Alert archive / Iowa / Mesoscale Discussions in 2011

Mesoscale Discussion 1013

May 29, 20116 states

The Storm Prediction Center issued this mesoscale discussion at May 29, 2011, 8:39 AM CDT for 6 states. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued
May 29, 2011, 8:39 AM CDT (13:39 UTC)
Expired
May 29, 2011, 9:45 AM CDT
In force
66 min
Issued by
the Storm Prediction Center
All 87 counties

Appanoose County, IA, Benton County, IA, Buchanan County, IA, Cedar County, IA, Clarke County, IA, Clinton County, IA, Davis County, IA, Delaware County, IA, Des Moines County, IA, Dubuque 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, Mahaska County, IA, Marion County, IA, Monroe County, IA, Muscatine County, IA, Poweshiek County, IA, Scott County, IA, Tama County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, McHenry County, IL, Mercer County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Warren County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Lake County, IN, LaPorte County, IN, Marshall County, IN, Porter County, IN, Saint Joseph County, IN, Starke County, IN, Allegan County, MI, Berrien County, MI, Cass County, MI, Van Buren County, MI, Clark County, MO, Putnam County, MO, Schuyler County, MO, Scotland County, MO, Green County, WI, Kenosha County, WI, Lafayette County, WI, Milwaukee County, WI, Racine County, WI, Rock County, WI, Walworth County, WI

The radar

The Quad Cities radar (KDVN), 56 km from the middle of the area, began a volume at 13:42 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

Davenport, (KDVN), launched 12:00Z, 1.7 hours before the alert went out and 49 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, Davenport, at 12:00Z on 2011-05-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Davenport, at 12:00Z on 2011-05-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
995 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
291 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

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

704 
ACUS11 KWNS 291340
SWOMCD
SPC MCD 291339
MIZ000-INZ000-ILZ000-WIZ000-IAZ000-MOZ000-291445-

MESOSCALE DISCUSSION 1013
NWS STORM PREDICTION CENTER NORMAN OK
0839 AM CDT SUN MAY 29 2011

AREAS AFFECTED...ERN IA...NRN MO...NRN IL...SRN WI...NRN IND...SRN
LAKE MI...SW LOWER MI

CONCERNING...SEVERE POTENTIAL...WATCH NEEDED SOON

VALID 291339Z - 291445Z

A SEVERE THREAT WILL DEVELOP AS A LINE OF SEVERE STORMS DEVELOPS AND
INCREASES IN INTENSITY. THE MAIN THREAT WITH THE LINE SHOULD BE WIND
DAMAGE BUT HAIL WILL ALSO BE POSSIBLE. WW ISSUANCE WILL BE NEEDED
ACROSS THE REGION SHORTLY.

A LINE OF STRONG TO SEVERE THUNDERSTORMS IS LOCATED ALONG THE NRN
EDGE OF MODERATE INSTABILITY WHERE MESOANALYSIS ESTIMATES MLCAPE
VALUES ARE IN THE 500 TO 1000 J/KG RANGE. THE INSTABILITY GRADIENT
EXTENDS ENEWD ACROSS CNTRL IL INTO NRN IND AND THE LINE SHOULD
PERSIST THROUGH THIS AFTERNOON. A ENEWD STORM MOTION AROUND 40 KT
SHOULD RESULT IN A WIND DAMAGE THREAT AS THE LINE MOVES EWD INTO THE
CHICAGO AREA EARLY THIS AFTERNOON. AN ENHANCED WIND DAMAGE THREAT
COULD EXIST ESPECIALLY IF A WELL-DEVELOPED BOWING-LINE SEGMENT CAN
ORGANIZE. HAIL WILL ALSO BE POSSIBLE WITH THE MORE INTENSE CELLS
WITH THE LINE.

..BROYLES.. 05/29/2011

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

ATTN...WFO...IWX...GRR...LOT...ILX...MKX...LSX...DVN...ARX...
DMX...EAX...

LAT...LON   41479363 40969388 40489357 40259241 40569043 40888848
            41228622 41828574 42358577 42888619 43048714 42978842
            42779084 42449239 41479363

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 29, 8:53 AM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 33 more6 hr
May 29, 11:59 AM CDTMesoscale DiscussionSPCCook, DeKalb, DuPage, Ford, Grundy, Iroquois and 9 more61 min
May 29, 12:29 PM CDTTornado WatchSPCAdams, Allen, Blackford, Cass, DeKalb, Elkhart and 18 more7 hr
May 29, 3:17 PM CDTMesoscale DiscussionSPCAllen, DeKalb, LaGrange, Noble, Steuben88 min
May 29, 1:41 AM CDTMesoscale DiscussionSPCAppanoose, Davis, Decatur, Jefferson, Monroe, Page and 5 more2 hr
May 29, 4:36 PM CDTMesoscale DiscussionSPCFremont, Mills, Page24 min
May 29, 5:51 PM CDTMesoscale DiscussionSPCGenesee, Lapeer, Lenawee, Livingston, Macomb, Monroe and 8 more54 min

Nearby

Mesoscale Discussions in Iowa, 2011Mesoscale Discussions in Illinois, 2011Mesoscale Discussions in Wisconsin, 2011Every mesoscale discussion in 2011

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.