Alert archive / South Dakota / Mesoscale Discussions in 2012

Mesoscale Discussion 835

May 19, 2012Brown County, Keya Paha County, Nebraska; 18 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 19, 2012, 12:51 AM CDT for Brown County, Keya Paha County, Nebraska; 18 counties in South Dakota. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: May 19, 2012, 12:51 AM CDT (05:51 UTC)
Expired: May 19, 2012, 2:15 AM CDT
In force: 84 min
Issued by: the Storm Prediction Center
Chance of a watch: 5%

Counties Brown County, NE, Keya Paha County, NE, Beadle County, SD, Brule County, SD, Buffalo County, SD, Edmunds County, SD, Faulk County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jerauld County, SD, Jones County, SD, Lyman County, SD, McPherson County, SD, Mellette County, SD, Potter County, SD, Spink County, SD, Sully County, SD, Todd County, SD, Tripp County, SD

The radar

The Aberdeen radar (KABR), 168 km from the middle of the area, began a volume at 05:52 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 00:00Z, 5.9 hours before the alert went out and 125 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: 180 J/kg
Mixed-layer CIN: -118 J/kg
Mixed-layer LCL: 3219 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: -2 m²/s²
0-3 km storm-relative helicity: 20 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

832 
ACUS11 KWNS 190551
SWOMCD
SPC MCD 190551 
SDZ000-NEZ000-190715-

MESOSCALE DISCUSSION 0835
NWS STORM PREDICTION CENTER NORMAN OK
1251 AM CDT SAT MAY 19 2012

AREAS AFFECTED...CNTRL SD...NRN NEB

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 190551Z - 190715Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A HAIL THREAT AND POTENTIAL FOR A FEW STRONG WIND GUSTS
WILL EXIST WITH THE MORE INTENSE CELLS ACROSS CNTRL SD AND NRN NEB
EARLY THIS MORNING. THE THREAT SHOULD REMAIN MARGINAL AND WW
ISSUANCE IS NOT EXPECTED.

DISCUSSION...SEVERAL CLUSTERS OF STRONG THUNDERSTORMS ARE ONGOING
FROM NRN NEB NWD INTO NCNTRL SD. THE CONVECTION IS LOCATED ALONG AN
AXIS OF ELEVATED INSTABILITY WHERE MUCAPE VALUES ARE ESTIMATED IN
THE 1000 TO 1500 J/KG RANGE. THIS COMBINED WITH EFFECTIVE SHEAR OF
25 TO 35 KT EVIDENT ON FORECAST SOUNDINGS AND 700 TO 500 MB LAPSE
RATES OF 8.5 C/KM SHOULD SUPPORT AN ISOLATED HAIL THREAT. ALTHOUGH
THE AIRMASS IN THE BOUNDARY LAYER IS QUITE STABLE...A FEW STRONG
WIND GUSTS COULD OCCUR ESPECIALLY WITH SHORT LINE SEGMENTS THAT CAN
DRIVE A WEDGE DOWN THROUGH THE COOLER AIR IN THE BOUNDARY LAYER.

..BROYLES.. 05/19/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FSD...ABR...LBF...UNR...

LAT...LON   45599862 45829907 45879943 45769968 45539986 45210002
            44490056 43880091 43270111 42380083 42040033 41980002
            42389948 43289928 44039853 44799794 45599862

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 19, 1:37 PM CDT	Mesoscale Discussion	SPC	Chase, Dundy, Hayes, Hitchcock, Red Willow	113 min
May 19, 2:36 PM CDT	Mesoscale Discussion	SPC	Butler, Cass, Clay, Douglas, Fillmore, Gage and 14 more	84 min
May 19, 3:25 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Burt, Butler, Cass, Clay, Colfax and 25 more	7 hr
May 19, 5:41 PM CDT	Mesoscale Discussion	SPC	Burt, Butler, Cass, Colfax, Cuming, Dakota and 20 more	64 min
May 19, 6:52 PM CDT	Severe Thunderstorm Watch	SPC	Dakota	5 hr
May 18, 7:22 PM CDT	Mesoscale Discussion	SPC	Brule, Buffalo, Hand, Hughes, Hyde, Jackson and 5 more	2 hr

Nearby

Mesoscale Discussions in South Dakota, 2012 Mesoscale Discussions in Nebraska, 2012 Every mesoscale discussion in 2012

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.