Alert archive / North Dakota / Mesoscale Discussions in 2021

Mesoscale Discussion 1353

July 26, 202115 counties in North Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 26, 2021, 4:42 PM CDT for 15 counties in North Dakota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 26, 2021, 4:42 PM CDT (21:42 UTC)
Expired: Jul 26, 2021, 6:45 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch possible
Chance of a watch: 60%

Counties Barnes County, ND, Burleigh County, ND, Cass County, ND, Dickey County, ND, Emmons County, ND, Foster County, ND, Griggs County, ND, Kidder County, ND, LaMoure County, ND, Logan County, ND, McIntosh County, ND, Ransom County, ND, Richland County, ND, Sargent County, ND, Stutsman County, ND

The radar

The Bismarck radar (KBIS), 118 km from the middle of the area, began a volume at 21:40 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 393Jul 26, 5:45 PM CDT

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 12:00Z, 9.7 hours before the alert went out and 113 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 184 J/kg
Mixed-layer CIN: -482 J/kg
Mixed-layer LCL: 2397 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 32 m²/s²
0-3 km storm-relative helicity: 115 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

617 
ACUS11 KWNS 262143
SWOMCD
SPC MCD 262142 
MNZ000-NDZ000-262345-

Mesoscale Discussion 1353
NWS Storm Prediction Center Norman OK
0442 PM CDT Mon Jul 26 2021

Areas affected...eastern North Dakota

Concerning...Severe potential...Watch possible 

Valid 262142Z - 262345Z

Probability of Watch Issuance...60 percent

SUMMARY...Thunderstorms may develop this afternoon across central
and eastern North Dakota. Very large hail and strong thunderstorm
outflow winds will be possible with any thunderstorm. A watch may
become necessary should confidence in initiation increase.

DISCUSSION...Recent visible satellite imagery depicts clumping
cumulus developing across Burleigh and Morton counties in central
North Dakota. This is in response to sustained low-level convergence
along a weak surface boundary within a broad area of lower pressure
across the northern Plains. Surface temperatures in the mid-to-upper
90s F coupled with dewpoints in the mid-60s to around 70 F have
resulted in a very unstable airmass, characterized by most-unstable
CAPE values in excess of 3500 J/kg and decreasing convective
inhibition. Some high-resolution guidance develops robust convection
within this area of sustained low-level convergence and decreasing
inhibition over the next couple of hours. Strong deep-layer shear
greater than 40 knots and mid-level lapse rates around 8 C/km will
support vigorous updrafts capable of producing very large hail and
gusty thunderstorm winds with any thunderstorm. 

If confidence in convective initiation increases, a watch may be
required for portions of eastern North Dakota. This area will
continue to be monitored.

..Marsh/Grams.. 07/26/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...FGF...BIS...

LAT...LON   46690103 47380046 47619940 47619820 47139688 46469669
            46079699 46049828 46009983 46190089 46400099 46690103

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 25, 9:49 PM CDT	Mesoscale Discussion	SPC	Ransom, Richland, Sargent	116 min
Jul 26, 5:22 PM CDT	Severe Thunderstorm Watch	SPC	Barnes, Cass, Dickey, Emmons, Kidder, LaMoure and 6 more	5 hr

Nearby

Mesoscale Discussions in North Dakota, 2021 Every mesoscale discussion in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.