Alert archive / Wisconsin / Severe Thunderstorm Warnings in 2010

Severe Thunderstorm Warning 102, NWS La Crosse, WI

August 20, 2010Adams County, Juneau County, Wisconsin

NWS La Crosse, WI issued this severe thunderstorm warning at Aug 20, 2010, 4:28 PM CDT for Adams County, Juneau County, Wisconsin. It was in force for 47 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 20, 2010, 4:28 PM CDT (21:28 UTC)
Expired: Aug 20, 2010, 5:15 PM CDT
In force: 47 min
Issued by: NWS La Crosse, WI
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Adams County, WI, Juneau County, WI

The radar

The La Crosse radar (KARX), 101 km from the middle of the area, began a volume at 21:31 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Aug 20, 1:42 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 9.5 hours before the alert went out and 158 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: 1534 J/kg
Mixed-layer CIN: -55 J/kg
Mixed-layer LCL: 674 m above ground
0-6 km bulk shear: 46 kt
0-1 km storm-relative helicity: 128 m²/s²
0-3 km storm-relative helicity: 211 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 8.6

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS La Crosse, WI wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 20, 2:54 PM CDT, 1 hour 34 minutes earlier.

Area forecast discussion, Aug 20, 2:54 PM CDT, 1 hour 34 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
250 PM FRI AUG 20 2010

.SHORT TERM...THROUGH MONDAY NIGHT

FORECAST PROBLEMS CENTERING ON THUNDERSTORM ACTIVITY THROUGH
EVENING...AND FOG AND LOW CLOUDS SATURDAY MORNING. OTHERWISE
EXPECTING CLEARING WITH PLEASANT WEATHER IN THE SHORT TERM.

CURRENT WATER VAPOR SATELLITE IMAGERY SHOWING A SMALLER SCALE
SHORTWAVE TROUGH OVER THE MN/IA BORDER NEAR KMCW. THIS IS PROVIDING
THE ORGANIZATIONAL ELEMENT TO UPSCALE CONVECTION OVER THE FORECAST
AREA. SEE AFD ISSUED AT 128 PM FOR CONVECTIVE ENVIRONMENT DETAILS.
BELIEVE THIS TO BE THE MAIN THREAT FOR THIS WEATHER SYSTEM...WITH
DAMAGING WIND AND LIGHTNING POTENTIAL. BELIEVE THE INSTABILITY WILL
BE USED BY THE CURRENT CONVECTIVE COMPLEX MOVING THROUGH...ALTHOUGH
IT CONTINUES TO BUILD OVER WESTERN MINNESOTA AHEAD OF THE WEAK
SURFACE COLD FRONT. THIS FRONT PARALLELS THE MN BORDER ABOUT 1 COUNTY
EAST AND PROVIDES A CONVERGENT BOUNDARY FOR ADDITIONAL CONVECTIVE
DEVELOPMENT. HOWEVER...ABOVE SURFACE SUPPORT LOOKS MINIMAL AND MORE
SUBSIDENT. LATEST RUC FORECASTS MOVE THE FRONT TO APPROXIMATELY THE
I-35 CORRIDOR BY 10 PM. AS THIS APPROACHES...WIND SHEAR IN THE 0-3KM
AND 0-6KM LAYER DROPS SUBSTANTIALLY TO LIMIT THE ORGANIZATION OF
THESE STORMS. BOTTOM LINE IS THAT WITH DEWPOINTS REMAINING IN THE 70F
RANGE...AND SBCAPE NEAR 2-3K J/KG THROUGH EVENING...HAVE LEFT A
CHANCE OF THUNDERSTORMS IN ALL OF THE FORECAST AREA. 12Z SPC WRF RUN
DOES CONVECT THE FRONT TO OUR WEST DURING THE EVENING WHICH
HIGHLIGHTS THE POSSIBILITY. SEVERE CHANCES LOOK MINIMAL.

WITH RAINS FALLING OVER THE FORECAST AREA TODAY AND THE LOW PRESSURE
CENTER / TROUGH BEING LOCATED OVER THE FORECAST AREA BY MORNING...
CONDITIONS ARE FAVORABLE FOR LOW CLOUDS AND FOG TO DEVELOP. WE HAVE
ADDED THESE INTO THE FORECAST FOR MORNING. IT MAY BE DENSE IN SOME
AREAS AND WILL PASS THIS ALONG TO THE LATER SHIFTS FOR MONITORING.
SOME FLOW ABOVE THE BOUNDARY LAYER IS INDICATED IN THE 20.12Z NAM AND
THE 20.18Z RUC WHICH MAY PRECLUDE DENSE FOG. EXPECT WITH RIDGE
BUILDING SATURDAY...A SLOW CLEARING OF CLOUD.

HAVE DECREASED TEMPERATURES 2-5F ON SUNDAY AND MONDAY AS THE AIR
MASS IS SLIGHTLY COOLER BUILDING INTO THE GREAT LAKES PER MOST
GUIDANCE. HOWEVER...THE GUIDANCE HAS BEEN RUNNING WARM AS HAS OUR
MAXT VERIFICATION AND THUS HAVE REMAINED BELOW THAT. A CONSENSUS
OF ALL MODELS AND MOS SUGGESTED A DROP OF 2-5F WAS APPROPRIATE. WITH
THE LOW-LEVEL THERMAL GRADIENT ACROSS THE AREA...THE COOLEST
TEMPERATURES WILL BY IN WI WITH WARMER CONDITIONS IN NERN IA.
HOWEVER...THESE WILL STILL BE NEAR NORMAL.

.LONG TERM...TUESDAY THROUGH FRIDAY

IN A SUBTLE WAY...THE PATTERN OVER THE NORTHERN CONUS IS SHIFTING
TOWARD A MORE AMPLIFIED PROGRESSIVE PATTERN. THIS IS CHARACTERIZED BY
A BIT STRONGER FRONTAL PASSAGES AND COOL DOWN POST-FRONTALLY...MORE
FALL-LIKE SIGNALS. ONGOING FORECAST HAD THE SHORTWAVE TROUGH MOVING
IN FOR LATE MONDAY INTO TUESDAY HANDLED WITH SOME SMALLER RAIN
CHANCES AND THIS LOOKS ON TRACK STILL. THE 20.00 ECMWF AND 20.06
GFS HAVE REMAINED CONSISTENT IN THEIR SIGNALS FOR THIS FROPA...WITH
A SLIGHT SLOWING...AND DEEPENING SEEN IN THE LATEST 20.00Z ECMWF.
THE GENERAL TIMING HAS BEEN FAIRLY CONSISTENT NOW FOR 2-3
RUNS BUT THE DEPTH SEEMS A BIT MORE INCONSISTENT. 20.00Z ECMWF HAS
ITS DEEPEST SHORTWAVE TROUGH PER 500MB HEIGHTS AND IF THIS
CONTINUES...A DEEPER QG CONVERGENT SIGNAL WOULD NEED HIGHER RAIN
CHANCES LATE MONDAY AND TUESDAY. OTHERWISE...A VERY PLEASANT AIR
MASS TO SETTLE IN FOR WED/THU...WITH LOWER DEWPOINTS AND HIGHS NEAR
NORMAL. MORE AMPLIFIED RIDGE MEANS A QUIET WEATHER STRETCH UNTIL
POSSIBLY THE WEEKEND /AUG 28/. ONLY VERY MINOR TWEAKS MADE FORECAST
IN THIS LONGER TERM PERIOD.
&&

.AVIATION...THIS AFTERNOON AND TONIGHT

INITIAL FOCUS FOR THE AREA IS WITH THE THUNDERSTORM CHANCES THIS
AFTERNOON AND VERY EARLY EVENING HOURS.  SHOWERS AND THUNDERSTORMS
HAVE ALREADY DEVELOPED ACROSS PORTIONS OF SOUTHEAST MINNESOTA AND
ARE EXPECTED TO TRACK EAST THROUGH THE AFTERNOON HOURS.  SOME
SHOWERS MAY LINGER AT RST...BUT THE MAIN SHOW IS GOING TO BE EARLIER
THIS AFTERNOON WHILE AT LSE THE BEST TIMING APPEARS TO BE IN THE MID
TO LATE AFTERNOON HOURS.

AFTER THESE SHOWERS AND STORMS MOVE THROUGH THE AREA TODAY...WINDS
ARE EXPECTED TO GO LIGHT TONIGHT WHICH...IN COMBINATION WITH THE
POSSIBLE RAIN FROM TODAY...COULD LEAD TO A DENSE FOG EVENT TONIGHT.
ONSET OF THE FOG WILL BE DEPENDENT ON WHEN/IF SKIES CLEAR...BUT IFR
CONDITIONS LOOK PROBABLE IN THE EARLY MORNING HOURS SATURDAY.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
SHORT/LONG TERM...BAUMGARDT
AVIATION..........HALBACH

Hazardous weather outlook, Aug 20, 5:02 AM CDT, 11 hours 26 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
502 AM CDT FRI AUG 20 2010

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-032>034-
041>044-053>055-061-211000-
ADAMS-ALLAMAKEE-BUFFALO-CHICKASAW-CLARK-CLAYTON-CRAWFORD-DODGE-
FAYETTE-FILLMORE-FLOYD-GRANT-HOUSTON-HOWARD-JACKSON-JUNEAU-LA CROSSE-
MITCHELL-MONROE-MOWER-OLMSTED-RICHLAND-TAYLOR-TREMPEALEAU-VERNON-
WABASHA-WINNESHIEK-WINONA-
502 AM CDT FRI AUG 20 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PARTS OF SOUTHEAST
MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST INTO CENTRAL WISCONSIN.

.DAY ONE...TODAY AND TONIGHT

A LOW PRESSURE SYSTEM AND ACCOMPANYING COLD FRONT WILL MOVE EAST
ACROSS THE AREA TODAY INTO THIS EVENING. THUNDERSTORMS WILL FIRE
ALONG THE FRONT...WITH INSTABILITY AND WIND PROFILES FAVORING STORM
ORGANIZATION. STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE...WITH
DAMAGING WINDS AND LARGE HAIL THE MAIN THREATS. THE COLD FRONT WILL
MOVE EAST OF THE AREA OVERNIGHT...SHIFTING THE THREAT FOR SEVERE
THUNDERSTORMS OUT OF THE AREA.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THUNDERSTORMS ARE ALSO POSSIBLE LATE MONDAY NIGHT AND TUESDAY.
IT IS TOO EARLY TO DETERMINE IF THERE WOULD BE A SEVERE WEATHER
THREAT WITH THIS THUNDERSTORM POTENTIAL.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED BETWEEN 3 PM AND 9 PM.

.EMERGENCY MANAGEMENT COORDINATION...

NO CALL IS SCHEDULED.

WETENKAMP

In the hours before

Local storm report, Aug 20, 2:36 PM CDT, 1 hour 52 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
236 PM CDT FRI AUG 20 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0236 PM     TSTM WND GST     LA CROSSE               43.83N 91.23W
08/20/2010  M40 MPH          LA CROSSE          WI   AMATEUR RADIO

&&

DAVIS

Special weather statement, Aug 20, 2:36 PM CDT, 1 hour 52 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
236 PM CDT FRI AUG 20 2010

IAZ011-030-MNZ096-WIZ029-034-041>043-053>055-061-202030-
ALLAMAKEE-CLARK-CLAYTON-CRAWFORD-GRANT-HOUSTON-JACKSON-JUNEAU-
LA CROSSE-MONROE-RICHLAND-VERNON-
236 PM CDT FRI AUG 20 2010

...STRONG THUNDERSTORMS MOVING INTO WESTERN WISCONSIN...

SCATTERED THUNDERSTORMS WERE OVER PARTS OF NORTHEAST IOWA...
FAR SOUTHEAST MINNESOTA AND NOW INTO WESTERN WISCONSIN. THESE
STORMS WILL CONTINUE TO TRACK NORTHEAST AND MAY PRODUCE OCCASIONAL
GUSTY WINDS...HEAVY RAIN AND A LIGHTNING RISK. AT TIMES...A SEVERE
THUNDERSTORM IS POSSIBLE WITH WIND GUSTS OF 60 MPH.

MOVE INDOORS WHEN STORMS PASS THROUGH YOUR AREA.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM FRIDAY
EVENING FOR WESTERN WISCONSIN.

SHEA

Local storm report, Aug 20, 2:42 PM CDT, 1 hour 46 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
242 PM CDT FRI AUG 20 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0240 PM     TSTM WND GST     1 N LA CRESCENT         43.84N 91.30W
08/20/2010  E50 MPH          HOUSTON            MN   NWS EMPLOYEE

&&

DTJ

Local storm report, Aug 20, 2:43 PM CDT, 1 hour 45 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
243 PM CDT FRI AUG 20 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0241 PM     TSTM WND DMG     3 NE HOKAH              43.79N 91.31W
08/20/2010                   HOUSTON            MN   AMATEUR RADIO

            TREE DOWN NORTHEAST OF HOKAH.

0242 PM     TSTM WND DMG     ONALASKA                43.89N 91.22W
08/20/2010                   LA CROSSE          WI   TRAINED SPOTTER

            LARGE TREE LIMBS DOWN IN ONALASKA.

&&

DAVIS

Local storm report, Aug 20, 3:10 PM CDT, 1 hour 18 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
310 PM CDT FRI AUG 20 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0309 PM     LIGHTNING        2 NW HOLMEN             43.98N 91.29W
08/20/2010                   LA CROSSE          WI   AMATEUR RADIO

            HAM RADIO REPORTS STRUCTURE FIRE CAUSED BY LIGHTNING
            STRIKE.

&&

DAVIS

Special weather statement, Aug 20, 3:29 PM CDT, 59 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE LA CROSSE WI
329 PM CDT FRI AUG 20 2010

WIZ034-042>044-053>055-202130-
ADAMS-CRAWFORD-JACKSON-JUNEAU-MONROE-RICHLAND-VERNON-
329 PM CDT FRI AUG 20 2010

...STRONG TO SEVERE THUNDERSTORMS CONTINUE ACROSS WESTERN
WISCONSIN...

SCATTERED THUNDERSTORMS WERE PRODUCING GUSTY WINDS...HEAVY RAIN AND
DEADLY LIGHTNING FROM NEAR BLACK RIVER FALLS...THROUGH THE FORT
MCCOY AREA TO VIROQUA AND PRAIRIE DU CHIEN. THESE STORMS WILL
CONTINUE TO MOVE NORTHEAST AND COULD BRING SOME LOCAL SEVERE
WEATHER THREATS OVER THE NEXT FEW HOURS.

IF A STORM MOVES INTO YOUR AREA...STAY OR MOVE INDOORS. EXPECT GUSTY
WINDS AND DANGEROUS LIGHTNING.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM.

SHEA

The office that day

Everything else NWS La Crosse, WI issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 20, 2:19 PM CDT	Severe Thunderstorm Warning	ARX	La Crosse	41 min
Aug 20, 2:58 PM CDT	Severe Thunderstorm Warning	ARX	La Crosse, Monroe	46 min
Aug 20, 3:42 PM CDT	Severe Thunderstorm Warning	ARX	Crawford, Richland, Vernon	47 min

Nearby

Severe Thunderstorm Warnings in Wisconsin, 2010 Every severe thunderstorm warning in 2010

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.