962
FXUS63 KBIS 122047
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
347 PM CDT Wed Jun 12 2024

.KEY MESSAGES...

- Breezy winds will decrease through the rest of the day. Later
  tonight, there is a slight chance (10 to 30%) of showers
  across the southern border of the state.

- Higher chances (30 to 50%) for more widespread precipitation,
  along with the potential for severe weather, is forecast
  Friday, extending through the weekend.

- High temperatures are forecast to peak in the 80s on Saturday,
  with a gradual cooling trend expected to follow.

&&

.DISCUSSION...
Issued at 348 PM CDT Wed Jun 12 2024

At the moment, a weak cold front oriented northeast to southwest is
positioned across the southern James River Valley and far south
central North Dakota. The winds aren`t necessarily shifting much
with this boundary, but dew point depressions have increased quite a
bit in locations behind the front. This front is expected to be one
of the main forcing mechanisms behind the severe weather potential
across the northern Great Lakes region, and as such, the severe
threat has diminished to near zero across the far southern James
River Valley due to how quickly it has moved through the area. While
we technically still have a very small Marginal Risk (level 1 of 5)
from the SPC across far eastern Dickey County, we are expecting the
front to be out of our area by the time this risk is the highest.
The PoPs in this area are also nearly negligible, a further
indicator of our confidence that severe storms are not likely in
this area. Otherwise, surface high pressure sits to our east across
Montana, with zonal upper level flow present across the northern
Plains. Mostly clear skies are present, with some pockets of diurnal
cumulus forming, mostly across the northwest. Skies will continue to
remain clear overnight, where overnight lows in the upper 40s to mid
50s are forecast. There is a slight chance (10 to 30%) for some
showers late tonight across the far south, with a very weak midlevel
trough stretching into South Dakota, however this area of
precipitation will be almost entirely confined to the South Dakota
side of the border.

Thursday will see the beginning of a shift in the pattern, with a
ridge building in from the west. A weak midlevel wave riding along
the apex of this ridge is forecast to move southeast across eastern
North Dakota through the day, bringing a slight chance (10 to 30%)
of showers and isolated thunderstorms to the northeastern portions
of our area, mostly in Bottineau and Rolette counties. Otherwise,
generally clear skies are expected under the presence of the ridge
building in from the west, with some breezy northwesterly winds.
Highs remain seasonable, with temperatures in the 70s to lower 80s.
Thursday night will remain quiet as well, with clear skies and lows
in the upper 40s to lower 50s.

As the ridge continues to transit east across the Plains on Friday,
a shortwave is expected to strengthen and help develop a surface low
pressure system across eastern Colorado and western South Dakota
Friday morning. This will bring about our next chances for
precipitation across the majority of the area, with nearly the
entire state seeing 30 to 50% chances for showers and thunderstorms
by late Friday night. Across the west, deterministic guidance is
suggesting a narrow corridor of instability (MUCAPE values from 1000
to 2000 J/kg) and modest buoyancy extending north into the
southwestern corner of the state. As a result, our southwestern
corner currently has a Marginal Risk (level 1 of 5) from the SPC for
Day 3. It is still a bit far out, so the exact placement and overlap
of these ingredients is still a bit uncertain. However, the CSU
machine learning guidance has continued to suggest this area as
seeing a low (5 to 15%) chance for severe weather, mostly driven by
hail and winds. Otherwise, the severe potential for the rest of the
area on Friday is rather low, with just showers and a few
thunderstorms expected during this time. Highs on Friday will warm
up a bit more under the presence of the ridge, with temperatures in
the upper 70s to lower 80s currently forecast.

Heading into the weekend, the ridge is expected to move fully east
of our area, bringing about southwesterly flow aloft and continuing
the active precipitation pattern. Saturday is expected to remain
rather warm, with continued chances for precipitation across nearly
the entire area. Chances are maximized across the northern half of
the state, and current deterministic guidance suggests ample
instability and forcing for thunderstorms across the area. The CSU
guidance has also continued to advertise the potential for severe
storms on Saturday, centered across western and central North
Dakota. While it is still far out, the continued signal for severe
storms in our area has definitely raised some concerns for the
possibility of our next decent chances for severe weather, and as
such we will continue to monitor this potential closely. A cooling
trend is expected to begin on Saturday as well, extending into the
middle of next week, with highs on Tuesday forecast to be only in
the 60s across the area. However, the NBM ensemble spread in high
temperatures is rather large at this point, which helps indicate the
uncertainty in the temperatures. The spread is high, but the overall
trend in cooling is rather apparent during this time. The active
southwesterly flow aloft is forecast to continue through next week,
with daily chances for precipitation continuing throughout.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 103 PM CDT Wed Jun 12 2024

VFR conditions are present across all terminals, with mostly clear
skies across the entire area. A few pockets of mid level clouds are
moving through the south central, and some fair weather cumulus are
forming across the northwest near KXWA. Northwesterly winds continue
to rise through the afternoon hours, with sustained winds up to 20
to 25 kts, and gusts up to 30 kts possible. These winds are expected
to diminish heading into the late evening, decreasing to around 10
kts through the overnight hours. These northwesterly winds will be
on the rise once more through the end of the TAF period.

&&

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

&&

$$

DISCUSSION...Besson
AVIATION...Besson