811
FXUS63 KBIS 151357
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
857 AM CDT Wed May 15 2024

.KEY MESSAGES...

- There will be daily chances for showers and thunderstorms
  through the week.

- Near average temperatures are expected this week, with highs
  in the mid 60s to mid 70s and lows in the 40s. Friday may be a
  bit warmer with highs in the 70s to low 80s.

&&

.UPDATE...
Issued at 855 AM CDT Wed May 15 2024

Rain showers continue over parts of south central North Dakota
into the James River Valley, but still expect a gradual
dissipation as the day goes on. With that said, the west edge
has been lingering longer than previously forecast, so will hold
higher chances in longer through much of the morning.

UPDATE
Issued at 634 AM CDT Wed May 15 2024

Some patchy fog has begun to develop across portions of the
state early this morning, most notably across the north central
portions of the state. We added in a large area of patchy fog,
mostly collocated with the lowest forecast cloud ceilings in
the north, until 10 AM, though this fog could certainly
dissipate earlier than that. Otherwise, some showers have begun
to form and move into the south central and southern James River
Valley, which is expected to continue through the day as it
moves east.

&&

.DISCUSSION...
Issued at 339 AM CDT Wed May 15 2024

Currently, surface low pressure to our south has been providing some
isolated to scattered showers across the border with South Dakota.
As the surface low moves to the northeast, these showers will
continue on moving along with it, increasing in coverage through the
morning, primarily in the eastern portions of the state. Otherwise,
mostly cloudy conditions are being observed across much of the area,
with some low stratus forming in the north. These low clouds are
forecast to expand south through the day, covering much of the area
by midday, then moving east heading into the evening. Lows this
morning will largely remain in the 40s to lower 50s.

A majority of the area will remain mostly dry through the day today,
while chances for precipitation begin to taper off across the
southern James River Valley. Much of that region will see 40 to 60%
chances for rain showers through the morning hours, before these
chances move out of the area heading into the evening. A quick
moving mid-level shortwave will then transit the state, bringing
about some weak chances (mostly 10 to 20%) of showers to the state
this evening and through the night. Thunderstorms are unlikely, and
the overall coverage seems pretty low, as the current chances for
wetting rain are rather low, maxing out at 20%. Highs today are
looking to be in the 60s, with overnight lows in the 40s.

Thursday appears to be a similar situation to today, with another
weak shortwave passing through the area, bringing about another
chance for showers and potentially some isolated thunderstorms,
mostly in the evening. PoPs are a bit higher with this system, with
widespread 30 to 40% chances for showers across essentially the
entire area. The threat for severe or strong storms remains minimal,
as the axis of highest instability is displaced off to the east,
though there is certainly still a chance for some thunderstorms to
develop throughout the day. Temperatures will trend a bit warmer,
with widespread highs in the mid 70s. Lows are expected to be in the
low 50s.

While Friday will once again see a similar situation to Thursday,
this wave appears to be a bit more pronounced and organized, which
may potentially raise the chances for strong to severe storm
development. These chances are still relatively low though, given
how conditional this threat will be. Long range deterministic
guidance suggests ample instability paired with a decent amount of
shear, with a brief period where these two corridors overlap.
However, the overall forcing for these storms seems to be lagging
behind to the west, which would hamper the development of anything
severe. If there is a brief moment where these all overlap with one
another, mostly across the central portions of the state, then there
could be a chance for one of those storms to become strong to
severe. We`ll continue to monitor this setup for anything
substantial, but at the moment, the SPC has our area in just a
General Thunderstorm risk area. The CSU machine learning severe
guidance has very low chances for severe hail across central
and eastern North Dakota, but these chances are not zero. Highs
on Friday are forecast to trend slightly higher, with highs in
the mid 70s to lower 80s. Lows are expected to be in the mid 40s
to lower 50s.

This active pattern is then expected to continue through the weekend
and into next week, with quite a bit of model spread in terms of the
upper level flow pattern. We can expect to see continued chances for
showers and thunderstorms, as well as high temperatures largely in
the 60s to 70s. Lows will remain firmly in the 40s to lower 50s, and
with low NBM spreads, the concerns for any frost development is
minimal.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 634 AM CDT Wed May 15 2024

Low clouds, fog, or rain showers have brought about MVFR and
IFR conditions to portions of the area, and will continue to
remain this way for at least a few more hours. KBIS and KMOT
currently have IFR ceilings, while KXWA and KDIK currently have
MVFR ceilings, with visibility reductions at KDIK due to fog.
KMOT currently has no reported fog, but multiple reports
surrounding the area have brought about reduced visibilities, so
added in fog for a few hours there as well. KJMS is currently
VFR, though showers in the vicinity and a lowering cloud deck
approaching from the northwest should bring them into MVFR and
IFR conditions within the next few hours. These low ceilings
will move south this morning, before sliding off to the east
through the 18z to 00z timeframe. The fog should dissipate
within the next few hours. Gradual cloud clearing can be
expected through the second half of the TAF period, along with a
shift in winds from northerly to southerly, specifically from
the 02z to 06z timeframe.

&&

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

&&

$$

UPDATE...Besson/JJS
DISCUSSION...Besson
AVIATION...Besson