Severe Thunderstorm Warning 141, NWS Bismarck, ND

173 
WWUS53 KBIS 262246
SVSBIS

Severe Weather Statement
National Weather Service Bismarck ND
446 PM MDT SAT AUG 26 2017

NDC087-262256-
/O.CAN.KBIS.SV.W.0141.000000T0000Z-170826T2315Z/
Slope ND-
446 PM MDT SAT AUG 26 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN SLOPE COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4595 10318 4628 10361 4628 10306 4595 10249
TIME...MOT...LOC 2246Z 309DEG 24KT 4621 10319 

$$

NDC001-011-262315-
/O.CON.KBIS.SV.W.0141.000000T0000Z-170826T2315Z/
Bowman ND-Adams ND-
446 PM MDT SAT AUG 26 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM MDT
FOR EASTERN BOWMAN AND SOUTHWESTERN ADAMS COUNTIES...

At 446 PM MDT, a severe thunderstorm was located near Scranton, or 10
miles east of Bowman, moving southeast at 25 mph.

HAZARD...Quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Damage to vehicles is expected. 

This severe storm will be near...
  Scranton around 455 PM MDT. 
  Reeder around 515 PM MDT. 

Other locations impacted by this severe thunderstorm include Bucyrus,
Buffalo Springs and Gascoyne.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4595 10318 4628 10361 4628 10306 4595 10249
TIME...MOT...LOC 2246Z 309DEG 24KT 4621 10319 

HAIL...1.00IN
WIND...<50MPH
 
$$

ABELING

119 
WWUS53 KBIS 262253
SVSBIS

Severe Weather Statement
National Weather Service Bismarck ND
453 PM MDT SAT AUG 26 2017

NDC001-011-262302-
/O.CAN.KBIS.SV.W.0141.000000T0000Z-170826T2315Z/
Bowman ND-Adams ND-
453 PM MDT SAT AUG 26 2017

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN BOWMAN AND
SOUTHWESTERN ADAMS COUNTIES IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.

LAT...LON 4595 10318 4628 10361 4628 10306 4595 10249
TIME...MOT...LOC 2252Z 314DEG 30KT 4618 10315 

$$

ABELING

Area Forecast Discussion
National Weather Service Bismarck ND
233 PM CDT Sat Aug 26 2017

.SHORT TERM...(This evening through Sunday)
Issued at 233 PM CDT Sat Aug 26 2017

Thunderstorm potential, mainly south and west of the Missouri
River, is the main weather concern through this evening.

As of 19 UTC, weak, elevated convection continues in advance of
a mid-level impulse in northwest flow aloft that's characterized
by a RAP-analyzed vorticity maximum approaching southwestern ND.
Weak low-level flow is contributing to correspondingly weak mixing
of the lower atmosphere, which is in part helping to maintain an
area of upper 50s to lower 60s F dewpoints across most of western
and central ND. That in turn is yielding MLCAPE of 1500-2000 J/kg.
Effective-layer shear this afternoon and evening is expected to
range from only 20 kt in the Turtle Mountain region (where the
threat of severe storms is thus negligible) to 30 to 40 kt in
western and south central ND. The primary uncertainty with the
convective forecast relates to the coverage of surface-based
storms in the late afternoon and evening due to a combination of
weak low-level convergence, the fact that the primary forcing
aloft tied to the mid-level wave will be focused in western SD by
00 UTC, and potential capping shown in some model soundings. In
regard to the latter concern, soundings from the 12 UTC NAM
suggest MLCIN in excess of -75 J/kg will persist through early
evening, while more recent RAP output suggests MLCIN may be more
minimized in favor of at least a few boundary-layer-based storms,
mainly in far southwestern ND.

While uncertainty in storm coverage continues, we have to note
that trends in the most recent HRRR and ESRL-HRRR runs reversed
their prior course of a muted event and instead are starting to
favor a severe risk centered on the Hettinger, Mott, and Elgin
areas in the 21-00 UTC time frame. Given those trends, we chose
to continue explicitly mentioning a risk of severe storms in the
gridded and point-and-click forecasts across all of southwest and
into Grant and Sioux Counties in far south central ND through the
early evening. Weak low-level wind fields and deep west-northwest
flow above 700 mb will yield elongated straight-line hodographs
in favor of splitting storms and multicell clusters, but the CAPE
and shear setting, mid-level lapse rates around 7 C/km, and
sounding analog matching techniques all favor a severe hail and
wind risk with any established storms. We will continue
advertising hail up to the size of half dollars and wind gusts up
to 60 mph as the primary hazards, though again, storm coverage is
uncertain and if anything we may end up with only one or two
severe storms before the main event becomes established further
south in SD.

Otherwise, a surface high is expected to shift southward into the
area tonight and Sunday. We leaned on the cooler edge of guidance
for lows tonight given the proximity of the surface ridge, with
forecast lows from the upper 40s to lower 50s F. Patchy fog may
form given light winds and minimal low-level turbulence, but we
refrained from adding it to the forecast at this time since not
much support exists for its formation in deterministic high-
resolution guidance. Highs by Sunday afternoon are forecast to
range from the upper 70s F in the James River valley to the mid
80s F in western ND.

.LONG TERM...(Sunday night through Saturday)
Issued at 233 PM CDT Sat Aug 26 2017

Warm and mainly dry weather is forecast next week under the
influence of a 500 mb ridge that is forecast to amplify out of the
western U.S. and into the northern Plains. The 00 and 12 UTC GFS
and ECMWF and their ensembles support widespread highs in the 80s
to lower 90s F, with the warmest days possibly coming Tuesday and
Friday. A lee surface trough will likely be present in eastern MT
during this period, and could offer a non-zero risk of convection
depending on low-level moisture return, but in the probability of
precipitation will generally be low until the ridge flattens late
in the week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 233 PM CDT Sat Aug 26 2017

VFR conditions will prevail this afternoon through Sunday morning.
However, there is a chance of thunderstorms in parts of western
and central ND this afternoon and evening. A few storms could be
severe in the southwest and far south central. Patchy fog is also
possible tonight and Sunday morning, with potential sub-VFR
conditions, but confidence in its occurrence was too low to
mention in the 18 UTC TAFs.

&&

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

SHORT TERM...CJS
LONG TERM...CJS
AVIATION...CJS

Hazardous Weather Outlook
National Weather Service Bismarck ND
251 PM CDT Sat Aug 26 2017

NDZ001>005-009>013-019>023-025-034>037-046>048-050-051-272000-
Divide-Burke-Renville-Bottineau-Rolette-Williams-Mountrail-Ward-
McHenry-Pierce-Mercer-Oliver-McLean-Sheridan-Wells-Foster-Morton-
Burleigh-Kidder-Stutsman-Emmons-Logan-La Moure-McIntosh-Dickey-
251 PM CDT Sat Aug 26 2017 /151 PM MDT Sat Aug 26 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...This Afternoon and Tonight

There is a slight chance of thunderstorms across portions of
northwest and central North Dakota this afternoon and early
evening, including the Turtle Mountain region. Severe weather is
not expected.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

There is a slight chance of thunderstorms Thursday and Thursday
night.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

NDZ017-018-031>033-040>045-272000-
McKenzie-Dunn-Golden Valley-Billings-Stark-Slope-Hettinger-Grant-
Bowman-Adams-Sioux-
251 PM CDT Sat Aug 26 2017 /151 PM MDT Sat Aug 26 2017/

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

.DAY ONE...This Afternoon and Tonight

Isolated to scattered thunderstorms are possible across southwest
and far south central North Dakota this afternoon and into the
early evening. A few thunderstorms may be severe with large hail
to half dollar size, damaging winds to 60 mph, and dangerous
lighting, especially near the North and South Dakota state line.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

There is a slight chance of thunderstorms Thursday and Thursday
night.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon and evening across
southwest and far south central North Dakota.

CJS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BISMARCK ND
433 PM CDT SAT AUG 26 2017

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

0422 PM     HAIL             12 WSW HEART BUTTE DAM  46.56N 102.06W
08/26/2017  E2.50 INCH       HETTINGER          ND   LAW ENFORCEMENT

&&

WA

Special Weather Statement
National Weather Service Bismarck ND
338 PM MDT SAT AUG 26 2017

NDZ040-262230-
Slope ND-
338 PM MDT SAT AUG 26 2017

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL SLOPE COUNTY UNTIL 430
PM MDT...

At 338 PM MDT, Doppler radar was tracking a strong thunderstorm 17
miles northeast of Marmarth, or 17 miles west of Amidon, moving east
at 25 mph.

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

This strong thunderstorm will be near...
  Amidon around 425 PM MDT.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

LAT...LON 4660 10376 4653 10315 4628 10326 4628 10329
      4643 10383
TIME...MOT...LOC 2138Z 286DEG 20KT 4650 10370

ABELING