Alert archive / Iowa / Mesoscale Discussions in 2012

Mesoscale Discussion 672

May 3, 201210 counties in Iowa; 6 counties in Missouri; Richardson County, Nebraska

The Storm Prediction Center issued this mesoscale discussion at May 3, 2012, 3:05 AM CDT for 10 counties in Iowa; 6 counties in Missouri; Richardson County, Nebraska. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued: May 3, 2012, 3:05 AM CDT (08:05 UTC)
Expired: May 3, 2012, 4:30 AM CDT
In force: 85 min
Issued by: the Storm Prediction Center

Counties Adair County, IA, Adams County, IA, Cass County, IA, Clarke County, IA, Decatur County, IA, Montgomery County, IA, Page County, IA, Ringgold County, IA, Taylor County, IA, Union County, IA, Atchison County, MO, Gentry County, MO, Harrison County, MO, Holt County, MO, Nodaway County, MO, Worth County, MO, Richardson County, NE

The radar

The Omaha radar (KOAX), 129 km from the middle of the area, began a volume at 08:08 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, 8.1 hours before the alert went out and 130 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: 2533 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 1223 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 46 m²/s²
0-3 km storm-relative helicity: 102 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.4

Open this sounding in Storm Lab

The text

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

496 
ACUS11 KWNS 030806
SWOMCD
SPC MCD 030805
MOZ000-IAZ000-NEZ000-030930-

MESOSCALE DISCUSSION 0672
NWS STORM PREDICTION CENTER NORMAN OK
0305 AM CDT THU MAY 03 2012

AREAS AFFECTED...FAR SERN NEB/SWRN IA/NWRN MO

CONCERNING...SEVERE THUNDERSTORM WATCH 228...

VALID 030805Z - 030930Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 228
CONTINUES.

SUMMARY...LIMITED/ISOLATED SEVERE THREAT WILL CONTINUE AS A BOWING
LINE OF STORMS CROSSES PARTS OF SWRN IA AND ADJACENT NWRN MO.

DISCUSSION...LATEST RADAR LOOP NOW SHOWS THE MORE INTENSE PORTION OF
THE BOWING STORM CLUSTER NOW ACROSS THE MO RIVER INTO SWRN
IA...WITHIN THE AXIS OF GREATEST INSTABILITY /1500 TO 2000 J/KG
MIXED-LAYER CAPE PER LATEST OBJECTIVE ANALYSIS/.  HOWEVER...WITH THE
LINE ITSELF MOVING ONLY AROUND 35 KT...AND WITH A DIURNALLY
STABILIZED BOUNDARY LAYER...WIND GUSTS REACHING THE SURFACE HAVE
BEEN LARGELY SUB-SEVERE.  WITH LITTLE INDICATION THAT FURTHER
INTENSIFICATION OF THE CONVECTION IS LIKELY ON THE LARGE
SCALE...DOWNSTREAM WW ISSUANCE APPEARS UNNECESSARY AS STORM NEAR THE
ERN FRINGE OF THE EXISTING WATCH.

..GOSS.. 05/03/2012

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

ATTN...WFO...DMX...EAX...OAX...

LAT...LON   40089594 40299598 40549550 41039517 41519517 41549442
            41009359 40059400 40089594

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 2, 10:43 PM CDT	Mesoscale Discussion	SPC	Harrison, Monona, Plymouth, Sioux, Woodbury	62 min
May 3, 12:50 AM CDT	Severe Thunderstorm Watch	SPC	Adams, Cass, Fremont, Mills, Montgomery, Page and 2 more	4 hr
May 3, 2:12 PM CDT	Mesoscale Discussion	SPC	Buena Vista, Calhoun, Cerro Gordo, Cherokee, Clay, Dickinson and 18 more	2 hr
May 3, 3:41 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Cass, Clarke, Fremont, Madison and 7 more	2 hr
May 3, 6:42 PM CDT	Mesoscale Discussion	SPC	Appanoose, Davis, Decatur, Des Moines, Henry, Lee and 5 more	63 min
May 2, 7:32 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Antelope, Boone, Buffalo, Burt, Butler and 36 more	6 hr

Nearby

Mesoscale Discussions in Iowa, 2012 Mesoscale Discussions in Missouri, 2012 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.