Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
652 PM CDT Fri Aug 5 2022

.UPDATE...
Issued at 633 PM CDT Fri Aug 5 2022

Updated for the 00z aviation discussion below.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 311 PM CDT Fri Aug 5 2022

KEY MESSAGES:

- Multiple rounds of slow moving thunderstorms expected at times
  tonight into Saturday morning and again Saturday night. Pockets of
  heavy rain with isolated amounts in excess of 3 inches are
  possible, but the flooding risk is low given the ongoing drought
  conditions.

Main concern through tonight will deal with what should be multiple
rounds of convection that develops along a cold front that this
afternoon stretches from the northwest corner of MN back to the
central ND/SD border. This front will enter our northwest CWA around
midnight, move through the Twin Cities Saturday morning, clear
Albert Lea and Eau Claire Saturday afternoon. This front will be
more or less oriented parallel to the h85-h3 flow, which will mean
slow progress for the front. This type of setup tends to favor an
overrunning setup for convection develop, with greatest coverage of
activity typically concentrate near and on the cool side of the
boundary. Often with slower storm motion and training of storms.
The NAM/GFS/RAP all increase PWATS on Saturday to up around 2.2" of
rain, so this will set the stage for heavy rain. The best signal for
heavy rain Saturday afternoon through Saturday night is across
southern MN into western WI, with the greatest uncertainty for where
the northern bound of this heavy rain will setup, which is
conveniently across the Twin Cities metro and the worst of the D2
drought we have in place. 48 hour Probability Matched Mean (PMM) QPF
from the HRRR is showing areas areas with 5-7" of rain, so the
signal definitely remains for seeing heavy rain Saturday night.

What's trick with this forecast is that each round of storms will in
turn impact where subsequent rounds end up. Looks like the greatest
severe risk will remain northwest of the MPX CWA this period, but
what we'll be watching are storms that are forecast to develop
tonight between Sioux Falls and Aberdeen in SD. They would track
east from there, but models differ on whether this would track more
into central MN or go on a trajectory closer to the Twin Cities.
What happens with these storms will help determine how far south the
front makes it Saturday afternoon, when storms are again expected to
erupt along it and slowly sag south through the night. Severe
weather doesn't look to be all that big of a front thanks to weak
lapse rates, but some heavy rain could certainly dampen any plans
you may have to attend, say a county fair, in southern MN.

.LONG TERM...(Sunday through Friday)
Issued at 311 PM CDT Fri Aug 5 2022

KEY MESSAGE:

- Temperatures will cool down Sunday and Monday, with another period
  of dry, warm, and uneventful weather the rest of next week.

The series of shortwaves off to our west will continue to advance
eastward through our region which allows for a continuation of
increased chances of showers and embedded thunderstorms through the
weekend's conclusion. Central and Southern MN counties should
anticipate to see an additional tenth to quarter an inch of rainfall
whereas Western WI could see potentially a quarter to a half-inch
with localized higher amounts associated with heavier rainfall.
Precipitation will gradually decrease from west to east as the final
shortwave departs our area overnight on Sunday. Skies will gradually
clear as surface high pressure builds in. Any rainfall that happened
over the weekend, will most likely be the last that we see through
the forecast period. Monday is shaping up to the best day "weather
wise" of the week as flow becomes more zonal aloft. Temperatures on
Monday will be below-normal in the upper 70's for most areas and
under mostly sunny skies. Tuesday will begin our next warm-up with
near normal temperatures in the low 80's. Wednesday through Friday,
strong upper-level ridging will build from the west allowing for
temperatures to return to the mid to upper 80's. Dew points look to
remain relatively steady ranging from 55-60F.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 633 PM CDT Fri Aug 5 2022

Northeast to southwest oriented cold front that is just now entering
northwest MN will slowly sag south across the MPX area late tonight
through Saturday. As the front moves through a terminal, it will
result in a several hour long window where showers and storms will be
possible. Given the uncertainty in coverage and timing of storms
along the boundary, kept thunderstorm mention in the 00z TAF set in
the prob30 category. Have mostly VFR TAFs as well, though any
terminal that gets a good soaking rain with the fropa, will have a
chance of developing some MVFR cigs in the post frontal environment.

KMSP...Current forecast has a 50% chance of TSRA starting between
13-14z with a brief break before another round of precipitation
develop in the afternoon. Opted to flavor the Prob30 to start a
little later in the period, closer to when our PoPs ramp back up.
Right now, we have the highest chances for precip at MSP (60% or
higher) coming in at 20z Sat and continuing through the end of this
period.

/OUTLOOK FOR KMSP/
Sun...Chc MVFR/-SHRA in A.M. Otherwise, VFR. Wind NE 5-10 kts.
Mon...VFR. Wind N 5-10 kts.
Tue...VFR. Wind SW 5-10 kts.

&&

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

SHORT TERM...MPG
LONG TERM...WFO MPX
AVIATION...BPH

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
232 PM CDT Fri Aug 5 2022

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
061945-
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-
232 PM CDT Fri Aug 5 2022

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

.DAY ONE...Tonight.

Heat index values this afternoon will approach 95 degrees in the
Twin Cities metro area and 100 degrees in west central Minnesota.

Thunderstorms are excected tonight from west central through
central Minnesota. Some heavy downpours will be possible with a
low threat for severe weather.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Thunderstorms are expected to continue off and on through the
weekend. Locally heavy rainfall, with a severe storm or two, is
possible Saturday afternoon into Saturday night from southern
Minnesota into western Wisconsin.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation may be needed late tonight in west
central Minnesota.

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
1029 PM CDT Fri Aug 5 2022

MNZ041-048-060400-
Pope MN-Douglas MN-
1029 PM CDT Fri Aug 5 2022

...A strong thunderstorm will impact portions of southern Douglas and
northern Pope Counties through 1100 PM CDT...

At 1028 PM CDT, Doppler radar was tracking a strong thunderstorm over
Lowry, or 15 miles southwest of Alexandria, moving east at 25 mph.

HAZARD...Winds in excess of 30 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.

Locations impacted include...
  Glenwood.

This includes Interstate 94 in Minnesota between mile markers 105 and
113.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4563 9565 4580 9570 4586 9517 4561 9514
TIME...MOT...LOC 0328Z 261DEG 23KT 4572 9557

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...30 MPH

NDC