Alert archive / Iowa / Mesoscale Discussions in 2012

Mesoscale Discussion 1341

July 1, 201219 counties in Iowa; 17 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at Jul 1, 2012, 3:35 PM CDT for 19 counties in Iowa; 17 counties in Minnesota. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued
Jul 1, 2012, 3:35 PM CDT (20:35 UTC)
Expired
Jul 1, 2012, 4:30 PM CDT
In force
55 min
Issued by
the Storm Prediction Center
Chance of a watch
40%
All 36 counties

Buena Vista County, IA, Calhoun County, IA, Cerro Gordo County, IA, Cherokee County, IA, Clay County, IA, Dickinson County, IA, Emmet County, IA, Franklin County, IA, Hancock County, IA, Humboldt County, IA, Kossuth County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Pocahontas County, IA, Sac County, IA, Webster County, IA, Winnebago County, IA, Wright County, IA, Blue Earth County, MN, Brown County, MN, Chippewa County, MN, Cottonwood County, MN, Faribault County, MN, Jackson County, MN, Kandiyohi County, MN, Martin County, MN, McLeod County, MN, Meeker County, MN, Murray County, MN, Nicollet County, MN, Nobles County, MN, Redwood County, MN, Renville County, MN, Sibley County, MN, Watonwan County, MN

The radar

The Sioux Falls radar (KFSD), 151 km from the middle of the area, began a volume at 20:39 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

Minneapolis, MN (KMPX), launched 12:00Z, 8.6 hours before the alert went out and 196 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, Minneapolis, MN at 12:00Z on 2012-07-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1200 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, Minneapolis, MN at 12:00Z on 2012-07-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 57 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
1200 J/kg
Mixed-layer CIN
-122 J/kg
Mixed-layer LCL
1457 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
57 m²/s²
0-3 km storm-relative helicity
62 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.

037 
ACUS11 KWNS 012036
SWOMCD
SPC MCD 012035
IAZ000-MNZ000-012130-

MESOSCALE DISCUSSION 1341
NWS STORM PREDICTION CENTER NORMAN OK
0335 PM CDT SUN JUL 01 2012

AREAS AFFECTED...NW AND N-CNTRL IA / SWRN MN

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 012035Z - 012130Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...AN ISOLD LARGE HAIL/STRONG TO SEVERE WIND THREAT SHOULD
PERSIST THIS AFTERNOON INTO THE EARLY EVENING OVER SWRN MN AND MAY
POSSIBLY DEVELOP FARTHER S OVER PORTIONS OF NRN IA -- CONTINGENT
UPON ROBUST STORM DEVELOPMENT.

DISCUSSION...LATEST SURFACE MESOANALYSIS PLACES A SLOWLY RETREATING
FRONTAL ZONE ACROSS NRN IA EXTENDING WNWWD INTO SWRN MN AND ERN SD.
A FEW STORMS HAVE DEVELOPED OVER THE PAST FEW HOURS NEAR THE FRONT
IN SWRN MN WITHIN A CU FIELD.  A REMNANT MCV IS LOCATED NEAR SUX BUT
UNCERTAINTY REMAINS REGARDING ITS ROLE IN PROMOTING ISOLD STORM
INITIATION AND SUBSEQUENT ROBUST UPDRAFT DEVELOPMENT IN LOCALES
FARTHER S ACROSS NWRN AND N-CNTRL IA.  IN THE MEANTIME...STRONG
POTENTIAL INSTABILITY /3000 J/KG MLCAPE PER OBJECTIVE ANALYSIS/
INVOF THE FRONT WILL ACT TO AT LEAST SUPPORT STRONG TO SEVERE
MULTICELLS CAPABLE OF A LARGE HAIL/WIND DAMAGE THREAT.

..SMITH/THOMPSON.. 07/01/2012

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

ATTN...WFO...MPX...DMX...FSD...

LAT...LON   42129498 42749613 45079572 45299454 42739294 42129498

Nearby

Mesoscale Discussions in Iowa, 2012Mesoscale Discussions in Minnesota, 2012Every 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.