997 
FXUS63 KBIS 210503
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1203 AM CDT Sat Jun 21 2025

.KEY MESSAGES...

- Thunderstorms with damaging winds continue over portions of
  the James River Valley. Storms will be diminishing over the
  next couple of hours. 

- There is a marginal risk (level 1 out of 5) for severe 
  weather both Saturday and Sunday. Cooler and breezy conditions
  are expected Sunday. 

- The active weather pattern continues, with additional chances
  for showers and thunderstorms next week along with
  temperatures trending cooler.

&&

.UPDATE...
Issued at 1156 PM CDT Fri Jun 20 2025

Quick update to cancel Tornado Watch 448 across all counties 
except for Wells, Foster, Kidder, Stutsman, LaMoure, and Dickey 
Counties where damaging winds continue to be observed. 

UPDATE
Issued at 948 PM CDT Fri Jun 20 2025

The remaining counties (west of the Missouri River) in the 
severe thunderstorm watch are expected to expire at 10 PM. The
Tornado watch remains in effect for much of central and eastern
North Dakota through 3 AM CDT. Very strong winds in excess of 80
mph and torrential rain have been reported with this line. The
potential also exists for tornados to spin up along the leading
edge of the line. To the east, tornadic supercells are moving 
into eastern ND.

Adjusted pops a bit with this update. Will send out updated text
products shortly. 

UPDATE
Issued at 838 PM CDT Fri Jun 20 2025

A tornado watch has been issued for much of central and eastern
North Dakota until 3 AM Saturday morning. The atmosphere remains
conducive for severe thunderstorms, including tornados across
central and eastern North Dakota. Farther west, a large complex
of storms is tracking through western and into central ND. Winds
of over 90 mph have been reported within this line of storms. Be
weather aware tonight.

UPDATE
Issued at 659 PM CDT Fri Jun 20 2025

Forecast thinking for this evening's severe threat remains
unchanged from earlier Mesoscale Discussion above. The most
intense supercell has remained just across the South Dakota
border thus far, and right moving Bunkers vectors would keep it
just south. Storms to the north are showing signs of
intensifying though. The most likely outcome is for congealing
into a linear system with bowing segments as it approaches south
central North Dakota mid to late evening. We are also now
starting to see attempts at convective initiation along an
elevated warm front southwest of Jamestown. If convection can
become fully established in this part of the state, explosive
growth into severe convection could occur.

&&

.DISCUSSION...
Issued at 255 PM CDT Fri Jun 20 2025

Currently, broad upper level ridge anchored just east of the 
Great Plains today, with ridging over eastern North Dakota and 
southwest flow aloft across the western Dakotas. 

An elevated Severe Weather risk remains for much of western and
central North Dakota this afternoon and evening, with robust
CAPE and wind shear. Height falls will start to spread across 
the western Dakotas later this afternoon and evening as a mid 
level S/WV lifts northeast into the region. CAMs have been 
fluctuating the past several hours, but it appears a more likely
scenario is for convection initializing across southeast 
Montana/southwestern North Dakota just ahead of the wave, then 
moving/propagating east-northeast into western and central ND 
by around and after 22-23z or so, along to just north of a west
to east orientated warm front. Noticed a CU field flaring up in
southeast MT the past hour. The chances for initial discrete 
convection over south central and southeastern ND appears 
minimal with BUFKIT sounding analysis indicating a rather stout 
capping inversion. At the same time, hodographs south central 
and southeast along the warm front continue to depict favorable 
shear/helicity highly favorable for rotating storms and possible
tornadoes, especially if convection remains discrete and lasts 
into the evening when hodographs become even more supportive of 
strong low level rotation. But, as mentioned, CAMs support 
convective initialization southwest, morphing into a wind threat
if bowing lines form. Will need to monitor closely for storm 
mode through the evening as anything sfc based south 
central/southeast could become problematic.

Models take storms quickly east out of our area by around 06z
tonight, though another embedded wave may lead to additional 
thunderstorm activity west overnight and into Saturday morning. 
A few elevated strong to severe storms could be possible with 
this activity as MUCAPE is forecast to still range from 1000 to
2000 J/kg with deep layer shear remaining robust up to 60 
knots. These storms may continue or re-develop into Sat 
afternoon across the north along an instability gradient but are
favored to remain elevated in nature. Large hail would likely 
be the main threat with this activity but a few damaging wind 
gusts would also be possible. Instability on Saturday is much 
stronger further south, but limited forcing and capping should 
keep convection from developing there.

Strong southwest flow aloft on Sunday with multiple embedded
S/WVs moving through in flow aloft will maintain a chance for
showers and thunderstorms. Despite cooler conditions and less
CAPE, cannot rule out a marginal risk (via SPC) for a few 
strong storms with 0-6km shear ranging from 50-75 kts. Any CAPE
will be decreasing from west to east though, so any robust
storms would have to be within the trailing instability
corridor.  

Upper trough over the western CONUS next week will maintain 
southwest flow aloft and an active weather pattern. Temperatures
trend cooler Sunday and onwards, with continued chances for 
showers and a few thunderstorms each day. Windy conditions also 
for Sunday as the initial cold front moves through the general 
region.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 659 PM CDT Fri Jun 20 2025

Scattered to numerous strong to severe thunderstorms are possible 
across much of western and central North Dakota this evening, 
especially across the southern half of the area. The most intense 
storms will be capable of very large hail and wind gusts as high as 
60-65 kts. Categorical visibility restrictions can be expected with 
any storm. Another batch of thunderstorms could cross northwest 
North Dakota early Saturday morning, but these are less likely to be 
severe. MVFR/IFR ceilings are forecast to develop across much of 
western and north central North Dakota later tonight into Saturday 
morning, and patchy fog cannot be ruled out at any location. Outside 
of storms, winds will mostly be northerly to easterly around 10
kts.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...ZH
DISCUSSION...NH
AVIATION...Hollan