Note:
The expiration time in the watch graphic is amended if the watch is
replaced, cancelled or extended.
Note: Click for
Watch Status Reports.
SEL6
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 576
NWS STORM PREDICTION CENTER NORMAN OK
1000 AM MDT MON JUL 13 2009
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
SOUTHWEST NORTH DAKOTA
CENTRAL SOUTH DAKOTA
EFFECTIVE THIS MONDAY MORNING AND AFTERNOON FROM 1000 AM UNTIL
400 PM MDT.
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 70 MILES NORTH
NORTHEAST OF LEMMON SOUTH DAKOTA TO 40 MILES WEST OF CHAMBERLAIN
SOUTH DAKOTA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).
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.
DISCUSSION...THREAT FOR ELEVATED SUPERCELLS CAPABLE OF PRODUCING
LARGE HAIL WILL PERSIST INTO THE AFTERNOON ALONG AND JUST NE OF THE
WARM FRONT IN ND/SD...WHERE LOW-LEVEL WAA AND ASCENT ARE FOCUSED IN
ADVANCE OF A WEAK LEAD SHORTWAVE TROUGH. BY MID AFTERNOON...THE WRN
PORTIONS OF THE WATCH AREA WILL LIKELY BE REPLACED WITH A TORNADO
WATCH TO REFLECT AN INCREASING TORNADO THREAT AS THE WARM FRONT
LIFTS SLOWLY NEWD AND THE BOUNDARY LAYER DESTABILIZES.
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 31020.
...THOMPSON
Note:
The Aviation Watch (SAW) product is an approximation to the watch area.
The actual watch is depicted by the shaded areas.
SAW6
WW 576 SEVERE TSTM ND SD 131600Z - 132200Z
AXIS..60 STATUTE MILES EAST AND WEST OF LINE..
70NNE Y22/LEMMON SD/ - 40W 9V9/CHAMBERLAIN SD/
..AVIATION COORDS.. 50NM E/W /39W BIS - 38S PIR/
HAIL SURFACE AND ALOFT..2 INCHES. WIND GUSTS..60 KNOTS.
MAX TOPS TO 500. MEAN STORM MOTION VECTOR 31020.
LAT...LON 46860033 43759891 43750131 46860287
THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
FOR WOU6.
Watch 576 Status Report Messages:
STATUS REPORT #3 ON WW 576
VALID 132040Z - 132140Z
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..MEAD..07/13/09
ATTN...WFO...BIS...ABR...UNR...
&&
STATUS REPORT FOR WS 576
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
NDC001-029-037-041-059-085-089-132140-
ND
. NORTH DAKOTA COUNTIES INCLUDED ARE
ADAMS EMMONS GRANT
HETTINGER MORTON SIOUX
STARK
$$
SDC017-021-031-041-069-107-119-129-132140-
SD
. SOUTH DAKOTA COUNTIES INCLUDED ARE
BUFFALO CAMPBELL CORSON
DEWEY HYDE POTTER
SULLY WALWORTH
$$
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.
$$
STATUS REPORT #2 ON WW 576
VALID 131935Z - 132040Z
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..MEAD..07/13/09
ATTN...WFO...BIS...ABR...UNR...
&&
STATUS REPORT FOR WS 576
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
NDC001-029-037-041-059-085-089-132040-
ND
. NORTH DAKOTA COUNTIES INCLUDED ARE
ADAMS EMMONS GRANT
HETTINGER MORTON SIOUX
STARK
$$
SDC017-021-031-041-069-107-119-129-132040-
SD
. SOUTH DAKOTA COUNTIES INCLUDED ARE
BUFFALO CAMPBELL CORSON
DEWEY HYDE POTTER
SULLY WALWORTH
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
STATUS REPORT #1 ON WW 576
VALID 131750Z - 131840Z
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..MEAD..07/13/09
ATTN...WFO...BIS...ABR...UNR...
&&
STATUS REPORT FOR WS 576
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
NDC001-029-037-041-059-085-089-131840-
ND
. NORTH DAKOTA COUNTIES INCLUDED ARE
ADAMS EMMONS GRANT
HETTINGER MORTON SIOUX
STARK
$$
SDC017-019-021-031-041-055-063-065-069-071-075-085-095-105-107-
117-119-123-129-137-131840-
SD
. SOUTH DAKOTA COUNTIES INCLUDED ARE
BUFFALO BUTTE CAMPBELL
CORSON DEWEY HAAKON
HARDING HUGHES HYDE
JACKSON JONES LYMAN
MELLETTE PERKINS POTTER
STANLEY SULLY TRIPP
WALWORTH ZIEBACH
$$
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
|
Low (20%)
|
Probability of 1 or more wind events > 65 knots
|
Mod (30%)
|
Hail
Probability of 10 or more severe hail events
|
Mod (50%)
|
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 (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.