Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
630 PM CDT Sun Oct 11 2020

.UPDATE...
Issued at 614 PM CDT Sun Oct 11 2020

Updated to include 00z aviation discussion below.

&&

.SHORT TERM...(This evening through Monday night)
Issued at 347 PM CDT Sun Oct 11 2020

Development of storms late this afternoon along the western border
appears to be on track with previous thinking. CAMs are in very
good agreement in general. Most CAMs suggest two lines at first,
which seems to match up with satellite trends this afternoon, and
then eventually one line. A surface low is also evident in east
central South Dakota. A narrow corridor exists with surface dew
points in the upper 50s to lower 60s, which is where the severe
weather is most likely. This low does translate to west central MN
by 7 pm, so a brief tornado cannot be ruled out early, but the
vast majority of concern is damaging wind from bowing segments
along with hail to some extent. SPC discussion describes all of
this very well.

Otherwise, the timing of storms has been slowed a bit from this
morning, with the storms reaching the west metro no earlier than
10 pm, and then Wisconsin after midnight. Light rain will linger
for a few hours, especially in eastern MN and western WI.

Monday will be a mostly sunny day in western MN, with clearing
Monday morning/midday in eastern MN and western WI. West winds
will become gusty, and there may be some fire weather concerns if
temps get a little warmer with lower dew points. For now, relative
humidity levels should drop to 25 to 30 percent. Another trough
approaches quickly Monday night, but it will be weak with no
appreciable effects other than some mid and high level clouds and
a switch in wind direction.

.LONG TERM...(Tuesday through Sunday)
Issued at 347 PM CDT Sun Oct 11 2020

The long term period begins with a large scale trough sliding
eastwards through central Canada with high pressure building to
our west as wide-scale subsidence becomes apparent. This brief
period of high pressure will be short lived as a deepening
shortwave trough pushes into the area by the second half of
Wednesday resulting in another chance for showers across the area.
Compared to yesterday, this area of showers is a bit further
south, affecting mainly central Minnesota, but this trend would be
good to mitigate some of the drought conditions seen across the
area. We once again see a return to wide-scale subsidence behind
this shortwave as the larger trough rotates eastwards across
southeastern Canada, with northwesterly flow aloft keeping
conditions relatively cool and dry.

Cool and dry conditions are expected to remain the case through
the end of the period with high temperatures struggling to get
out of the 40s beginning Thursday and continuing through the
weekend. On the other side of things, low temperatures will be in
the mid 20s to low 30s likely giving us our first stretch of
sustained below freezing conditions for this fall season. Most
areas will likely see below freezing overnight temps except in the
warmer parts of the Twin Cities metro.

Overall weather threat is low for the period, with some showers
possible on Wednesday and maybe a slight chance on Friday, with a
period of cooler weather to go along with this.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 614 PM CDT Sun Oct 11 2020

Strong SSE winds to continue this evening in advance of the
developing line of thunderstorms along the MN/Dakota border. As
the line shifts east, winds will shift to W and NW while still
maintaining the breezy speeds. Have used TEMPO groups to give some
wiggle room for the initiation of the storms into each terminal
with more solid RA/TSRA afterwards. MVFR conditions are likely
with IFR conditions, mainly due to visibility, possible as the
storms move across the area. Lingering showers behind the line
look to develop overnight along with MVFR ceilings in eastern MN
and western WI that will persist through daybreak before VFR
conditions return during the day Monday.

KMSP...Start time of storms into MSP looks to be around 04z with
thunderstorms persisting thru midnight. Showers will linger
overnight along with MVFR ceilings in the 025-030 range (nothing
below 2 kft expected). Conditions will improve out of MVFR range
by late morning, so the MVFR ceilings will remain through the
Monday morning push.

/OUTLOOK FOR KMSP/
Tue...VFR. Wind WNW 10-20 kts.
Wed...Mainly VFR. Chance -RA/MVFR. Wind SE 10-15 kts becoming W.
Thu...VFR. Wind NW 10-20 kts.

&&

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

UPDATE...JPC
SHORT TERM...TDK
LONG TERM...TDH
AVIATION...JPC

Hazardous Weather Outlook...UPDATED
National Weather Service Twin Cities/Chanhassen MN
108 PM CDT Sun Oct 11 2020

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
121200-
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-
108 PM CDT Sun Oct 11 2020

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

.DAY ONE...This Afternoon and Tonight.

Thunderstorms are likely to develop after 5:00 p.m. in far
western Minnesota, move eastward across the rest of Minnesota this
evening, reaching western Wisconsin around midnight. Some storms
could be severe, especially in western Minnesota. The main threat
is damaging wind. Hail is a secondary threat. The threat for
tornadoes is low, but cannot be ruled out in west central or
southwest Minnesota.

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

Dry and breezy conditions could lead to elevated fire weather
concerns for Monday afternoon, and also Tuesday, especially
across western Minnesota.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation will likely be needed tonight.

tdk

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
706 PM CDT SUN OCT 11 2020

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

0655 PM     TSTM WND GST     2 NNE CANBY             44.73N 96.26W
10/11/2020  M57 MPH          YELLOW MEDICINE    MN   ASOS

&&

CTG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
708 PM CDT SUN OCT 11 2020

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

0649 PM     TSTM WND GST     CYRUS                   45.61N 95.74W
10/11/2020  E57 MPH          POPE               MN   TRAINED SPOTTER

&&

CTG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
731 PM CDT SUN OCT 11 2020

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

0721 PM     TSTM WND GST     2 WSW GARFIELD          45.93N 95.53W
10/11/2020  M65 MPH          DOUGLAS            MN   MESONET

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
737 PM CDT SUN OCT 11 2020

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

0655 PM     TSTM WND GST     2 NNE CANBY             44.73N 96.27W
10/11/2020  M66 MPH          YELLOW MEDICINE    MN   AWOS

            AWOS STATION KCNB CANBY AP.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
744 PM CDT SUN OCT 11 2020

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

0655 PM     TSTM WND DMG     CANBY                   44.71N 96.27W
10/11/2020                   YELLOW MEDICINE    MN   911 CALL CENTER

            FEW POWER POLES DOWN IN CANBY.

&&

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
817 PM CDT Sun Oct 11 2020

MNZ042-043-048-049-055>057-064-065-073-120215-
Chippewa-Morrison-Yellow
Medicine-Stearns-Kandiyohi-Renville-Pope-Swift-Redwood-Todd-
817 PM CDT Sun Oct 11 2020

...A LINE OF STORMS WILL AFFECT EASTERN POPE...EASTERN CHIPPEWA...
WESTERN REDWOOD...EASTERN YELLOW MEDICINE...TODD...WESTERN STEARNS...
EASTERN SWIFT...WESTERN MORRISON...NORTHWESTERN RENVILLE AND
KANDIYOHI COUNTIES...

At 816 PM CDT, radar indicated strong thunderstorms were located
along a line extending from 5 miles northeast of Clarissa to near
Sauk Centre to 10 miles west of New London to 6 miles south of
Cottonwood. Movement was northeast at 40 mph.

Wind gusts up to 50 mph are possible with these storms.

These storms will be near...
  Sauk Centre and Clarissa around 820 PM CDT.
  Staples, Brooten, Belgrade and Hanley Falls around 830 PM CDT.
  Grey Eagle and Echo around 835 PM CDT.
  Long Prairie and Motley around 840 PM CDT.
  Swanville around 845 PM CDT.
  Sacred Heart around 850 PM CDT.
  Renville around 855 PM CDT.
  Melrose around 900 PM CDT.

These of these storms may intensify, so be certain to monitor local
radio stations and available television stations for additional
information and possible warnings from the National Weather Service.

LAT...LON 4636 9467 4631 9455 4633 9443 4629 9435
      4621 9440 4615 9434 4568 9455 4419 9539
      4420 9558 4420 9559 4462 9561 4464 9574
      4527 9538 4576 9518 4576 9514 4637 9496
TIME...MOT...LOC 0116Z 225DEG 36KT 4618 9485 4578 9502 4533 9514 4452
9562

Borghoff