274
FXUS63 KBIS 111738
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1238 PM CDT Tue Jun 11 2024

.KEY MESSAGES...

- Near average temperatures are expected today. Highs on
  Wednesday will be the warmest of the week, with highs in the
  upper 70s to upper 80s. Some locations in the southern James
  River Valley could reach the lower 90s.

- Isolated showers and a few thunderstorms are possible tonight,
  with additional showers and storms (30% chance) Wednesday
  night and Thursday. Higher and more widespread precipitation
  chances are then forecast Friday night through the weekend.

&&

.UPDATE...
Issued at 1238 PM CDT Tue Jun 11 2024

In line with the CuRule tool, scattered diurnal cu has
developed over much of the eastern third of the CWA, especially
over the James River Valley through the Turtle Mountains.
Updated sky cover through the afternoon to cover the diurnal cu
trend. Otherwise, the forecast remains on track.

UPDATE Issued at 856 AM CDT Tue Jun 11 2024

The forecast remains on track with mostly sunny skies and quiet
weather this morning.

UPDATE
Issued at 642 AM CDT Tue Jun 11 2024

Deep low is in south central Manitoba, with breezy westerly
winds in north central North Dakota from the surface pressure
gradient. A few low clouds are drifting across the International
Border under the influence of the cyclonic flow, so did adjust
sky cover with this update. Otherwise quiet weather to start the
day, with current temperatures in the 50s. Some of the most
recent high-res guidance is showing slightly higher amounts of
instability tonight (although still relatively low), so made
sure to have mention of thunder across our southern counties,
although still expecting any activity to be very isolated.

&&

.DISCUSSION...
Issued at 418 AM CDT Tue Jun 11 2024

A compact shortwave trough and closed low were analyzed over
southwest Manitoba this morning, with a frontal boundary
exiting the eastern portion of the forecast area. Breezy winds
are ongoing across the north central under the influence of a
tightened pressure gradient from the surface low. Morning lows
will be in the upper 40s to upper 50s, with limited cloud cover
to start the day.

Under the cyclonic flow aloft today/tonight, isolated showers
are possible with any impulses that move through, with blended
POPs producing slight (20%) chances across the far north and
south central this evening, and across the southwest overnight.
Both today and tonight the main caveat with rain potential is
that forecast soundings are showing high clouds bases (over 10k
feet) and a significant dry layer above the surface, so either
very light rain or virga is the most likely scenario. Highs
today will be near to slightly above normal, in the upper 70s to
lower 80s.

The synoptic flow becomes more zonal on Wednesday, with an
approaching embedded wave and a low- level thermal ridge trying
to build in. The timing of the upper wave and attendant cold
front will determine how warm temperatures get, with forecast
highs in the upper 70s northwest (where the front reaches first)
to the upper 80s southern James River Valley. It is not out of
the question that we see some highs in the lower 90s in this
area, especially if the front slows up at all. The timing of the
front will also be critical for any thunderstorm potential.
Deterministic guidance is advertising bulk shear of 40-50 knots
and MLCAPE of 1000-2000 J/kg, with CSU Machine Learning
indicating higher hail and tornado probabilities just east of
the forecast area. The Day 2 outlook has the Marginal Risk
(level 1 out of 5) just clipping LaMoure and Dickey Counties,
which seems appropriate given what current high-res guidance is
advertising.

Scattered showers and thunderstorms are possible Wednesday
night into Thursday across the far north and south as additional
impulses move through the mean zonal flow, although POPs have
been changing the past few forecast cycles as the impulses are
low predictability. A shallow ridge is progged to build in
Thursday into Friday, while a deep upper low begins developing
off the coast of the Pacific Northwest. Ensemble guidance is in
fairly good agreement on southwest flow aloft persisting across
the Northern Plains through the weekend, helping an active
pattern set up starting Friday. Blended POPs begin increasing
during the day Friday and remain relatively stable through the
weekend as the aforementioned closed low starts to sink south
across the western CONUS. Southerly low-level flow to start the
weekend does look to increase available instability, and machine
learning probs highlight persistent (but low) probabilities for
severe weather through the weekend. Temperatures are favored to
be relatively steady, with highs generally in the lower 70s to
lower 80s, before potentially a slight cool down to start next
work week.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1238 PM CDT Tue Jun 11 2024

Breezy winds this afternoon will become light as the sun sets.
Breezy to windy conditions are expected out of the northwest again
Wednesday as a cold frontal boundary passes through. With the
frontal boundary, isolated showers may develop in the southwest
late tonight into Wednesday morning, although confidence on
timing and exact location is low at this time. Models also
suggest precipitation over northwestern ND tonight and south
central ND Wednesday morning. However, with dry air in place
near the surface, virga or sprinkles seem more favored than
anything. Overall, VFR ceilings and visibility are expected
through the period barring any passing precipitation.

&&

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

&&

$$

UPDATE...Telken
DISCUSSION...Jones
AVIATION...Telken