Alert archive / Wisconsin / Mesoscale Discussions in 2005

Mesoscale Discussion 2016

August 18, 20054 states

The Storm Prediction Center issued this mesoscale discussion at Aug 18, 2005, 2:09 PM CDT for 4 states. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued
Aug 18, 2005, 2:09 PM CDT (19:09 UTC)
Expired
Aug 18, 2005, 3:45 PM CDT
In force
96 min
Issued by
the Storm Prediction Center
All 48 counties

Allamakee County, IA, Cedar County, IA, Clayton County, IA, Clinton County, IA, Delaware County, IA, Dubuque County, IA, Fayette County, IA, Jackson County, IA, Jones County, IA, Scott County, IA, Winneshiek County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Henry County, IL, Jo Daviess County, IL, Lee County, IL, Ogle County, IL, Putnam County, IL, Rock Island County, IL, Stephenson County, IL, Whiteside County, IL, Winnebago County, IL, Fillmore County, MN, Houston County, MN, Winona County, MN, Adams County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Dodge County, WI, Grant County, WI, Green 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, Richland County, WI, Rock County, WI, Sauk County, WI, Trempealeau County, WI, Vernon County, WI, Waushara County, WI

The radar

The La Crosse radar (KARX), 126 km from the middle of the area, began a volume at 19:10 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

Davenport, (KDVN), launched 12:00Z, 7.2 hours before the alert went out and 153 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, Davenport, at 12:00Z on 2005-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 757 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, Davenport, at 12:00Z on 2005-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 212 square meters per square second.1939587897Sfc1 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
757 J/kg
Mixed-layer CIN
-54 J/kg
Mixed-layer LCL
763 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
212 m²/s²
0-3 km storm-relative helicity
226 m²/s²
Significant tornado parameter
0.8
Supercell composite
5.9

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 181909
SWOMCD
SPC MCD 181909 
WIZ000-ILZ000-IAZ000-MNZ000-182045-

MESOSCALE DISCUSSION 2016
NWS STORM PREDICTION CENTER NORMAN OK
0209 PM CDT THU AUG 18 2005

AREAS AFFECTED...PORTIONS NERN AND EXTREME E-CENTRAL IA...NWRN
IL...SWRN/S-CENTRAL WI...EXTREME SERN MN

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 181909Z - 182045Z

WW MAY BE REQUIRED ACROSS SOME PORTION OF THIS REGION...WITH SEVERE
POTENTIAL INCREASING OVER NEXT FEW HOURS.  DAMAGING
GUSTS...TORNADOES AND OCCASIONAL LARGE HAIL ARE POSSIBLE.

SFC MESOANALYSIS SHOWS WELL-DEFINED LOW OVER SERN MN -- N RST AS OF
19Z -- FCST TO MOVE EWD INTO SWRN/S-CENTRAL WI THROUGH REMAINDER
AFTERNOON.  WARM FRONT EXTENDS SEWD FROM LOW ACROSS SWRN WI INTO
OUTFLOW POOL LEFT BY MORNING MCS.  WARM FRONT WILL CONTINUE LIFTING
NWD AND WRN PORTION OF OLD OUTFLOW POOL WILL FAVORABLY MODIFY. 80S
SFC TEMPS AND 70S DEW POINTS -- EVIDENT IN WARM SECTOR ALONG AND S
OF WARM FRONT AND OUTFLOW BOUNDARY -- SHOULD SUPPORT MLCAPES AROUND
2000 J/KG BASED ON MODIFIED RUC SOUNDINGS.  LOW LEVEL VERTICAL SHEAR
PROFILES SHOULD REMAIN MAXIMIZED INVOF WARM FRONT...WHERE BACKED SFC
WINDS CONTRIBUTE TO ENLARGED LOW LEVEL HODOGRAPHS AND 0-1 KM SRH OF
150-250 J/KG SRH IN 0-1 KM AGL LAYER.  THOSE VALUES -- DERIVED FROM
OBSERVED REGIONAL VWP DATA...ARE SUBSTANTIALLY HIGHER THAN INDICATED
BY SHORT TERM RUC ANALYSES AND FCSTS...AND SUPPORT SUPERCELL/TORNADO
THREAT PARTICULARLY NEAR WARM FRONT.

FARTHER S...ISALLOBARICALLY FORCED VEERING OF SFC FLOW OVER MUCH OF
IA SHOULD SHIFT EWD INTO IL THIS AFTERNOON S OF OUTFLOW
BOUNDARY...LIMITING CONVERGENCE AND LOW LEVEL SHEAR...HOWEVER SEVERE
GUSTS AND HAIL WILL BE POSSIBLE.

IN IMMEDIATE VICINITY OF LOW/MIDDLE LEVEL CYCLONE OVER SERN MN...0-1
KM SRH APPEARS SMALL BECAUSE OF WEAKER FLOW...HOWEVER VERY LOCALIZED
AREA OF JUXTAPOSITION EXISTS BETWEEN FAVORABLE SFC VORTICITY MAX AND
LOW LEVEL CAPE FIELD.  POSSIBILITY OF NONSUPERCELL TORNADOES CANNOT
BE RULED OUT AS THAT REGIME SHIFTS EWD ACROSS REMAINDER EXTREME SERN
MN AND LSE REGION INTO SWRN WI.

..EDWARDS.. 08/18/2005

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

ATTN...WFO...GRB...LOT...ILX...MKX...DVN...ARX...DMX...

41189032 41939139 42939212 43919236 44279184 44479098
44469000 44378957 44098911 43708862 43128861 42498873
41408896 41098934

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 18, 9:00 AM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cook, DeKalb, DeWitt and 34 more2 hr
Aug 18, 9:25 AM CDTSevere Thunderstorm WatchSPCBoone, Cook, DeKalb, DuPage, Grundy, Kane and 8 more6 hr
Aug 18, 1:16 PM CDTMesoscale DiscussionSPCFord, Grundy, Iroquois, Kankakee, Kendall, LaSalle and 2 more89 min
Aug 18, 4:49 PM CDTMesoscale DiscussionSPCAdams, Brown, Hancock, Pike, Schuyler116 min
Aug 18, 5:35 PM CDTSevere Thunderstorm WatchSPCAdams, Brown, Cass, Fulton, Greene, Hancock and 9 more6 hr
Aug 18, 2:50 PM CDTTornado WatchSPCAllamakee, Clayton6 hr
Aug 17, 9:22 PM CDTMesoscale DiscussionSPCBecker, Beltrami, Clay, Clearwater, Grant, Hubbard and 7 more23 min
Aug 18, 5:47 PM CDTMesoscale DiscussionSPCAdams, Columbia, Crawford, Dane, Dodge, Fond du Lac and 24 more58 min
Aug 18, 5:50 PM CDTTornado WatchSPCDodge, Fond du Lac, Green Lake, Jefferson, Kenosha, Walworth and 2 more5 hr

Nearby

Mesoscale Discussions in Wisconsin, 2005Mesoscale Discussions in Illinois, 2005Mesoscale Discussions in Iowa, 2005Every mesoscale discussion in 2005

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.