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 584
NWS STORM PREDICTION CENTER NORMAN OK
815 PM CDT TUE JUL 14 2009
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
CENTRAL AND NORTHERN IOWA
SOUTHEAST MINNESOTA
EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 815 PM
UNTIL 300 AM CDT.
HAIL TO 2.5 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 75
STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES NORTH
NORTHEAST OF MASON CITY IOWA TO 70 MILES SOUTH OF FORT DODGE
IOWA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).
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 583...
DISCUSSION...THUNDERSTORMS HAVE BEGUN TO INTENSIFY ALONG A COLD
FRONT OVER NORTHWEST IA AND SOUTHWEST MN. THESE STORMS WILL BECOME
MORE NUMEROUS THROUGH THE EVENING AND SPREAD EAST-SOUTHEASTWARD
ACROSS THE WATCH AREA. SUPERCELLS CAPABLE OF LARGE HAIL AND
DAMAGING WINDS ARE EXPECTED.
AVIATION...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 500. MEAN STORM
MOTION VECTOR 28030.
...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 584 SEVERE TSTM IA MN 150115Z - 150800Z
AXIS..75 STATUTE MILES EAST AND WEST OF LINE..
30NNE MCW/MASON CITY IA/ - 70S FOD/FORT DODGE IA/
..AVIATION COORDS.. 65NM E/W /29NNE MCW - 25WNW DSM/
HAIL SURFACE AND ALOFT..2.5 INCHES. WIND GUSTS..60 KNOTS.
MAX TOPS TO 500. MEAN STORM MOTION VECTOR 28030.
LAT...LON 43549159 41529275 41529565 43549459
THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
FOR WOU4.
Watch 584 Status Report Messages:
STATUS REPORT #1 ON WW 584
VALID 150555Z - 150640Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 10 E DSM TO
10 N ALO TO 15 ENE ALO.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1564
..SPC..07/15/09
ATTN...WFO...DMX...ARX...
&&
STATUS REPORT FOR WS 584
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC013-099-157-171-150640-
IA
. IOWA COUNTIES INCLUDED ARE
BLACK HAWK JASPER POWESHIEK
TAMA
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
Note:
Click for Complete Product Text.
Tornadoes
Probability of 2 or more tornadoes
|
Low (20%)
|
Probability of 1 or more strong (F2-F5) tornadoes
|
Low (5%)
|
Wind
Probability of 10 or more severe wind events
|
Mod (40%)
|
Probability of 1 or more wind events > 65 knots
|
Mod (30%)
|
Hail
Probability of 10 or more severe hail events
|
High (70%)
|
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 
