Note:
The expiration time in the watch graphic is amended if the watch is
replaced, cancelled or extended.
Note: Click for
Watch Status Reports.
SEL4
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 424
NWS Storm Prediction Center Norman OK
605 AM CDT Mon Aug 10 2020
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Northwest Iowa
Northeast Nebraska
Southeast South Dakota
* Effective this Monday morning from 605 AM until 1100 AM CDT.
* Primary threats include...
Scattered damaging winds likely with isolated significant gusts
to 75 mph possible
Scattered large hail and isolated very large hail events to 2
inches in diameter possible
SUMMARY...A cluster of thunderstorms along the South Dakota/Nebraska
border is expected to intensify this morning and track across the
watch area. Damaging winds are the primary threat, along with some
hail potential.
The severe thunderstorm watch area is approximately along and 40
statute miles north and south of a line from 40 miles west of
Yankton SD to 15 miles north northeast of Storm Lake IA. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU4).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
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.
&&
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 65 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
28035.
...Hart
SEL4
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 424
NWS Storm Prediction Center Norman OK
605 AM CDT Mon Aug 10 2020
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Northwest Iowa
Northeast Nebraska
Southeast South Dakota
* Effective this Monday morning from 605 AM until 1100 AM CDT.
* Primary threats include...
Scattered damaging winds likely with isolated significant gusts
to 75 mph possible
Scattered large hail and isolated very large hail events to 2
inches in diameter possible
SUMMARY...A cluster of thunderstorms along the South Dakota/Nebraska
border is expected to intensify this morning and track across the
watch area. Damaging winds are the primary threat, along with some
hail potential.
The severe thunderstorm watch area is approximately along and 40
statute miles north and south of a line from 40 miles west of
Yankton SD to 15 miles north northeast of Storm Lake IA. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU4).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
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.
&&
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 65 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
28035.
...Hart
Note:
The Aviation Watch (SAW) product is an approximation to the watch area.
The actual watch is depicted by the shaded areas.
SAW4
WW 424 SEVERE TSTM IA NE SD 101105Z - 101600Z
AXIS..40 STATUTE MILES NORTH AND SOUTH OF LINE..
40W YKN/YANKTON SD/ - 15NNE SLB/STORM LAKE IA/
..AVIATION COORDS.. 35NM N/S /35NE ONL - 38WNW FOD/
HAIL SURFACE AND ALOFT..2 INCHES. WIND GUSTS..65 KNOTS.
MAX TOPS TO 500. MEAN STORM MOTION VECTOR 28035.
LAT...LON 43509817 43389512 42229512 42349817
THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
FOR WOU4.
Watch 424 Status Report Messages:
STATUS REPORT #2 ON WW 424
VALID 101430Z - 101540Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 NW OMA TO
15 W DNS TO 20 NW SLB TO 30 NW FOD.
..GLEASON..08/10/20
ATTN...WFO...FSD...OAX...
&&
STATUS REPORT FOR WS 424
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC021-035-093-101540-
IA
. IOWA COUNTIES INCLUDED ARE
BUENA VISTA CHEROKEE IDA
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
STATUS REPORT #1 ON WW 424
VALID 101355Z - 101440Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 NNE OLU
TO 5 SSW SUX TO 35 NNE SUX TO 30 SE SPW.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1447
..GLEASON..08/10/20
ATTN...WFO...FSD...OAX...
&&
STATUS REPORT FOR WS 424
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC021-035-093-133-149-193-101440-
IA
. IOWA COUNTIES INCLUDED ARE
BUENA VISTA CHEROKEE IDA
MONONA PLYMOUTH WOODBURY
$$
NEC021-039-173-101440-
NE
. NEBRASKA COUNTIES INCLUDED ARE
BURT CUMING THURSTON
$$
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 (<5%)
|
Probability of 1 or more strong (EF2-EF5) tornadoes
|
Low (<2%)
|
Wind
Probability of 10 or more severe wind events
|
Mod (60%)
|
Probability of 1 or more wind events > 65 knots
|
Mod (30%)
|
Hail
Probability of 10 or more severe hail events
|
Mod (40%)
|
Probability of 1 or more hailstones > 2 inches
|
Mod (30%)
|
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% (EF2-EF5 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 
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