Flooding in Minnesota, May 10 to 31, 2022

Area Forecast Discussion
National Weather Service Duluth MN
1240 PM CDT Tue May 10 2022

.DISCUSSION...(Today through Monday)
Issued at 526 AM CDT Tue May 10 2022

A very isolated chance for showers and thunderstorms today but
otherwise dry conditions before the next chance for severe weather
arrives Wednesday into Thursday. High temperatures warm through
Thursday, with anomalous warmth expected.

Evidence of yesterday's rounds of severe weather has mostly exited
the area, sans the tree and hail damage that was caused across
portions of the CWA. Some moisture continues to linger over parts of
NW WI with dewpoints in the high 50s. A little wiggle in the upper
level flow over the entrance region of a LLJ may bring some
sprinkles and cloud cover to NE MN this morning. We've seen radar
returns out of this precipitation but a layer of dry air near the
ground and very elevated storm bases has limited accumulations so
far. As the sun rises this morning, there is still a lingering
chance of thunderstorms over Price, southern Ashland, and southern
Iron County through midday along a moisture and instability gradient
with remaining 40-50 knots of bulk shear. Storms should remain
elevated in our CWA but severe hail and wind may be a possibility
before these storms become more enhanced in southern Wisconsin.

Mostly dry weather is expected after mid-afternoon today and into
midday Wednesday, with partly clear skies and warming
temperatures thanks to upper level ridging over the Ohio River
Valley and lower Great Lakes. Southerly 850-500mb flow will return
to the region over the day Wednesday, bringing moisture, warmth,
and our next chance of severe weather. Some CAMs indicate the
potential for some showers and thunderstorms Wednesday midday
along the exit region of a morning 850mb LLJ but the primary
severe threat is expected to move in Wednesday evening into
Thursday morning and then another round Thursday evening.

- Wednesday evening into Thursday morning: convection will move
northward over Minnesota spurred on by a 500mb vort max and
developing small 300mb jet streak over a warm front. Minimal capping
and CIN is largely expected to not be able to inhibit convection
with good synoptic forcing and large values of modeled CAPE (upwards
of 3000-4000 J/kg MUCAPE and 1000-1500 J/kg of SBCAPE earlier in the
evening). Storms may begin surface based and would have plenty of
shear and SRH to work with, producing a tornado threat which should
transition to more of a wind and hail threat into the night as
storms become elevated. CAMs and global models suggest the warm
front may stall along and south of Highway 2 with somewhat parallel
mean winds, which could lead to a nocturnal flash flood threat for
the southern half of the CWA, especially over the I-35 corridor. The
warm front is currently progged to lift north and out of the
Northland by mid-morning Thursday.

- Thursday evening into Friday morning: Very anomalous WAA and
moisture transport is expected to continue through the day Thursday,
with NAEFS and Euro ENS indicating near max temperature and moisture
percentiles for the CWA and the Euro ENS EFI score for cities in our
southern tier of counties is well into the 80 and low 90 percents
for mean temperature suggesting an extreme high temperature event
along our southern border. Exact values will be determined by how
well skies clear Thursday afternoon but high temperatures into the
mid to high 80s seems very plausible with temps in the mid 70s
further north in the CWA. This will generate a large area of high
CAPE and steep lapse rates available to feed storms on top of PW
values of nearly 1.5 inches and dew points in the mid 60s. A cold
front should sweep east across Minnesota and Wisconsin, impacting
our region beginning Thursday evening. A discrete mode is expected
at first with all hazards on the table including tornadoes with
surface-based storms. As the front progresses east storm mode should
become more linear with a wind, hail and minor flash flood threat
depending on the residence time of storms overnight into Friday
morning. Better syntopic forcing over NW MN may lead to heavy
rainfall in the more occluded part of the system, notably
potentially over the Rainy River Basin.

Cooler temperatures (relative to Thursday) and drier air should

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1239 PM CDT Tue May 10 2022

VFR conditions expected through the period with high pressure in
place today. Some breezy westerly winds will persist through the
afternoon at BRD/HIB/INL, but winds will become light and variable
at all terminals tonight. Winds will become east to northeasterly
on Wednesday as a system approaches from the south, with breezy
conditions developing especially at DLH with onshore flow.

&&

.MARINE...
Issued at 458 AM CDT Tue May 10 2022

A stable marine layer should help lead to fairly calm southwesterly
winds today which should help any lingering waves to dissipate.
Winds switch to the northeast Wednesday. Warm temperatures on land
should help to spur a lake breeze which will enhance winds,
especially in the afternoon over the Twin Ports where afternoon
gusts up to 25 knots will be possible. A small craft advisory may be
needed. Rain and thunderstorms are expected to build across Western
Lake Superior Wednesday evening into Thursday, with another round of
storms possible Thursday afternoon and evening. Background winds
should stay northeasterly through Friday, but erratic and gusty
winds will be a possibility under any thunderstorms that develop.
Winds turn southwesterly into Friday.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  71  47  63  49 /  20   0  50  80
INL  68  41  73  51 /   0   0  60  90
BRD  73  47  76  60 /  20  10  80  90
HYR  76  48  79  62 /  20  10  40  70
ASX  73  44  61  51 /  20  10  40  70

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&

DISCUSSION...Levens
AVIATION...JDS
MARINE...Levens

Hazardous Weather Outlook...UPDATED
National Weather Service Duluth MN
526 AM CDT Tue May 10 2022

MNZ010>012-018>021-025-026-033>038-WIZ001>004-006>009-111030-
Koochiching-North St. Louis-Northern Cook/Northern Lake-
North Itasca-Central St. Louis-Southern Lake/North Shore-
Southern Cook/North Shore-North Cass-South Itasca-South Cass-
Crow Wing-Northern Aitkin-South Aitkin-Carlton/South St. Louis-
Pine-Douglas-Bayfield-Ashland-Iron-Burnett-Washburn-Sawyer-Price-
526 AM CDT Tue May 10 2022

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

.DAY ONE...Today and Tonight

Thunderstorms are likely this afternoon over a small portion of
northwest Wisconsin. Strong winds and large hail are possible.
High water levels will continue over the Rainy River Basin over
far northern Minnesota. Minor flooding will continue along the
Mississippi River between Aitkin and Brainerd in Crow Wing County.
Rivers and creeks along the North Shore are expected to remain
high and fast- flowing.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Severe thunderstorms are possible Wednesday and especially
Thursday. Flash flooding, isolated tornados, damaging wind, large
hail, and frequent lightning are all possible.

Water levels will remain high across many of the Northlands
rivers, creeks, and streams.

.SPOTTER INFORMATION STATEMENT...

Skywarn spotters are encouraged to report hail of any size and
rainfall amounts to the National Weather Service.

LSZ121-140>148-150-111030-
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-
Outer Apostle Islands Beyond 5 NM from Mainland-
526 AM CDT Tue May 10 2022

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

.DAY ONE...Today and Tonight

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Severe thunderstorms are possible Wednesday and Thursday.
Damaging wind, large hail, and frequent lightning are all
possible. General winds and waves will pose a threat to small
craft on Wednesday

Wolfe

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