Severe Thunderstorm Warning 84, NWS Bismarck, ND

Area Forecast Discussion
National Weather Service Bismarck ND
713 PM CDT Sun Jun 28 2020

.UPDATE...
Issued at 710 PM CDT Sun Jun 28 2020

Updated to mention the next wave of storms was into northwest
South Dakota and pushing east-northeast toward Hettinger.

UPDATE Issued at 700 PM CDT Sun Jun 28 2020

Severe weather including the tornado threat continues over the
watch area. With that said, mesoscale convective parameters across
the western two-thirds of Dunn County and western two-thirds of
Stark County have significantly decreased. That well behind the
stationary boundary. The action is actually east of those counties
but close enough to hold them in the watch. Am hopeful we will be
able to remove them over the next hour or two and provide a sense
of relief to (drop the watch) to folks there.

Another concern is flash flooding. Despite the D1-D2 drought
designation, with rain rates of 1-2 inches per hour, even on dry
ground, could lead to flooding, and smaller waterways need to be
considered as well. Storms have been redeveloping on south and
west flanks, slow moving, and to some extent training. All that
leads to us keeping a close eye on those water issues.

Take a look at the Bismarck Radar reflectivity product to see the
well defined boundary just west of Bismarck, which will continue
to be the focus for thunderstorm development. Little movement,
more of a wiggle east and west, is expected with that boundary
over the next 6 hours.

&&

.SHORT TERM...(This evening through Monday night)
Issued at 131 PM CDT Sun Jun 28 2020

Convection initiation and storm mode will be the main forecast
issues this afternoon/evening, with likely the same question
again on Monday.

An upper low to our west will keep a chance of storms, some
severe, through the short term period.

It looks more and more like convection will ire along a frontal
boundary that is currently situated from around Stanley south New
Salem to west of Mobridge SD. Very unstable airmass is currently
situated along and ahead of this boundary with ML Cape values in
excess of 3500-4000 J/KG over much of central ND. With continued
daytime heating and what appears to be a modest cap at best, think
storms will begin to develop along this boundary around  3-5 PM
this afternoon, probably in the north where CAP is weakest, and
then building south along the front. Although very unstable, bulk
shear is minimal, but with 20-25 knots of effective bulk shear
along the boundary, some storms could be supercells, with very
large hail. A tornado can not be ruled out given the potential for
supercells and a favorable thermodynamic profile with low LCL
heights and high LCL to LFC humidity. Helicity is not off the
charts, but sufficient, if supercells can develop.

There is still uncertainty with storm mode as initial movement
would likely be nearly parallel to the boundary, and bulk shear
decreases rapidly east of the boundary. Thus a mix of multicell
clusters and supercells could develop with very large hail, as
well as winds to 70 mph being the main threats.

There will also be a risk of very heavy rain with any storms that
do develop. Precipitable water is maximized over the north central
with continued strong moisture transport along and east of the
highway 83 corridor. The north central would probably be the area
of most concern, but with best potential for training storms a
little farther north into Canada. As you go south of the
International border, the storm coverage gets spottier pretty
quick. Also given our lack of rainfall, most area outside of any
city limits would be able to handle a good amount of rainfall
before runoff becomes a significant issue.

As for thunderstorms moving into the southwest later this
evening, the risk for strong to severe storms remains with strong
winds being the main threat. Latest HREF does show some UH tracks
approaching the west central and southwest but most are farther
south into western South Dakota. Will certainly need to continue
to monitor. The bulk shear environment over western ND is much
stronger, but the instability is quite a bit weaker. Will see how
things develop with convection in the high plains this afternoon.

On Monday, the frontal boundary sets back up to our west as the
closed upper low tracks from Idaho into western Montana. It looks
like we could see another round of thunderstorms develop in an
area of convergence along the boundary as it sits over western ND
Late Monday afternoon into Tuesday evening with very unstable air
once again to the east. A similar solution to Today might again
play out with the best bulk shear along and west of the boundary,
and a very unstable airmass with modest shear to the east. Any
storm that do develop would again have the potential to develop
quickly with a mix of linear segments and supercells possible once
again. Convection will probably dissipate over central ND late
Monday night, with strong capping holding over the James River
Valley into the Turtle Mountains and points east.

.LONG TERM...(Tuesday through Sunday)
Issued at 131 PM CDT Sun Jun 28 2020

Near daily thunderstorm chances will continue through the long term
portion of the forecast.

On Tuesday, the upper low lifts from Montana into southern British
Columbia, Canada, while additional energy rotates through the base
of the upper low. This will push the quasi-stationary boundary
that has been lingering over western and central ND, into the
eastern portion of the state. Very unstable airmass will shift
into the James to Red River Valley Tuesday afternoon, with
meridional flow continuing over western and central ND. Showers
and thunderstorms will remain a threat over the west, but the
higher risk of severe storms will shift to along and east of the
Highway 83 corridor.

Potentially a little bit of a break from severe weather Wednesday
and Thursday with some drier air pushing into the forecast area.
However, we will remain within a broad area of southwest upper
flow with diurnally driven showers and thunderstorms not out of
the question either day. Daytime highs will be in the upper 70s to
mid 80s Wednesday and warming into the 80s on Thursday.

Potentially a little more upper level ridging on Friday and into
next weekend. Thus warmer temperatures in the 80s and 90s would
be in store with more isolated to scattered convection.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 710 PM CDT Sun Jun 28 2020

As of this writing a north-south oriented stationary boundary
extended from just west of KMOT through just west of KBIS. It has
been and will continue to be the focus for thunderstorm
development through at least 29/0500Z. The boundary will move
little, just a wiggle east and back west with storms moving
generally north along it. The highest chances for storms is at
KMOT and KBIS. The lowest chances are at KJMS and KXWA, then KDIK.
Where there are storms they will have a high chance of being
severe with large hail the main threat. MVFR to IFR ceilings are a
possibility early Monday morning at all TAF sites.

&&

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

UPDATE...JPM
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...JPM

Hazardous Weather Outlook
National Weather Service Bismarck ND
350 PM CDT Sun Jun 28 2020

NDZ001-002-009-017-031-032-040-043-292100-
Divide-Burke-Williams-McKenzie-Golden Valley-Billings-Slope-
Bowman-
350 PM CDT Sun Jun 28 2020 /250 PM MDT Sun Jun 28 2020/

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

.DAY ONE...This Afternoon and Tonight

Thunderstorms are forecast the rest of this afternoon and tonight,
some could be severe. The main hazards will be large hail around
quarter size and damaging wind gusts around 60 mph. Very heavy
rain is also possible with the storms.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Chances for thunderstorms Monday through Wednesday and some
could be severe and with heavy rain, but there remains
uncertainty in the timing and location of the greatest risks.

.SPOTTER INFORMATION STATEMENT...

Weather spotters may be needed.

NDZ023-025-036-037-046>048-050-051-292100-
Wells-Foster-Kidder-Stutsman-Emmons-Logan-La Moure-McIntosh-
Dickey-
350 PM CDT Sun Jun 28 2020

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

.DAY ONE...This Afternoon and Tonight

Isolated thunderstorms are forecast tonight, some could be
severe. The main hazards will be large hail around quarter size
and damaging wind gusts around 60 mph. Very heavy rain is also
possible with the storms.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Chances for thunderstorms Monday through Wednesday and some
could be severe and with heavy rain, but there remains
uncertainty in the timing and location of the greatest risks.

.SPOTTER INFORMATION STATEMENT...

Weather spotters may be needed.

NDZ003>005-010>013-018>022-033>035-041-042-044-045-292100-
Renville-Bottineau-Rolette-Mountrail-Ward-McHenry-Pierce-Dunn-
Mercer-Oliver-McLean-Sheridan-Stark-Morton-Burleigh-Hettinger-
Grant-Adams-Sioux-
350 PM CDT Sun Jun 28 2020 /250 PM MDT Sun Jun 28 2020/

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

.DAY ONE...This Afternoon and Tonight

Numerous severe thunderstorms are expected. The main hazards will
be tornadoes, very large and destructive hail up to tennis ball
size, and damaging wind gusts around 70 mph. Very heavy rain is
also possible with the storms.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Chances for thunderstorms Monday through Wednesday and some
could be severe and with heavy rain, but there remains
uncertainty in the timing and location of the greatest risks.

.SPOTTER INFORMATION STATEMENT...

Weather spotters will be needed.

JP Martin

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BISMARCK ND
615 PM CDT SUN JUN 28 2020

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

0532 PM     TSTM WND GST     3 NNE SAWYER            48.13N 101.04W
06/28/2020  M52 MPH          WARD               ND   MESONET

            NDAWN SITE.

&&

JP MARTIN

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BISMARCK ND
622 PM CDT SUN JUN 28 2020

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

0600 PM     HAIL             FOXHOLM                 48.37N 101.57W
06/28/2020  E0.88 INCH       WARD               ND   PUBLIC

            TIME ESTIMATED FROM RADAR.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BISMARCK ND
638 PM CDT SUN JUN 28 2020

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

0620 PM     HAIL             CENTER                  47.12N 101.30W
06/28/2020  E0.88 INCH       OLIVER             ND   PUBLIC

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BISMARCK ND
648 PM CDT SUN JUN 28 2020

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

0645 PM     HAIL             CENTER                  47.12N 101.30W
06/28/2020  E1.00 INCH       OLIVER             ND   TRAINED SPOTTER

            HAIL UP TO THE SIZE OF QUARTERS OCCURRED ON
            AN OFF FOR 15 MINUTES ENDING AT 645 PM.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BISMARCK ND
659 PM CDT SUN JUN 28 2020

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

0645 PM     HAIL             1 WSW LORAINE           48.86N 101.59W
06/28/2020  E1.00 INCH       RENVILLE           ND   PUBLIC

            TIME ESTIMATED FROM RADAR.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BISMARCK ND
721 PM CDT SUN JUN 28 2020

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

0718 PM     HAIL             6 E CENTER              47.12N 101.18W
06/28/2020  M1.00 INCH       OLIVER             ND   PUBLIC

&&