Alert archive / Wisconsin / Mesoscale Discussions in 2012

Mesoscale Discussion 557

April 15, 20127 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2012, 9:33 PM CDT for 7 counties in Wisconsin. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued
Apr 15, 2012, 9:33 PM CDT (02:33 UTC)
Expired
Apr 15, 2012, 11:00 PM CDT
In force
87 min
Issued by
the Storm Prediction Center

Counties Chippewa County, WI, Forest County, WI, Lincoln County, WI, Oneida County, WI, Price County, WI, Rusk County, WI, Taylor County, WI

The radar

The Green Bay radar (KGRB), 199 km from the middle of the area, began a volume at 02:35 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

Green Bay/Straub, WI (KGRB), launched 00:00Z, 2.6 hours before the alert went out and 201 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, Green Bay/Straub, WI at 00:00Z on 2012-04-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 744 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, Green Bay/Straub, WI at 00:00Z on 2012-04-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 329 square meters per square second.1939587897117Sfc1 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
744 J/kg
Mixed-layer CIN
-92 J/kg
Mixed-layer LCL
971 m above ground
0-6 km bulk shear
66 kt
0-1 km storm-relative helicity
329 m²/s²
0-3 km storm-relative helicity
519 m²/s²
Significant tornado parameter
1.5
Supercell composite
12.4

Open this sounding in Storm Lab

The text

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

820 
ACUS11 KWNS 160234
SWOMCD
SPC MCD 160233
WIZ000-160400-

MESOSCALE DISCUSSION 0557
NWS STORM PREDICTION CENTER NORMAN OK
0933 PM CDT SUN APR 15 2012

AREAS AFFECTED...PARTS OF NW/N CNTRL WISCONSIN

CONCERNING...TORNADO WATCH 178...

VALID 160233Z - 160400Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 178 CONTINUES.

ALTHOUGH NOT YET CERTAIN...IT IS STILL POSSIBLE THAT A NEW WW MAY BE
NEEDED ACROSS PARTS OF NORTHERN WISCONSIN...EAST OF WW 178...BY 04Z.

FORCING DOWNSTREAM OF A DEEP MID-LEVEL CYCLONE...WHICH IS IN THE
PROCESS OF LIFTING NORTHEAST OF THE MID MISSOURI VALLEY TOWARD THE
UPPER GREAT LAKES REGION LATE THIS EVENING...IS MAINTAINING A NARROW
PRE-FRONTAL LINE OF THUNDERSTORMS.  ACTIVITY HAS NOT SHOWN RECENT
SUBSTANTIVE SIGNS OF INTENSIFICATION.  BUT STRONG LOW-LEVEL WARM
ADVECTION AND CONVERGENCE ALONG THE WARM FRONTAL ZONE EXTENDING
ACROSS NORTHERN WISCONSIN STILL SEEMS TO PROVIDE AT LEAST SOME
POTENTIAL FOR AN INCREASINGLY ORGANIZED MESOSCALE CONVECTIVE SYSTEM
IN THE PRESENCE OF WEAK CONDITIONAL INSTABILITY AND STRONG VERTICAL
SHEAR.  ON THE NOSE OF A 60-70 KT 850 MB JET...IT IS STILL NOT OUT
OF THE QUESTION THAT POTENTIAL FOR CONVECTIVELY ENHANCED DAMAGING
WIND GUSTS COULD INCREASE ACROSS NORTH CENTRAL WISCONSIN...TOWARD
THE RHINELANDER AREA BY 04-05Z.

..KERR.. 04/16/2012

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

ATTN...WFO...GRB...DLH...ARX...MPX...

LAT...LON   45459178 45949073 46128982 45898889 45618849 45368860
            45318954 45029093 44909145 45459178

Nearby

Mesoscale 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.