Special Weather Statement, NWS Bismarck, ND

Area Forecast Discussion
National Weather Service Bismarck ND
100 AM CDT Tue Jun 13 2017

.UPDATE...

Issued at 100 AM CDT Tue Jun 13 2017

Modified POPs based on latest high res model runs and latest radar
imagery and trends. Convection breaking out as expected south
central, with this trend continuing elsewhere tonight as divergent
flow aloft increases across the region. Latest HRRR runs indicate
potential for strong to severe storms south central/southeast
9-10Z, through 12-14Z.

UPDATE Issued at 839 PM CDT Mon Jun 12 2017

Updated the forecast based on latest trends and short-term model
guidance. Thunderstorms are developing across northwest South
Dakota this evening. These storms will continue to develop and
push into southern North Dakota within the next few hours. This
will just be the beginning of a complex that forms in South Dakota
and sweeps across southern North Dakota overnight.

UPDATE Issued at 640 PM CDT Mon Jun 12 2017

The latest short-term models continue to indicate a complex of
thunderstorms developing across western South Dakota and spreading
into southern North Dakota by around Midnight. A few stronger
storms are possible across far southern North Dakota late tonight
into early tomorrow morning. Further north, conditions will be a
bit more stable...with only a few rumbles of thunder and much
needed rain falling. The threat for severe weather remains on
track for tomorrow.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 334 PM CDT Mon Jun 12 2017

Forecast highlights in the short term period will be showers and
thunderstorms developing tonight, increasing in coverage and
intensity towards morning with ingredients for the threat of severe
thunderstorms in the offing.

Currently, a mid-upper level shortwave ridge was established from
southern Alberta across northeastern Montana and southwestern North
Dakota. The large closed upper low was located over
Idaho/Utah/Nevada, with the leading edge of upper level impulses
emerging from its base near the 4-corners area moving
northeastward...with the leading edge having reached
Wyoming/Nebraska this afternoon.

The mid-upper level ridge will act to inhibit convection for the
rest of this afternoon into early evening, after which the upper
level impulses are progged to reach southwestern North Dakota. The
closed upper low is progged to reach western MT/WY by daybreak
Tuesday with upper level impulses becoming more numerous and
spreading quickly north and east. Thus kept any mention of showers
or thunderstorms out of the early evening period, but isolated to
scattered showers and thunderstorms are expected to develop
southwest and south central before midnight, then quickly become
more widespread across western and central North Dakota after
midnight.

Regarding the severe weather threat: 0-6km bulk shear
values will be strong in the 40-60 knot range, but high CAPE values
will remain south of the South Dakota border for tonight. However,
the Nam/GFS do depict some CAPE values over 2000 J/kg moving into
south central/southeastern ND from South Dakota late tonight. Thus
mentioned possible severe storms before daybreak far south central.

Upper low continues slowly eastward into eastern Montana by Tuesday
afternoon, across western and north central North Dakota Tuesday
night, then into far south central Canada on Wednesday. Very dynamic
system with all areas seeing some chance for precipitation. Appears
the more favorable area for severe weather will be across south
central North Dakota before noon Tuesday, then mainly east of
Highway 83 in the afternoon along the instability and shear axis,
which may also wrap back northwest into portions of northwest and
north central North Dakota in the late afternoon and early evening.
Lingering clouds from the morning hours will contribute to
uncertainty regarding severe convection.

The James Valley is in the best position (within western and central
North Dakota) for receiving organized severe convection. The
tornadic threat is also highest in the James Valley, with Sig Tor
parameter values in the 1-3 range, indicating good low level severe
ingredients including shear, storm relative helicity and LCL height.
This area is close to a surface low poised to be in northeastern
South Dakota by late morning Tuesday.

A dry slot is forecast to wrap into the upper low across
southwestern and eventually into central ND Tuesday afternoon and
will bring decreasing chances for storms to these areas. However,
will need to keep an eye on the potential for cold core funnels and
or tornadoes where it can destabilize.

The dry slot continues pushing into north central and northeastern
North Dakota Tuesday evening, thus decreasing chances of showers and
thunderstorms with time during the evening, with the severe threat
waning in the James Valley as well.

.LONG TERM...(Wednesday through Monday)
Issued at 334 PM CDT Mon Jun 12 2017

The upper low over southern Saskatchewan/Manitoba on Wednesday and
over Manitoba Thursday provide gusty west winds across North Dakota.
Cyclonic flow aloft will keep showers and isolated thunderstorms in
the forecast for northern North Dakota on Wednesday.

Another shortwave in the upper level flow moves across the Northern
Plains Friday/Saturday bringing chances of showers and isolated
thunderstorms. A dry northwesterly flow then develops over the state
as a broad western ridge begins to build.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)

Issued at 100 AM CDT Tue Jun 13 2017

Showers and thunderstorms will spread to the north and east
tonight into Tuesday morning. Localized MVFR and IFR conditions
are possible in thunderstorms tonight, especially southwest and
south central. MVFR with areas of IFR ceilings will then develop
early Tuesday morning, possibly lingering into the afternoon.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

UPDATE...NH
SHORT TERM...JV
LONG TERM...JV
AVIATION...NH

Hazardous Weather Outlook
National Weather Service Bismarck ND
1252 AM CDT Tue Jun 13 2017

NDZ002>005-010>013-019>023-025-034>037-042-045>048-050-051-140600-
Burke-Renville-Bottineau-Rolette-Mountrail-Ward-McHenry-Pierce-
Mercer-Oliver-McLean-Sheridan-Wells-Foster-Morton-Burleigh-Kidder-
Stutsman-Grant-Sioux-Emmons-Logan-La Moure-McIntosh-Dickey-
1252 AM CDT Tue Jun 13 2017 /1152 PM MDT Mon Jun 12 2017/

This Hazardous Weather Outlook is for portions of north central
North Dakota, northwest North Dakota, south central North Dakota,
and southeast North Dakota.

.DAY ONE...Tonight

Thunderstorms will spread north and east across western and
central North Dakota through the early morning hours. A few
stronger storms are possible across south central North Dakota,
otherwise the threat for severe weather is low.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Thunderstorms are likely Tuesday. Some storms could be severe
over central and eastern North Dakota, with large hail, damaging
wind and a few tornadoes.

There is a chance of thunderstorms Wednesday mainly across
northern North Dakota.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed late tonight, and with a greater
chance for activation on Tuesday.

NDZ001-009-017-018-031>033-040-041-043-044-140600-
Divide-Williams-McKenzie-Dunn-Golden Valley-Billings-Stark-Slope-
Hettinger-Bowman-Adams-
1252 AM CDT Tue Jun 13 2017 /1152 PM MDT Mon Jun 12 2017/

This Hazardous Weather Outlook is for portions of northwest North
Dakota and southwest North Dakota.

.DAY ONE...Tonight

Thunderstorms will spread north and east across western and
central North Dakota through the early morning hours. A few
stronger storms are possible across south central North Dakota,
otherwise the threat for severe weather is low.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

There is a chance for thunderstorms Tuesday. The threat for severe
weather is low at this time.

There is a chance of thunderstorms Wednesday mainly across
northern North Dakota.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is unlikely in western North Dakota.

Special Weather Statement
National Weather Service Bismarck ND
133 AM CDT TUE JUN 13 2017

NDZ035-130700-
Burleigh ND-
133 AM CDT TUE JUN 13 2017

...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN BURLEIGH COUNTY
UNTIL 200 AM CDT...

At 132 AM CDT, Doppler radar was tracking a strong thunderstorm 6
miles south of Menoken, or 15 miles east of Bismarck, moving
northeast at 20 mph.

Penny size hail and wind gusts to 40 mph will be possible with this
storm.

Locations impacted include...
Menoken, Sterling and Mckenzie.

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

&&

LAT...LON 4667 10060 4694 10054 4686 10019 4663 10041
      4663 10047
TIME...MOT...LOC 0632Z 200DEG 19KT 4673 10048

AYD