Note:
The expiration time in the watch graphic is amended if the watch is
replaced, cancelled or extended.
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Watch Status Reports.
SEL3
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 743
NWS STORM PREDICTION CENTER NORMAN OK
1045 PM CDT WED JUL 23 2008
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
WESTERN IOWA
NORTHEAST AND PARTS OF EASTERN NEBRASKA
EXTREME SOUTHEAST SOUTH DAKOTA
EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 1045 PM
UNTIL 600 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 65
STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES NORTH OF
YANKTON SOUTH DAKOTA TO 35 MILES SOUTH SOUTHEAST OF OMAHA
NEBRASKA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).
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 741...WW 742...
DISCUSSION...STORMS ARE FORECAST TO INCREASE ALONG EASTERN GRADIENT
OF CENTRAL PLAINS INSTABILITY AXIS AS WEAK HEIGHT FALLS AND
INCREASINGLY STRONG LOW LEVEL JET AID ASCENT ACROSS THE REGION.
INFLOW AIR MASS IS STRONGLY UNSTABLE AND EFFECTIVE SHEAR OF 40-50KT
WILL SUPPORT UPDRAFT ROTATION AND PERSISTENCE WITH THE STRONGER
CELLS...GENERALLY ROOTED ABOVE 850MB. PRIMARY THREAT WITH THIS
OVERNIGHT ACTIVITY SHOULD BE LARGE HAIL. GRADUAL UPSCALE EVOLUTION
INTO A SMALL/COMPACT MCS WITH STRONG/DAMAGING WINDS IS POSSIBLE AS
COLD POOL STRENGTHENS AND MESOSCALE FORCING/LIFT IS ENHANCED WITHIN
STRONGLY UNSTABLE REGIME.
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 500. MEAN STORM
MOTION VECTOR 29025.
...CARBIN
Note:
The Aviation Watch (SAW) product is an approximation to the watch area.
The actual watch is depicted by the shaded areas.
SAW3
WW 743 SEVERE TSTM IA NE SD 240345Z - 241100Z
AXIS..65 STATUTE MILES EAST AND WEST OF LINE..
40N YKN/YANKTON SD/ - 35SSE OMA/OMAHA NE/
..AVIATION COORDS.. 55NM E/W /28WSW FSD - 21SSE OVR/
HAIL SURFACE AND ALOFT..2 INCHES. WIND GUSTS..60 KNOTS.
MAX TOPS TO 500. MEAN STORM MOTION VECTOR 29025.
LAT...LON 43499608 40839440 40839688 43499868
THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
FOR WOU3.
Watch 743 Status Report Messages:
STATUS REPORT #2 ON WW 743
VALID 240935Z - 241040Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 5 WNW SDA TO
15 S OMA TO 15 SE SUX TO 20 S SLB.
..BROYLES..07/24/08
ATTN...WFO...DMX...FSD...OAX...
&&
STATUS REPORT FOR WS 743
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC001-003-009-027-029-047-077-085-129-133-137-145-155-159-161-
165-173-175-241040-
IA
. IOWA COUNTIES INCLUDED ARE
ADAIR ADAMS AUDUBON
CARROLL CASS CRAWFORD
GUTHRIE HARRISON MILLS
MONONA MONTGOMERY PAGE
POTTAWATTAMIE RINGGOLD SAC
SHELBY TAYLOR UNION
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
STATUS REPORT #1 ON WW 743
VALID 240540Z - 240640Z
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..BROYLES..07/24/08
ATTN...WFO...DMX...FSD...OAX...
&&
STATUS REPORT FOR WS 743
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC001-003-009-027-029-035-047-071-077-085-093-119-129-133-137-
141-145-149-155-159-161-165-167-173-175-193-240640-
IA
. IOWA COUNTIES INCLUDED ARE
ADAIR ADAMS AUDUBON
CARROLL CASS CHEROKEE
CRAWFORD FREMONT GUTHRIE
HARRISON IDA LYON
MILLS MONONA MONTGOMERY
O'BRIEN PAGE PLYMOUTH
POTTAWATTAMIE RINGGOLD SAC
SHELBY SIOUX TAYLOR
UNION WOODBURY
$$
NEC003-011-021-023-025-027-037-039-043-051-053-055-107-109-119-
139-141-153-155-159-167-173-177-179-240640-
NE
. NEBRASKA COUNTIES INCLUDED ARE
ANTELOPE BOONE BURT
BUTLER CASS CEDAR
COLFAX CUMING DAKOTA
DIXON DODGE DOUGLAS
KNOX LANCASTER MADISON
PIERCE PLATTE SARPY
SAUNDERS SEWARD STANTON
THURSTON WASHINGTON WAYNE
$$
SDC009-023-027-043-067-083-125-127-135-240640-
SD
. SOUTH DAKOTA COUNTIES INCLUDED ARE
BON HOMME CHARLES MIX CLAY
DOUGLAS HUTCHINSON LINCOLN
TURNER UNION YANKTON
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
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
|
Low (20%)
|
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
|
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 
