Alert archive / Illinois / Mesoscale Discussions in 2014

Mesoscale Discussion 331

April 13, 201411 counties in Illinois; 4 counties in Iowa; 6 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Apr 13, 2014, 1:37 AM CDT for 11 counties in Illinois; 4 counties in Iowa; 6 counties in Wisconsin. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Apr 13, 2014, 1:37 AM CDT (06:37 UTC)
Expired: Apr 13, 2014, 3:00 AM CDT
In force: 83 min
Issued by: the Storm Prediction Center

All 21 counties

Clinton County, IA, Jackson County, IA, Muscatine County, IA, Scott County, IA, Boone County, IL, Carroll County, IL, DeKalb County, IL, Jo Daviess County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Rock Island County, IL, Stephenson County, IL, Whiteside County, IL, Winnebago County, IL, Green County, WI, Kenosha County, WI, Lafayette County, WI, Milwaukee County, WI, Rock County, WI, Walworth County, WI

The radar

The Quad Cities radar (KDVN), 85 km from the middle of the area, began a volume at 06:39 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

Davenport, (KDVN), launched 00:00Z, 6.6 hours before the alert went out and 80 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: 661 J/kg
Mixed-layer CIN: -152 J/kg
Mixed-layer LCL: 1978 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 34 m²/s²
0-3 km storm-relative helicity: 80 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

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

450 
ACUS11 KWNS 130638
SWOMCD
SPC MCD 130637 
ILZ000-WIZ000-IAZ000-130800-

MESOSCALE DISCUSSION 0331
NWS STORM PREDICTION CENTER NORMAN OK
0137 AM CDT SUN APR 13 2014

AREAS AFFECTED...FAR EAST CENTRAL IA/NRN IL/SRN WI

CONCERNING...SEVERE THUNDERSTORM WATCH 72...

VALID 130637Z - 130800Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 72
CONTINUES.

SUMMARY...A THREAT FOR STRONG TO LOCALLY SEVERE WINDS SHOULD BE
MAINLY CONFINED ACROSS FAR EAST CENTRAL IA INTO FAR NRN IL...AND
PERHAPS INTO ADJACENT FAR SRN WI THROUGH 07-09Z.  COUNTIES IN THE
WAKE OF THE ENEWD MOVING BOWING LINE SEGMENT...NOW EXTENDING FROM 5
WSW DBQ TO 20 WNW MLI...CAN BE CLEARED FROM WW 72.  MEANWHILE...
EXPECTED ENEWD TRACK OF THIS BOW SHOULD REMAIN WITHIN THE CURRENT
NRN IL COUNTIES THAT RESIDE IN WW 72. HOWEVER...A FEW ADDITIONAL
COUNTIES MAY NEED TO BE ADDED...IF THIS BOW TAKES A MORE EWD
TRAJECTORY.

DISCUSSION...EARLY OVERNIGHT SURFACE ANALYSIS SHOWED A COLD FRONT
EXTENDING WWD ACROSS FAR NRN IL...JUST S OF THE IL/WI BORDER...INTO
FAR NWRN IL WHERE IT MERGED WITH A SWD MOVING NE-SW ORIENTED
CONVECTIVE OUTFLOW BOUNDARY EXTENDING INTO FAR EAST CENTRAL IA.  A
FAST-MOVING /NEAR 50 KT/ BOWING LINE SEGMENT...CURRENTLY MOVING INTO
FAR EAST CENTRAL IA SHOULD CONTINUE TO TRACK ENEWD AND POSSIBLY MORE
EWD THROUGH 07-09Z AS IT ADVANCES INTO FAR NRN IL.  WHILE THE
STRONGEST REFLECTIVITY WITHIN THIS BOW WAS LOCATED N OF THE
AFOREMENTIONED CONVECTIVE OUTFLOW...DVN WSR-88D SHOWED 60 KT WSWLY
WINDS AT 0.5 KM AGL WHICH COULD STILL BE TRANSFERRED TO THE SURFACE.
GIVEN THE POSITION OF THE OUTFLOW BOUNDARY AND COLD FRONT...THE
GREATEST SEVERE WIND THREAT THROUGH 08-09Z SHOULD BE CONFINED TO FAR
NRN IL AS THE BOWING LINE MOVES ENEWD FROM FAR EAST CENTRAL IA INVOF
THE COLD FRONT.

..PETERS.. 04/13/2014

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

ATTN...WFO...LOT...MKX...DVN...

LAT...LON   42379091 42519035 42928993 42988875 43008780 42538774
            42178798 41808885 41528972 41309033 41319107 41459120
            41769093 42009091 42379091

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 12, 9:08 PM CDT	Mesoscale Discussion	SPC	Boone, Carroll, Jo Daviess, McHenry, Ogle, Stephenson and 1 more	67 min
Apr 12, 9:38 PM CDT	Severe Thunderstorm Watch	SPC	Boone, Carroll, Jo Daviess, Lake, McHenry, Ogle and 4 more	6 hr
Apr 12, 11:26 PM CDT	Mesoscale Discussion	SPC	Boone, Carroll, Jo Daviess, McHenry, Ogle, Rock Island and 3 more	64 min
Apr 13, 7:41 AM CDT	Mesoscale Discussion	SPC	Adams, Brown, Calhoun, Greene, Hancock, Henderson and 5 more	2 hr
Apr 12, 9:12 PM CDT	Mesoscale Discussion	SPC	Decatur, Page, Ringgold, Taylor	63 min
Apr 13, 1:16 PM CDT	Mesoscale Discussion	SPC	Buena Vista, Carroll, Cherokee, Crawford, Harrison, Ida and 7 more	6 hr

Nearby

Mesoscale Discussions in Illinois, 2014 Mesoscale Discussions in Wisconsin, 2014 Mesoscale Discussions in Iowa, 2014 Every mesoscale discussion in 2014

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.