Tornadoes and Hail in Minnesota, May 30, 2022

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
151 PM CDT Mon May 30 2022

.MESOSCALE DISCUSSION...
Issued at 146 PM CDT Mon May 30 2022

19Z Mesoscale Update:

An area of thunderstorms have developed along a line from Redwood
Falls to Buffalo, MN over the past hour. These storms have formed
along the warm front/MUCAPE gradient and should remain elevated as
they lift northward through the next few hours. This activity is
within an area with steep mid-level lapse rates and could be capable
of producing large hail (1" or larger) and heavy rainfall,
lightning, and gusty winds.

This threat is separate from the more intense severe weather
outbreak that is expected later this afternoon into the evening
hours.

Our "main event" is still on track to begin after 19Z. This is a
rare, high-end environment that will be capable of producing a
severe weather outbreak across the MPX forecast area. The first
concern is the potential for a few supercells to develop in the warm
sector ahead of the approaching cold front. The WoFS has picked up a
on these supercells forming over northwest IA/southwest MN and moving
northeast into central MN by 21Z. This potential will be monitored
closely as they'd be capable of producing all severe hazards
including tornadoes.

The storms that form along the cold front will be capable of
producing all severe hazards too. This will track into western
Minnesota into western Wisconsin later this evening. Storm mode is
expected to transition from embedded supercells along the cold front to
a QLCS-like linear set up. The LLJ will enhance low level shear this
evening across western WI. This is concerning as it could promote an
environment capable of a QLCS tornado threat this evening/early
tonight.

Areas in the warm sector continue to recover with
temperatures warming back into the low/mid 80s. The mid level clouds
have likely helped our dew points stay in the mid to upper 60s
across southern MN, with less mixing due to stubborn cloud cover.
This has kept our LCLs on the lower side and if this trend
continues, would be more favorable for potential tornado
development. Steep mid-level lapse rates of 8.0C/km or greater are
located with the area of best CAPE with values of 2500J/kg or
greater. KMPX VAD profile shows a highly sheared environment present
with 25+ kts of 0-1km shear and 300+ m2/s2 0-1km storm relative
helicity. These storms will be moving quickly with storm motions
likely 60s kts or greater so it will be important to plan ahead and
act quickly after receiving any severe or tornado warnings this
afternoon. Once again, this environment has analogs to some of
historical, higher-end severe weather outbreaks across the Upper
Midwest.

&&

.UPDATE...
Issued at 146 PM CDT Mon May 30 2022

Updated for the mesoscale discussion above.

&&

.DISCUSSION...(Today through Sunday)
Issued at 344 AM CDT Mon May 30 2022

...SEVERE STORMS EXPECTED WITH A TORNADO OUTBREAK POSSIBLE THIS
AFTERNOON AND EVENING IN WESTERN MINNESOTA...

- Western Minnesota, widespread severe weather likely this afternoon
  into the evening, and a tornado outbreak possible in western MN.
  There is some uncertainty in storm mode.

- Eastern Minnesota and western Wisconsin, a line of strong to
  severe storms likely.

- Storms could be fast moving, so please have your safe sheltering plan
  in place so you can seek shelter quickly if a warning is issued
  for your location.

TODAY AND THIS EVENING... A rare severe weather set up will be in
place later today. We ask that people pay extra attention to the
forecast, and make sure they can seek shelter if warnings are issued.
There are no significant changes to the severe weather threat from
the previous forecast, but one quick mention that southerly winds
across southern Minnesota are strong enough for wind advisory later
this morning into the early evening.

The highest confidence is in damaging wind. Given the strength of
the mid and upper level jet, storms should be fairly fast moving. In
addition, forecast soundings show speeds in excess of 50 kts around
800mb prior to convective initiation. The Storm Prediction Center
has a 45 percent hatched area for wind across the far northwest part
of the forecast area, which means there is relatively high confidence
in this elevated wind threat.

The tornado threat across western Minnesota hinges somewhat on the
storm mode. Given the rare parameter space of CAPE/Shear, the
potential certainly exists for a few hour window of supercells with
very strong mesocyclone capable of producing strong tornadoes. This
mornings convection could end up keeping the boundary layer less
mixed, and the LCLs lower, which would allow the surface winds to
become more easterly in nature as the surface low develops across the
eastern Dakotas. This would favor tornadic supercells. However, if
the boundary layer manages to mix deeper, dry out, and have a
straighter hodograph, then the tornado threat would be lower.
Speaking of hodographs, the mid and upper level shear is fairly
unidirectional. Some of the higher end Midwest tornado outbreaks have
more of westerly jet, which seems to favor more discrete cells. To
that end, there is a scenario that would lead to more of a linear
complex, which as alluded to above would favor more of the damaging
wind threat and limit the tornado potential. This is plausible given
the strong forcing for ascent.

Farther east, a line of storms should develop along a cold front in
central Minnesota and move into western Minnesota. MLCAPE values near
2500 J/kg along with a veering wind profile in the warm sector should
lead to organized convection. Again, depending on the storm mode,
could have a tornadic threat, although the higher likelihood is
damaging wind and hail.

Speaking of hail, 2 inch or greater hail is possible with these
storms. This normally would be the headliner, but the elevated
wind/tornado threat is more concerning.

Heavy rain is also possible with thunderstorms. They should be moving
fast enough to limit a significant hydro threat, but areas that saw
heavy rain last night will be more vulnerable to additional rain
today.

TUESDAY THROUGH SUNDAY...
Cooler weather will settle in the rest of the week. An upper-level
zonal flow pattern then sets up for the remainder of the week. Cooler
temperatures begin Wednesday with highs in the high 60s and 70s
expected for the rest of the forecast period. Intermittent chances
for showers Wednesday night into the weekend are possible as bits of
shortwave energy move across the area. There could be some thunder
associated with the showers, mainly mid-week. Not great model
consensus on the timing of showers later in the week, so still some
uncertainty on that end.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1235 PM CDT Mon May 30 2022

Mainly VFR conditions except MVFR/IFR possible with thunderstorms
this afternoon/evening. It looks like an initial cluster of strong to
severe storms will affect western Minnesota and move NNE. As this
cluster moves into northern Minnesota a line of strong to severe storms
will form along a cold front and sweep eastward across the area.
Winds will be strong and gusty from the S/SE, becoming W/NW behind
the cold front. Strong LLWS also looks likely this evening.

KMSP...A shower or thunderstorm can not be ruled out this afternoon,
but the best timing for storms at the terminal looks to be between
1z and 3z this evening. It looks like the line of storms will move
through pretty quickly with drier air moving in behind it.

/OUTLOOK FOR KMSP/
Wed...VFR. Wind NW 10 kts.
Thu...VFR. Wind W 10-15 kts.
Fri...VFR. Wind W 5-10 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Wind Advisory until 6 PM CDT this evening for Blue Earth-Brown-
     Faribault-Freeborn-Le Sueur-Martin-Nicollet-Redwood-Rice-
     Steele-Waseca-Watonwan.

WI...None.
&&

MESOSCALE...BPH
DISCUSSION...JRB
AVIATION...CEO

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
1142 AM CDT Mon May 30 2022

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
311645-
Douglas-Todd-Morrison-Mille Lacs-Kanabec-Stevens-Pope-Stearns-
Benton-Sherburne-Isanti-Chisago-Lac Qui Parle-Swift-Chippewa-
Kandiyohi-Meeker-Wright-Hennepin-Anoka-Ramsey-Washington-
Yellow Medicine-Renville-McLeod-Sibley-Carver-Scott-Dakota-
Redwood-Brown-Nicollet-Le Sueur-Rice-Goodhue-Watonwan-Blue Earth-
Waseca-Steele-Martin-Faribault-Freeborn-Polk-Barron-Rusk-
St. Croix-Pierce-Dunn-Pepin-Eau Claire-
1142 AM CDT Mon May 30 2022

This Hazardous Weather Outlook is for portions of central and
southern Minnesota, and west central Wisconsin.

.DAY ONE...This Afternoon and Tonight.

An outbreak of severe thunderstorms, including the potential for
multiple strong tornadoes, remains on track this afternoon and
evening across Minnesota, particularly west of the I-35 corridor.
Additional hazards include large hail in excess of 2 inches and
wind gusts in excess of 70 mph. Locally heavy rainfall and
flooding are also possible.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation will likely be needed this afternoon.

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
118 PM CDT Mon May 30 2022

MNZ057-058-065-301845-
Kandiyohi MN-Renville MN-Meeker MN-
118 PM CDT Mon May 30 2022

...A strong thunderstorm will impact portions of Meeker, southeastern
Kandiyohi and northeastern Renville Counties through 145 PM CDT...

At 118 PM CDT, Doppler radar was tracking a strong thunderstorm 7
miles southwest of Cosmos, or 20 miles southeast of Willmar, moving
northeast at 70 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

This strong thunderstorm will be near...
  Litchfield, Atwater and Grove City around 135 PM CDT.

Other locations in the path of this storm include Watkins.

This includes the following highways...
 U.S. Highway 12 between mile markers 83 and 108.
 U.S. Highway 212 between mile markers 87 and 93.
 U.S. Highway 71 between mile markers 105 and 107.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4533 9472 4532 9439 4528 9438 4528 9426
      4524 9426 4498 9447 4498 9450 4494 9450
      4471 9469 4486 9507
TIME...MOT...LOC 1818Z 206DEG 61KT 4487 9482

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH