Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
701 PM CDT Sun Jul 31 2022

.DISCUSSION...(This evening through Sunday)
Issued at 131 PM CDT Sun Jul 31 2022

KEY MESSAGES:

- Some severe thunderstorms are possible late this afternoon and
  evening, primarily north of I-94 and east of I-35.

- Heat and humidity returns Tuesday, but the intensity continues to
  trend down.

- More thunderstorms, some severe, are possible Tuesday night.

A band of showers and thunderstorms that tracked eastward across
western and southern Minnesota has largely dissipated with clouds
scattering. Atmospheric recovery is taking place across western
Minnesota early this afternoon ahead of a vigorous short wave over
North Dakota and an approaching cold front. Clusters of thunderstorms
are expected to develop after 4 PM over central Minnesota, then
spread southeast into Wisconsin during the early evening hours. A
somewhat dry boundary layer will favor damaging wind gusts with these
clusters, but if a few embedded supercells can develop then they
would also pose a large hail threat. Veered surface winds near the
front will limit the tornado potential. A cooler and drier airmass
will arrive Monday with high pressure sliding across the Upper
Midwest.

A warm front will follow Monday night as it shifts east across the
Plains into Minnesota. The front may provide enough focus for a
couple nocturnal storms, provided 850 mb moisture increases markedly
overnight. Warm air advection throughout Tuesday will bring a very
warm and increasingly humid airmass northward. As temperatures climb
well into the 90s across western Minnesota, heat indices in the low
to mid 100s are possible depending on whether dew points continue
rising through mid to late afternoon. Held off on an Excessive Heat
Watch due to the trend for slightly cooler temperatures in the last
several runs of the NBM, but heat headlines in some form appear
likely for Tuesday.

A cold front will sag south Tuesday night and Wednesday. Forecast
soundings (aside from the GFS which is way too hot and dry) generate
robust instability, but also appear strongly capped. Likely PoPs
from the NBM seemed too high given the low level capping, so reduced
them to around 40 percent or less.

Beyond midweek, ridging will return to the Rockies and high Plains,
keeping the pattern tranquil here until maybe next weekend when the
next trough approaches from the northwest.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 632 PM CDT Sun Jul 31 2022

Cold front moving across MN pretty much on schedule with the going
forecast. It is in the process of clearing STC now, with chances for
TS continuing at MKT/MSP/RNH/EAU until the front clears a location.
Tonight, the question becomes how far southwest do the post frontal
MVFR cigs currently up over northeast ND/northwest MN spread. HREF
probs for MVFR cigs show the greatest probability for reduced cigs
going across northern MN into western WI, though showing potential
for lower cigs for all terminals but RWF. This summer, LAV guidance
has had a tendency to over predict MVFR cigs, so tried to be a
little bit more optimistic than the LAV at MN locations. By late
morning, expect skies to become mostly clear skies with northwest
wind diminishing during the day as high pressure moves across the
area.

KMSP...cold front is now approaching Glencoe and will clear MSP
between 2z and 3z. You can't rule out TS until the front passes,
though it is looking like MSP will once again miss the rain. Not
convinced on MSP seeing MVFR for a prolonged period of time, so did
back that off to a tempo group, but will continue to monitor trends.

/OUTLOOK FOR KMSP/
Tue...VFR. Chc TSRA overnight. Wind S 10-20G30 kts.
Wed...VFR. Chc A.M. SHRA/TSRA. Wind NW 10-15 kts.
Thu...VFR. Wind SE 5-10 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&

DISCUSSION...Borghoff
AVIATION...MPG

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
329 PM CDT Sun Jul 31 2022

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
012030-
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-
329 PM CDT Sun Jul 31 2022

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

.DAY ONE...Tonight.

Scattered thunderstorms can be expected this evening, a few of
which may be severe, particularly over eastern Minnesota through
western Wisconsin. The main hazards are large hail and damaging
winds but a tornado cannot be ruled out.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Heat and humidity will increase this week, peaking on Tuesday
with highs in the mid to upper 90s for much of the coverage area.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation may be needed this evening.

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
704 PM CDT Sun Jul 31 2022

MNZ083-084-010100-
Waseca MN-Blue Earth MN-
704 PM CDT Sun Jul 31 2022

...A strong thunderstorm will impact portions of southeastern Blue
Earth and southwestern Waseca Counties through 800 PM CDT...

At 704 PM CDT, Doppler radar was tracking a strong thunderstorm over
Good Thunder, or 13 miles south of Mankato, moving east at 25 mph.

HAZARD...Winds in excess of 40 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...
  Mapleton around 715 PM CDT.

Other locations in the path of this storm include St. Clair and
Pemberton.

This includes U.S. Highway 14 near mile marker 145.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4388 9413 4400 9417 4414 9375 4385 9366
      4384 9372
TIME...MOT...LOC 0004Z 249DEG 21KT 4397 9407

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH

CTG