Alert archive / Iowa / Mesoscale Discussions in 2011

Mesoscale Discussion 1104

June 5, 201125 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at Jun 5, 2011, 5:17 PM CDT for 25 counties in Iowa. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Jun 5, 2011, 5:17 PM CDT (22:17 UTC)
Expired: Jun 5, 2011, 6:45 PM CDT
In force: 88 min
Issued by: the Storm Prediction Center

All 25 counties

Benton County, IA, Black Hawk County, IA, Boone County, IA, Buchanan County, IA, Buena Vista County, IA, Butler County, IA, Calhoun County, IA, Franklin County, IA, Greene County, IA, Grundy County, IA, Hamilton County, IA, Hardin County, IA, Humboldt County, IA, Iowa County, IA, Johnson County, IA, Jones County, IA, Linn County, IA, Marshall County, IA, Palo Alto County, IA, Pocahontas County, IA, Poweshiek County, IA, Story County, IA, Tama County, IA, Webster County, IA, Wright County, IA

The radar

The Des Moines radar (KDMX), 79 km from the middle of the area, began a volume at 22:18 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 12:00Z, 10.3 hours before the alert went out and 241 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: 2556 J/kg
Mixed-layer CIN: -178 J/kg
Mixed-layer LCL: 910 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 40 m²/s²
0-3 km storm-relative helicity: 124 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 9.2

Open this sounding in Storm Lab

The text

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

362 
ACUS11 KWNS 052218
SWOMCD
SPC MCD 052217
IAZ000-052345-

MESOSCALE DISCUSSION 1104
NWS STORM PREDICTION CENTER NORMAN OK
0517 PM CDT SUN JUN 05 2011

AREAS AFFECTED...IA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 052217Z - 052345Z

MONITORING FOR AN INCREASING SURFACE BASED SEVERE TSTM RISK ACROSS
PORTIONS OF IA. A WATCH IS NOT CURRENTLY EXPECTED IN THE SHORT TERM
AMID CONSIDERABLE UNCERTAINTY...BUT CONVECTIVE TRENDS WILL CONTINUE
TO BE CLOSELY MONITORED THIS EVENING FOR A POSSIBLE WATCH.

MID LEVEL CONVECTION HAS INCREASED SINCE MID AFTERNOON ACROSS
NORTHERN/CENTRAL IA IMMEDIATELY TO THE NORTH OF NORTHWEST-SOUTHEAST
ORIENTED WARM FRONT THAT CONTINUES TO SLOWLY RETURN NORTHWARD. WHILE
THIS CONVECTION IS CURRENTLY ELEVATED ON THE IMMEDIATE COOL SIDE OF
THE FRONT...THERE IS AT LEAST SOME POTENTIAL THAT A FEW STORMS COULD
BECOME SURFACE/NEAR-SURFACE BASED THROUGH EARLY EVENING AMID
NEGLIGIBLE NEAR-BOUNDARY CINH. THE PRIMARY UNCERTAINTY RELATES TO
LIMITED LARGE SCALE FORCING FOR ASCENT/WEAK MASS CONVERGENCE AMID
SHORTWAVE RIDGING. IF SURFACE BASED DEVELOPMENT WOULD OCCUR AND/OR
IF ONGOING ACTIVITY GRADUALLY ROOTS WITHIN THE BOUNDARY LAYER NEAR
THE WARM FRONT...AMPLE EFFECTIVE SHEAR/STRONG BUOYANCY WOULD SUPPORT
SUPERCELLS CAPABLE OF LARGE HAIL AND PERHAPS EVEN A TORNADO.
OTHERWISE...EVEN WITH A RELATIVELY MODEST LOW LEVEL JET LATER
TONIGHT...ELEVATED SEVERE TSTMS MAY BE A BIT MORE PROBABLE LATER
TONIGHT ACROSS THIS REGION...WITH SOME POTENTIAL FOR SEVERE HAIL AS
ELEVATED THERMODYNAMIC PROFILES TREND MORE FAVORABLE FOR HAIL
PRODUCTION.

..GUYER.. 06/05/2011

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

ATTN...WFO...DVN...DMX...FSD...

LAT...LON   42739560 43269486 42289088 41509166 42099464 42739560

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 5, 2:52 AM CDT	Mesoscale Discussion	SPC	Adams, Appanoose, Clarke, Davis, Decatur, Des Moines and 18 more	2 hr
Jun 5, 5:00 AM CDT	Severe Thunderstorm Watch	SPC	Davis, Des Moines, Henry, Jefferson, Keokuk, Lee and 7 more	7 hr

Nearby

Mesoscale Discussions in Iowa, 2011 Every 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.