603
FXUS63 KBIS 170550
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1250 AM CDT Tue Jun 17 2025

.KEY MESSAGES...

- Isolated thunderstorm chances will remain through tonight,
  mainly in southern North Dakota. An isolated strong to severe
  storm is possible, with winds to 60 mph and hail to the size
  of a quarter.

- Patchy fog possible in central and eastern North Dakota
  overnight tonight into Tuesday morning.

- Active pattern with periodic shower and thunderstorm chances
  during the workweek into the weekend. A few severe storms are
  possible, more notably later in the week.

- Overall temperatures remain around average for this time of
  year.

&&

.UPDATE...
Issued at 1246 AM CDT Tue Jun 17 2025

Storms have decreased across our area as surface high pressure
moves into the region. No updates are needed at this time as the
forecast remains on track.

UPDATE
Issued at 1052 PM CDT Mon Jun 16 2025

Thunderstorm coverage is starting to diminish as instability
becomes more capped after sunset. A broad trough pattern and
elevated instability could still linger at least isolated
thunderstorm chances through tonight, mainly across southern
North Dakota where MUCAPE is modest. Effective bulk shear could
remain up to 40 knots, with some elevated 0 to 3 km shear, and
modest DCAPE. Thus winds to 60 mph are possible in any stronger
storms tonight. With enough elevated CAPE, some hail is also
possible. These will likely stay sub severe, unless any weak
rotation can be found in a stronger storm. Overall the threat
for severe weather is low tonight, although thunderstorms are
still possible across the south. Meanwhile, light winds and
increased moisture from recent rains could bring some patchy
fog tonight into Tuesday morning mainly across central and
eastern portions. Although confidence in this occurring are low
to moderate given dryer soundings than previous nights, added
mention of patchy fog in for this update.


UPDATE
Issued at 750 PM CDT Mon Jun 16 2025

Unstable air in a northwest flow pattern is providing for a few
showers and thunderstorms to develop across the northcentral.
MUCAPE in these areas is up to 2000 J/KG, with effective bulk
shear 30 to 40 knots. So far the storm mode has been discrete to
multicluster with limited rotation in them. They appear to be
more pulse like storms, with abundant CAPE and modest shear.
These storm can produce near severe criteria and will be worth
monitoring this evening. Remnant boundaries from past storms may
also play a role in enhancing these storms. All things
considered, the main hazards could be hail up to an inch in
diameter, or abundant small hail, and winds up to 60 mph. Worth
watching too are some thunderstorms in eastern MT that could
clip the far southwest. Timing for this would be later this
evening into the early overnight hours. Made some minor updates
to PoPs to account for thunderstorm potential through tonight.

&&

.DISCUSSION...
Issued at 147 PM CDT Mon Jun 16 2025

Currently, the remnants of the MCV are pushing from eastern
North Dakota into Minnesota. Surface pressure rises behind the
MCV are situated over southwest into south central ND with
meager pressure falls starting to develop from north central
into west central ND. Latest WV loop shows quite a bit of drier
air in the lower atmosphere pushing in behind the MCV but we
remain modestly unstable with MLCAPE values of 500-1000 J/KG
across the forecast area. There is a shortwave noted over
southern Saskatchewan with showers and thunderstorms increasing
over the southern Prairie Provinces, and even a couple cells
developing over northern North Dakota. Most of ND is within the
SPC general thunderstorm risk area. Area forecast soundings
indicate a couple hours of slight to moderate instability and
modest (north) to strong (far southwest) bulk shear. The far
southwest is the only area within the SPC marginal risk for
severe weather. Convection is beginning to fire in the higher
terrain of central Montana and northern Wyoming. The 12Z HREF
indicates the strongest path of UH tracks remaining to the south
of far southwest ND. Will have to keep an eye on this, but
right now, think the better probabilities here will stay out of
the state. In the north, and really the rest of the forecast
area, overall the severe potential looks to remain low, but a
few stronger cells can not be ruled out. Convection is expected
to taper this evening with the loss of heating.

Tuesday looks to be another day similar to today (temperature
wise) but with less instability and less bulk shear over the
area. Diurnally driven, isolated showers and possibly a
thunderstorm will be possible, but by and large expect a mostly
dry day with little to no severe potential.

Wednesday will bring another day with highs in the upper 70s to
lower 80s. Currently SPC has a general thunderstorm risk across
the forecast area. We do see a cold front drop south into the
forecast area from Canada. Forecast soundings from central and
northern ND do show an environment with more CAPE than today and
Tuesday, but not a lot of bulk shear. Soundings also show a
inverted V signature, with some speed and directional shear.
We`ll see how things develop, but think there might be some
potential for an upgrade to a marginal severe thunderstorm risk.
Thursday may bring a mostly dry day with high pressure at the
surface and aloft behind the Canadian cold front, although an
isolated diurnally driven thunderstorm chance will likely remain
in the forecast.

Thursday night into Friday we transition into a southwest upper
flow with surface low pressure ejecting from the central and
northern Rockies into the Northern Plains. A strong eastern
Pacific upper low will also move onto the Pacific Northwest
coast and track into the Northern Rockies, keeping a chance of
thunderstorms over the Northern Plains. The CSU ML page shows a
decent signal for severe storms Friday and Saturday. As the
upper trough approaches, cooler temperatures move in for Sunday,
although thunderstorm chances will probably linger.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1246 AM CDT Tue Jun 17 2025

VFR conditions will continue across the state today. There is a
low chance in patchy fog forming in low areas, the TAFs will be
amended if fog forms. Winds will remain light and variable this
morning veering to northwesterly to northerly this afternoon.

&&

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

&&

$$

UPDATE...Anglin/Johnson
DISCUSSION...TWH
AVIATION...Johnson