Alert archive / Iowa / Mesoscale Discussions in 2012

Mesoscale Discussion 367

March 27, 20127 counties in Illinois; 23 counties in Iowa; 7 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Mar 27, 2012, 3:58 PM CDT for 7 counties in Illinois; 23 counties in Iowa; 7 counties in Wisconsin. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Mar 27, 2012, 3:58 PM CDT (20:58 UTC)
Expired
Mar 27, 2012, 6:00 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 37 counties

Benton County, IA, Cedar County, IA, Clayton County, IA, Clinton County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Mahaska County, IA, Muscatine County, IA, Scott County, IA, Van Buren County, IA, Wapello County, IA, Washington County, IA, Carroll County, IL, Henderson County, IL, Jo Daviess County, IL, Mercer County, IL, Rock Island County, IL, Stephenson County, IL, Whiteside County, IL, Crawford County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Lafayette County, WI, Richland County, WI, Sauk County, WI

The radar

The Quad Cities radar (KDVN), 77 km from the middle of the area, began a volume at 21:02 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

Davenport, (KDVN), launched 12:00Z, 9.0 hours before the alert went out and 81 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 2012-03-27Temperature 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 2012-03-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 676 square meters per square second.19395878Sfc1 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
1061 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
676 m²/s²
0-3 km storm-relative helicity
729 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

058 
ACUS11 KWNS 272058
SWOMCD
SPC MCD 272058 
WIZ000-ILZ000-IAZ000-MOZ000-272300-

MESOSCALE DISCUSSION 0367
NWS STORM PREDICTION CENTER NORMAN OK
0358 PM CDT TUE MAR 27 2012

AREAS AFFECTED...EASTERN IA/SOUTHERN WI/NORTHWEST IL/NORTHEAST MO

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 272058Z - 272300Z

MONITORING FOR AN INCREASING SEVERE THREAT...WHICH COULD INITIALLY
OCCUR ACROSS PORTIONS OF THE REGION INTO THE 23Z-02Z TIME FRAME. A
WATCH MAY BE NEEDED THIS EVENING.

A WEAK COLD FRONT CONTINUES TO MAKE A GRADUAL EASTWARD PROGRESSION
TOWARD THE UPPER MS RIVER VALLEY AT MID AFTERNOON WITHIN A
NORTHEAST-SOUTHWEST ORIENTED CORRIDOR FROM WESTERN WI TO
SOUTH-CENTRAL IA/NORTHWEST MO. MODEST LOW-LEVEL MOISTURE...WITH
SURFACE DEWPOINTS GENERALLY IN THE 50S F...OTHERWISE CONTINUES TO
STEADILY INCREASE WITH NORTH-NORTHEASTWARD EXTENT IMMEDIATELY AHEAD
OF THE FRONT. NEAR/AHEAD OF THIS FRONT...LOW-LEVEL CONVERGENCE
REMAINS MODEST AS WINDS AT/JUST ABOVE THE SURFACE HAVE CONTINUED TO
VEER PER SURFACE OBSERVATIONS/REGIONAL DERIVED WIND DATA.
HOWEVER...A LOW-AMPLITUDE EASTWARD-MOVING SHORTWAVE TROUGH/SPEED MAX
CURRENTLY OVER SD/SOUTHWEST MN PER WATER VAPOR IMAGERY MAY PROVIDE
AN IMPETUS FOR AT LEAST ISOLATED DEEP CONVECTIVE DEVELOPMENT OVER
THE NEXT FEW HOURS...AS INHIBITION OTHERWISE CONTINUES TO ERODE
WITHIN THE MODESTLY MOIST NEAR-FRONTAL WARM SECTOR.

WHILE CONFIDENCE IN CONVECTIVE DETAILS ARE NOT PARTICULARLY
HIGH...AN ASSORTMENT OF NUMERICAL GUIDANCE INCLUDING A NUMBER OF 15Z
SREF MEMBERS IMPLY THAT SUCH DEVELOPMENT WILL BE MORE PROBABLE INTO
THE 23Z-02Z TIME FRAME ESPECIALLY ACROSS FAR EASTERN IA/FAR
NORTHWEST IL AND ADJACENT PARTS OF NORTHERN MO...ALTHOUGH A GRADUAL
DEEPENING OF THE CUMULUS FIELD HAS BEEN NOTED AS FAR NORTHEAST AS
SOUTHWEST WI AT MID-AFTERNOON. IF/WHERE DEEP CONVECTIVE DEVELOPMENT
DOES OCCUR INTO THIS EVENING...STRONG EFFECTIVE SHEAR /45-50 KT OR
GREATER/ WILL SUPPORT ORGANIZED/SUSTAINED STORMS INCLUDING INITIAL
MODE SUPERCELLS CAPABLE OF SEVERE HAIL/PERHAPS A TORNADO...WITH
DAMAGING WINDS A POSSIBILITY AS WELL. CONVECTIVE TRENDS WILL
CONTINUE TO BE MONITORED FOR A POSSIBLE WATCH.

..GUYER.. 03/27/2012

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

ATTN...WFO...LOT...MKX...DVN...ARX...DMX...

LAT...LON   41099298 42569163 43789064 43698967 42328921 40329133
            41099298

Nearby

Mesoscale Discussions in Iowa, 2012Mesoscale Discussions in Illinois, 2012Mesoscale Discussions in Wisconsin, 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.