Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
253 PM CDT Wed Aug 17 2022

.DISCUSSION...(This evening through Wednesday)
Issued at 233 PM CDT Wed Aug 17 2022

Weak ascent aloft from a shortwave over western Ontario and modest
instability have led to isolated thunderstorm development this
afternoon across east-central Minnesota and west-central Wisconsin.
These thunderstorms will expand in coverage over more of Minnesota
and Wisconsin later this afternoon, but still remain fairly brief and
isolated. Wind shear is very low so no severe weather is expected,
but slow storm motions mean that a few heavy downpours are likely.
The thunderstorms this afternoon should dissipate shortly after
sunset, but another round of showers and thunderstorms looks
possible during the morning as another weak lobe of vorticity passes
over the region. Thunderstorms look more likely during the
afternoon, however, as the main shortwave drops into the region out
of the Canadian prairies.

This shortwave develops into a vertically-stacked low Friday, and
proceeds to sit and spin over the area through Saturday. String
forcing aloft will lead to an extended period of unsettled weather,
with multiple periods of showers and thunderstorms likely. A total
washout is not expected from Thursday night through saturday, rather,
multiple waves of showers and thunderstorms with dry periods in
between. Precipitation appears to be most likely overnight Thursday
and Friday afternoon through Friday night. Precipitation comes to an
end Saturday evening as the upper level low moves east of the
region. Widespread rainfall amounts of around an inch are expected
through saturday, although locally higher amounts are likely in
locations that receive multiple rounds of thunderstorms. Brief heavy
downpours are likely and perhaps some minor flooding issues are
possible with slow storm motions, but modest precipitable water
values around 1.5" suggest widespread heavy rain is not likely. No
severe weather is expected either given the modest instability and
shear values.

Temperatures will be cool through the weekend given the mostly
cloudy skies and periodic chances for precipitation. Highs in the low
70s are likely most locations. temperatures remain o the cooler end
through the middle of next week with the return of northwest flow
aloft. Mainly dry weather is expected Sunday through Wednesday with
weak high pressure overhead.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1251 PM CDT Wed Aug 17 2022

Multiple rounds of isolated to scattered showers and thunderstorms
are possible through the period. The first comes late this afternoon
through early evening, mainly at STC/MSP/RNH. Dry conditions are
expected late tonight with another chance for light showers coming
early tomorrow morning, again mainly across central MN and western
WI. Finally thunderstorm chances become more likely tomorrow
afternoon, but a few could begin by late morning. VFR conditions are
expected through the period outside of any showers or thunderstorms,
with scattered diurnal cumulus this afternoon and increasing mid-
level clouds overnight into tomorrow morning.

KMSP...Isolated thunderstorms are likely in the vicinity of the Twin
Cities metro by late afternoon, any thunderstorm impacts at the
terminal would likely be brief. Better chances for thunderstorms
come tomorrow afternoon, especially during the late afternoon and
evening

/OUTLOOK FOR KMSP/
Fri...Periods of -SHRA/MVFR chc -TSRA. Wind S 5-10 kts.
Sat...MVFR/SHRA likely. Wind SE 5-10 kts.

&&

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

DISCUSSION...ETA
AVIATION...ETA

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
228 PM CDT Wed Aug 17 2022

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
181930-
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-
228 PM CDT Wed Aug 17 2022

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

.DAY ONE...Tonight.

Isolated thunderstorms are expected through this evening, and
again Thursday morning. No severe weather is expected.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation will not be needed.

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
425 PM CDT Wed Aug 17 2022

MNC123-163-172300-
Washington-Ramsey-
425 PM CDT Wed Aug 17 2022

...URBAN AND SMALL STREAM FLOODING EXPECTED...

Thunderstorms with heavy rain will cause minor flooding in the
following counties...

Washington...Ramsey...

* Until 600 PM CDT.

* At 425 PM CDT, Doppler radar indicated heavy rain due to
  thunderstorms. This will cause urban and small stream flooding in
  the area. Up to one inch of rain has already fallen.

* Some locations that will experience minor flooding include...
  St. Paul, Woodbury, Maplewood, Oakdale, Lake Elmo, North St. Paul,
  Landfall, Pine Springs, Lake Phalen and South Maplewood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

&&

LAT...LON 4503 9293 4494 9292 4494 9306 4503 9305

TDH

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
455 PM CDT Wed Aug 17 2022

MNC037-163-172330-
Dakota-Washington-
455 PM CDT Wed Aug 17 2022

...URBAN AND SMALL STREAM FLOODING EXPECTED...

Thunderstorms with heavy rain will cause minor flooding in the
following counties...

Dakota...Washington...

* Until 630 PM CDT.

* At 455 PM CDT, Doppler radar indicated heavy rain due to
  thunderstorms. This will cause urban and small stream flooding in
  the area. Up to one inch of rain has already fallen.

* Some locations that will experience minor flooding include...
  Woodbury, Maplewood, Cottage Grove, Inver Grove Heights, South St.
  Paul, West St. Paul, St. Paul Park, Afton, Newport, Sunfish Lake,
  St Paul Park and South St Paul.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

&&

LAT...LON 4492 9311 4492 9305 4489 9302 4489 9299
      4494 9298 4494 9290 4479 9280 4478 9303

TDH