Alert archive / Nebraska / Mesoscale Discussions in 2016

Mesoscale Discussion 992

June 20, 201613 counties in Iowa; 45 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jun 20, 2016, 12:51 PM CDT for 13 counties in Iowa; 45 counties in Nebraska. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued
Jun 20, 2016, 12:51 PM CDT (17:51 UTC)
Expired
Jun 20, 2016, 2:45 PM CDT
In force
114 min
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 58 counties

Adair County, IA, Adams County, IA, Audubon County, IA, Cass County, IA, Fremont County, IA, Harrison County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Shelby County, IA, Taylor County, IA, Union County, IA, Adams County, NE, Boone County, NE, Buffalo County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Custer County, NE, Dawson County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Franklin County, NE, Frontier County, NE, Furnas County, NE, Garfield County, NE, Gosper County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Harlan County, NE, Howard County, NE, Kearney County, NE, Lancaster County, NE, Lincoln County, NE, Logan County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Otoe County, NE, Phelps County, NE, Platte County, NE, Polk County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Sherman County, NE, Stanton County, NE, Valley County, NE, Washington County, NE, Wheeler County, NE, York County, NE

The radar

The Omaha radar (KOAX), 75 km from the middle of the area, began a volume at 17:51 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.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 5.9 hours before the alert went out and 75 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, Omaha, NE at 12:00Z on 2016-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1650 joules per kilogram.LCLLFCEL10008507005003002001001 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, Omaha, NE at 12:00Z on 2016-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 188 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
1650 J/kg
Mixed-layer CIN
-104 J/kg
Mixed-layer LCL
1054 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
188 m²/s²
0-3 km storm-relative helicity
147 m²/s²
Significant tornado parameter
0.5
Supercell composite
4.5

Open this sounding in Storm Lab

The text

As transmitted.

675 
ACUS11 KWNS 201752
SWOMCD
SPC MCD 201751 
IAZ000-MOZ000-NEZ000-201945-

MESOSCALE DISCUSSION 0992
NWS STORM PREDICTION CENTER NORMAN OK
1251 PM CDT MON JUN 20 2016

AREAS AFFECTED...CNTRL/ERN NEB...WRN IA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 201751Z - 201945Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED SEVERE HAIL IS POSSIBLE THIS AFTERNOON WITH
ELEVATED THUNDERSTORMS. WATCH ISSUANCE IS CONSIDERED UNLIKELY DUE TO
LIMITED COVERAGE.

DISCUSSION...AT 1745Z...THUNDERSTORMS ARE SLOWLY INCREASING IN
COVERAGE AND INTENSITY NORTH OF A SWD-MOVING COLD FRONT THAT IS
MOVING INTO SRN NEB/IA AND NRN KS/MO. FORECAST SOUNDINGS AND THE OAX
VWP INDICATE THAT THIS ACTIVITY IS LIKELY ROOTED AROUND 800 MB. RICH
MOISTURE ABOVE THE FRONTAL SURFACE IS SUPPORTING 1000-1500 J/KG OF
MUCAPE...WHILE MODERATE MIDLEVEL WLY FLOW IS SUPPORTING EFFECTIVE
SHEAR OF 25-35 KTS...WHICH IS SUFFICIENT TO SUPPORT SOME STORM
ORGANIZATION AND LONGEVITY. WHILE RELATIVELY WEAK MIDLEVEL LAPSE
RATES WILL TEMPER THE OVERALL SEVERE HAIL RISK...A FEW INSTANCES OF
HAIL IN EXCESS OF 1 INCH IN DIAMETER WILL BE POSSIBLE WITH THE
STRONGEST UPDRAFTS. AT THIS TIME...THE MAGNITUDE AND COVERAGE OF THE
RISK APPEARS TOO LIMITED FOR WATCH ISSUANCE.

..DEAN/GUYER.. 06/20/2016

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

ATTN...WFO...DMX...EAX...OAX...GID...LBF...GLD...

LAT...LON   40569582 40319751 40040004 41050092 41630045 41769999
            42039906 42029767 42069619 41799472 41359415 40789417
            40649498 40569582

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 20, 3:07 PM CDTMesoscale DiscussionSPCAppanoose, Davis, Decatur, Des Moines, Henry, Lee and 2 more83 min
Jun 20, 4:10 PM CDTSevere Thunderstorm WatchSPCAdair, Adams, Appanoose, Cass, Clarke, Davis and 17 more5 hr
Jun 20, 6:42 PM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Audubon, Cass, Clarke and 22 more63 min

Nearby

Mesoscale Discussions in Nebraska, 2016Mesoscale Discussions in Iowa, 2016Every mesoscale discussion in 2016

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.