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The expiration time in the watch graphic is amended if the watch is
replaced, cancelled or extended.
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Watch Status Reports.
SEL8
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 458
NWS STORM PREDICTION CENTER NORMAN OK
420 AM CDT THU JUN 18 2009
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
NORTHWEST IOWA
EXTREME NORTHEAST NEBRASKA
SOUTHEAST SOUTH DAKOTA
EFFECTIVE THIS THURSDAY MORNING FROM 420 AM UNTIL 900 AM CDT.
HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 45
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 35 MILES WEST
SOUTHWEST OF YANKTON SOUTH DAKOTA TO 20 MILES SOUTHEAST OF
SPENCER IOWA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).
REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.
OTHER WATCH INFORMATION...CONTINUE...WW 454...WW 455...WW
456...WW 457...
DISCUSSION...SMALL BUT INTENSE COMPLEX OF TSTMS MOVING ACROSS NRN
NEB WILL MOVE TO NWRN IA OVER THE NEXT COUPLE OF HOURS WITH SOME
POTENTIAL FOR WIND DAMAGE AND HAIL. THIS COMPLEX IS BEING SUPPORTED
BY WEAK LARGER SCALE HEIGHT FALLS AND MID LEVEL JET STREAK
ASSOCIATED WITH LOW AMPLITUDE SHORT WAVE TROUGH. ABUNDANT
INSTABILITY FEEDING STORM UPDRAFTS ON THE EDGE OF PLAINS CAPPING
INVERSION...COMBINED WITH MORE THAN ADEQUATE SHEAR...SHOULD ALLOW
THE COMPLEX TO MAINTAIN INTENSITY AND INTEGRITY AS IT SPREADS ACROSS
THE MO RIVER VALLEY EARLY TODAY.
AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM
MOTION VECTOR 26035.
...CARBIN
Note:
The Aviation Watch (SAW) product is an approximation to the watch area.
The actual watch is depicted by the shaded areas.
SAW8
WW 458 SEVERE TSTM IA NE SD 180920Z - 181400Z
AXIS..45 STATUTE MILES NORTH AND SOUTH OF LINE..
35WSW YKN/YANKTON SD/ - 20SE SPW/SPENCER IA/
..AVIATION COORDS.. 40NM N/S /33ENE ONL - 33NW FOD/
HAIL SURFACE AND ALOFT..2 INCHES. WIND GUSTS..60 KNOTS.
MAX TOPS TO 550. MEAN STORM MOTION VECTOR 26035.
LAT...LON 43389801 43619487 42319487 42069801
THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
FOR WOU8.
Watch 458 Status Report Messages:
STATUS REPORT #2 ON WW 458
VALID 181150Z - 181240Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 SE SUX TO
30 NNE SUX TO 10 ESE FSD.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1200
..CARBIN..06/18/09
ATTN...WFO...FSD...OAX...
&&
STATUS REPORT FOR WS 458
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC021-035-041-059-093-119-141-143-167-193-181240-
IA
. IOWA COUNTIES INCLUDED ARE
BUENA VISTA CHEROKEE CLAY
DICKINSON IDA LYON
O'BRIEN OSCEOLA SIOUX
WOODBURY
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
STATUS REPORT #1 ON WW 458
VALID 181055Z - 181140Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 NE OFK TO
30 WSW FSD.
..CARBIN..06/18/09
ATTN...WFO...FSD...OAX...
&&
STATUS REPORT FOR WS 458
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC021-035-041-059-093-119-141-143-149-167-193-181140-
IA
. IOWA COUNTIES INCLUDED ARE
BUENA VISTA CHEROKEE CLAY
DICKINSON IDA LYON
O'BRIEN OSCEOLA PLYMOUTH
SIOUX WOODBURY
$$
NEC027-043-051-181140-
NE
. NEBRASKA COUNTIES INCLUDED ARE
CEDAR DAKOTA DIXON
$$
SDC027-083-125-127-181140-
SD
. SOUTH DAKOTA COUNTIES INCLUDED ARE
CLAY LINCOLN TURNER
UNION
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
Note:
Click for Complete Product Text.
Tornadoes
Probability of 2 or more tornadoes
|
Low (10%)
|
Probability of 1 or more strong (F2-F5) tornadoes
|
Low (5%)
|
Wind
Probability of 10 or more severe wind events
|
Mod (30%)
|
Probability of 1 or more wind events > 65 knots
|
Mod (30%)
|
Hail
Probability of 10 or more severe hail events
|
Low (20%)
|
Probability
of 1 or
more hailstones > 2 inches
|
Low (20%)
|
Combined Severe Hail/Wind
Probability of 6 or more combined severe hail/wind events
|
Mod (60%)
|
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 
