Special Weather Statement, NWS Twin Cities, MN

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

.UPDATE...For 00Z Aviation discussion below

&&

.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 00Z TAFS through 00Z Wednesday evening)
Issued at 523 PM CDT Tue Aug 14 2018

Scattered showers and thunderstorms will be possible at
central/southern sites through sunset (KRWF/KMKT/KMSP/KRNH/KEAU).
Attendant MVFR Ceilings and MVFR/IFR visibilities are possible
with any showers/storms. MVFR ceilings are also developing behind
the front, and should become more widespread from south/east
central MN across west central WI overnight through a good portion
of Wednesday. KMSP/KRWS/KRNH will be on the northern fringes,
while KMKT/KEAU have the highest chance to see a prolonged MVFR
deck. Variable winds will be primarily north/northeast for
Wednesday at 5-8 knots. Another round of showers/storms is
possible on Wednesday afternoon, but currently anticipate the
area to be south/east of the sites, with possibly the exception of
KEAU.

KMSP...
There will be a threat for thunder at the site to start the TAF
period as a boundary passes, but that will diminish with sunset.
The next concern is the potential for MVFR ceilings (above 1800
feet) overnight. Have included a scattered mention for now and
will monitor trends.

/OUTLOOK FOR KMSP/
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...LS

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
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

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
240 PM CDT TUE AUG 14 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0229 PM     FUNNEL CLOUD     2 NNW SPRING LAKE       45.57N 93.09W
08/14/2018                   CHISAGO            MN   TRAINED SPOTTER

            TRAINED SPOTTER IN DOWNTOWN CAMBRIDGE, MN
            REPORTED A FUNNEL CLOUD WHILE LOOKING EAST.
            NO PHOTO GIVEN. DISTANCE FROM CAMBRIDGE
            ESTIMATED FROM RADAR.

&&

CTG

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

MNZ051-059-142030-
Sherburne-Wright-
315 PM CDT TUE AUG 14 2018

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT CENTRAL WRIGHT AND
SOUTHEASTERN SHERBURNE COUNTIES THROUGH 330 PM CDT...

At 315 PM CDT, radar indicated strong thunderstorms were located
along a line extending from near Otsego to near French Lake. Movement
was east at 15 mph.

Half inch hail is possible with these storms.

Locations impacted include...
Buffalo, Elk River, St. Michael, Otsego, Monticello, Big Lake,
Albertville, Annandale, Maple Lake and Silver Creek.

This includes the following highways...
 Interstate 94 in Minnesota between mile markers 189 and 201.
 U.S. Highway 10 in Minnesota between mile markers 200 and 205, and
between mile markers 207 and 211.

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 4515 9396 4523 9419 4536 9383 4530 9356
      4527 9356
TIME...MOT...LOC 2015Z 271DEG 13KT 4533 9366 4521 9414

JPC

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

MNZ059-142130-
Wright-
336 PM CDT TUE AUG 14 2018

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT CENTRAL WRIGHT
COUNTY THROUGH 430 PM CDT...

At 335 PM CDT, radar indicated strong thunderstorms were located
along a line extending from near Monticello to Cokato. Movement was
south at 10 mph.

Half inch hail is possible with these storms.

Locations impacted include...
Buffalo, St. Michael, Otsego, Monticello, Albertville, Cokato, Maple
Lake, Howard Lake, Buffalo Airport, Rassat and Smith Lake.

This includes the following highways...
 Interstate 94 in Minnesota between mile markers 192 and 203.
 U.S. Highway 12 between mile markers 115 and 126.

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 4530 9377 4530 9373 4525 9356 4498 9423
      4499 9425 4514 9425 4532 9381
TIME...MOT...LOC 2035Z 015DEG 9KT 4528 9381 4510 9421

JPC

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

MNZ091>093-142230-
Martin-Freeborn-Faribault-
442 PM CDT TUE AUG 14 2018

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT NORTHWESTERN
FREEBORN...CENTRAL FARIBAULT AND SOUTHEASTERN MARTIN COUNTIES
THROUGH 530 PM CDT...

At 441 PM CDT, radar indicated strong thunderstorms were located
along a line extending from near Freeborn to Okamanpedan State Park.
Movement was northeast at 10 mph.

Half inch hail is possible with these storms.

Locations impacted include...
Fairmont, Blue Earth, Wells, Ceylon, Freeborn, Easton, Delavan, Iowa
Lake, Granada, East Chain, Brush Creek and Fairmont Airport.

This includes the following highways...
 Interstate 90 between mile markers 100 and 139.
 U.S. Highway 169 between mile markers 5 and 19.

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 4351 9465 4367 9454 4385 9372 4384 9346
      4367 9367 4349 9438
TIME...MOT...LOC 2141Z 229DEG 8KT 4377 9363 4349 9456

JPC

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

MNZ084-092-093-142330-
Waseca-Freeborn-Faribault-
525 PM CDT TUE AUG 14 2018

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT NORTHWESTERN
FREEBORN...NORTHERN FARIBAULT AND SOUTHERN WASECA COUNTIES THROUGH
630 PM CDT...

At 523 PM CDT, radar indicated strong thunderstorms were located
along a line extending from near Matawan to Huntley. Movement was
northeast at 5 mph.

Half inch hail is possible with these storms.

Locations impacted include...
Blue Earth, Wells, Winnebago, New Richland, Minnesota Lake, Hartland,
Freeborn, Easton, Delavan, Huntley, Matawan and Guckeen.

This includes the following highways...
 Interstate 90 between mile markers 113 and 121.
 U.S. Highway 169 between mile markers 11 and 21.

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 4376 9425 4385 9389 4385 9377 4388 9376
      4397 9341 4380 9340 4361 9425
TIME...MOT...LOC 2223Z 215DEG 5KT 4382 9360 4368 9418

JPC