of light system
snow to the rest of the cwa.

Tuesday into Wednesday, flow shifts from easterly Tuesday to
northeast Tuesday night into Wednesday. A shortwave passing just
south and southeast of the region could provide some weak
enhancement to LES in the east and northeast snow belts respectively
for these days.

Thursday into the weekend, a series of shortwaves from the Northern
Plains and south central Canada will provide more opportunities
for lake enhancement, especially for the west to northwest snow
belts while ushering in increasingly colder air for the weekend.
850 mb temps will lower from -11 to -12C on Thursday to -16 to
-18C by later in the weekend. Would not be surprised if the colder
airmass combined with the enhancement from the shortwaves could
result in moderate to heavy LES at times for the west to northwest
wind snow belts from late week into the weekend.
&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 634 PM EST SUN NOV 13 2022

Mostly VFR conditions at all TAF sites as lake effect showers are
diminishing. What lake effect bands are remaining could still drop
vis and cig to MVFR from VFR, though they`re going to be
intermittent in nature. North winds turn light and variable tonight
and emerge tomorrow out of the east. MVFR conditions return to IWD
and CMX tomorrow afternoon.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 336 PM EST SUN NOV 13 2022

High pressure settles across Lake Superior tonight as winds
generally remain 20 knots or less through Thursday. West-northwest
winds will increase by Friday above 20 knots on Thursday as an
arctic air mass begins to spill across the Upper Great Lakes. There
could be occasional west to northwest gale force gusts over lake
this weekend.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&

$$

UPDATE...Rolfson
SHORT TERM...lg
LONG TERM...Voss
AVIATION...GS
MARINE...Voss