Alert archive / Nebraska / Mesoscale Discussions in 2012

Mesoscale Discussion 977

May 30, 201226 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at May 30, 2012, 10:50 AM CDT for 26 counties in Nebraska. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued: May 30, 2012, 10:50 AM CDT (15:50 UTC)
Expired: May 30, 2012, 12:15 PM CDT
In force: 85 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 26 counties

Adams County, NE, Buffalo County, NE, Clay County, NE, Custer County, NE, Dawson County, NE, Fillmore County, NE, Franklin County, NE, Frontier County, NE, Furnas County, NE, Gosper County, NE, Hall County, NE, Hamilton County, NE, Harlan County, NE, Howard County, NE, Kearney County, NE, Lincoln County, NE, Merrick County, NE, Nuckolls County, NE, Phelps County, NE, Polk County, NE, Saline County, NE, Seward County, NE, Sherman County, NE, Thayer County, NE, Webster County, NE, York County, NE

The radar

The Grand Island radar (KUEX), 62 km from the middle of the area, began a volume at 15:52 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

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 3.8 hours before the alert went out and 144 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: 1457 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 343 m²/s²
0-3 km storm-relative helicity: 487 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.

709 
ACUS11 KWNS 301551
SWOMCD
SPC MCD 301550
NEZ000-KSZ000-301715-

MESOSCALE DISCUSSION 0977
NWS STORM PREDICTION CENTER NORMAN OK
1050 AM CDT WED MAY 30 2012

AREAS AFFECTED...CNTRL AND ERN NEB

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 301550Z - 301715Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...AN ISOLATED LARGE HAIL THREAT ASSOCIATED WITH ELEVATED
THUNDERSTORMS WILL CONTINUE TO MOVE EWD ACROSS SCNTRL NEB INTO EARLY
THIS AFTERNOON. TRENDS WILL CONTINUED TO BE MONITORED FOR THE
POSSIBILITY OF WW ISSUANCE.

DISCUSSION...A CLUSTER OF STRONG THUNDERSTORMS IS ONGOING JUST TO
THE EAST OF NORTH PLATTE NEB LOCATED ON THE ERN EDGE OF A 30 TO 35
KT LOW-LEVEL JET. THE STORMS ARE BEING SUPPORTED BY THE LOW-LEVEL
JET ALONG WITH LIFT ASSOCIATED WITH A SHORTWAVE TROUGH EVIDENT ON
WATER VAPOR IMAGERY MOVE SEWD OUT OF THE CNTRL HIGH PLAINS. THIS
ALONG WITH INCREASING INSTABILITY SHOULD RESULT IN A GRADUAL
INCREASE IN STORM COVERAGE THROUGH EARLY AFTERNOON. FORECAST
SOUNDINGS IN SCNTRL NEB FROM 15Z TO 21Z INCREASE MUCAPE VALUES TO
ABOUT 1500 J/KG WITH THE INSTABILITY MOSTLY ABOVE 700 MB. THIS
SHOULD KEEP THE STORMS ELEVATED BUT MAY HELP INCREASE STORM
INTENSITY THIS AFTERNOON. THE INSTABILITY ALONG WITH 40 TO 45 KT OF
EFFECTIVE SHEAR AND STEEP MID-LEVEL LAPSE RATES OF 8.0 C/KM SHOULD
SUPPORT A THREAT FOR ISOLATED LARGE HAIL.

..BROYLES/WEISS.. 05/30/2012

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

ATTN...WFO...OAX...TOP...GID...LBF...GLD...

LAT...LON   41120088 40430080 39969933 39799813 39859764 40279702
            40889700 41199733 41579939 41540040 41120088

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 30, 3:57 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Buffalo, Clay, Dawson, Dundy, Fillmore and 11 more	7 hr
May 30, 4:41 PM CDT	Mesoscale Discussion	SPC	Buffalo, Custer, Dawson, Frontier, Furnas, Gosper and 3 more	94 min
May 30, 6:57 PM CDT	Mesoscale Discussion	SPC	Franklin, Furnas, Harlan, Nuckolls, Thayer, Webster	2 hr

Nearby

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.