616
FXUS63 KBIS 191935
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
235 PM CDT Sun Jul 19 2026

.KEY MESSAGES...

- Isolated to scattered severe thunderstorms are possible this
  afternoon and evening. Expected hazards include hail as large
  as 2 inches in diameter and damaging winds up to 70 mph, with
  a tornado possible.

- Hot and humid today, with high temperatures and heat index
  values around 95 to 100.

- Windy on Monday, with near-critical to possibly critical fire
  weather conditions in the southwest and south central North
  Dakota.

- Cooler on Tuesday, then becoming hot once again by the end of
  the week.

&&

.DISCUSSION...
Issued at 235 PM CDT Sun Jul 19 2026

Currently there is near zonal flow over the Northern Plains as
the large ridge that is mostly over the CONUS has a flat top
now. An upper level low near Vancouver is creating a slight
southwest tilt in the flow over the northern Rockies and North
Dakota. This, along with some speed shear at the mid levels is
creating our severe storm risk today. At the surface there is
weak low pressure influence in the state, and a surface
trough/front that has moved east into western North Dakota.
Little to no clouds are currently floating around, except some
cumulus forming on the boundary in the southwest.

As the afternoon progresses, strong diurnal surface heating and
mixing will bring temperatures near 100 degrees across the west
and south. There is generally a large cap across most of the
severe risk area, however the forecast high temperatures are
near or above the convective temp to start surface based storms.
Otherwise storms may stay elevated like previously forecasted.
Model soundings across the area continue to show a strong dry
level near the surface shown by large invert V soundings.
Looking at DCAPE across the west and central, values are well
over 1000 J/kg. This lower dry air is a big limiting factor for
surface based storms to form, leading to the idea that these
will likely be elevated. MUCAPE is currently elevated and is
1000-2000 J/kg. The forecast CAPE axis by 00z is north to south
in the James River Valley with values up to 3000 J/kg. The shear
vector is currently straight off the boundary leading to
isolated (possibly supercells) forming, however with the
straighter hodographs splitting storms will be a very real
thing. Eventually the CAMs have these storms forming into a line
as the boundary becomes more parallel with the shear vectors.
This will be when 70 to 80 mph winds are possible as the dry air
surges the wind towards the surface.

Timing looks to be around 22/23z somewhere west of Highway 83.
When these isolated cells then hit the bigger CAPE to the east,
and the boundary is less straight on with the shear vectors is
when it would go linear around 8pm (somewhere east of Highway
83). With the high CAPE and shear values around 45kts, we are
still advertising 2 inch hail, which would happen when storms
are isolated still. Since storms could be splitting and possibly
reforming on outflow boundaries, there is a low brief tornado
risk when these storms interact with these boundaries. Based on
the CAMs these storms should be in the Red River Valley by
midnight.

Behind all these storms is a surface cold front that will move
into the northwest corner of the state by midnight.
Unfortunately this will carry near surface smoke with it.
Expected a hazy and smokey day Monday whether the smoke stays
elevated or mixes down. The thickest surface smoke is forecast
to move through the southwest half of the state overnight, but
may linger in the post frontal air through the day. Temperatures
from the cold front will generally only be cooler in the far
north around 80 degrees with the rest of the area still in the
90s. As with most cold fronts, northwest winds will gust 20 to
40 mph, especially in the central and James River Valley. There
are some fire weather concerns in the southwest and south
central but the wildland grasses just aren`t dry enough to be
concerned with the large uncontrollable fires that the Red Flag
Warning is intended for. We opted to just stick with the near to
possibly critical wording without any products. There is also a
low chance of isolated rain showers in the north Monday.

The rest of the week will restart the extreme warming trend as
another large ridge builds back in. By next weekend temperatures
will be back into the 100s, with likely heat headlines.


&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1236 PM CDT Sun Jul 19 2026

Mostly VFR through the period. This evening and early tonight
severe thunderstorms are possible, and may produce large hail
and erratic and gusty winds. A PROB30 was used where there is
higher confidence. Near surface smoke is likely tonight through
Monday carried in by a cold front, reducing VIS to at least
6SM. Winds this afternoon will be mostly southerly before
turning to the northwest overnight. Monday will be breezy with
winds gusting near 40kts in the afternoon.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 9 PM CDT /8 PM MDT/ this evening for
NDZ017>020-022-023-025-031>033-035>037-040>044-046>048-050-051-
057>062.

&&

$$

DISCUSSION...Smith
AVIATION...Smith