Note:
The expiration time in the watch graphic is amended if the watch is
replaced, cancelled or extended.
Note: Click for
Watch Status Reports.
SEL0
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 270
NWS STORM PREDICTION CENTER NORMAN OK
125 PM CDT FRI MAY 8 2009
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
MUCH OF IOWA
EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 125 PM UNTIL 800
PM 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 80
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES SOUTH
SOUTHWEST OF DENISON IOWA TO 50 MILES NORTH NORTHEAST OF OTTUMWA
IOWA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).
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 267...WW 268...WW 269...
DISCUSSION...STRONG S/WV TROUGH AND JET MAX MOVING RAPIDLY EWD
ACROSS NEB WILL PROVIDE SHEAR AND ASCENT TO DEVELOP SEVERE
THUNDERSTORMS ACROSS WATCH AREA WHERE AIR MASS IS MODESTLY MOIST AND
UNSTABLE. PRIMARY THREAT INITIALLY WILL BE LARGE HAIL WITH WIND
DAMAGE INCREASING DURING THE AFTERNOON AS STORMS DEVELOP UPSCALE
INTO BOWS AND LINE SEGMENTS.
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 450. MEAN STORM
MOTION VECTOR 27030.
...HALES
Note:
The Aviation Watch (SAW) product is an approximation to the watch area.
The actual watch is depicted by the shaded areas.
SAW0
WW 270 SEVERE TSTM IA 081825Z - 090100Z
AXIS..80 STATUTE MILES NORTH AND SOUTH OF LINE..
25SSW DNS/DENISON IA/ - 50NNE OTM/OTTUMWA IA/
..AVIATION COORDS.. 70NM N/S /30NNE OVR - 26NW IOW/
HAIL SURFACE AND ALOFT..2 INCHES. WIND GUSTS..60 KNOTS.
MAX TOPS TO 450. MEAN STORM MOTION VECTOR 27030.
LAT...LON 42799556 42939208 40619208 40499556
THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
FOR WOU0.
Watch 270 Status Report Messages:
STATUS REPORT #4 ON WW 270
VALID 082345Z - 090040Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 E LWD TO
25 SSE OXV TO 20 NNW OTM TO 25 SW CID TO 15 N CID.
..JEWELL..05/08/09
ATTN...WFO...DMX...OAX...
&&
STATUS REPORT FOR WS 270
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC007-051-123-135-179-090040-
IA
. IOWA COUNTIES INCLUDED ARE
APPANOOSE DAVIS MAHASKA
MONROE WAPELLO
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
STATUS REPORT #3 ON WW 270
VALID 082305Z - 090040Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 ESE LWD
TO 30 NE LWD TO OXV TO 20 E ALO.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 767
..JEWELL..05/08/09
ATTN...WFO...DMX...OAX...
&&
STATUS REPORT FOR WS 270
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC007-051-117-123-125-135-157-179-185-090040-
IA
. IOWA COUNTIES INCLUDED ARE
APPANOOSE DAVIS LUCAS
MAHASKA MARION MONROE
POWESHIEK WAPELLO WAYNE
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
STATUS REPORT #2 ON WW 270
VALID 082155Z - 082240Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 SE SDA TO
30 ENE SDA TO 45 SW DSM TO 20 N DSM TO 40 ESE FOD TO 10 ESE MCW.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 765
..JEWELL..05/08/09
ATTN...WFO...DMX...OAX...
&&
STATUS REPORT FOR WS 270
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC007-013-017-023-039-049-051-053-069-075-083-099-117-121-123-
125-127-135-153-157-159-169-171-173-175-179-181-185-082240-
IA
. IOWA COUNTIES INCLUDED ARE
APPANOOSE BLACK HAWK BREMER
BUTLER CLARKE DALLAS
DAVIS DECATUR FRANKLIN
GRUNDY HARDIN JASPER
LUCAS MADISON MAHASKA
MARION MARSHALL MONROE
POLK POWESHIEK RINGGOLD
STORY TAMA TAYLOR
UNION WAPELLO WARREN
WAYNE
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
STATUS REPORT #1 ON WW 270
VALID 082045Z - 082140Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 5 W SDA TO
35 SE DNS TO 20 NNW FOD.
..GRAMS..05/08/09
ATTN...WFO...DMX...OAX...
&&
STATUS REPORT FOR WS 270
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC001-003-007-009-013-015-017-023-029-039-049-051-053-069-073-
075-077-079-083-091-099-117-121-123-125-127-135-137-145-153-157-
159-169-171-173-175-179-181-185-187-197-082140-
IA
. IOWA COUNTIES INCLUDED ARE
ADAIR ADAMS APPANOOSE
AUDUBON BLACK HAWK BOONE
BREMER BUTLER CASS
CLARKE DALLAS DAVIS
DECATUR FRANKLIN GREENE
GRUNDY GUTHRIE HAMILTON
HARDIN HUMBOLDT JASPER
LUCAS MADISON MAHASKA
MARION MARSHALL MONROE
MONTGOMERY PAGE POLK
POWESHIEK RINGGOLD STORY
TAMA TAYLOR UNION
WAPELLO WARREN WAYNE
WEBSTER WRIGHT
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
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 (30%)
|
Probability of 1 or more wind events > 65 knots
|
Low (20%)
|
Hail
Probability of 10 or more severe hail events
|
Mod (60%)
|
Probability
of 1 or
more hailstones > 2 inches
|
Low (20%)
|
Combined Severe Hail/Wind
Probability of 6 or more combined severe hail/wind events
|
High (80%)
|
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 
