Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
846 PM CDT Sat Jun 20 2020

.UPDATE...
Issued at 846 PM CDT Sat Jun 20 2020

Main change to the forecast for the rest of tonight was to start
increasing mention of the dense fog threat in west central WI.
For example, EAU received 0.25" of rain through the afternoon,
with the temperature as we near sunset just 64 degrees. Clearing
skies are working across our WI counties now and with sunset
occurring shortly, we expect areas out toward Eau Claire,
Ladysmith, and Rice Lake to quickly cool past their cross-over
temperatures, with fog becoming locally dense in spots overnight.

As for thunderstorms coming out of the Dakotas, they are running
out of the reservoir of MUCAPE and will continue their weakening
trend as they move into our western CWA. The RAP shows the MUCAPE
tongue that has fed these storms weakening considerably as it
moves east, so like the going forecast, with it looking unlikely
any activity makes it as far east as St. Cloud and Redwood Falls
this evening.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 254 PM CDT Sat Jun 20 2020

Widespread showers across western Wisconsin will continue eastward
late this afternoon. Meanwhile, a band of thunderstorms across
eastern North Dakota will also head eastward through the
evening. They may become more numerous south into South Dakota
late this afternoon, and then may pose a threat to western MN
this evening. They should be on a weakening trend after sunset
with the loss of instability and it's likely they will completely
dissipate before reaching St. Cloud and Redwood Falls. Aside from
the possibility for a few rogue showers or storms overnight, it
should be dry for the vast majority until at least late Sunday
morning.

Increasing theta-e throughout the day with a cold front slowly
sagging southeast across the CWA will spark thunderstorm
development during the afternoon. Lapse rates continue to look
poor, so CAPE shouldn't be too impressive. Up to 2000 J/kg are
possible across far southern MN where rich low level moisture
coincide with slightly better mid level lapse rates. SPC has
upgraded this area to a slight risk. 0-6 km bulk shear of 30-40
kts could allow a few supercells to develop where the best pockets
of instability develop. Otherwise, CAMs favor short line segments
along the cold front, capable mostly of wind damage. The severe
threat will diminish Sunday evening, but shower and thunderstorm
chances will continue into Monday as the front continues to limp
through.

.LONG TERM...(Monday through Saturday)
Issued at 254 PM CDT Sat Jun 20 2020

The best chances for storms Monday will be across southern MN into
western WI. The front will clear the area Monday evening. A large
trough will spin multiple weak disturbances across the region
Tuesday and Wednesday. Coupled with modest daytime heating,
isolated to scattered showers and thunderstorms are likely to
develop each afternoon. This trough will clear to the east late
week, but several waves continuing eastward across the northern
CONUS will keep chances for storms in our future into next
weekend. Temperatures will warm back into the 80s as heights rise
following the departure of the deeper trough from midweek.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 701 PM CDT Sat Jun 20 2020

Four concerns this period are 1) how far convection over the
eastern Dakotas makes it into MN this evening, 2) potential for
dense fog at EAU, 3) threat for light showers as early as Sunday
morning, and 4) threat for another round of thunderstorms late
Sunday afternoon. So we'll tackle all of those briefly.

1) Storms over the Dakotas have remained discrete, with little
organization. Think the HRRR is overdoing their strength into
western MN and the lack of instability over the state leads us to
believe we don't see much of this activity tonight and only have a
tempo shower threat at AXN.

2) EAU has had rain most of the afternoon and will likely start
the night with temperatures only in the mid 60s, with clearing
expected overnight, don't think it will take long to get fog
going at EAU given the fresh rain and cool temps, so hit that
threat pretty hard with the 00z TAF.

3) Shortwave energy will be moving across central/southern MN
Sunday morning. This looks to result in mainly mid level clouds,
but could see a few light showers scattered about as seen with the
HRRR and NMM. If we see anything, it looks to be of little impact
and lack thunder.

4) For the late afternoon TS threat, delayed it's threat at MSP.
Still a good deal of spread in the models with where/when storms
develop, so stuck with prob30s for now. Front will be diffuse, but
greatest threat for TS by 00z should be from south central MN up
toward the Twin Cities given expected frontal placement.

KMSP...We could see a light shower or two by late morning with
shortwave energy moving through, but right now greatest TS threat
looks to be in the 22z to 04z window.

/OUTLOOK FOR KMSP/
Mon...VFR. Chc aftn SHRA/TSRA. Wind NW 10 kts.
Tue...VFR. Chc aftn SHRA/TSRA. Wind NW 10 kts.
Wed...VFR. Chc aftn SHRA/TSRA. Wind WNW 10 kts.

&&

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

UPDATE...MPG
SHORT TERM...Borghoff
LONG TERM...Borghoff
AVIATION...MPG

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
839 PM CDT Sat Jun 20 2020

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
220145-
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-
839 PM CDT Sat Jun 20 2020

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

.DAY ONE...Tonight.

A few non-severe thunderstorms are possible this evening across
western into central Minnesota.

Areas of dense fog will be possible tonight in west central
Wisconsin, in particular for areas along and east of a Menomonie
to Rice Lake line.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Chances for thunderstorms exist for most of next week. There is a
Slight Risk for severe thunderstorms Sunday and Sunday evening
across southern Minnesota with a Marginal Risk elsewhere. The
main hazards will be damaging winds and localized heavy rainfall.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation may be needed Sunday and Sunday
evening.

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
1045 PM CDT Sat Jun 20 2020

MNZ054-056-210415-
Chippewa-Lac Qui Parle-
1045 PM CDT Sat Jun 20 2020

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL LAC QUI PARLE AND
NORTHWESTERN CHIPPEWA COUNTIES...

At 1045 PM CDT, a strong thunderstorm was located 7 miles south of
Appleton, or 20 miles northwest of Montevideo, moving southeast at 20
mph.

Nickel size hail is possible with this storm.

Locations impacted include...
Milan and Cerro Gordo.

LAT...LON 4518 9610 4517 9607 4515 9604 4514 9586
      4496 9595 4505 9620
TIME...MOT...LOC 0345Z 293DEG 17KT 4510 9607