Alert archive / South Dakota / Mesoscale Discussions in 2017

Mesoscale Discussion 903

May 28, 20175 states

The Storm Prediction Center issued this mesoscale discussion at May 28, 2017, 3:54 PM CDT for 5 states. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued: May 28, 2017, 3:54 PM CDT (20:54 UTC)
Expired: May 28, 2017, 5:00 PM CDT
In force: 66 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 77 counties

Becker County, MN, Big Stone County, MN, Clay County, MN, Douglas County, MN, Grant County, MN, Lac qui Parle County, MN, Norman County, MN, Otter Tail County, MN, Pope County, MN, Stevens County, MN, Swift County, MN, Todd County, MN, Traverse County, MN, Wadena County, MN, Wilkin County, MN, Barnes County, ND, Cass County, ND, Dickey County, ND, Emmons County, ND, LaMoure County, ND, Logan County, ND, McIntosh County, ND, Ransom County, ND, Richland County, ND, Sargent County, ND, Sioux County, ND, Box Butte County, NE, Dawes County, NE, Sheridan County, NE, Sioux County, NE, Beadle County, SD, Bennett County, SD, Brown County, SD, Buffalo County, SD, Butte County, SD, Campbell County, SD, Clark County, SD, Codington County, SD, Corson County, SD, Custer County, SD, Day County, SD, Deuel County, SD, Dewey County, SD, Edmunds County, SD, Fall River County, SD, Faulk County, SD, Grant County, SD, Haakon County, SD, Hamlin County, SD, Hand County, SD, Harding County, SD, Hughes County, SD, Hyde County, SD, Jackson County, SD, Jones County, SD, Lawrence County, SD, Lyman County, SD, Marshall County, SD, McPherson County, SD, Meade County, SD, Mellette County, SD, Oglala Lakota County, SD, Pennington County, SD, Perkins County, SD, Potter County, SD, Roberts County, SD, Spink County, SD, Stanley County, SD, Sully County, SD, Walworth County, SD, Ziebach County, SD, Campbell County, WY, Converse County, WY, Crook County, WY, Johnson County, WY, Niobrara County, WY, Weston County, WY

The radar

The Aberdeen radar (KABR), 161 km from the middle of the area, began a volume at 20:56 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, 8.9 hours before the alert went out and 164 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2208 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 153 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

821 
ACUS11 KWNS 282054
SWOMCD
SPC MCD 282054 
MNZ000-SDZ000-NDZ000-NEZ000-MTZ000-WYZ000-282200-

Mesoscale Discussion 0903
NWS Storm Prediction Center Norman OK
0354 PM CDT Sun May 28 2017

Areas affected...Northeastern Wyoming...southeastern
Montana...northwestern Nebraska...much of South Dakota...southern
North Dakota...and far western Minnesota

Concerning...Severe potential...Watch unlikely 

Valid 282054Z - 282200Z

Probability of Watch Issuance...20 percent

SUMMARY...Scattered convection continues to move southeastward
through the discussion area, with strong to isolated severe wind
gusts being the primary threats with this activity.

DISCUSSION...Several 40-45 knot wind gusts have been reported over
the past hour with scattered, relatively high-based thunderstorms
across the discussion area.  An isolated severe wind gusts (54
knots) was also reported at Faith, SD (KD07) in the past few
minutes.  These storms are in an environment characterized by weak
instability (generally less than 1000 J/kg MUCAPE) and strong flow
aloft (around 50 knots at 500mb) that, when mixed with scattered
updrafts and 30-45 F surface dewpoint depression, are fostering the
occasional strong wind gusts.  A WW will likely not be needed for
this activity given the ongoing sub-severe nature of most of the
gusty winds.  This activity should wane after sunset with the onset
of nocturnal boundary layer cooling.

..Cook.. 05/28/2017

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

ATTN...WFO...DLH...MPX...FGF...FSD...ABR...BIS...LBF...UNR...
CYS...BYZ...RIW...

LAT...LON   44410681 45130554 45930257 46010219 46650000 47089826
            47259732 47369623 47159516 47059481 46239445 45609463
            44769651 43420068 42570163 42140309 42470507 43230665
            44410681

Nearby

Mesoscale Discussions in South Dakota, 2017 Mesoscale Discussions in Minnesota, 2017 Mesoscale Discussions in North Dakota, 2017 Every mesoscale discussion in 2017

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.