Note:
The expiration time in the watch graphic is amended if the watch is
replaced, cancelled or extended.
Note: Click for
Watch Status Reports.
SEL7
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 397
NWS Storm Prediction Center Norman OK
230 PM MDT Thu Jul 23 2020
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Eastern Montana
Western North Dakota
Northwest South Dakota
* Effective this Thursday afternoon and evening from 230 PM until
900 PM MDT.
* Primary threats include...
Scattered large hail and isolated very large hail events to 2
inches in diameter possible
Scattered damaging wind gusts to 70 mph possible
A tornado or two possible
SUMMARY...Thunderstorms are expected to develop this afternoon over
eastern Montana and build north-northeastward across the watch area.
The strongest cells will be capable of large hail and damaging
winds.
The severe thunderstorm watch area is approximately along and 55
statute miles east and west of a line from 70 miles north northwest
of Williston ND to 50 miles south southeast of Buffalo SD. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU7).
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.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 395...WW 396...
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
21030.
...Hart
Note:
The Aviation Watch (SAW) product is an approximation to the watch area.
The actual watch is depicted by the shaded areas.
SAW7
WW 397 SEVERE TSTM MT ND SD 232030Z - 240300Z
AXIS..55 STATUTE MILES EAST AND WEST OF LINE..
70NNW ISN/WILLISTON ND/ - 50SSE 2WX/BUFFALO SD/
..AVIATION COORDS.. 50NM E/W /61NNW ISN - 56N RAP/
HAIL SURFACE AND ALOFT..2 INCHES. WIND GUSTS..60 KNOTS.
MAX TOPS TO 500. MEAN STORM MOTION VECTOR 21030.
LAT...LON 49110301 44900201 44900425 49110544
THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
FOR WOU7.
Watch 397 Status Report Messages:
STATUS REPORT #2 ON WW 397
VALID 240145Z - 240240Z
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 NE DIK TO
35 NE BHK TO 15 SE GDV TO 75 N OLF.
..BROYLES..07/24/20
ATTN...WFO...GGW...BYZ...BIS...UNR...
&&
STATUS REPORT FOR WS 397
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MTC083-085-091-109-240240-
MT
. MONTANA COUNTIES INCLUDED ARE
RICHLAND ROOSEVELT SHERIDAN
WIBAUX
$$
NDC007-023-025-033-053-105-240240-
ND
. NORTH DAKOTA COUNTIES INCLUDED ARE
BILLINGS DIVIDE DUNN
GOLDEN VALLEY MCKENZIE WILLIAMS
$$
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.
$$
STATUS REPORT #1 ON WW 397
VALID 232305Z - 240040Z
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..BROYLES..07/23/20
ATTN...WFO...GGW...BYZ...BIS...UNR...
&&
STATUS REPORT FOR WS 397
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MTC019-021-025-079-083-085-091-109-240040-
MT
. MONTANA COUNTIES INCLUDED ARE
DANIELS DAWSON FALLON
PRAIRIE RICHLAND ROOSEVELT
SHERIDAN WIBAUX
$$
NDC001-007-011-023-025-033-041-053-087-089-105-240040-
ND
. NORTH DAKOTA COUNTIES INCLUDED ARE
ADAMS BILLINGS BOWMAN
DIVIDE DUNN GOLDEN VALLEY
HETTINGER MCKENZIE SLOPE
STARK WILLIAMS
$$
SDC019-063-105-240040-
SD
. SOUTH DAKOTA COUNTIES INCLUDED ARE
BUTTE HARDING PERKINS
$$
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 (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
|
Mod (50%)
|
Probability of 1 or more hailstones > 2 inches
|
Mod (30%)
|
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% (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.
weather.gov 
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