Alert archive / Iowa / Mesoscale Discussions in 2016

Mesoscale Discussion 735

May 25, 201626 counties in Iowa; 21 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at May 25, 2016, 11:34 PM CDT for 26 counties in Iowa; 21 counties in Nebraska. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued
May 25, 2016, 11:34 PM CDT (04:34 UTC)
Expired
May 26, 2016, 1:00 AM CDT
In force
86 min
Issued by
the Storm Prediction Center
All 47 counties

Audubon County, IA, Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cherokee County, IA, Clay County, IA, Crawford County, IA, Dickinson County, IA, Emmet County, IA, Harrison County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Mills County, IA, Monona County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Pottawattamie County, IA, Sac County, IA, Shelby County, IA, Sioux County, IA, Webster County, IA, Woodbury County, IA, Burt County, NE, Butler County, NE, Cass County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Lancaster County, NE, Platte County, NE, Polk County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, York County, NE

The radar

The Omaha radar (KOAX), 75 km from the middle of the area, began a volume at 04:37 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

Omaha, NE (KOAX), launched 00:00Z, 4.6 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 00:00Z on 2016-05-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1496 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 00:00Z on 2016-05-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 4 square meters per square second.19395878Sfc1 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
1496 J/kg
Mixed-layer CIN
-40 J/kg
Mixed-layer LCL
1029 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
4 m²/s²
0-3 km storm-relative helicity
150 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.9

Open this sounding in Storm Lab

The text

As transmitted.

945 
ACUS11 KWNS 260434
SWOMCD
SPC MCD 260434 
MNZ000-IAZ000-NEZ000-SDZ000-260600-

MESOSCALE DISCUSSION 0735
NWS STORM PREDICTION CENTER NORMAN OK
1134 PM CDT WED MAY 25 2016

AREAS AFFECTED...PORTIONS ERN NEB...WRN IA...EXTREME SRN MN.

CONCERNING...SEVERE THUNDERSTORM WATCH 211...

VALID 260434Z - 260600Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 211
CONTINUES.

SUMMARY...POTENTIAL FOR SPORADIC DAMAGING...ISOLATED SEVERE GUSTS
AND MARGINALLY SVR HAIL WILL PERSIST ACROSS ERN PORTIONS WW...AND
MAY SHIFT EWD ACROSS PORTIONS SERN NEB AND WRN IA DURING NEXT 2-3
HOURS.  CONVECTIVE/INSTABILITY TRENDS WILL BE MONITORED FOR
POSSIBILITY OF THREAT EXTENDING E OF CURRENT WW.

DISCUSSION...BKN/WAVY SQUALL LINE IS EVIDENT AS OF 430Z FROM SWRN
CORNER OF MN TO CLAY COUNTY NEB.  THOUGH GUST FRONT HAS REMAINED AS
MUCH AS 10-15 NM AHEAD OF E-CENTRAL/S-CENTRAL NEB
SEGMENT...SUFFICIENT DOWNWARD MOMENTUM TRANSFER HAS OCCURRED TO
PRODUCE ISOLATED SVR GUSTS.  FOR EXAMPLE...52-KT GUST WAS MEASURED
AT HSI AT 0339Z.  MOISTURE TRANSPORT AND LOW-LEVEL WAA WILL PERSIST
FOR AT LEAST A FEW MORE HOURS AHEAD OF THIS COMPLEX...ENABLING
FORCED ASCENT OF FAVORABLY BUOYANT NEAR-SFC AIR ATOP GUST FRONT AND
INTO UPDRAFTS.  GRADUALLY INCREASING WARM-SECTOR SBCINH IS EXPECTED
THROUGH REMAINDER OF TONIGHT...HOWEVER MUCAPE SHOULD CONTINUE TO
RANGE FROM ABOUT 1000 J/KG OVER SRN MN TO 2500 J/KG OVER SERN
NEB...AMIDST ROUGHLY 40-KT SWLY EFFECTIVE-SHEAR VECTORS...BASED ON
MODIFIED RAOBS AND MODEL SOUNDINGS.  ISOLATED SVR HAIL ALSO MAY
OCCUR WITH ANY TSTMS THAT DEVELOP BEHIND OUTFLOW BOUNDARY OVER SRN
NEB...AND ISOLATED SMALL CLUSTER OF TSTMS OVER EXTREME SRN MN.

..EDWARDS.. 05/26/2016

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

ATTN...WFO...MPX...DMX...FSD...OAX...GID...

LAT...LON   40619796 41819787 42079717 42569683 42639648 43039628
            43449619 43759400 42259419 40939560 40239704 40619796

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 25, 8:36 PM CDTSevere Thunderstorm WatchSPCCherokee, Ida, Monona, O'Brien, Plymouth, Sioux and 1 more5 hr
May 26, 10:33 AM CDTMesoscale DiscussionSPCFremont, Page, Taylor57 min
May 26, 1:53 PM CDTTornado WatchSPCFremont, Harrison, Mills, Montgomery, Page, Pottawattamie and 1 more8 hr
May 26, 2:09 PM CDTTornado WatchSPCAdair, Adams, Audubon, Cass, Clarke, Dallas and 10 more8 hr
May 26, 5:27 PM CDTMesoscale DiscussionSPCFremont, Page, Taylor63 min
May 25, 7:23 PM CDTMesoscale DiscussionSPCDawson, Frontier, Furnas, Gosper, Hayes, Hitchcock and 3 more97 min
May 26, 6:46 PM CDTMesoscale DiscussionSPCDundy, Hitchcock, Red Willow59 min

Nearby

Mesoscale Discussions in Iowa, 2016Mesoscale Discussions in Nebraska, 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.