180
FXUS63 KBIS 061756
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1256 PM CDT Sat Jul 6 2024

.KEY MESSAGES...

- Scattered showers and thunderstorms (30 to 60%) are again
  expected today across western and central North Dakota.

- One more day of shower and thunderstorm chances (30 to 60%) on
  Sunday, with the better chances east.

- A gradual warming and drying trend is still expected for next
  week, with temperatures above normal by the end of the week.

&&

.UPDATE...
Issued at 1227 PM CDT Sat Jul 6 2024

Early this afternoon, an upper low continues to spin along the
North Dakota/South Dakota border over the south central. This
has kept shower and thunderstorm activity going over the James
River Valley. We continue to see new development on the western
edge of the precipitation shield in the wake of outflow and we
will have to watch the heavy rain potential with this activity
if we keep redeveloping over areas where heavy rain has already
fallen. The other thing to keep any eye on through the afternoon
is the potential for another round of potential weak
funnels/landspouts. Background surface vorticity from the upper
low, strong low level instability, and low shear all point to a
favorable environment; especially along the ongoing convection
across the James River Valley where the non-supercell tornado
parameter is already showing values up to 3.

UPDATE
Issued at 947 AM CDT Sat Jul 6 2024

No major changes were needed for this update. The heaviest
lightning activity remains generally in the Devil`s Lake Basin
and portions of the James River Valley. This activity will
slowly continue moving north northeast over the next couple
hours before exiting into the the Grand Forks forecast area. We
are still expecting numerous hit or miss showers and storms to
form once again this afternoon.

UPDATE
Issued at 624 AM CDT Sat Jul 6 2024

Two areas of showers/thunderstorms continue early this morning.
Line of storms continues to flare up along a sfc trough/boundary
as forcing associated with a mid level wave interacts across the
James River Valley. Second area is associated with the base of
the wave, which likely is closed off into a 700-500mb low, with
showers and at times thunderstorms arcing around the circulation
over south central into parts of southwest North Dakota. Both
areas will migrate east with time this morning. Could see
convection persisting over south central ND through much of the
morning based on model projections of the low`s movement. A few
lighter returns elsewhere within the larger mid level trough
over the region. POPs and other hourly weather elements were
updated based on latest observations and trends.

UPDATE
Issued at 504 AM CDT Sat Jul 6 2024

Quick update to expand POPs over the James River Valley.
Convection starting to flare up here along the sfc boundary and
in response to the incoming wave.

&&

.DISCUSSION...
Issued at 350 AM CDT Sat Jul 6 2024

Currently, mid level S/WV continues to develop easterly into
the Dakotas, centered over southwest North Dakota, with a sfc
trough extending from south central into northeastern North
Dakota. Showers and a few isolated thunderstorms persist along
the sfc trough, with an arc of showers wrapping around the main
circulation area of the mid level wave over my southwest. Expect
the activity along the sfc boundary to slowly diminish early
this morning as the boundary washes out/moves farther east.
Precipitation near the center of the mid level wave should
persist and develop eastward this morning as this feature
continues east along to slightly south of the ND/SD border.
While MLCAPE is decreasing, enough elevated instability present
to maintain thunder wording.

For today, expect another day of scattered showers and
thunderstorms with an unsettled atmosphere and decent
instability once again present over the local region. Shear
remain minimal so the threat for severe weather remains very
low. Mean flow aloft is weak today with a mid level trough over
the Northern Plains, so some potential for a few heavy rainers
with expected slow moving convection. Non-supercell Tor
parameters (NST) is also similar to the past couple of days, so
wouldn`t be surprised to see more funnel cloud reports during
the daytime. Showers and isolated storms will continue into this
evening, before diminishing later tonight as we lose heating.

Sunday looks like another active day, though we start to see the
better shower/storm coverage pushing more to the east as our
persistent trough sets up more over the Western Great Lakes
region and eastern Dakotas, in response to a strong upper level
ridge developing onshore over the west coastal region.

The aforementioned strong upper level ridge moving into the
western CONUS will continue to slowly nudge eastward through
next week. Ensemble blends continue to keep us in a
north/northwest flow pattern both Monday and Tuesday, and sure
enough NBM has now come in with some low POPs over my far east
both days. Most of our area will remain dry, though any wave
within the flow aloft could fire off diurnally driven
convection. Temperatures are still favored to slowly warm
through next week, finally approaching seasonal normal values
(low/mid 80s) by the middle of the week. Once the ridge moves
into and across the Rockies mid to late next week, temperatures
are favored to be above normal and the weather will be mainly
dry. High temperatures Thursday - Saturday are favored to be
well into the 80s and into the low/mid 90s.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1227 PM CDT Sat Jul 6 2024

For the most part we should see VFR conditions across western
and central North Dakota through the period. However, we will
see more scattered showers and thunderstorms again through the
day, diminishing in the evening. The best chances will generally
be north and east, including sites KXWA, KMOT, and KJMS. Due to
the hit or miss variety of these storms, will heavily lean on
vicinity wording in the forecast for now. The one exception is
at KJMS where ongoing showers and storms in and around the area
may lead to brief MVFR conditions over the next hour or so.
Further west and south (including KDIK and KBIS), shower and
storm coverage is a bit more uncertain and will refrain to
include precip in the forecast for these sites at this time.

&&

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

&&

$$

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