Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
730 PM CDT Thu Sep 16 2021

.UPDATED for 00Z Aviation Discussion...
Issued at 712 PM CDT Thu Sep 16 2021

&&

.SHORT TERM...(This evening through Friday night)
Issued at 253 PM CDT Thu Sep 16 2021

Regional radar and enhanced satellite imagery is showing convection
developing along the international border in northwest Minnesota. RGB
enhanced satellite does show more glaciated clouds across northern
Minnesota with only water clouds across the central part of the
state. Southern Minnesota remains clear and windy as surface winds
have gusted up to 40 to 45 mph along the Buffalo Ridge in southwest
Minnesota, to 25 to 40 mph elsewhere over the southern half of
Minnesota, and parts of west central Wisconsin.

Temperatures this afternoon have even exceeded the 90% of the NBM
along the Buffalo Ridge where local effects allowed temperatures to
rise into the 90s. I wouldn't be surprised to see additional 90s in
southern Minnesota before the late afternoon. Even with these
temperatures a strong mid-level CAP has suppressed any clouds to
form in most of MPX CWA. In addition to the RGB images, the
satellite derived stability indices does show an enhanced area of
both higher K-Indices, and CAPE values over west central Minnesota
this afternoon. Farther to the west along the cold front, these
indices are much lower which indicates that once the cold front
arrives later this afternoon/early evening along this enhanced area
of greater instability and moisture, convection should develop. This
area is also under 45 to 55 knots of bulk wind shear which will
force any convection to become organized quickly. Therefore, once
convection develops, there will be a small window where both the
instability and higher wind shear values allow for severe storms.

Later this evening, as a potent shortwave that is evident across
western North Dakota this afternoon arrives over the Upper Midwest,
the isolated/scattered nature of the convection will likely congeal
into a large area of showers and thunderstorms along and behind this
cold front. Any severe storms early will likely weaken as the
instability weakens overnight. The bulk of the showers and
thunderstorms will occur late this evening and overnight before
becoming more scattered toward morning as this system exits
Minnesota, and west central Wisconsin. Friday will see some residual
showers in the far southeast CWA but clearing will occur by the
afternoon. High pressure will dominate the weather Friday night with
lows dropping into the 40s, with a few upper 30s possible in the
typical cools spots in central Minnesota, and west central
Wisconsin.

.LONG TERM...(Saturday through Thursday)
Issued at 253 PM CDT Thu Sep 16 2021

The upper-level pattern will amplify through the weekend as ridging
centers over the eastern CONUS, providing subsidence aloft to build
high pressure across the region.

A chilly start to the long term period is likely with low
temperatures in the 40s Saturday morning. Temperatures quickly
rebound into the 70s in the afternoon. As the high pressure shifts
to the east, a warm front lifts through the area associated with a
low pressure in southern Canada. This allows strong WAA to develop
and push high temperatures into the mid to upper 80s on Sunday.
Additionally, a longwave trough working across the CONUS will
generate a sub-1000mb low pressure that will track from the Northern
Plains into Hudson Bay during the first half of next week. The cold
front is expected to move into western Minnesota by Tuesday and
continue through the area by Tuesday evening. This front will bring
our next chance at precipitation with scattered
showers/thunderstorms along the frontal boundary.

For Wednesday and Thursday, the cold front shifts into the Great
Lakes region leaving behind little in the way of sensible weather. A
few diurnal showers could pop up Wednesday afternoon as the core of
cold air aloft is overhead. Otherwise, both days will feature highs
in the 60s with lows in the 40s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 712 PM CDT Thu Sep 16 2021

Thunderstorms with a passing cold front this evening and overnight,
with VFR conditions expected to return for Friday. Winds will be
southerly ahead of the front, and then take on a north/northwesterly
direction behind it. The first round of storms will be this evening,
and hail/wind is a threat with these storms. The second round is
expected to lift up from South Dakota overnight. These storms have a
lesser chance of producing severe weather.

KMSP...
A cold front will pass through late this evening. Winds will be
southerly ahead of it, and northerly after it passes. This frontal
passage could bring thunderstorms this evening to MSP, with another
round possible after midnight tonight.

/OUTLOOK FOR KMSP/
Fri late...VFR. Wind NW 5-10 kts early bcmg light and variable.
Sat...VFR. Wind Increasing SSE 10-15 kts by aftn.
Sun...VFR. Wind SSW 10-20G25 kts.

&&

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

SHORT TERM...JLT
LONG TERM...BPH
AVIATION...JRB

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
211 PM CDT Thu Sep 16 2021

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
171915-
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-
211 PM CDT Thu Sep 16 2021

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

.DAY ONE...Tonight.

There will be a small window where both wind shear and instability
will be maximized to support severe thunderstorms this evening.
This area is across portions of west central and central
Minnesota between 6 and 10 pm. These storms will be capable of
producing large hail and damaging winds. Even a brief tornado can
not be ruled out. The area of thunderstorms will congeal into a
larger area of showers and thunderstorms across southern Minnesota
overnight. These storms are not expected to be severe but will
produce locally gusty winds, small hail and heavy rainfall.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

A few strong storms will be possible Monday night and Tuesday.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation may be needed late this afternoon, and
early evening across west central and central Minnesota.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
828 PM CDT THU SEP 16 2021

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

0810 PM     HAIL             WAHKON                  46.12N 93.53W
09/16/2021  M1.00 INCH       MILLE LACS         MN   PUBLIC

&&

MED

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
838 PM CDT Thu Sep 16 2021

MNZ051-052-059-061-170215-
Anoka MN-Isanti MN-Sherburne MN-Wright MN-
838 PM CDT Thu Sep 16 2021

...A strong thunderstorm will impact portions of northeastern Wright,
northern Anoka, southern Isanti and southeastern Sherburne Counties
through 915 PM CDT...

At 838 PM CDT, Doppler radar was tracking a strong thunderstorm over
Big Lake, or 10 miles northeast of Buffalo, moving east at 55 mph.

HAZARD...Winds in excess of 30 mph and penny 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...
  Elk River around 845 PM CDT.
  Zimmerman around 850 PM CDT.
  Ramsey and St. Francis around 855 PM CDT.

Other locations in the path of this storm include Cambridge, East
Bethel and Isanti.

This includes the following highways...
 Interstate 94 in Minnesota between mile markers 188 and 199.
 U.S. Highway 10 in Minnesota between mile markers 197 and 215.
 U.S. Highway 169 between mile markers 159 and 171.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

A Severe Thunderstorm Watch remains in effect until 200 AM CDT for
central and east central Minnesota.

&&

LAT...LON 4557 9314 4556 9314 4556 9313 4535 9303
      4523 9383 4538 9391 4560 9315
TIME...MOT...LOC 0138Z 251DEG 49KT 4532 9377

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...30 MPH

NDC

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
847 PM CDT THU SEP 16 2021

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

0825 PM     HAIL             1 NNW ISLE              46.15N 93.48W
09/16/2021  M1.00 INCH       MILLE LACS         MN   COCORAHS

&&

MED

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
857 PM CDT THU SEP 16 2021

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

0854 PM     HAIL             1 SSE ELK RIVER         45.30N 93.55W
09/16/2021  M0.25 INCH       SHERBURNE          MN   TRAINED SPOTTER

&&

MED

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
907 PM CDT THU SEP 16 2021

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

0905 PM     HAIL             2 ENE HUTCHINSON        44.90N 94.34W
09/16/2021  M0.70 INCH       MCLEOD             MN   TRAINED SPOTTER

&&

MED

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
912 PM CDT Thu Sep 16 2021

MNZ059-060-066-068-170245-
Hennepin MN-McLeod MN-Carver MN-Wright MN-
912 PM CDT Thu Sep 16 2021

...A strong thunderstorm will impact portions of southern Wright,
northwestern Hennepin, northeastern McLeod and northwestern Carver
Counties through 945 PM CDT...

At 911 PM CDT, trained weather spotters reported a strong
thunderstorm over Winsted, or 15 miles east of Hutchinson, moving
east at 55 mph.

HAZARD...Penny size hail.

SOURCE...Trained weather spotters.

IMPACT...Minor damage to outdoor objects is possible.

This strong thunderstorm will be near...
  Montrose and Mayer around 920 PM CDT.
  Delano and Watertown around 925 PM CDT.
  Rockford around 930 PM CDT.

Other locations in the path of this storm include Mound, Orono,
Minnetrista, Independence, Maple Plain, Medina, Wayzata, Plymouth,
Maple Grove, Minnetonka and Corcoran.

This includes U.S. Highway 12 between mile markers 124 and 140.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

A Severe Thunderstorm Watch remains in effect until 200 AM CDT for
central Minnesota.

&&

LAT...LON 4495 9341 4484 9420 4501 9426 4502 9426
      4521 9351
TIME...MOT...LOC 0211Z 254DEG 48KT 4497 9408

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...<30 MPH

NDC