Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
337 PM CDT Wed May 17 2017

.SHORT TERM...(This evening through Thursday)
Issued at 336 PM CDT Wed May 17 2017

A potent upper level wave will bring multiple rounds of storms
capable of producing severe weather. Damaging wind, tornadoes, and
large hail are all possible. These storms will be moving quickly
from the south at speeds near 50 mph.

Early afternoon water vapor imagery together with RAP13 heights and
winds showed a compact upper level PV anomaly across eastern
Nebraska. Forecast models continue to lift this low up across
southern and eastern Minnesota later today.  A surface low will
track along this same path. Since this is vertically stacked system,
the minimum pressure will be fairly steady and may even rise
slightly.

This system is dynamically driven meaning there is very strong
forcing in the presence of a marginal thermodynamic environment.
Storm should develop and move quickly this afternoon and evening. It
appears there will be two waves. The first is currently lifting
across southern MN, and the second is across southwest Iowa and will
rotate northeast later this evening. All modes of severe weather are
possible. Hail and tornadoes are more favored early on, with
damaging wind expected as the low level shear increases later this
evening. Heavy rain is also a threat this evening. Storm will be
moving quickly, but multiple rounds could lead to a few more inches
of rain by the time the system exits the region Thursday morning.
Run accumulation from the HiRes models show local maxima of 2 to 3
inches. Did not issue a flash flood watch due the progressive speed
of the storms, and the fact that any high-end potential flooding
event is very low.

.LONG TERM...(Thursday night through Wednesday)
Issued at 336 PM CDT Wed May 17 2017

By tomorrow evening, a large area of high pressure will be centered
across south central Canada, with dry northeasterly flow at the
surface making its way into Minnesota and cool 850H temps falling to
0 to +2 C.  Meanwhile, a closed upper low will be over the four
corners region and will be our next system of interest.  By Friday
morning the jet will intensify with the streak pointed from near the
TX panhandle pointed into Iowa.  POPs increase from south to north
on Friday as this system begins ejecting northeast and perturbations
in the flow are sent ahead of the main upper trough toward our area.

The main forcing with the large upper trough will arrive early
Saturday, so fully expect rain to be moving through early Saturday
morning from the south, and lasting through the day as the surface
low moves northward directly through our area.  Instability will be
limited to the warm sector so we could see thunderstorms in eastern
Minnesota and western Wisconsin as this lifts through.  As this
system continues on its northeasterly course this Saturday night
into Sunday, we will see northwesterly flow but with conditions
drying out, we should see highs a few degrees warmer than Saturday
(which with plentiful rain will be held in the low to mid 50s).

As we get into early next week, an upper shortwave trough will drop
southeast through Canada and bring more rain chances for early next
week.  This shortwave could support the formation of a deep longwave
trough, but the models diverge quite a bit at this point for our
sensible weather as the ECMWF differs in pushing a ridge in from
the west which would confine the trough to our northeast, and the
end result for us in this area would be different when compared to
some of the other medium range guidance such as the GFS.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 204 PM CDT Wed May 17 2017

A frontal boundary will linger across the region for most of the
afternoon and evening. Expect MVFR/IFR CIGS with -RA north of the
frontal boundary today, and -TSRA south of the boundary today. A
surface low will track across southeast MN and central WI. Winds
will become northerly as the low pressure moves through with low
clouds expected to continue overnight and into Thursday.

KMSP...
A few thunderstorms will develop across northern Iowa and lift
northward this afternoon. They should reach KMSP by 22Z. Expect
showers and thunderstorms to continue this evening, with MVFR
conditions developing tonight and lasting through most of
Thursday.

/OUTLOOK FOR KMSP/
Fri...VFR with MVFR/-TSRA possible in afternoon. Wind NE at 10kt
Sat...MVFR/RA with IFR possible. Wind E at 10G20kt
Sun...VFR with MVFR possible. Wind NW at 15G25kt

&&

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

SHORT TERM...JRB
LONG TERM...SPD
AVIATION...JRB

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
159 PM CDT Wed May 17 2017

MNZ051>053-059>063-065>070-073>078-082>085-091>093-WIZ014>016-
023>028-181900-
Sherburne-Isanti-Chisago-Wright-Hennepin-Anoka-Ramsey-Washington-
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-
Chippewa-Eau Claire-
159 PM CDT Wed May 17 2017

This Hazardous Weather Outlook is for portions of central
Minnesota...east central Minnesota...south central Minnesota...
southeast Minnesota...southwest Minnesota...northwest Wisconsin
and west central Wisconsin.

.DAY ONE...This Afternoon and Tonight

Severe thunderstorms with large hail, damaging winds, heavy rain,
and a tornadoes are possible this afternoon and tonight.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation may be needed.

MNZ041>045-047>050-054>058-064-181900-
Douglas-Todd-Morrison-Mille Lacs-Kanabec-Stevens-Pope-Stearns-
Benton-Lac Qui Parle-Swift-Chippewa-Kandiyohi-Meeker-
Yellow Medicine-
159 PM CDT Wed May 17 2017

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

.DAY ONE...This Afternoon and Tonight

A few thunderstorms are possible this afternoon and tonight. The
threat for severe weather in western Minnesota is low.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation may be needed.

jrb

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
545 PM CDT WED MAY 17 2017

MNZ060-068-172315-
Hennepin-Carver-
545 PM CDT WED MAY 17 2017

...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN HENNEPIN AND CARVER
COUNTIES...

At 545 PM CDT, a strong thunderstorm was located over Cologne, or 28
miles east of Hutchinson, moving northeast at 30 mph.

Winds in excess of 40 mph are possible with this storm.

Locations impacted include...
Plymouth, Minnetonka, Chaska, Chanhassen, Waconia, Mound, Orono,
Victoria, Minnetrista, Medina, Watertown and Carver.

This storm 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 4468 9377 4467 9385 4469 9389 4472 9390
      4472 9396 4473 9399 4498 9383 4498 9377
      4508 9376 4508 9373 4497 9343 4465 9376
TIME...MOT...LOC 2245Z 209DEG 28KT 4476 9383

SPD

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
550 PM CDT WED MAY 17 2017

MNZ053-061-172315-
Anoka-Chisago-
550 PM CDT WED MAY 17 2017

...A STRONG THUNDERSTORM WILL AFFECT SOUTH CENTRAL CHISAGO AND
NORTHEASTERN ANOKA COUNTIES...

At 550 PM CDT, a strong thunderstorm was located over Wyoming, or 15
miles southeast of Cambridge, moving northeast at 20 mph.

Winds in excess of 40 mph and nickel size hail are possible with this
storm.

Locations impacted include...
Forest Lake, North Branch, Chisago City, Lindstrom, Stacy, Center
City and Wyoming.

This includes the following highways...
 Interstate 35 between mile markers 133 and 145.
 U.S. Highway 8 in Minnesota between mile markers 2 and 5, and
between mile markers 7 and 11.
 U.S. Highway 61 between mile markers 163 and 164.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4542 9281 4529 9296 4529 9302 4527 9303
      4533 9314 4541 9309 4541 9302 4548 9301
TIME...MOT...LOC 2250Z 209DEG 18KT 4535 9304

SPD

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
555 PM CDT WED MAY 17 2017

WIZ027-028-180000-
Chippewa-Eau Claire-
555 PM CDT WED MAY 17 2017

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT EASTERN CHIPPEWA AND
EAU CLAIRE COUNTIES...

At 555 PM CDT, radar indicated strong thunderstorms were located
along a line extending from Eau Claire Airport to near Augusta to
near Alma Center. Movement was northeast at 35 mph.

Wind gusts up to 50 mph and dime size hail are possible with these
storms.

Locations impacted include...
Eau Claire, Chippewa Falls, Altoona, Lake Hallie, Stanley, Lake
Wissota, Augusta, Cornell, Cadott, Fall Creek, Boyd and Fairchild.

This includes the following highways...
 Interstate 94 in Wisconsin between mile markers 61 and 87.
 U.S. Highway 53 between mile markers 86 and 100.

Torrential rainfall is also occurring with these storms, and may
cause localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4459 9141 4475 9166 4521 9120 4497 9092
      4460 9093
TIME...MOT...LOC 2255Z 216DEG 32KT 4486 9153 4465 9116 4438 9088

SPD

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
557 PM CDT WED MAY 17 2017

WIZ023-024-172330-
Pierce-St. Croix-
557 PM CDT WED MAY 17 2017

...A STRONG THUNDERSTORM WILL AFFECT NORTH CENTRAL PIERCE AND EASTERN
ST. CROIX COUNTIES...

At 557 PM CDT, a strong thunderstorm was located near Woodville, or
14 miles east of River Falls, moving northeast at 40 mph.

Winds in excess of 40 mph and dime size hail are possible with this
storm.

Locations impacted include...
Baldwin, Woodville, Glenwood City, Forest, Emerald, Cylon, Downing,
Wilson and Hersey.

This includes Interstate 94 in Wisconsin between mile markers 17 and
28.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4481 9232 4486 9248 4521 9233 4521 9231
      4515 9215 4512 9215 4512 9213 4499 9214
TIME...MOT...LOC 2257Z 211DEG 36KT 4492 9234

SPD

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
604 PM CDT WED MAY 17 2017

MNZ051-059-060-068>070-076-077-180000-
Le Sueur-Dakota-Rice-Hennepin-Sherburne-Carver-Wright-Scott-
604 PM CDT WED MAY 17 2017

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT CENTRAL WRIGHT...
HENNEPIN...WESTERN DAKOTA...NORTHEASTERN LE SUEUR...SCOTT...
SOUTHEASTERN SHERBURNE...NORTHERN RICE AND EASTERN CARVER COUNTIES...

At 604 PM CDT, radar indicated strong thunderstorms were located
along a line extending from near Rassat to near Carver to near
Kilkenny. Movement was northeast at 30 mph.

Wind gusts up to 50 mph and pea size hail are possible with these
storms.

Locations impacted include...
Minneapolis, Northfield, Buffalo, Bloomington, Brooklyn Park,
Plymouth, Eagan, Maple Grove, Coon Rapids, Eden Prairie, Burnsville
and Lakeville.

This includes the following highways...
 Interstate 35 between mile markers 61 and 80.
 Interstate 94 in Minnesota between mile markers 192 and 205.
 U.S. Highway 10 in Minnesota between mile markers 202 and 217.
 U.S. Highway 12 between mile markers 128 and 140.
 U.S. Highway 169 between mile markers 159 and 160.

Torrential rainfall is also occurring with these storms, and may
cause localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4433 9357 4477 9367 4515 9410 4540 9369
      4529 9351 4525 9352 4521 9342 4514 9330
      4510 9327 4504 9328 4504 9321 4491 9320
      4434 9305
TIME...MOT...LOC 2304Z 218DEG 25KT 4515 9408 4478 9367 4437 9357

SPD

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
608 PM CDT WED MAY 17 2017

MNZ091-172345-
Martin-
608 PM CDT WED MAY 17 2017

...A STRONG THUNDERSTORM WILL AFFECT WESTERN MARTIN COUNTY...

At 608 PM CDT, a strong thunderstorm was located near Ceylon, or 11
miles northeast of Estherville, moving north at 50 mph.

Winds in excess of 40 mph and dime size hail are possible with this
storm.

Locations impacted include...
Sherburn, Trimont, Welcome, Ceylon, Dunnell, Ormsby and Foxlake.

This includes Interstate 90 between mile markers 85 and 96.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4385 9479 4385 9451 4384 9450 4350 9461
      4350 9477
TIME...MOT...LOC 2308Z 187DEG 43KT 4354 9470

SPD