Alert archive / Minnesota / Mesoscale Discussions in 2004

Mesoscale Discussion 623

May 9, 20045 states

The Storm Prediction Center issued this mesoscale discussion at May 9, 2004, 5:38 PM CDT for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
May 9, 2004, 5:38 PM CDT (22:38 UTC)
Expired
May 9, 2004, 7:45 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 64 counties

Dickinson County, IA, Emmet County, IA, Lyon County, IA, Osceola County, IA, Sioux County, IA, Anoka County, MN, Blue Earth County, MN, Brown County, MN, Carver County, MN, Chisago County, MN, Cottonwood County, MN, Dakota County, MN, Dodge County, MN, Faribault County, MN, Freeborn County, MN, Goodhue County, MN, Hennepin County, MN, Jackson County, MN, Le Sueur County, MN, Martin County, MN, Mower County, MN, Murray County, MN, Nicollet County, MN, Nobles County, MN, Olmsted County, MN, Pipestone County, MN, Ramsey County, MN, Rice County, MN, Rock County, MN, Scott County, MN, Sibley County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Washington County, MN, Watonwan County, MN, Cedar County, NE, Clay County, SD, Hutchinson County, SD, Lincoln County, SD, McCook County, SD, Minnehaha County, SD, Moody County, SD, Turner County, SD, Union County, SD, Yankton County, SD, Barron County, WI, Buffalo County, WI, Burnett County, WI, Chippewa County, WI, Clark County, WI, Douglas County, WI, Dunn County, WI, Eau Claire County, WI, Pepin County, WI, Pierce County, WI, Polk County, WI, Price County, WI, Rusk County, WI, Saint Croix County, WI, Sawyer County, WI, Taylor County, WI, Trempealeau County, WI, Washburn County, WI

The radar

The Minneapolis radar (KMPX), 72 km from the middle of the area, began a volume at 22:38 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.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 10.6 hours before the alert went out and 70 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, Minneapolis, MN at 12:00Z on 2004-05-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 8 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, Minneapolis, MN at 12:00Z on 2004-05-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 207 square meters per square second.19395878Sfc1 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
8 J/kg
Mixed-layer CIN
-483 J/kg
Mixed-layer LCL
802 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
207 m²/s²
0-3 km storm-relative helicity
170 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 092239
SWOMCD
SPC MCD 092238 
WIZ000-MNZ000-IAZ000-SDZ000-NEZ000-100045-

MESOSCALE DISCUSSION 0623
NWS STORM PREDICTION CENTER NORMAN OK
0538 PM CDT SUN MAY 09 2004

AREAS AFFECTED...NW/W CNTRL WI...CNTRL/SRN MN

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 092238Z - 100045Z

CONTINUE TORNADO WW 173 AND SEVERE WW 171.

PRE-FRONTAL THERMAL RIDGE AXIS EXTENDS NORTHEASTWARD OUT OF THE
NORTH CENTRAL PLAINS...ACROSS THE SIOUX FALLS SD AREA INTO THE
MINNEAPOLIS MN AREA...AND IS PROVIDING FOCUS FOR STRONG
DESTABILIZATION.  STEEP MID-LEVEL LAPSE RATES AND STRONG HEATING
HAVE CONTRIBUTED TO MEAN MIXED LAYER CAPE OF 1500 TO 2000 J/KG...
SUPPORTIVE OF VIGOROUS UPDRAFTS

EVOLUTION OF LARGE SEVERE MESOSCALE CONVECTIVE SYSTEM IS CURRENTLY
ONGOING ON NOSE OF THERMAL RIDGE...NEAR THE MINNEAPOLIS AREA...WHERE
DIVERGENT UPPER FLOW FIELD HAS BECOME FOCUSED AHEAD OF NORTHERN
BRANCH SHORT WAVE TROUGH.  THIS REGIME WILL GRADUALLY SPREAD INTO
NORTHERN WISCONSIN THIS EVENING...AS UPSTREAM TROUGH AXIS PROGRESSES
ACROSS SASKATCHEWAN.

STRONGER 2 HOUR SURFACE PRESSURE FALLS HAVE ALREADY DEVELOPED
EASTWARD ALONG WARM FRONT INTO NORTHERN WISCONSIN...AND INTENSE
LEADING EDGE OF ONGOING CONVECTIVE CLUSTER SHOULD SPREAD INTO AREAS
NEAR/NORTH THROUGH NORTHEAST OF EAU CLAIRE BY 10/00-01Z.

OTHER INTENSE CONVECTION IS EXPECTED TO CONTINUE DEVELOPING ALONG
TRAILING UPSTREAM LOW-LEVEL CONFLUENT ZONE...BENEATH THERMAL
RIDGE...SOUTH OF MINNEAPOLIS TOWARD THE SIOUX FALLS AREA.

VERY WARM BOUNDARY LAYER WITH LARGE TEMPERATURE/DEW POINTS SPREADS
WILL SUPPORT STRONG DOWNBURSTS...AND EVOLUTION OF SEVERAL SURGING
COLD POOL WITH GUSTY WINDS...IN ADDITION TO LARGE HAIL. 
HOWEVER...ENHANCED LOW-LEVEL HODOGRAPHS ALONG WARM FRONT EAST OF
MINNEAPOLIS INTO WEST CENTRAL WISCONSIN WILL CONTINUE TO SUPPORT
RISK OF ISOLATED TORNADOES ANOTHER COUPLE OF HOURS.

..KERR.. 05/09/2004

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

ATTN...WFO...GRB...DLH...ARX...MPX...DMX...FSD...OAX...

44199637 44199517 44709446 45289327 45929288 46489227
46629108 46048981 44939022 44319107 43679269 43459390
43389464 43169586 42679702 42499765 43559782 44039709

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 8, 7:54 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Carroll, Cass, Clarke and 19 more2 hr
May 8, 8:25 PM CDTSevere Thunderstorm WatchSPCAdair, Adams, Allamakee, Appanoose, Audubon, Benton and 58 more6 hr
May 8, 10:44 PM CDTMesoscale DiscussionSPCAdair, Adams, Cass, Clarke, Decatur, Fremont and 12 more2 hr
May 9, 1:22 AM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Cass, Cedar, Clarke and 30 more23 min
May 9, 2:30 PM CDTSevere Thunderstorm WatchSPCLyon, Sioux6 hr
May 9, 4:46 PM CDTMesoscale DiscussionSPCAllamakee, Buchanan, Clayton, Clinton, Delaware, Dubuque and 4 more59 min
May 9, 2:00 PM CDTMesoscale DiscussionSPCBig Stone, Blue Earth, Brown, Carver, Chippewa, Kandiyohi and 19 more3 hr
May 9, 3:29 PM CDTMesoscale DiscussionSPCChisago, Dakota, Goodhue, Hennepin, Le Sueur, Ramsey and 4 more91 min
May 9, 3:55 PM CDTTornado WatchSPCAnoka, Blue Earth, Brown, Carver, Dakota, Dodge and 24 more5 hr
May 8, 9:17 PM CDTMesoscale DiscussionSPCBoyd88 min
May 9, 2:42 PM CDTMesoscale DiscussionSPCArthur, Blaine, Brown, Chase, Cherry, Custer and 19 more3 hr
May 9, 3:30 PM CDTSevere Thunderstorm WatchSPCAdams, Antelope, Blaine, Boone, Boyd, Buffalo and 29 more6 hr
May 9, 6:12 PM CDTMesoscale DiscussionSPCAdams, Antelope, Blaine, Boone, Buffalo, Butler and 37 more2 hr
May 8, 7:15 PM CDTSevere Thunderstorm WatchSPCBrown, Buffalo, Campbell, Corson, Dewey, Edmunds and 20 more6 hr
May 8, 9:55 PM CDTMesoscale DiscussionSPCColumbia, Dane, Dodge, Green, Iowa, Jefferson and 9 more2 hr
May 9, 11:48 AM CDTMesoscale DiscussionSPCColumbia, Dane, Dodge, Fond du Lac, Green, Green Lake and 10 more2 hr
May 9, 12:55 PM CDTSevere Thunderstorm WatchSPCKenosha, Milwaukee, Ozaukee, Racine, Washington6 hr
May 9, 2:46 PM CDTMesoscale DiscussionSPCKenosha, Milwaukee, Ozaukee, Racine89 min
May 9, 6:15 PM CDTSevere Thunderstorm WatchSPCAshland, Barron, Bayfield, Douglas, Forest, Iron and 6 more8 hr

Nearby

Mesoscale Discussions in Minnesota, 2004Mesoscale Discussions in Wisconsin, 2004Mesoscale Discussions in South Dakota, 2004Every mesoscale discussion in 2004

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.