898
FXUS63 KBIS 090554
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1254 AM CDT Sun Jun 9 2024

.KEY MESSAGES...

- High temperatures the next few days normal to just below for
  early June (normal is mid 70s). Above normal temperatures are
  expected with increasing confidence for Wednesday (80-85
  degrees).

- Widespread showers and thunderstorms (80 percent chance) expected
  Monday afternoon and Monday night, with an isolated stronger
  storm possible over the southwest and south central. Then
  stronger thunderstorms possible again on Wednesday.

&&

.UPDATE...
Issued at 1254 AM CDT Sun Jun 9 2024

Quiet weather across the forecast area tonight, with only a few
radar returns still persisting. At this point not expecting any
rain to be falling from them with ceilings around 10k feet in
the vicinity of these weak returns. Only change was to adjust
sky cover a bit with a modest swath of midlevel clouds across
much of central North Dakota, otherwise going forecast looks
good.

UPDATE
Issued at 952 PM CDT Sat Jun 8 2024

No big changes for tonight with this update. Band of mid level
clouds continues to propagate southward, associated with an
embedded wave that ejected earlier out of the close upper low to
our northwest across central Saskatchewan. A few lingering
showers over the next hour or two, but as mentioned earlier much
is not even reaching the ground.

UPDATE
Issued at 641 PM CDT Sat Jun 8 2024

The forecast for this evening remains mainly on track. Did
extend in time the chance for showers northwest with radar
echos still evident and a few observing sites reported traces of
moisture. All and all, most moisture is not reaching the ground
with cloud bases at or greater than 9K Ft AGL. Area of mid level
clouds northwest will slowly meander south and southeastward
tonight.

&&

.DISCUSSION...
Issued at 235 PM CDT Sat Jun 8 2024

An upper level low that has stalled over the Canadian Prairies
will slightly retrograde to the southwest through the afternoon
while beginning to open. Weak cyclonic flow is briefly dipping
into the northwest, allowing for a period where isolated showers
will be possible over the northwest and north central through
the early evening. With ample dry air near and above the
surface, much of the rain that does fall out of these showers
will likely become virga. Where these showers or virga do fall,
some slightly enhanced gusts up to 25 mph will be possible.
Otherwise, winds are anticipated to remain fairly light out of
the northwest this afternoon, from 5 to 10 mph, then beginning
to turn northerly and diminishing overnight. High temperatures
today remain at or slightly below seasonable normals, forecast
from the upper 60s northwest to the mid 70s southeast. Overnight
low temperatures are forecast from around 40 in the northwest
to the upper 40s in the southern James River Valley.

The upper level low will continue to diminish overnight into
Sunday, and will eventually be absorbed by an incoming shortwave
trough that is slated to push into the northern Plains by early
Monday. As such, conditions on Sunday are anticipated to remain
mainly dry with slightly lower temperatures compared to today,
from the mid to upper 60s across the International Border to the
lower 70s over the south.

A surface low center associated with the upper level trough
will dig into the northern Plains on Monday, pushing chances (60
to 80%) for showers across North Dakota through the day. As the
surface low pushes into western South Dakota Monday afternoon,
some modest instability will develop along a N-S orientated
boundary across our west. With model SBCAPE forecast from
500-1000 J/KG and bulk shear from 30-40 knots, there will be
some potential for conditionally strong storms to develop over
the southwest and south central Monday afternoon and evening.
CSU Machine Learning has begun to paint portions of the far
southwest and south central with a 15% probability for severe
hail in this timeframe. The better instability is currently
expected to remain further to our south, however, and the SPC
has place a Marginal (level 1 of 5) just over the border in
South Dakota. WPC is painting an area of Marginal potential for
Excessive Rainfall over much of central North Dakota for this
system, with this area slated for a 40-50% chance of exceeding
0.50" of rainfall by Tuesday morning. Highs on Monday are
expected to remain seasonably cool, forecast from the mid 60s
north to the lower 70s south.

Conditions behind this system will rapidly dry out Tuesday
morning as upper level ridging builds into the northern Plains,
promoting warming temperatures with highs broadly peaking into
upper 70s and mid 80s by Wednesday. By Wednesday afternoon, the
ridge will begin to erode as another progressive pacific
shortwave travels up the ridge. As another associate surface low
system pushes eastward across North Dakota, there will be a
brief period Wednesday afternoon where stronger storms will be
possible across the Southern James River Valley. SPC has already
begun to advertise a 15% chance for severe thunderstorms across
eastern North Dakota on its Day 4 Outlook. Timing will make or
break this system, however, with a majority of ensemble members
(~80%) championing a very progressive system that exits the
forecast area by the early afternoon period, which would greatly
limit the chance for us to see much of anything on Wednesday.
We will have to continue monitoring forecast trends with this
system over the next few days.

Through the later half of next week, flow aloft will become
increasing northwesterly as longwave ridging begins to push in
from the west. Temperatures will return remain fairly
seasonable, with highs forecast in the mid 70s to low 80s
through the end of the workweek. Conditions will remain dry
through the early Friday, when a few ridge riders will promote
chances for precipitation each day through the end of the week.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1254 AM CDT Sun Jun 9 2024

VFR conditions expected at all terminals through the TAF period.
Midlevel clouds will continue across much of the area, with
additional clouds moving in through the period. Light and
variable winds overnight will become easterly through the day
Sunday, becoming southeasterly late in the TAF period.

&&

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

&&

$$

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