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.
SEL1
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 641
NWS Storm Prediction Center Norman OK
240 PM MDT Tue Aug 20 2024
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Southwest and Central Montana
* Effective this Tuesday afternoon and evening from 240 PM until
1000 PM MDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph possible
Isolated large hail events to 1.5 inches in diameter possible
SUMMARY...Thunderstorms will develop over the mountains of southwest
Montana this afternoon and spread quickly eastward across the watch
area through the evening. Damaging wind gusts are the main threat
with the strongest storms.
The severe thunderstorm watch area is approximately along and 85
statute miles north and south of a line from 20 miles north of
Dillon MT to 125 miles east northeast of Lewistown MT. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU1).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
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.
&&
AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
25030.
...Hart
Note:
The Aviation Watch (SAW) product is an approximation to the watch area.
The actual watch is depicted by the shaded areas.
SAW1
WW 641 SEVERE TSTM MT 202040Z - 210400Z
AXIS..85 STATUTE MILES NORTH AND SOUTH OF LINE..
20N DLN/DILLON MT/ - 125ENE LWT/LEWISTOWN MT/
..AVIATION COORDS.. 75NM N/S /17N DLN - 33SSW GGW/
HAIL SURFACE AND ALOFT..1.5 INCHES. WIND GUSTS..60 KNOTS.
MAX TOPS TO 500. MEAN STORM MOTION VECTOR 25030.
LAT...LON 46771255 48950699 46490699 44311255
THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
FOR WOU1.
Watch 641 Status Report Messages:
STATUS REPORT #6 ON WW 641
VALID 210230Z - 210340Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 ENE SHR
TO 65 N SHR TO 70 SSW GGW TO 70 NE LWT TO 65 NE HVR.
..HALBERT..08/21/24
ATTN...WFO...TFX...BYZ...GGW...
&&
STATUS REPORT FOR WS 641
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MTC033-071-087-105-210340-
MT
. MONTANA COUNTIES INCLUDED ARE
GARFIELD PHILLIPS ROSEBUD
VALLEY
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
STATUS REPORT #5 ON WW 641
VALID 210145Z - 210240Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 WNW SHR
TO 40 ENE BIL TO 45 NNE LWT TO 45 NNE HVR.
..HALBERT..08/21/24
ATTN...WFO...TFX...BYZ...GGW...
&&
STATUS REPORT FOR WS 641
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MTC003-005-033-069-071-087-103-105-210240-
MT
. MONTANA COUNTIES INCLUDED ARE
BIG HORN BLAINE GARFIELD
PETROLEUM PHILLIPS ROSEBUD
TREASURE VALLEY
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
STATUS REPORT #4 ON WW 641
VALID 210015Z - 210140Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 SSE MQM
TO 20 N DLN TO 25 WNW BZN TO 30 NW GTF AND 50 ENE WEY TO 50 ENE
GTF.
..HALBERT..08/21/24
ATTN...WFO...TFX...BYZ...GGW...
&&
STATUS REPORT FOR WS 641
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MTC003-005-009-015-027-033-037-041-045-065-069-071-087-095-097-
103-105-107-111-210140-
MT
. MONTANA COUNTIES INCLUDED ARE
BIG HORN BLAINE CARBON
CHOUTEAU FERGUS GARFIELD
GOLDEN VALLEY HILL JUDITH BASIN
MUSSELSHELL PETROLEUM PHILLIPS
ROSEBUD STILLWATER SWEET GRASS
TREASURE VALLEY 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 #3 ON WW 641
VALID 202345Z - 210040Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 SSE MQM
TO 20 N DLN TO 25 WNW BZN TO 30 NW GTF.
..HALBERT..08/20/24
ATTN...WFO...TFX...BYZ...GGW...
&&
STATUS REPORT FOR WS 641
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MTC003-005-007-009-013-015-027-031-033-037-041-045-057-059-065-
067-069-071-087-095-097-103-105-107-111-210040-
MT
. MONTANA COUNTIES INCLUDED ARE
BIG HORN BLAINE BROADWATER
CARBON CASCADE CHOUTEAU
FERGUS GALLATIN GARFIELD
GOLDEN VALLEY HILL JUDITH BASIN
MADISON MEAGHER MUSSELSHELL
PARK PETROLEUM PHILLIPS
ROSEBUD STILLWATER SWEET GRASS
TREASURE VALLEY 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 #2 ON WW 641
VALID 202230Z - 202340Z
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..HALBERT..08/20/24
ATTN...WFO...TFX...BYZ...GGW...
&&
STATUS REPORT FOR WS 641
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MTC001-003-005-007-009-013-015-027-031-033-037-041-043-045-049-
057-059-065-067-069-071-087-095-097-103-105-107-111-202340-
MT
. MONTANA COUNTIES INCLUDED ARE
BEAVERHEAD BIG HORN BLAINE
BROADWATER CARBON CASCADE
CHOUTEAU FERGUS GALLATIN
GARFIELD GOLDEN VALLEY HILL
JEFFERSON JUDITH BASIN LEWIS AND CLARK
MADISON MEAGHER MUSSELSHELL
PARK PETROLEUM PHILLIPS
ROSEBUD STILLWATER SWEET GRASS
TREASURE VALLEY 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 641
VALID 202150Z - 202240Z
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..HALBERT..08/20/24
ATTN...WFO...TFX...BYZ...GGW...
&&
STATUS REPORT FOR WS 641
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MTC001-003-005-007-009-013-015-027-031-033-037-041-043-045-049-
057-059-065-067-069-071-087-095-097-103-105-107-111-202240-
MT
. MONTANA COUNTIES INCLUDED ARE
BEAVERHEAD BIG HORN BLAINE
BROADWATER CARBON CASCADE
CHOUTEAU FERGUS GALLATIN
GARFIELD GOLDEN VALLEY HILL
JEFFERSON JUDITH BASIN LEWIS AND CLARK
MADISON MEAGHER MUSSELSHELL
PARK PETROLEUM PHILLIPS
ROSEBUD STILLWATER SWEET GRASS
TREASURE VALLEY 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 (<5%)
|
Probability of 1 or more strong (EF2-EF5) tornadoes
|
Low (<2%)
|
Wind
Probability of 10 or more severe wind events
|
Mod (50%)
|
Probability of 1 or more wind events > 65 knots
|
Low (20%)
|
Hail
Probability of 10 or more severe hail events
|
Low (20%)
|
Probability of 1 or more hailstones > 2 inches
|
Low (10%)
|
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% (EF2-EF5 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.
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