Alert archive / Wisconsin / Mesoscale Discussions in 2011

Mesoscale Discussion 1713

July 23, 201115 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 23, 2011, 5:26 PM CDT for 15 counties in Wisconsin. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued: Jul 23, 2011, 5:26 PM CDT (22:26 UTC)
Expired: Jul 23, 2011, 6:30 PM CDT
In force: 64 min
Issued by: the Storm Prediction Center

Counties Adams County, WI, Clark County, WI, Eau Claire County, WI, Jackson County, WI, Juneau County, WI, Marathon County, WI, Marquette County, WI, Monroe County, WI, Pepin County, WI, Portage County, WI, Taylor County, WI, Trempealeau County, WI, Waupaca County, WI, Waushara County, WI, Wood County, WI

The radar

The La Crosse radar (KARX), 102 km from the middle of the area, began a volume at 22:28 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 680Jul 23, 6:35 PM CDT

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 10.4 hours before the alert went out and 179 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: 2346 J/kg
Mixed-layer CIN: -15 J/kg
Mixed-layer LCL: 615 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: -42 m²/s²
0-3 km storm-relative helicity: -11 m²/s²
Significant tornado parameter: -0.3
Supercell composite: -1.9

Open this sounding in Storm Lab

The text

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

449 
ACUS11 KWNS 232226
SWOMCD
SPC MCD 232226 
WIZ000-232330-

MESOSCALE DISCUSSION 1713
NWS STORM PREDICTION CENTER NORMAN OK
0526 PM CDT SAT JUL 23 2011

AREAS AFFECTED...WRN INTO CNTRL WI

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 232226Z - 232330Z

TRENDS ARE BEING MONITORED FOR THE POSSIBILITY OF AN INCREASING
SEVERE THREAT THAT COULD REQUIRE A WW WITHIN THE NEXT HOUR OR TWO.

SUSTAINED CONVECTION IS NOW UNDERWAY NEAR/SOUTH AND WEST OF EAU
CLAIRE WI...LIKELY MOSTLY ASSOCIATED WITH LOW-LEVEL WARM ADVECTION
ALONG A REMNANT OUTFLOW BOUNDARY GENERATED BY OVERNIGHT CONVECTION. 
AN INCREASINGLY DIVERGENT UPPER FLOW FIELD IS PROBABLY CONTRIBUTING
TO DEVELOPMENT...WHICH MAY CONTINUE TO GROW UPSCALE AND ORGANIZE
DURING THE NEXT FEW HOURS.  THIS WILL BE AIDED BY LOW-LEVEL INFLOW
OF HIGH MOISTURE CONTENT AIR POSSESSING LARGE CAPE...IN THE PRESENCE
OF STRONG SHEAR BENEATH 35-40 KT NORTHWESTERLY 500 MB FLOW.  GIVEN
DEEP LAYER WESTERLY MEAN FLOW FIELDS STRENGTHENING TO AROUND 30
KTS...THIS MAY BE ACCOMPANIED BY AN INCREASING RISK FOR DAMAGING
WIND GUSTS...IN ADDITION TO AT LEAST MARGINALLY SEVERE HAIL...ACROSS
CENTRAL WISCONSIN BY 00-02Z.

..KERR.. 07/23/2011

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

ATTN...WFO...GRB...MKX...ARX...MPX...

LAT...LON   45189092 45349003 45068903 44238874 43808943 43539012
            43919089 44349154 44609195 45189092

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 22, 7:38 PM CDT	Mesoscale Discussion	SPC	Grant, Green, Lafayette	97 min
Jul 23, 4:38 AM CDT	Mesoscale Discussion	SPC	Burnett, Polk	67 min
Jul 23, 9:37 AM CDT	Mesoscale Discussion	SPC	Adams, Brown, Buffalo, Calumet, Chippewa, Clark and 25 more	53 min
Jul 23, 10:14 AM CDT	Severe Thunderstorm Watch	SPC	Adams, Buffalo, Crawford, Jackson, Juneau, La Crosse and 4 more	4 hr
Jul 23, 1:10 PM CDT	Mesoscale Discussion	SPC	Crawford, Jackson, Juneau, La Crosse, Monroe, Richland and 1 more	65 min
Jul 23, 6:36 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Clark, Columbia, Dane, Dodge, Fond du Lac and 19 more	7 hr

Nearby

Mesoscale Discussions in Wisconsin, 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.