Alert archive / South Dakota / Mesoscale Discussions in 2018

Mesoscale Discussion 367

May 8, 20184 counties in Minnesota; Sargent County, North Dakota; 10 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 8, 2018, 2:58 PM CDT for 4 counties in Minnesota; Sargent County, North Dakota; 10 counties in South Dakota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
May 8, 2018, 2:58 PM CDT (19:58 UTC)
Expired
May 8, 2018, 5:00 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
5%

Counties Big Stone County, MN, Lac qui Parle County, MN, Stevens County, MN, Traverse County, MN, Sargent County, ND, Brown County, SD, Clark County, SD, Codington County, SD, Day County, SD, Deuel County, SD, Grant County, SD, Hamlin County, SD, Marshall County, SD, Roberts County, SD, Spink County, SD

The radar

The Aberdeen radar (KABR), 100 km from the middle of the area, began a volume at 20:01 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 nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 8.0 hours before the alert went out and 94 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-pSkew-T log-p diagram, Aberdeen, SD at 12:00Z on 2018-05-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Aberdeen, SD at 12:00Z on 2018-05-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 43 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1505 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
43 m²/s²
0-3 km storm-relative helicity
34 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

779 
ACUS11 KWNS 081959
SWOMCD
SPC MCD 081958 
MNZ000-SDZ000-NDZ000-082200-

Mesoscale Discussion 0367
NWS Storm Prediction Center Norman OK
0258 PM CDT Tue May 08 2018

Areas affected...Northeast SD...far southeast ND...far western MN.

Concerning...Severe potential...Watch unlikely 

Valid 081958Z - 082200Z

Probability of Watch Issuance...5 percent

SUMMARY...Storm development expected in the next hour or two. A
watch is not expected.

DISCUSSION...Clearing in the wake of morning convection has led to
destabilization in eastern SD. This area is characterized by an
environment with surface dewpoints in the upper-50s and temperatures
in the mid to upper-70s. A cumulus field developed in this area with
a few areas of better towers starting to show up southeast of
Aberdeen. Latest RAP mesoanalysis indicates the inhibition has just
about eroded across this area with MLCAPE around 1000 J/kg.
Therefore, expect storms to develop within the next hour or two.
Additional destabilization is expected northeast of these developing
towers where solar insolation has led to rapid heating as morning
clouds have cleared. Weak effective shear around 25 knots will lead
to semi-organized multicell clusters as the primary mode. The main
threat from these storms will be damaging winds due to the
well-mixed, inverted-v sounding in the area. In addition, there will
be an isolated risk of large hail as mid-level lapse rates have
increased above 7 C/km. However, the steeper mid-level lapse rates
will remain in far southern SD and eastern Nebraska.

..Bentley/Grams.. 05/08/2018

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

ATTN...WFO...MPX...FGF...FSD...ABR...BIS...

LAT...LON   45339869 45049870 44749842 44579788 44579739 44439682
            44469652 44549636 44729610 45119581 45569582 46019636
            46119707 46169791 45339869

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 7, 7:17 PM CDTMesoscale DiscussionSPCEmmons, McIntosh118 min

Nearby

Mesoscale Discussions in South Dakota, 2018Mesoscale Discussions in Minnesota, 2018Mesoscale Discussions in North Dakota, 2018Every mesoscale discussion in 2018

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.