Alert archive / Iowa / Mesoscale Discussions in 2013

Mesoscale Discussion 710

May 19, 20136 counties in Illinois; 55 counties in Iowa; Clark County, Missouri

The Storm Prediction Center issued this mesoscale discussion at May 19, 2013, 7:13 PM CDT for 6 counties in Illinois; 55 counties in Iowa; Clark County, Missouri. It was in force for 62 min.

The area

The outline as issued.

The facts

Issued
May 19, 2013, 7:13 PM CDT (00:13 UTC)
Expired
May 19, 2013, 8:15 PM CDT
In force
62 min
Issued by
the Storm Prediction Center
All 62 counties

Adair County, IA, Adams County, IA, Appanoose County, IA, Audubon County, IA, Benton County, IA, Boone County, IA, Carroll County, IA, Cass County, IA, Cedar County, IA, Clarke County, IA, Clinton County, IA, Crawford County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Des Moines County, IA, Greene County, IA, Guthrie County, IA, Harrison County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monona County, IA, Monroe County, IA, Montgomery County, IA, Muscatine County, IA, Page County, IA, Polk County, IA, Pottawattamie County, IA, Poweshiek County, IA, Ringgold County, IA, Scott County, IA, Shelby County, IA, Story County, IA, Tama County, IA, Taylor County, IA, Union County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Hancock County, IL, Henderson County, IL, Henry County, IL, Mercer County, IL, Rock Island County, IL, Warren County, IL, Clark County, MO

The radar

The Des Moines radar (KDMX), 79 km from the middle of the area, began a volume at 00:16 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 00:00Z, 0.2 hours before the alert went out and 278 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 2013-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 588 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 2013-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 116 square meters per square second.1939587897Sfc1 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
588 J/kg
Mixed-layer CIN
-122 J/kg
Mixed-layer LCL
1386 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
116 m²/s²
0-3 km storm-relative helicity
207 m²/s²
Significant tornado parameter
0.1
Supercell composite
3.4

Open this sounding in Storm Lab

The text

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

833 
ACUS11 KWNS 200014
SWOMCD
SPC MCD 200013 
ILZ000-IAZ000-MOZ000-200115-

MESOSCALE DISCUSSION 0710
NWS STORM PREDICTION CENTER NORMAN OK
0713 PM CDT SUN MAY 19 2013

AREAS AFFECTED...CNTRL AND SRN IA

CONCERNING...TORNADO WATCH 183...

VALID 200013Z - 200115Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 183 CONTINUES.

SUMMARY...THE SEVERE WEATHER THREAT CONTINUES ACROSS THE WATCH AREA
WITH THE GREATEST NEAR-TERM RISK FOR TORNADOES...DAMAGING
WINDS...AND HAIL OVER CNTRL IA.

DISCUSSION...A NOTABLE INCREASE IN TSTMS HAS BEEN OBSERVED OVER THE
PAST HOUR BETWEEN OMA AND DSM...LIKELY IN RESPONSE TO THE INFLUENCE
OF A VORTICITY MAXIMUM RAPIDLY MOVING NEWD THROUGH NWRN IA.  AS OF
2355Z...THE MOST INTENSE STORM /A SUPERCELL/ WAS LOCATED OVER DALLAS
COUNTY IA WHICH HAS RECENTLY PRODUCED A TORNADO.  GIVEN A
MOIST...MODERATELY UNSTABLE AIR MASS WHICH COINCIDES WITH A
KINEMATIC ENVIRONMENT FEATURING LARGELY UNIDIRECTIONAL SLY WINDS
THROUGH THE LOWEST 4 KM AGL BEFORE VEERING SLIGHTLY TO SSWLY AND
INCREASING TO 50-60 KT IN THE UPPER TROPOSPHERE...THE THREAT FOR
EMBEDDED SUPERCELL STRUCTURES WILL PERSIST OVER CNTRL IA THIS
EVENING.  WHILE DAMAGING WINDS AND LARGE HAIL WILL BE THE PRIMARY
HAZARDS...ISOLATED TORNADOES WILL BE POSSIBLE WITH THE MOST
INTENSE/PERSISTENT SUPERCELLS.

OVER ERN IA...A CLUSTER OF STRONG TO SEVERE STORMS CONTINUES ALONG
THE MS RIVER NEAR MLI.  WHILE VERTICAL SHEAR IS COMPARATIVELY WEAKER
THAN POINTS TO THE WEST...THE 00Z DVN SOUNDING SUGGESTS THAT
SUFFICIENT INSTABILITY EXISTS TO SUPPORT AT LEAST AN ISOLATED SEVERE
WEATHER THREAT FOR THE NEXT COUPLE OF HOURS.

..MEAD.. 05/20/2013

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

ATTN...WFO...ILX...DVN...DMX...EAX...FSD...OAX...

LAT...LON   42229623 42339029 41549002 40599050 40319093 40439204
            40729316 40629534 41289577 42229623

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 19, 7:46 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Henry, Jo Daviess, Knox and 11 more59 min
May 19, 8:10 PM CDTTornado WatchSPCBoone, Bureau, Carroll, DeKalb, Fulton, Hancock and 25 more6 hr
May 19, 10:16 PM CDTMesoscale DiscussionSPCAdams, Brown, Pike59 min
May 19, 10:58 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, DeKalb, Fulton, Hancock and 22 more62 min
May 20, 3:27 PM CDTMesoscale DiscussionSPCBrown, Calhoun, Cass, Champaign, Christian, DeWitt and 21 more63 min
May 20, 5:07 PM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, Greene, Jersey and 9 more23 min
May 20, 5:24 PM CDTTornado WatchSPCAdams, Bond, Brown, Calhoun, Cass, Christian and 31 more7 hr
May 20, 6:35 PM CDTSevere Thunderstorm WatchSPCHenderson, Mercer, Warren5 hr
May 19, 8:21 PM CDTMesoscale DiscussionSPCButler, Cerro Gordo, Emmet, Franklin, Grundy, Hamilton and 9 more54 min
May 19, 9:11 PM CDTMesoscale DiscussionSPCAppanoose, Davis, Decatur, Jasper, Lucas, Mahaska and 7 more64 min
May 20, 5:38 PM CDTMesoscale DiscussionSPCBoone, Butler, Clarke, Dallas, Decatur, Franklin and 14 more67 min
May 19, 7:55 PM CDTMesoscale DiscussionSPCAndrew, Atchison, Buchanan, Clay, Clinton, DeKalb and 4 more65 min
May 19, 11:49 PM CDTMesoscale DiscussionSPCBarry, Barton, Camden, Cedar, Christian, Dade and 17 more56 min
May 20, 8:46 AM CDTMesoscale DiscussionSPCBates, Benton, Cass, Henry, Jackson, Johnson and 4 more59 min
May 20, 12:26 PM CDTMesoscale DiscussionSPCBarry, Barton, Bates, Benton, Camden, Cedar and 20 more2 hr
May 20, 12:46 PM CDTTornado WatchSPCBarry, Barton, Bates, Benton, Boone, Callaway and 41 more8 hr
May 20, 6:53 PM CDTMesoscale DiscussionSPCCarter, Dent, Douglas, Howell, Iron, Madison and 8 more67 min

Nearby

Mesoscale Discussions in Iowa, 2013Mesoscale Discussions in Illinois, 2013Mesoscale Discussions in Missouri, 2013Every mesoscale discussion in 2013

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.