Note:
The expiration time in the watch graphic is amended if the watch is
replaced, cancelled or extended.
Note: Click for
Watch Status Reports.
SEL1
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 471
NWS STORM PREDICTION CENTER NORMAN OK
900 PM CDT THU JUN 18 2009
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
NORTHEAST IOWA
SOUTHEAST MINNESOTA
SOUTHWEST AND SOUTH CENTRAL WISCONSIN
EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 900 PM
UNTIL 400 AM CDT.
TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE
MILES EAST AND WEST OF A LINE FROM 65 MILES NORTH OF LA CROSSE
WISCONSIN TO 50 MILES SOUTH SOUTHWEST OF LONEROCK WISCONSIN. FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU1).
REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.
OTHER WATCH INFORMATION...CONTINUE...WW 465...WW 467...WW
468...WW 469...WW 470...
DISCUSSION...ISOLATED THUNDERSTORMS ARE BEGINNING TO DEVELOP OVER NE
IA/SW WI ALONG AN INSTABILITY GRADIENT/DIFFUSE WARM FRONT NEAR THE
MS RIVER. DESPITE THE LOSS OF DAYTIME HEATING...STRONG INSTABILITY
REMAINS OVER THIS AREA...AND VERTICAL SHEAR IS FAVORABLE FOR
SUPERCELLS. GIVEN THE POTENTIAL FOR CONVECTION TO BECOME ROOTED IN
THE NEAR-SURFACE LAYER WITH DEW POINTS IN THE 70S...SUPERCELLS WILL
BE CAPABLE OF PRODUCING A FEW TORNADOES AND VERY LARGE HAIL. LATER
TONIGHT...CONVECTION COULD ALSO MOVE INTO THIS AREA FROM THE W/NW IN
THE FORM OF AN MCS WITH AN ACCOMPANYING THREAT FOR DAMAGING WINDS
AND LARGE HAIL.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 28025.
...THOMPSON
Note:
The Aviation Watch (SAW) product is an approximation to the watch area.
The actual watch is depicted by the shaded areas.
SAW1
WW 471 TORNADO IA MN WI 190200Z - 190900Z
AXIS..80 STATUTE MILES EAST AND WEST OF LINE..
65N LSE/LA CROSSE WI/ - 50SSW LNR/LONEROCK WI/
..AVIATION COORDS.. 70NM E/W /11ESE EAU - 11NE DBQ/
HAIL SURFACE AND ALOFT..2.5 INCHES. WIND GUSTS..60 KNOTS.
MAX TOPS TO 550. MEAN STORM MOTION VECTOR 28025.
LAT...LON 44818962 42548898 42549212 44819287
THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
FOR WOU1.
Watch 471 Status Report Messages:
STATUS REPORT #1 ON WW 471
VALID 190745Z - 190840Z
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..GUYER..06/19/09
ATTN...WFO...ARX...MKX...
&&
STATUS REPORT FOR WT 471
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC005-037-043-065-067-089-131-191-190840-
IA
. IOWA COUNTIES INCLUDED ARE
ALLAMAKEE CHICKASAW CLAYTON
FAYETTE FLOYD HOWARD
MITCHELL WINNESHIEK
$$
MNC039-045-055-099-109-157-169-190840-
MN
. MINNESOTA COUNTIES INCLUDED ARE
DODGE FILLMORE HOUSTON
MOWER OLMSTED WABASHA
WINONA
$$
WIC001-011-023-043-045-053-057-063-065-081-103-105-121-123-
190840-
WI
. WISCONSIN COUNTIES INCLUDED ARE
ADAMS BUFFALO CRAWFORD
GRANT GREEN JACKSON
JUNEAU LA CROSSE LAFAYETTE
MONROE RICHLAND ROCK
TREMPEALEAU VERNON
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
Note:
Click for Complete Product Text.
Tornadoes
Probability of 2 or more tornadoes
|
Mod (50%)
|
Probability of 1 or more strong (F2-F5) tornadoes
|
Low (20%)
|
Wind
Probability of 10 or more severe wind events
|
Mod (50%)
|
Probability of 1 or more wind events > 65 knots
|
Mod (40%)
|
Hail
Probability of 10 or more severe hail events
|
Mod (50%)
|
Probability
of 1 or
more hailstones > 2 inches
|
Mod (40%)
|
Combined Severe Hail/Wind
Probability of 6 or more combined severe hail/wind events
|
High (90%)
|
For each watch, probabilities for particular events inside the watch
(listed above in each table) are determined by the issuing forecaster.
The "Low" category contains probability values ranging from less than 2%
to 20% (F2-F5 tornadoes), less than 5% to 20% (all other probabilities),
"Moderate" from 30% to 60%, and "High" from 70% to greater than 95%.
High values are bolded and lighter in color to provide awareness of
an increased threat for a particular event.
weather.gov 
