Note:
The expiration time in the watch graphic is amended if the watch is
replaced, cancelled or extended.
Note: Click for
Watch Status Reports.
SEL3
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 283
NWS STORM PREDICTION CENTER NORMAN OK
655 PM CDT SAT MAY 19 2012
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
NORTHWEST IOWA
FAR NORTHEAST NEBRASKA
EFFECTIVE THIS SATURDAY NIGHT AND SUNDAY MORNING FROM 655 PM
UNTIL 200 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 60
STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES SOUTH OF
SIOUX CITY IOWA TO 30 MILES NORTHEAST OF SPENCER IOWA. 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 281...WW 282...
DISCUSSION...SEVERE TSTMS IN PROGRESS OVER ERN NEB ARE EXPECTED TO
MOVE/DEVELOP NEWD ACROSS THE WATCH AREA THIS EVENING INTO TONIGHT IN
ADVANCE OF MIDLEVEL VORTICITY MAXIMUM CURRENTLY OVER S-CNTRL NEB.
00Z OAX SOUNDING INDICATES THAT PRE-FRONTAL AIR MASS HAS BECOME
MODERATELY UNSTABLE OWING TO STEEP LAPSE RATES AND A RELATIVELY
MOIST BOUNDARY LAYER. WHEN COUPLED WITH AROUND 40 KT OF DEEP SWLY
SHEAR...SETUP WILL SUPPORT POSSIBLE SUPERCELL STRUCTURES WITH A RISK
FOR LARGE HAIL AND DAMAGING WINDS.
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 24025.
...MEAD
Note:
The Aviation Watch (SAW) product is an approximation to the watch area.
The actual watch is depicted by the shaded areas.
SAW3
WW 283 SEVERE TSTM IA NE 192355Z - 200700Z
AXIS..60 STATUTE MILES EAST AND WEST OF LINE..
35S SUX/SIOUX CITY IA/ - 30NE SPW/SPENCER IA/
..AVIATION COORDS.. 50NM E/W /52NNW OVR - 55NNW FOD/
HAIL SURFACE AND ALOFT..2 INCHES. WIND GUSTS..60 KNOTS.
MAX TOPS TO 500. MEAN STORM MOTION VECTOR 24025.
LAT...LON 41889755 43479591 43479352 41889520
THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
FOR WOU3.
Watch 283 Status Report Messages:
STATUS REPORT #4 ON WW 283
VALID 200430Z - 200540Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 10 NNW TQE
TO 15 SSE FRM.
..GRAMS..05/20/12
ATTN...WFO...DMX...FSD...
&&
STATUS REPORT FOR WS 283
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC001-009-021-025-027-029-047-073-077-091-093-109-147-151-161-
187-200540-
IA
. IOWA COUNTIES INCLUDED ARE
ADAIR AUDUBON BUENA VISTA
CALHOUN CARROLL CASS
CRAWFORD GREENE GUTHRIE
HUMBOLDT IDA KOSSUTH
PALO ALTO POCAHONTAS SAC
WEBSTER
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
STATUS REPORT #3 ON WW 283
VALID 200335Z - 200440Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 WNW TQE
TO 25 NE SUX TO 20 SW OTG.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 845.
..GRAMS..05/20/12
ATTN...WFO...DMX...FSD...
&&
STATUS REPORT FOR WS 283
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC001-009-021-025-027-029-035-041-047-059-063-073-077-091-093-
109-141-147-151-161-187-193-200440-
IA
. IOWA COUNTIES INCLUDED ARE
ADAIR AUDUBON BUENA VISTA
CALHOUN CARROLL CASS
CHEROKEE CLAY CRAWFORD
DICKINSON EMMET GREENE
GUTHRIE HUMBOLDT IDA
KOSSUTH O'BRIEN PALO ALTO
POCAHONTAS SAC WEBSTER
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 #2 ON WW 283
VALID 200230Z - 200340Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 W TQE TO
30 ESE YKN.
..ROGERS..05/20/12
ATTN...WFO...DMX...FSD...
&&
STATUS REPORT FOR WS 283
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC009-021-025-027-035-041-047-059-063-073-091-093-109-141-147-
149-151-161-187-193-200340-
IA
. IOWA COUNTIES INCLUDED ARE
AUDUBON BUENA VISTA CALHOUN
CARROLL CHEROKEE CLAY
CRAWFORD DICKINSON EMMET
GREENE HUMBOLDT IDA
KOSSUTH O'BRIEN PALO ALTO
PLYMOUTH POCAHONTAS SAC
WEBSTER WOODBURY
$$
NEC043-200340-
NE
. NEBRASKA COUNTIES INCLUDED ARE
DAKOTA
$$
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.
$$
STATUS REPORT #1 ON WW 283
VALID 200135Z - 200240Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 W TQE TO
30 ESE YKN.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 843
..ROGERS..05/20/12
ATTN...WFO...DMX...FSD...
&&
STATUS REPORT FOR WS 283
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC009-021-025-027-035-041-047-059-063-073-091-093-109-141-147-
149-151-161-187-193-200240-
IA
. IOWA COUNTIES INCLUDED ARE
AUDUBON BUENA VISTA CALHOUN
CARROLL CHEROKEE CLAY
CRAWFORD DICKINSON EMMET
GREENE HUMBOLDT IDA
KOSSUTH O'BRIEN PALO ALTO
PLYMOUTH POCAHONTAS SAC
WEBSTER WOODBURY
$$
NEC043-200240-
NE
. NEBRASKA COUNTIES INCLUDED ARE
DAKOTA
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
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
|
Mod (30%)
|
Hail
Probability of 10 or more severe hail events
|
Mod (30%)
|
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 (70%)
|
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.