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000
FXUS63 KBIS 250004
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
704 PM CDT Wed Apr 24 2024

.KEY MESSAGES...

- Above normal temperatures Thursday, with widespread highs in
  the 70s.

- Strong southeast winds are likely across the south and
  central on Thursday.

- Showers and thunderstorms are likely (60-90%) Thursday evening
  through Friday, with the highest probabilities across the
  southern half of the state.

- Cooler temperatures on Saturday and Sunday, with low to medium
  chances of rain showers. The highest chances are across the
  southern half of the state.

&&

.UPDATE...
Issued at 658 PM CDT Wed Apr 24 2024

Quiet weather continues across the region as high clouds are
moving eastward. Therefore, no updates are needed at this time.

&&

.DISCUSSION...
Issued at 324 PM CDT Wed Apr 24 2024

Currently, surface high pressure sits to the east of our area across
eastern Minnesota, while an upper level ridge builds across the
western CONUS. The north-south oriented surface pressure gradient
will tighten slightly through the day, with southeasterly surface
winds increasing to around 15 to 20 mph, occasionally gusting to 25
mph at times. Relative humidity values are rather low, ranging from
15 to 20% across much of the northern parts of the area, however
these are expected to rebound within the next few hours. Current
observations support near critical fire weather conditions, but
nothing has reached critical fire weather conditions. Highs today
are mainly in the upper 60s to lower 70s, while overnight lows range
from the low to mid 40s.

Through the rest of the day today and into tomorrow, the
aforementioned ridge will slowly build east, helping boost high
temperatures even further. Highs tomorrow will range from the low to
mid 70s, with some areas in the west potentially reaching into the
80s. As the ridge moves across the state, a more active pattern is
expected to set up, with southwesterly upper level flow and multiple
embedded shortwaves, giving us a few chances for precipitation over
the extended period. Windy conditions are expected to return across
the south and central portions of the area, as the surface pressure
gradient is expected to tighten through this area. Current forecast
soundings indicate mixed layer winds of around 30 to 40 kts, which
could mix down through the afternoon and evening hours. These winds
are forecast to decrease heading into the overnight hours.

Thursday evening will see chances for showers and thunderstorms
across the southwest and south central. Current model runs have
indicated a corridor of 1000-2000 J/kg of MUCAPE centered across the
southwest and south central, specifically for the afternoon and
evening hours, along with modest low level lapse rates. Our main
limiting factor will be shear, with multiple bulk shear parameters
remaining rather low at this time, including 0-6 km bulk shear only
reaching into the 20-25 kt range across the area of highest
instability. If any strong storms do break through and develop, they
will likely struggle to sustain themselves for extended periods of
time. CSU machine learning has continued to advertise low
probabilities for severe hail in this area, with the extent of this
expanding slightly north with each model run. While we are currently
only in a general thunder risk from the SPC, parts of western South
Dakota are in a Marginal Risk (level 1 of 5), which has also
extended slightly north from the previous SPC outlook.

The unsettled pattern is forecast to continue heading into the
weekend, as a warm season Colorado low is expected to deepen as it
moves northeast towards South Dakota. As moisture wraps around the
northern periphery of this low, much of North Dakota will receive
chances for precipitation starting late Thursday. This precipitation
is expected to last through Saturday, with the highest chances for
precipitation Friday afternoon and into the night. The area with the
lowest chances for precipitation will be the northwestern corner of
the state, ranging anywhere from 10 to 30%, with the highest chances
in the southern James River Valley and south central North Dakota,
ranging from 80 to 90%. Chances for this wave of precipitation
gradually increases from northwest to southeast. While our overall
total QPF for this event has decreased slightly, the chances for
exceeding 0.50" of rain through Friday night remains roughly the
same for the south central and southeast, ranging from 40 to 60%
across this area. Chances remain low for any of these areas
exceeding 1.00" of rain, only maxing out around 15 to 20%.

Along with this wave of precipitation, a weak cold front is forecast
to drop south across the Upper Plains through the weekend, bringing
about slightly cooler high temperatures for Saturday and Sunday.
Highs in the upper 40s to upper 50s are possible through the
weekend, while overnight lows will drop into the lower to mid 30s.
The precipitation will likely remain well to the south of any below
freezing temperatures, so the concern for any snow is minimal.

Confidence continues to increase in Sunday seeing a second, less
robust wave of precipitation passing across the same area as a
secondary low pressure system moves northeast into Minnesota, taking
a very similar track to the first low. The spread of chances will
take on a similar shape, with the lowest chances in the northwest,
and the highest chances in the southeast. However, both the chances
for rain as well as the total QPF associated with this system are
lower, with PoPs maxing out at 50 to 60% across the southeast, and 5
to 10% across the northwest. There are low chances for exceeding
0.50" across the southeast, ranging from 10 to 20%.

After this system moves through, next week is looking to remain a
bit more mild, with zonal upper level flow establishing itself over
the area again. Temperatures are forecast to be on the rise again as
another upper level ridge builds east across the area, with highs in
the mid to upper 60s forecast into the middle of next week. Daily 20
to 30% chances for precipitation remain under this pattern as well,
though nothing as robust as this weekend`s events.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 658 PM CDT Wed Apr 24 2024

VFR conditions will continue across the region. Breezy winds
will remain out of the south to southeast tonight with afternoon
gusts tomorrow. Skies will remain clear with some high clouds
moving to the eastward.

&&

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

&&

$$

UPDATE...Johnson
DISCUSSION...Besson
AVIATION...Johnson