Heavy Snow in Minnesota, March 28 to 29, 2020

Area Forecast Discussion
National Weather Service Duluth MN
931 PM CDT Sat Mar 28 2020

.UPDATE...
Issued at 931 PM CDT Sat Mar 28 2020

A strong spring storm was affecting the Northland this evening
with rain over northern Wisconsin and from central in portions of
northeast Minnesota this evening. Area radars showed stronger
echoes from east central Minnesota into much of northern Wisconsin
and surface temperatures were from 35 to 40F under this area. A
quick look out the window here at the office showed some flakes
falling with a temperature of 36F. We increased QPF from far
southeast Aitkin to Burnett Counties and a bit north for this
evening. This is based on the latest radar trends and has support
from the NAM/RAP. We did increase snowfall some tonight,
mainly from the Aitkin/Pine County area north toward the Twin
Ports and a bit into the North Shore. We may have to upgrade the
Winter Weather Advisory in spots but we will wait a bit longer to
make that call. Lightning was occurring over parts of northern
Wisconsin into far east central Minnesota and expanded the mention
into late evening there.

Strong winds continued as well with gusts of 35 to around 45 mph
occurring at the head of Lake Superior. Water levels near Duluth
remain just under 603ft but the stronger winds are still expected
later tonight. No changes to the Lakeshore Flood
Warnings/Advisories are expected at this time.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 322 PM CDT Sat Mar 28 2020

The well-advertised spring storm system will be moving into the
region this afternoon and evening, bringing a rain/snow mix to the
region. Initially, precipitation type will be as all rain, with a
transition to a rain/snow mix this evening, then nearly all snow
overnight. This evening through Sunday morning will be the main time
frame for wet, heavy snow accumulations. It appears that some of the
latest guidance, particularly the 28.12z HREF, is indicating a
slightly later transition onset from rain to snow. Much of the
guidance was indicating phase change occurring late this afternoon,
but the latest guidance is indicating more in the mid-evening hours,
around 02z to 04z. However, it appears that the higher-resolution
models are going with a good bit more snow compared to the global
models, such as the GFS and ECMWF. The ensemble mean of these models
for total snowfall near Ashland are in the 2 to 4 inch range, while
the high-resolution ensemble means are much higher, between 7 to 9
inches, especially for Douglas and Bayfield counties in northwest
Wisconsin. In total, we are expecting widespread 4 to 9 inches of
snow possible. Due to the increase in snow amounts, we have decided
to upgrade the Winter Weather Advisory to a Winter Storm Warning for
these two counties.

We are still anticipating very strong northeast flow tonight as the
surface low approaches the region, and a tight surface pressure
gradient sets up. Gusts between 25 to 35 mph are expected, strongest
along the shoreline of western Lake Superior, especially along the
South Shore where gusts up to 40 mph will be possible. This will
lead to the potential for lakeshore flooding. Lakeshore Flood
Warnings and Advisories remain in effect. One additional concern we
have with this northeast flow is on the potential for ice shoves
developing onshore of Chequamegon Bay along US Highway 2 near and
west of Ashland. Moreover, rainfall amounts over northwest Wisconsin
have increased, with most locations seeing between 1 to 2+ inches of
precipitation. This will likely lead to rises in area creeks,
streams, and rivers. This rain, coupled with recent snowmelt and
fairly saturated soils, will lead to the potential for basement
flooding, as well as ponding of water on clogged storm drains. We
will update our current Hydrologic Outlook to message this threat.

Eventually, this precipitation will transition back to rain during
the day Sunday, and gradually exit the region Sunday afternoon and
evening. The latest global models are indicating an 850-700 mb level
deformation zone that will linger through Sunday morning. We have
maintained higher PoPs due to the lingering nature of precipitation
into the afternoon hours over northeast Minnesota, and northwest
Wisconsin into the evening. As this system departs to the east,
winds will turn more northerly and weaken. There may be a bit of a
gravity wave signature that will develop into Sunday afternoon, but
p-type should remain as rain. Eventually, precipitation will
diminish entirely late Sunday night as drier air filters in from the
west, along with a ridge of high pressure. This high pressure looks
to bring much calmer conditions for Monday.

.LONG TERM...(Monday through Saturday)
Issued at 322 PM CDT Sat Mar 28 2020

The main concern for the long term periods is the potential for
wintry mixed precipitation Wednesday and Wednesday night.

Surface high pressure and ridging aloft will be over western
Ontario and the Upper Midwest Monday morning with fair conditions
expected through the first few days of the week. Weak flow at the
surface and aloft over the Northland should support the potential
for lake breezes pushing inland from Lake Superior each day and
will keep max temps limited near the lake with abrupt cool downs
during the afternoon hours. Elsewhere look for temperatures to
climb into the upper 40s and low 50s.

A closed upper-level low will move into the Canadian Prairies
during the pre-dawn hours of Wednesday with a 300 mb jet streak
nosing into South Dakota and Nebraska by 12Z. A cold front will
move down the lee side of the Canadian Rockies and into the
Northern Plains setting up an arcing baroclinic zone from the
western Great Lakes into northwest Ontario and Manitoba and south
into the western Dakotas and Manitoba. Precipitation will develop
along and ahead of the cold front in response to isentropic
forcing for ascent and frontogenesis. A wintry mix of rain and
snow is expected over the Northland Wednesday and Wednesday night
as the trough and associated forcing mechanisms move through the
region. With most of the precipitation falling during daylight
hours, any snow accumulation will be higher on grassy/snow
covered surfaces versus roadways.

The closed upper low will meander eastward through the remainder
of the week keeping clouds and snow or rain shower chances in
forecast through the end of the week along with cooler
temperatures.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 646 PM CDT Sat Mar 28 2020

A strong area of low pressure was centered in central Iowa early
this evening and it will move northeast to Green Bay around 18Z
Sunday. Rain will become widespread over northern Wisconsin into
far northeast and central Minnesota this evening then it will mix
with or change to snow overnight over much of northwest Wisconsin
into central to northeast Minnesota. Moderate to at times heavy
snow will occur at KDLH and possibly KHYR. The ceiling and
visibility will lower through the night for most areas with far
northern Minnesota remaining dry and mostly VFR. In addition to
the precipitation, strong winds will occur along with low level
wind shear. As the storm moves northeast, winds will back to
northeast then northerly. The precipitation will mix with or
change back to rain Sunday as it diminishes from west to east. VFR
conditions will also develop further east over northern Minnesota
Sunday afternoon.

&&

.MARINE...
Issued at 322 PM CDT Sat Mar 28 2020

An area of low pressure located over western Iowa this afternoon
will move through the region to northern Lower Michigan by 00Z
Monday. The pressure gradient over western Lake Superior will
tighten tonight and will produce strong northeast winds. Strong
winds aloft will be able to mix down to the surface resulting in
gale-force gusts. The strongest winds will occur in the southwest
arm of Lake Superior, between the North Shore and Bayfield
Peninsula. Small Craft Advisory and Gale Warning still look good
and no changes have been made. As low moves over northeast
Wisconsin and over Lake Michigan on Sunday, winds will back
northerly and wind speeds and gusts will decrease. Conditions
will likely remain hazardous to smaller vessels through Sunday
afternoon and additional advisories will likely be needed after
the Gale Warning expires. High pressure will settle over the
region for Monday and Monday night with northerly winds veering
northeasterly at 5 to 15 knots.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  33  44  27  45 / 100 100  10   0
INL  28  49  21  49 /   0   0   0   0
BRD  33  47  25  51 /  80  70   0   0
HYR  34  43  28  51 / 100  80  60   0
ASX  33  42  29  43 / 100 100  80   0

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory until 11 AM CDT Sunday for WIZ003-004-
     006-007.

     Lakeshore Flood Warning until 7 AM CDT Sunday for WIZ001.

     Lakeshore Flood Advisory until noon CDT Sunday for WIZ002>004.

     Winter Storm Warning until 11 AM CDT Sunday for WIZ001-002.

MN...Winter Weather Advisory until 11 AM CDT Sunday for MNZ012-
     019>021-035>038.

     Lakeshore Flood Advisory until 7 AM CDT Sunday for MNZ020.

     Lakeshore Flood Warning until 7 AM CDT Sunday for MNZ037.

LS...Gale Warning until 10 AM CDT Sunday for LSZ121-140>148.

&&

UPDATE...Melde
SHORT TERM...JTS
LONG TERM...Huyck
AVIATION...Melde
MARINE...Huyck

Hazardous Weather Outlook
National Weather Service Duluth MN
329 PM CDT Sat Mar 28 2020

MNZ012-019>021-035>038-WIZ001>004-006-007-292030-
Northern Cook/Northern Lake-Central St. Louis-
Southern Lake/North Shore-Southern Cook/North Shore-
Northern Aitkin-South Aitkin-Carlton/South St. Louis-Pine-Douglas-
Bayfield-Ashland-Iron-Burnett-Washburn-
329 PM CDT Sat Mar 28 2020

This Hazardous Weather Outlook is for portions of northeast
Minnesota and northwest Wisconsin.

.DAY ONE...This afternoon and Tonight

A strong spring storm system will build into the Northland this
afternoon and evening, bringing a rain/snow mix to the region.
Initially, rain is anticipated for northwest Wisconsin and east-
central Minnesota this afternoon before transitioning to the
rain/snow mix or all snow this evening and overnight. Snowfall
amounts between 4 to 9 inches will be common, mainly from east-
central Minnesota northeast towards adjoining areas of Lake
Superior. The heaviest of these amounts are expected along the
South Shore over Douglas and Bayfield counties. Due to the
increase in snowfall amounts, we have upgraded the Winter Weather
Advisory to a Winter Storm Warning.

Furthermore, strong northeast winds gusting to 30 to 40 mph late
this afternoon through tonight will lead to building waves along the
western Lake Superior shoreline. This will lead to the potential for
lakeshore flooding and erosion, primarily along the Canal Park and
Park Point areas east towards the Bayfield Peninsula and Saxon
Harbor. Due to the strong northeast winds, there may be some ice
shoves occurring over downwind areas of Chequamegon Bay, including
Ashland and areas west along US Highway 2. A Lakeshore Flood Warning
and Advisory remains in effect.

Heavy rainfall associated with this system will be possible over
northwest Wisconsin tonight. This, combined with a recent melting
snowpack, could lead to rises in area creeks, streams, and rivers,
as well as basement flooding and ponding of water near clogged storm
drains.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

The strong storm will gradually shift eastward Sunday. The snow will
switch back to rain before ending Sunday afternoon and evening.
Precipitation will linger longest along the South Shore of Lake
Superior through Sunday evening. The Winter Weather Advisory will
expire Sunday morning. The strong winds from overnight will also
gradually diminish, becoming more northerly during the day Sunday,
allowing waves on Lake Superior to subside. The Lakeshore Flood
Warning and Advisory will also expire Sunday morning.

A wintry mix of rain and snow is possible Wednesday and Wednesday
night. Light snow accumulation is possible.

.SPOTTER INFORMATION STATEMENT...

Snow spotters are requested to report their snowfall measurements
tonight and Sunday to the National Weather Service.

MNZ010-011-018-025-026-033-034-WIZ008-009-292030-
Koochiching-North St. Louis-North Itasca-North Cass-South Itasca-
South Cass-Crow Wing-Sawyer-Price-
329 PM CDT Sat Mar 28 2020

This Hazardous Weather Outlook is for portions of northeast
Minnesota and northwest Wisconsin.

.DAY ONE...This afternoon and Tonight

A strong spring storm system will bring a rain and snow mix to
the Northland this evening which is expected to change to snow
tonight. Snowfall amounts of 1 to 2 inches are possible by Sunday
morning. Higher amounts will be found closer to Lake Superior
where a Winter Weather Advisory and Winter Storm Warning is in
effect.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

A wintry mix of rain and snow is possible Wednesday and Wednesday
night. Light snow accumulation is possible.

.SPOTTER INFORMATION STATEMENT...

Snow spotters are requested to report their snowfall measurements
tonight and Sunday to the National Weather Service.

LSZ121-140>148-292030-
Bayfield to Oak Point WI-Grand Portage to Grand Marais MN-
Grand Marais to Taconite Harbor MN-
Taconite Harbor to Silver Bay Harbor MN-
Silver Bay Harbor to Two Harbors MN-Two Harbors to Duluth MN-
Duluth MN to Port Wing WI-Port Wing to Sand Island WI-
Sand Island to Bayfield WI-Oak Point to Saxon Harbor WI-
329 PM CDT Sat Mar 28 2020

This Hazardous Weather Outlook is for portions of the Nearshore
waters of western Lake Superior.

.DAY ONE...This afternoon and Tonight

Strong northeast winds are expected over western Lake Superior
tonight with gales of 35 to 45 knots possible. Please refer to
the latest Marine Weather Message and Nearshore Marine Forecast
for additional details regarding the Small Craft Advisory and Gale
Warnings in effect.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Gales will continue Sunday morning and will weaken by late
morning. Another Small Craft Advisory will likely be needed after
Gale Warnings expire, as conditions will remain hazardous to
smaller vessels through Sunday afternoon.

JTS/Huyck

More information may be obtained at the following web address:
http://www.weather.gov/duluth (all lower case)

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DULUTH MN
936 PM CDT SAT MAR 28 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0936 PM     HAIL             4 NNW NEW POST          45.95N 91.22W
03/28/2020  E0.25 INCH       SAWYER             WI   TRAINED SPOTTER

&&