Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
223 PM CDT Tue Aug 14 2018

.SHORT TERM...(This evening through Wednesday)
Issued at 218 PM CDT Tue Aug 14 2018

The main forecast concern is initiation of thunderstorms along two
boundaries depicted on regional radar and satellite imagery this
afternoon. The first was located just south of the Twin Cities,
with a diffuse area in south central Minnesota where earlier
convection had dissipated prior to 2 pm. The second area was near
Willmar, east-northeast to Elk River and northeast into northwest
Wisconsin. Between these two areas, a dense cirrus shield had led
to lower temperatures and limiting the potential of convective
initiation. However, with the mid-level short wave still west of
west central/central Minnesota and ample mid-level moisture
remaining across southern Minnesota into west central Wisconsin,
the potential is high that thunderstorms will continue to increase
in areal coverage between these two boundaries this afternoon.

Once the sun sets, coverage will decrease along with the activity
slowly propagating to the southeast across southern Minnesota. I
wouldn't be surprised to see additional activity develop toward
sunrise if a weak low level jet develops along the weak front
sagging into far southern Minnesota. Most of the thunderstorms
should be across Iowa and into southern Wisconsin by Wednesday
afternoon as the main short wave holds south of the area. Only far
southwest/south central Minnesota may see a few showers or storms
Wednesday afternoon if the current upper level low in Montana
meanders further to the north across South Dakota, and northwest
Iowa Wednesday afternoon.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 218 PM CDT Tue Aug 14 2018

Overall, there is very little change from the previous forecast
into this one as the models have remained fairly consistent in the
idea of a split flow pattern keeping the area mostly dry through
the rest of this week with a little more active pattern for next
week.

Wednesday night through Saturday...A upper level ridge over the
western CONUS midweek will ever-so-slowly nudge itself east over
the Rockies and extend into the Northern Plains during the latter
portion of the week. The incoming ridge will help suppress to the
south a weak mid-to-upper level shortwave which may produce a few
isolated showers over far southern portions of the WFO MPX
coverage area Wednesday night into Thursday. Otherwise, the area
will remain dry with building heights aloft and general surface
high pressure prevailing over the area. The main result will be a
slight uptick in temperatures from the midweek period into the
weekend. Highs will climb from around 80 degrees on Thursday to
the mid-80s on Friday and Saturday.

Sunday through Tuesday...Several factors will come into play
during the start of next week which will force the inclusion of
chance-range pops for early next week. A potent upper level
shortwave will drive southeast from western Canada, evolving into
a deep upper level low over the Hudson Bay area with weaker
shortwaves riding around the periphery of the upper low. At the
surface, a cold front will drop into the region from south-central
Canada then stall out over MN/WI Sunday-Tuesday. In addition, a
plume of western GOMEX moisture will be shunted well north into
the Mid-and-Upper Mississippi River Valley regions around the
Bermuda High, giving the features at the surface and aloft
moisture to work with to produce at least scattered showers and
storms early next week. These features will also act to bump down
temperatures once again for the early portion of next week. Highs
will drop into the mid-to-upper 70s with lows back into the 50s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1215 PM CDT Tue Aug 14 2018

Ample, deep moisture, an upper short wave, and a frontal boundary
will all combine to produce scattered SHRA/TSRA this afternoon,
through the early evening. The main problem is timing and how
widespread the activity becomes this afternoon. Two areas that
satellite/regional radar have been depicted that will have the
best chance of widespread SHRA/TSRA for the first couple of hours
will be near KRWF/KMKT and KAXN. Elsewhere, the main dilemma would
be outflow from the TSRA currently developing and where another
updraft develops. Although it is not the best scenario, VCTS
looks reasonable for the first several hours, then taking out VCTS
after 1-2z. This forecast has low confidence, but enough to
continue the VCTS or some TEMPOs based on the current radar
trends. The next concern is whether redevelopment occurs toward
12z from KRWF- KMSP-KRNH. This scenario has low confidence once
again, but based a mid-level trough holding back until Wednesday
afternoon, I wouldn't be surprised to see more activity toward
sunrise.

KMSP...Timing and how long will the TSRA/SHRA continue this
afternoon is the main forecast concern. Confidence is high that
TSRA will develop in the vicinity, but timing remains low. Will
continue the same trend with most of the TSRA developing after
21z, and ending toward sunset. As previously mentioned, more
TSRA/SHRA is possible toward 12z. Winds will be generally from the
west- northwest, then north-northeast Wednesday.

/OUTLOOK FOR KMSP/
Wed evening...VFR. Wind NE 5 kts.
Thu...VFR. Wind NNE 5 kts.
Fri...VFR. Wind NE 5 kts.
Sat...VFR. Wind light/Variable bcmg SE 5 kts.

&&

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

SHORT TERM...JLT
LONG TERM...JPC
AVIATION...JLT

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
1234 PM CDT Tue Aug 14 2018

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
151745-
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-
1234 PM CDT Tue Aug 14 2018

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

.DAY ONE...This Afternoon and Tonight

Scattered thunderstorms will occur across central and southern
Minnesota, as well as portions of west central Wisconsin through
the early evening. The main weather hazard will be locally heavy
rainfall and gusty winds.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

The next best chance for showers and thunderstorms will be Sunday
night through Monday. The threat for severe weather is low at
this
time.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation will not be needed.

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
1112 AM CDT TUE AUG 14 2018

MNZ065-073-141700-
Renville-Redwood-
1112 AM CDT TUE AUG 14 2018

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT CENTRAL REDWOOD AND
SOUTH CENTRAL RENVILLE COUNTIES THROUGH 1200 PM CDT...

At 1111 AM CDT, radar indicated strong thunderstorms were located
along a line extending from near Morton to near Lucan. Movement was
northeast at 5 mph.

Half inch hail is possible with these storms.

Locations impacted include...
Redwood Falls, Wabasso, Franklin, Morton, Wanda, North Redwood and
Redwood Falls Airport.

This includes U.S. Highway 71 between mile markers 62 and 83.

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

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4459 9479 4457 9510 4434 9548 4424 9527
TIME...MOT...LOC 1611Z 235DEG 5KT 4453 9501 4436 9539

JPC

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
1144 AM CDT TUE AUG 14 2018

MNZ041-141730-
Douglas-
1144 AM CDT TUE AUG 14 2018

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT NORTHERN DOUGLAS
COUNTY THROUGH 1230 PM CDT...

At 1144 AM CDT, radar indicated strong thunderstorms were located
along a line extending from near Millerville to near Charlesville.
Movement was east at 20 mph.

Half inch hail is possible with these storms.

Locations impacted include...
Alexandria, Evansville, Brandon, Leaf Valley, Miltona, Garfield,
Millerville and Melby.

This includes Interstate 94 in Minnesota between mile markers 81 and
94.

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

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4611 9518 4592 9539 4589 9575 4593 9577
      4611 9577
TIME...MOT...LOC 1644Z 280DEG 16KT 4604 9559 4592 9622

JPC

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
1157 AM CDT TUE AUG 14 2018

MNZ073-074-141800-
Brown-Redwood-
1157 AM CDT TUE AUG 14 2018

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT CENTRAL REDWOOD AND
BROWN COUNTIES THROUGH 100 PM CDT...

At 1156 AM CDT, radar indicated strong thunderstorms were located
along a line extending from Searles to near Seaforth. Movement was
north at 10 mph.

Half inch hail is possible with these storms.

Locations impacted include...
New Ulm, Redwood Falls, Sleepy Eye, Springfield, Morgan, Wabasso,
Hanska, Vesta, Lucan, Clements, Seaforth and Evan.

This includes the following highways...
 U.S. Highway 14 between mile markers 75 and 103.
 U.S. Highway 71 between mile markers 57 and 74.

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

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4436 9556 4454 9539 4455 9536 4460 9534
      4433 9445 4427 9442 4426 9438 4411 9437
TIME...MOT...LOC 1656Z 199DEG 7KT 4423 9446 4444 9535

JPC

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
150 PM CDT TUE AUG 14 2018

MNZ041-048-141930-
Pope-Douglas-
150 PM CDT TUE AUG 14 2018

...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN DOUGLAS AND
NORTHWESTERN POPE COUNTIES THROUGH 230 PM CDT...

At 149 PM CDT, a strong thunderstorm was located near Kensington, or
14 miles northeast of Morris, moving southeast at 15 mph.

Half inch hail is possible with this storm.

Locations impacted include...
Lowry, Kensington and Farwell.

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

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4575 9532 4560 9567 4569 9576 4582 9576
      4585 9575 4586 9575
TIME...MOT...LOC 1849Z 297DEG 14KT 4576 9575

JPC

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
229 PM CDT TUE AUG 14 2018

MNZ057-142015-
Kandiyohi-
229 PM CDT TUE AUG 14 2018

...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN KANDIYOHI COUNTY
THROUGH 315 PM CDT...

At 228 PM CDT, a strong thunderstorm was located near Kandiyohi, or
near Willmar, moving east at 15 mph.

Half inch hail is possible with this storm.

Locations impacted include...
Willmar, Atwater and Kandiyohi.

This includes the following highways...
 U.S. Highway 12 between mile markers 75 and 88.
 U.S. Highway 71 between mile markers 122 and 126.

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

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4516 9503 4517 9476 4505 9475 4494 9476
      4503 9504
TIME...MOT...LOC 1928Z 285DEG 14KT 4508 9493

JPC

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
232 PM CDT TUE AUG 14 2018

MNZ051>053-061-WIZ014-142030-
Anoka-Isanti-Sherburne-Chisago-Polk-
232 PM CDT TUE AUG 14 2018

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT CENTRAL CHISAGO...
NORTHERN ANOKA...SOUTHERN ISANTI...SOUTHEASTERN SHERBURNE AND
NORTHERN POLK COUNTIES THROUGH 330 PM CDT...

At 231 PM CDT, radar indicated strong thunderstorms were located
along a line extending from Trade River to near Big Lake. Movement
was southeast at 10 mph.

Winds in excess of 30 mph and half inch hail are possible with these
storms.

Locations impacted include...
Cambridge, Andover, Ramsey, Elk River, Otsego, East Bethel, Big Lake,
North Branch, St. Francis, Isanti, Stacy and Frederic.

This includes the following highways...
 Interstate 35 between mile markers 140 and 154.
 U.S. Highway 10 in Minnesota between mile markers 200 and 216.
 U.S. Highway 169 between mile markers 159 and 168.

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

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4563 9221 4525 9348 4527 9356 4530 9357
      4529 9358 4530 9365 4535 9385 4565 9283
      4565 9253 4573 9252 4572 9228
TIME...MOT...LOC 1931Z 297DEG 11KT 4565 9269 4534 9370

JPC