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.
SEL9
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 539
NWS STORM PREDICTION CENTER NORMAN OK
410 PM MDT THU JUL 2 2009
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
SOUTH CENTRAL MONTANA
EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 410 PM UNTIL
1100 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 55
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 20 MILES NORTHWEST
OF LIVINGSTON MONTANA TO 80 MILES EAST OF BILLINGS MONTANA. FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU9).
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 538...
DISCUSSION...INTENSE THUNDERSTORMS OVER CENTRAL MT WILL CONTINUE TO
SLOWLY DRIFT SOUTHEASTWARD THIS EVENING THROUGH AN AXIS OF MODERATE
INSTABILITY AND FAVORABLE VERTICAL SHEAR. ISOLATED SUPERCELLS
CAPABLE OF LARGE HAIL AND DAMAGING WINDS ARE POSSIBLE ACROSS THE
WATCH AREA.
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 30025.
...HART
Note:
The Aviation Watch (SAW) product is an approximation to the watch area.
The actual watch is depicted by the shaded areas.
SAW9
WW 539 SEVERE TSTM MT 022210Z - 030500Z
AXIS..55 STATUTE MILES NORTH AND SOUTH OF LINE..
20NW LVM/LIVINGSTON MT/ - 80E BIL/BILLINGS MT/
..AVIATION COORDS.. 50NM N/S /66SE HLN - 52SW MLS/
HAIL SURFACE AND ALOFT..2 INCHES. WIND GUSTS..60 KNOTS.
MAX TOPS TO 450. MEAN STORM MOTION VECTOR 30025.
LAT...LON 46701073 46580687 44990687 45111073
THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
FOR WOU9.
Watch 539 Status Report Messages:
STATUS REPORT #3 ON WW 539
VALID 030140Z - 030240Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 NE WEY TO
35 SE 3HT TO 40 SE LWT.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1410.
..PETERS..07/03/09
ATTN...WFO...BYZ...
&&
STATUS REPORT FOR WS 539
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MTC003-009-037-065-095-097-103-111-030240-
MT
. MONTANA COUNTIES INCLUDED ARE
BIG HORN CARBON GOLDEN VALLEY
MUSSELSHELL STILLWATER SWEET GRASS
TREASURE YELLOWSTONE
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
STATUS REPORT #2 ON WW 539
VALID 030040Z - 030140Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 SW LVM TO
25 S 3HT TO 20 NE 3HT.
..PETERS..07/03/09
ATTN...WFO...BYZ...
&&
STATUS REPORT FOR WS 539
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MTC003-009-037-065-067-095-097-103-107-111-030140-
MT
. MONTANA COUNTIES INCLUDED ARE
BIG HORN CARBON GOLDEN VALLEY
MUSSELSHELL PARK STILLWATER
SWEET GRASS TREASURE WHEATLAND
YELLOWSTONE
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
STATUS REPORT #1 ON WW 539
VALID 022345Z - 030040Z
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..PETERS..07/02/09
ATTN...WFO...BYZ...
&&
STATUS REPORT FOR WS 539
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MTC003-009-037-065-067-095-097-103-107-111-030040-
MT
. MONTANA COUNTIES INCLUDED ARE
BIG HORN CARBON GOLDEN VALLEY
MUSSELSHELL PARK STILLWATER
SWEET GRASS TREASURE WHEATLAND
YELLOWSTONE
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
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.
weather.gov 
