208
FXUS63 KBIS 201125
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
625 AM CDT Thu Jun 20 2024

.KEY MESSAGES...

- Chances for showers and thunderstorms will increase through
  this afternoon and evening. A stronger storm with small hail
  and gusty winds will be possible across the northwest this
  evening.

- Widespread showers and scattered thunderstorms are expected on
  Friday, with a Marginal Risk (level 1 of 5) for isolated
  severe storms over portions of the southwest and south
  central.

- Showers and thunderstorms will continue through Saturday
  morning, before diminish in the afternoon.

- Daily chances for thunderstorms Sunday through early next
  week, with strong to severe storms possible on Monday.

- Temperatures will continue warming through the weekend, with
  expected highs on Monday in the 80s to lower 90s.

&&

.UPDATE...
Issued at 625 AM CDT Thu Jun 20 2024

The forecast remains on track at this time, and with no updates
needed for this update. Generally dry conditions are observed
across western and central North Dakota. Lows have been from the
mid 40s west to the lower 50s east. Some lingering mid to high
level clouds remain over central North Dakota, but have been
diminishing over the past hour. Winds are generally light, and
out of the south southeast at this time.

&&

.DISCUSSION...
Issued at 400 AM CDT Thu Jun 20 2024

The northern Plains lies under a southwesterly flow pattern
this morning, as a near stationary H5 trough over the Rockies is
expected to gradually diminish through the end of the workweek.
Some weak radar returns linger over portions of the northwest
and southeast, though are expected to quickly dissipate by the
mid morning hours. Cloud cover is clear out from the west, and
winds winds are light and generally out of the south. Lows this
morning are forecast from the mid 40s west to lower 50s east.

Today, an inverted trough will approach from the west as a slow
moving warm front begins to push into the northern Plains from
the south. Chances (20 to 40%) for showers and a thunderstorms
will gradually increase across the west and south as moisture
streams northward ahead of the warm front. With the inverted
trough approaching from the west, modest model MUCAPE values
around 1000 to 1500 J/KG in the northwest and north central, and
0 to 6 KM Shear of 25 to 30 knots, there will be a short
window this afternoon where a stronger storm with small hail
and gusty winds could develop over the northwest in the late
evening to early morning hours. Chances for showers and
thunderstorms will continue across the north through the early
morning hours. Showers will be more widespread across the south
this afternoon and evening, also with the occasional embedded
thunderstorm, before briefly diminishing overnight. Highs this
afternoon are forecast from around 70 in the southern James
River Valley up the mid 70s in the north and west. Overnight
lows Friday morning are expected to be broadly in the 50s. Winds
are generally light, though will briefly become breezing in
portions of the south, and will gradually turn out of the south
into the east through the afternoon and evening.

Chances for showers will redevelop across the south and west
early Friday morning as a energetic shortwave digs across the
northern Plains, expanding to encompass the entire forecast area
by the early afternoon. The highest chances for these showers
will be across the southwest and much of the north. Modeled
MUCAPE broadly around 500 to 1000 J/KG will allow for widespread
chances for thunderstorms Friday afternoon and evening. An axis
of higher MUCAPE, from modeled from 1000 to 2000 J/KG, will
drape itself across the South Dakota border Friday afternoon,
and currently represents the highest, yet still limited, risk
for severe thunderstorm development in the short term. Baseline
hazards of quarter sized hail and isolated gusts up to 60 MPH
would be expected with any severe storm, with the period of
opportunity being from around 12 to 8 PM CDT. With morning
showers and thunderstorms expected across our southern counties,
however, we currently think that the worked- over atmosphere
and prevalent cloud cover could work against development of
severe thunderstorms. Thus, the risk for severe weather remains
on the lower side, with the SPC Day 2 Outlook assigning only a
sliver the southwest a Marginal (level 1 of 2) at this time.
Highs on Friday are similar to today`s, from the upper 60s to
mid 70s. Overnight lows temperatures on Saturday morning are
forecast to be from the mid 50s northwest, to the lower 60s
southeast. Winds will generally remain easterly, with modest
speeds from 10 to 15 MPH expected through the afternoon and
evening hours.

Chances for showers and thunderstorms will continue overnight
into Saturday morning, before diminishing through the afternoon
as the inciting upper level shortwave exits to our northeast.
There currently little to no severe weather concerns on
Saturday as any potential is expected to be far to our east.
Shortwave ridging will establish itself across the northern
Plains Saturday morning, promoting both west southwesterly flow
and a warming trend. Highs on Saturday are forecast from the
lower 70s south to the lower 80s north. Winds will become
westerly Saturday morning as surface high pressure moves in from
Montana.

The overall ridging pattern squashes down early Sunday, with a
series of shortwaves traveling down the overall westerly flow
pattern that will promote chances for showers and thunderstorms
each day through Tuesday next week. There is fairly good
agreement in the ensemble for seasonably warm temperatures, with
highs broadly in the upper 70s to lower 90s each day, and high
moisture availability across the forecast area as we get a
little taste of the heat dome here in North Dakota. Exact timing
and locations of any severe threat is difficult to place this
far out, though Monday, as the peak of the heating trend,
currently looks to have the highest severe potential in the long
term. We will have to continue monitoring trends over the next
few days.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 625 AM CDT Thu Jun 20 2024

VFR ceilings and visibility are expected at all terminals at the
start of the 12Z TAF period. This afternoon, chances for
showers and potentially some thunderstorms will increase across
the south and the west. MVFR to LIFR ceilings and MVFR
visibility are expected to move over the southern terminals of
KDIK, KBIS, and KJMS with these showers this afternoon and
evening. Scattered thunderstorms are also expected across the
south today, though the confidence is currently too low to place
it at any given TAF site. KXWA may briefly experience showers
and MVFR ceilings this afternoon, along with the potential for
a stronger thunderstorm with small hail and gusty winds through
the early evening. Showers and thunderstorms will diminish
overnight, before redeveloping and becoming widespread over the
forecast area Friday morning. Winds are generally light and out
of the south southeast this morning, but will turn easterly
through the afternoon and overnight into Friday morning. Where
showers or thunderstorms do develop, gusty and erratic winds are
expected.

&&

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

&&

$$

UPDATE...Adam
DISCUSSION...Adam
AVIATION...Adam