Special Weather Statement, NWS Twin Cities, MN

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1213 AM CDT Sat Jun 30 2018

.SHORT TERM...(This evening through Saturday)
Issued at 340 PM CDT Fri Jun 29 2018

Surface analysis this afternoon shows a low pressure center over
northwest MN with a trailing cold front extending SSW into central
Nebraska and a leading warm front extending ENE through the
Arrowhead into Lake Superior. Aloft, a NW-SE oriented ridge axis
emanating from a large dome of high pressure over the southeastern
CONUS is slowly shifting off to the E. This deep ridge combined
with warm sectoring of the surface system has allowed across the
WFO MPX coverage area to soar into the low-mid 90s with dewpoints
in the mid-70s, easily creating heat index values of 100-110
degrees. Little in the way of relief will come through this
evening due to strong capping in place but there is at least
modest expectation that the atmosphere will recover in terms of
instability from the overnight to early morning activity up north
while capping influences wane to produce isolated to scattered
showers and thunderstorms in mainly western-central MN overnight
through daybreak Saturday. This activity is still highly
conditional due to a warm EML (roughly +15C at H7) but a strong
H925-H850 jet in advance of the progressing cold front may still
ably provide forcing within a still unstable environment to create
at least elevated convection. Any nocturnal activity looks to time
itself away from the area by daybreak Saturday morning, allowing
the atmosphere to restock itself with instability once again while
the cold front is more actively crossing the area. The front looks
to push into western portions of the coverage area around daybreak
then reach the MN/WI border late afternoon Saturday. More robust
convection is then expected for Saturday, mainly south and east of
the TC metro, with clusters of storms potentially organizing into
an MCS for western WI and southern MN. Less capping, stronger
lapse rates and better dynamics look to mesh to bring more storms
capable of large hail and damaging winds late Saturday afternoon
through Saturday evening.

.LONG TERM...(Saturday night through Friday)
Issued at 340 PM CDT Fri Jun 29 2018

Saturday Night-Sunday...The pattern of a large dome of high
pressure in the southeast with a trough in the southwest, keeping
southwest flow aloft our region, will promote additional
shower/t-storm development over the WFO MPX coverage area through
Sunday, but mainly for the southeastern portions of the area. The
main issue becomes more of a heavy rain hazard rather than severe
storms due to PWATs increasing to near 2" in far southern/eastern
portions of the area with storms near the front and the
progression of the front slowing with upper level support waning.
Training of storms, decent storm coverage and slow moving storms
all add up to at least an isolated flooding hazard for areas which
have already received plenty of rain and have multiple sites of
river flooding. The bulk of the rain looks to come Saturday
evening with gradually improving conditions through the day on
Sunday behind the cold front. Humidity levels will be much less
while highs on Sunday will only hit the upper 70s to around 80
degrees.

Monday-Friday...A more zonal pattern aloft will prevail to start
the week, resulting in lesser chances for precipitation with drier
air in place and little upper level support along with no nearby
surface frontal systems. Chances increase a bit Tuesday as a pre-
frontal wave in advance of a warm front to the southwest
approaches the region but not looking for anything significant. A
more organized storm system looks to slowly move through the area
Wednesday-Thursday which may bring better coverage of
showers/t-storms but prospects for any severe weather remain
rather low. There will be a small temperature swing with this
midweek system, nudging temperatures closer to 90 for Wednesday-
Thursday in its warm sector before highs drop back to the lower
80s on Friday as the system exits the area.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1212 AM CDT Sat Jun 30 2018

As the HRRR/RAP were showing leading into the 00z TAF issuance, the
cap finally gave way out in western MN at 4z. However, forcing is
weak and shear is marginal and storms have shown little
organization. Expect AXN to be the only terminal that will be
impacted by storms tonight. After this, we'll be waiting until
Saturday afternoon for destabilization to occur along the remnants
of the cold front that is currently over western MN. Greatest threat
for afternoon convection looks to occur along/east of a MKT/MSP/RNH
line. We should see a lull in activity between 4z and 8z before
shra/tsra chances increase over a broader area as the main shortwave
finally begins working into southern MN.

KMSP...Main question for Saturday is where does the boundary. 00z
CAMS say majority of afternoon convection ends up southeast of
MSP, but close enough to keep the VCTS mention going. Better
precip chances arrive after 06z as the main upper wave approaches.
NAM/ARW/NMM all show more widespread precip developing with this.

/OUTLOOK FOR KMSP/
Sun...VFR. Chc TSRA in mrng. Wind WNW 5-10kt.
Mon...VFR. Chc TSRA overnight. Wind SW 10-15 kt.
Tue...VFR. Chc TSRA. Wind SSE 10-15 kt.

&&

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

SHORT TERM...JPC
LONG TERM...JPC
AVIATION...MPG

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
910 PM CDT Fri Jun 29 2018

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
010215-
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-
910 PM CDT Fri Jun 29 2018

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

.DAY ONE...Tonight

There is a slight chance of thunderstorms through the night. If
any thunderstorms do occur, there is a chance they could be
severe, with with large hail and damaging winds being the primary
threat. The greatest threat for thunderstorms tonight will exist
across central MN.

Flooding continues along the Minnesota River and its tributaries.
Please refer to the Minnesota Department of Transportation for
any road closures due to flooding.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Thunderstorms will remain possible on Saturday, with a continued
threat for severe storms. At this time the highest chance for
severe storms looks to be on Saturday afternoon and evening,
primarily south and east of a New Ulm to Twin Cities to Taylors
Falls Wisconsin line. In addition to heavy rainfall, the main
threats would be large hail and damaging winds.

River flooding will continue along the Minnesota River and its
tributaries into next week. Please refer to the Minnesota
Department of Transportation for any road closures due to
flooding.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation will not be needed.

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
1125 PM CDT FRI JUN 29 2018

MNZ041-042-048-049-300515-
Stearns-Pope-Douglas-Todd-
1125 PM CDT FRI JUN 29 2018

...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN DOUGLAS...
NORTHEASTERN POPE...SOUTHERN TODD AND NORTHWESTERN STEARNS
COUNTIES...

At 1125 PM CDT, a strong thunderstorm was located near Westport, or
14 miles southeast of Alexandria, moving northeast at 35 mph.

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

Locations impacted include...
Sauk Centre, Long Prairie, Lake Osakis, Little Sauk, Round Prairie,
West Union, and Westport.

LAT...LON 4563 9511 4575 9530 4610 9494 4592 9465
TIME...MOT...LOC 0425Z 221DEG 31KT 4576 9514

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1230 AM CDT SAT JUN 30 2018

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

1211 AM     HAIL             6 WSW MILTONA           46.02N 95.40W
06/30/2018  M0.75 INCH       DOUGLAS            MN   PUBLIC

            MPING REPORT.

&&

Special Weather Statement
National Weather Service Twin Cities/Chanhassen MN
100 AM CDT SAT JUN 30 2018

MNZ043-300645-
Morrison-
100 AM CDT SAT JUN 30 2018

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT WESTERN MORRISON
COUNTY...

At 1259 AM CDT, radar indicated strong thunderstorms were located
along a line extending from near Philbrook to near Swanville to near
Sauk Centre. Movement was east at 50 mph.

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

Locations impacted include...
Little Falls, Motley, Randall, Upsala, Swanville, Bowlus, Flensburg,
Camp Ripley, Cushing, Sobieski, Elmdale and Camp Ripley Junction.

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 4631 9455 4631 9451 4633 9443 4630 9436
      4627 9434 4623 9440 4618 9437 4616 9437
      4615 9403 4578 9447 4577 9464 4634 9466
TIME...MOT...LOC 0559Z 248DEG 42KT 4629 9467 4599 9468 4578 9499