487
FXUS63 KBIS 070614
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
114 AM CDT Fri Jun 7 2024

.KEY MESSAGES...

- By daybreak there will be chances (30 percent) for showers
  across the northwest. Then for the afternoon, chances (40
  percent) for thunderstorms over all but the far west and far
  north.

- Isolated showers (20 percent chance for rain) are forecast for
  Saturday and Sunday. Chances for rain with thunderstorms
  increase for the start of the work week (back to 30 to 40
  percent).

- With high confidence it is expected to be on the cooler side
  for Sunday and Monday, then warmer for the middle of next week
  with high temperatures in the 80s.

&&

.UPDATE...
Issued at 100 AM CDT Fri Jun 7 2024

Current surface analysis shows high pressure centered over
western North Dakota with a clear sky overhead. With the high
center over the forecast area winds had decreased to light and
variable (in direction). Temperatures were on track with
expectations for the midnight to 1 am hour and so subsequently
our forecast lows were also on track with no changes needed to
that forecast.

The first hint of our showers that are in the forecast for later
today are appearing on radar north of Glasgow, Montana, in
Saskatchewan. Movement was, as expected, to the southeast.

UPDATE
Issued at 927 PM CDT Thu Jun 6 2024

Winds have become light in most locations, although remain a
little breezy in the north. These winds will become light over
the next hour or two as well. All in all, the forecast remains
on track.

UPDATE
Issued at 708 PM CDT Thu Jun 6 2024

Windy conditions persist in a few locations, although most areas
have dropped below advisory criteria. In addition, winds will
continue to rapidly diminish this evening. Therefore, have
allowed the Wind Advisory to expire. Otherwise, mostly clear
skies are present and the forecast remains on track.

&&

.DISCUSSION...
Issued at 348 PM CDT Thu Jun 6 2024

At the moment, North Dakota sits under northwesterly upper level
flow, with a large trough digging across the Great Lakes to the
east, and a very broad ridge positioned across the western CONUS.
With lower surface pressure to the east, and higher pressure to the
west, a somewhat strong pressure gradient oriented northwest to
southeast also sits across the entire state, helping bring about
some rather strong northwesterly winds to much of western and
central North Dakota. Earlier model soundings suggested the
potential for 40 to 50 kt winds atop the mixed layer paired with
inverted-V profiles, which seems to have nearly entirely
transitioned these winds to the ground at this point. Many reports
of sustained northwesterly wind speeds in the mid to upper 30 mph
range have been reported today, with some gusts approaching 50 mph,
exceeding 50 mph in isolated instances. As such, we`ve continued our
Wind Advisory, which goes until 7 PM CDT tonight, when winds are
expected to decrease around sunset. There have also been some
reports of these winds kicking up dust, most notably across the
southern James River Valley, which could potentially reduce
visibilities to a half mile at times. We`ve added in some patchy
blowing dust to the forecast in this area as well, until the Wind
Advisory ends. While wind speeds are approaching warning criteria,
they`ve largely remained below, so we will continue with a Wind
Advisory at this time. Otherwise, generally clear skies are
expected, with some fair weather cumulus across the central and
James River Valley areas through the daytime hours. Highs today are
largely in the 70s, with overnight lows tonight in the 40s.

Heading into Friday, the aforementioned ridge is expected to flatten
out somewhat, as a quick moving shortwave trough drops southeast
through the area. Due to the transient nature of this wave, chances
for precipitation (mostly 20 to 40%) moves through the area from the
northwest corner to the southern James River Valley essentially
through the daytime hours. A small corridor of modest instability
and buoyancy across the south central may bring about some
thunderstorms for a few hours in the evening, though the chance for
these becoming severe is near 0. Otherwise, highs on Friday are
expected to range from the mid 60s in the north to the upper 70s in
the south. Some areas in the far south may see temperatures climb
into the 80s. Overnight lows are expected to remain largely in the
40s.

Through the weekend, the upper level pattern does not change very
much, and as such, the conditions across our area will be rather
similar Saturday through Monday morning. With a trough positioned to
our north, slowly descending south through Saskatchewan and
Manitoba, we remain under northwesterly upper level flow. Northern
portions of our area may see occasional sprinkles or showers, but
for the most part, we are expecting drier conditions, with highs
consistently in the upper 60s to mid 70s during this time. A relaxed
surface pressure gradient will help keep winds reduced as well. All
in all, it seems like it will be a rather quiet period of weather
through Monday morning.

Our next decent chances for precipitation arrives Monday through
Tuesday, as the aforementioned upper level low descends south into
the northern Great Plains. With ample forcing associated with this
wave, we may see a large swath of 20 to 40% chances for showers and
thunderstorms sweep across the state from west to east during this
time. Tentatively, long range guidance suggests the potential for
some strong storms associated with this wave, however confidence
remains rather low. The confidence in this upper level setup in
general is somewhat low as well, as the spread in NBM high
temperatures also increases during this time.

Following this precipitation, long range guidance suggests broad
ridging across the western CONUS, building into the Plains and
sitting there through the remainder of the week. As such, a warming
trend is currently forecast, with highs ranging from the mid 70s to
mid 80s by Tuesday and Wednesday. As mentioned before, the NBM
spreads in high temperatures are somewhat large, so the confidence
in the pattern progressing like this is still not set in stone, but
in general, we can anticipate warmer temperatures and drier
conditions through the second half of next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 100 AM CDT Fri Jun 7 2024

High pressure over western north Dakota will drift east as the
overnight hours drag on. A weak surface trough oriented
northeast to southwest will approach by daybreak Friday with an
increase in wind speed and a shift in direction. Along with
that will be isolated (20 percent) showers around KXWA through
the morning. Showers will move east and south toward KMOT and
KBIS into a more unstable atmosphere where isolated
-TSRA will be possible. By late afternoon -TSRA will be possible
 in the KJMS area. For now TAFs reflect VCSH during a several
 hour window of time until we can better refine timing of when
 thunder might be possible, if at all at the actual TAF
 locations. Ceilings and visibility will remain VFR through the
 TAF valid period.

&&

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

&&

$$

UPDATE...JPM
DISCUSSION...Besson
AVIATION...JPM