Alert archive / Wisconsin / Mesoscale Discussions in 2007

Mesoscale Discussion 182

February 23, 20076 counties in Iowa; 6 counties in Minnesota; 24 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Feb 23, 2007, 7:59 PM CST for 6 counties in Iowa; 6 counties in Minnesota; 24 counties in Wisconsin. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Feb 23, 2007, 7:59 PM CST (01:59 UTC)
Expired: Feb 24, 2007, 12:30 AM CST
In force: 5 hr
Issued by: the Storm Prediction Center

All 36 counties

Allamakee County, IA, Chickasaw County, IA, Clayton County, IA, Fayette County, IA, Howard County, IA, Winneshiek County, IA, Fillmore County, MN, Houston County, MN, Mower County, MN, Olmsted County, MN, Wabasha County, MN, Winona County, MN, Adams County, WI, Buffalo County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Dodge County, WI, Eau Claire County, WI, Grant County, WI, Green Lake County, WI, Iowa County, WI, Jackson County, WI, Jefferson County, WI, Juneau County, WI, La Crosse County, WI, Lafayette County, WI, Marquette County, WI, Monroe County, WI, Pepin County, WI, Richland County, WI, Sauk County, WI, Trempealeau County, WI, Vernon County, WI, Waushara County, WI, Wood County, WI

The radar

The La Crosse radar (KARX), 42 km from the middle of the area, began a volume at 01:59 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, 2.0 hours before the alert went out and 216 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1291 m above ground
0-6 km bulk shear: 60 kt
0-1 km storm-relative helicity: -7 m²/s²
0-3 km storm-relative helicity: 95 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.

000 
ACUS11 KWNS 240159
SWOMCD
SPC MCD 240159 
WIZ000-ILZ000-IAZ000-MNZ000-240630-

MESOSCALE DISCUSSION 0182
NWS STORM PREDICTION CENTER NORMAN OK
0759 PM CST FRI FEB 23 2007

AREAS AFFECTED...SOUTHEAST MN/NORTHEAST IA INTO WESTERN/SOUTH
CENTRAL WI

CONCERNING...HEAVY SNOW 

VALID 240159Z - 240630Z

WHILE THUNDERSNOW AND SLEET IS LIKELY TO PERSIST THROUGH MUCH OF THE
EVENING ACROSS SOUTHEAST MN/NORTHEAST IA...SNOW SHOULD BECOME
INCREASINGLY HEAVY THROUGH MID/LATE EVENING ACROSS SOUTHWEST WI INTO
SOUTH CENTRAL WI...INCLUDING THE I-90/I-94 CORRIDOR. SNOW RATES OF 1
IN/HR WILL BE POSSIBLE WITH THE HEAVIEST BANDS.

NUMEROUS THUNDERSTORMS/CLOUD-GROUND LIGHTNING STRIKES HAVE BEEN
COMMON ACROSS THE EASTERN HALF OF IA INTO SOUTHEAST MN SINCE MID
AFTERNOON...WITH A NUMBER OF REPORTS OF THUNDERSNOW AND SLEET.
WITHIN A LOW LEVEL WARM ADVECTION/ISENTROPIC LIFT REGIME...THIS
PLUME OF CONVECTIVELY ENHANCED PRECIPITATION WILL OVERSPREAD MUCH OF
WESTERN/SOUTH CENTRAL WI THE REMAINDER OF THE EVENING PER
OBSERVATIONAL TRENDS/LATEST MODEL GUIDANCE. GIVEN PRESENCE OF
ELEVATED CONVECTIVE INSTABILITY -- UP TO 200 J/KG MUCAPE ALONG THE
MISSISSIPPI RIVER PER LATEST RUC SOUNDINGS -- AND
NORTHWEST-SOUTHEAST ORIENTED LOW TO MID LEVEL FRONTOGENETICAL
FORCING...MODERATE/LOCALLY HEAVY SNOW WILL BECOME INCREASINGLY
PREVALENT OVER THE NEXT SEVERAL HOURS FROM SOUTHWEST WI INTO SOUTH
CENTRAL WI. IT APPEARS 1 IN/HR SNOW RATES WILL BE POSSIBLE WITH
EMBEDDED NORTHWEST-SOUTHEAST ORIENTED MESOSCALE BANDS THROUGH 06Z.

..GUYER.. 02/24/2007

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

ATTN...WFO...GRB...MKX...DVN...ARX...MPX...DMX...

44689039 44508987 43928853 42988850 42489046 42679201
43749298 44569235 44819135

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 24, 12:08 AM CST	Mesoscale Discussion	SPC	Allamakee	4 hr
Feb 24, 7:25 AM CST	Mesoscale Discussion	SPC	Benton, Black Hawk, Bremer, Buchanan, Butler, Cedar and 39 more	4 hr
Feb 24, 12:19 PM CST	Mesoscale Discussion	SPC	Allamakee, Benton, Black Hawk, Boone, Bremer, Buchanan and 42 more	5 hr
Feb 24, 1:34 PM CST	Mesoscale Discussion	SPC	Cherokee, Clay, Dickinson, Emmet, Lyon, O'Brien and 3 more	5 hr

Nearby

Mesoscale Discussions in Wisconsin, 2007 Mesoscale Discussions in Iowa, 2007 Mesoscale Discussions in Minnesota, 2007 Every mesoscale discussion in 2007

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.