Alert archive / Wisconsin / Mesoscale Discussions in 2012

Mesoscale Discussion 1385

July 4, 2012Ramsey County, Washington County, Minnesota; 15 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 4, 2012, 6:53 AM CDT for Ramsey County, Washington County, Minnesota; 15 counties in Wisconsin. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Jul 4, 2012, 6:53 AM CDT (11:53 UTC)
Expired: Jul 4, 2012, 8:30 AM CDT
In force: 97 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Ramsey County, MN, Washington County, MN, Adams County, WI, Buffalo County, WI, Chippewa County, WI, Clark County, WI, Dunn County, WI, Eau Claire County, WI, Jackson County, WI, Marathon County, WI, Pepin County, WI, Pierce County, WI, Portage County, WI, Saint Croix County, WI, Taylor County, WI, Trempealeau County, WI, Wood County, WI

The radar

The La Crosse radar (KARX), 99 km from the middle of the area, began a volume at 11:53 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

Minneapolis, MN (KMPX), launched 00:00Z, 11.9 hours before the alert went out and 166 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: 3627 J/kg
Mixed-layer CIN: -100 J/kg
Mixed-layer LCL: 1378 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 50 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 7.0

Open this sounding in Storm Lab

The text

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

531 
ACUS11 KWNS 041154
SWOMCD
SPC MCD 041153
WIZ000-MNZ000-041330-

MESOSCALE DISCUSSION 1385
NWS STORM PREDICTION CENTER NORMAN OK
0653 AM CDT WED JUL 04 2012

AREAS AFFECTED...SOUTHEAST MN TO WESTERN/CENTRAL WI

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 041153Z - 041330Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...SOME SEVERE HAIL POTENTIAL WILL EXIST THIS MORNING ACROSS
SOUTHEAST MN INTO WESTERN/CENTRAL WI. CURRENT THINKING IS THAT THE
OVERALL SCENARIO SHOULD REMAIN ISOLATED/MARGINAL...SUCH THAT A
SEVERE TSTM WATCH IS NOT ANTICIPATED AT THIS TIME.

DISCUSSION...ISOLATED ELEVATED TSTMS HAVE DEVELOPED/INCREASED IN
INTENSITY EARLY THIS MORNING EAST-SOUTHEAST OF THE TWIN CITIES METRO
IN VICINITY OF THE WI/MN BORDER AREA AS OF 1145Z. THIS ACTIVITY IS
OCCURRING NEAR AND JUST NORTH-NORTHEAST OF A WARM FRONT ACROSS THE
REGION...AND APPEARS TO ALSO COINCIDE WITH A WEAK EASTERN BRANCH OF
THE LOW LEVEL JET AND ASSOCIATED ELEVATED MOISTURE TRANSPORT NEAR
THE CREST OF THE PLAINS/MO VALLEY UPPER RIDGE. IT SEEMS LIKELY THAT
THESE STORMS ARE BASED AROUND 800-750 MB OR ABOVE...WITH STEEP
MID-LEVEL LAPSE RATES /7.8 C PER KM/ AND AMPLE ELEVATED INSTABILITY
SAMPLED BY THE 12Z MINNEAPOLIS OBSERVED SOUNDING. WHILE OVERALL
FORCING FOR ASCENT AND LOW-MID TROPOSPHERIC FLOW COINCIDENT WITH THE
CLOUD BEARING LAYER ARE MODEST FACTORS...THE DEGREE OF LAPSE
RATES/BUOYANCY ALOFT MAY ALLOW FOR ISOLATED BOUTS OF AT LEAST
NEAR-SEVERE HAIL AS TSTMS SPREAD EASTWARD FROM FAR SOUTHEAST MN INTO
WESTERN/CENTRAL WI.

..GUYER/MEAD.. 07/04/2012

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

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

LAT...LON   44839358 45439225 45148952 43818926 44059086 44839358

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 4, 6:25 AM CDT	Mesoscale Discussion	SPC	Kittson, Lake of the Woods, Marshall, Pennington, Polk, Red Lake and 1 more	95 min
Jul 4, 8:10 AM CDT	Severe Thunderstorm Watch	SPC	Beltrami, Clearwater, Kittson, Lake of the Woods, Marshall, Pennington and 3 more	6 hr
Jul 4, 12:25 PM CDT	Mesoscale Discussion	SPC	Aitkin, Beltrami, Carlton, Clearwater, Itasca, Koochiching and 1 more	95 min
Jul 4, 12:34 PM CDT	Severe Thunderstorm Watch	SPC	Aitkin, Carlton, Cass, Cook, Crow Wing, Itasca and 4 more	7 hr
Jul 4, 3:57 PM CDT	Mesoscale Discussion	SPC	Cook, Lake	93 min
Jul 4, 5:36 PM CDT	Mesoscale Discussion	SPC	Brown, Door, Florence, Forest, Kewaunee, Langlade and 7 more	54 min

Nearby

Mesoscale Discussions in Wisconsin, 2012 Mesoscale Discussions in Minnesota, 2012 Every 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.