427
FXUS63 KBIS 230606
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
106 AM CDT Thu May 23 2024

.KEY MESSAGES...

- Scattered to numerous showers are expected tonight across
  western and central North Dakota. A stray rumble of thunder is
  possible.

- A low pressure system moves into the region Thursday, bringing
  chances for strong to severe thunderstorms to portions of the
  area. Gusty winds, large hail, and one or two tornadoes will
  be possible, particularly for areas along the ND/SD state
  line.

- Periodic showers and thunderstorms are expected over the
  holiday weekend.

- Drier weather and a warm up are in store heading into the
  middle of next week.

&&

.UPDATE...
Issued at 104 AM CDT Thu May 23 2024

Latest radar imagery shows showers becoming more prevalent along the
Highway 2 corridor and also between Highways 85 and 83, though the
second area has higher ceilings which may be inhibiting rain from
reaching the ground to some extent. The forecast for tonight remains
on track. The Storm Prediction Center has expanded a slight risk
(level 2 out of 5) of severe thunderstorms across much of southern
North Dakota for Thursday afternoon and evening, now along and south
of a line from Bowman to Bismarck to Carrington. Forecast details to
come in the next AFD issuance.

&&

.DISCUSSION...
Issued at 408 PM CDT Wed May 22 2024

Visible satellite shows a few clouds moving across the northwestern
corner of North Dakota as a surface ridge moves over the center of
the state.  Winds have slackened west to east over the past few
hours as a closed low has lifted to the northeast, over portions of
Minnesota, the UP of Michigan, and Canada.  Expect light and
variable winds to continue for the rest of the afternoon.  A few
showers and thunderstorms have developed across northern Montana and
are starting to move toward the Montana/North Dakota state line.
There is a 20-50% chance of a few scattered showers and/or weak
thunderstorms expected, particularly for the northwestern and north
central part of the state this evening and tonight.  At this time,
severe storms are not expected.

Tonight, a shortwave trough will move from the PACNW to the
Bighorns.  A low pressure system is expected to develop as the
system comes over the Black Hills and West River region of South
Dakota Thursday afternoon.  A warm front is expected to develop over
tomorrow, with still some uncertainty as to where it will set up.
Locations range from northern South Dakota to central North Dakota.
Instability will increase heading into the afternoon, with the warm
front in place.  Thunderstorms are expected to develop along the
front and within the warm sector, which again brings some
uncertainty into which areas may see the best chance for storms and
possible severe weather.  Any thunderstorms that are able to develop
tomorrow in the southeastern part of the area where the warm front
will be and a cold front moves through will have the potential of
becoming strong to severe.  The Storm Prediction Center has placed
this area in a Marginal (1/5) to Slight (2/5) Risk for severe
storms.  The main hazards with any storms will be winds gusting to
60 mph and hail up to ping pong ball size. An isolated tornado or
two cannot be entirely ruled out.  Overnight, temperatures will fall
into the mid-30s in a few locations, bringing a chance of a
rain/snow mix to portions of the area.

Friday, the low will continue to lift to the northeast, with wrap
around moisture expected.  Rain chances will continue through the
daytime hours and into the evening, eventually ending west to east
across the region.  Afternoon highs will be slightly warmer than the
previous day, at least in the west, climbing into the mid to upper
50s.  Heading toward the central part of the state, expect highs in
the low to mid-50s.

Expect a warm up over the holiday weekend as the are comes under
westerly to northwesterly flow.  Temperatures will return to the mid
to upper 60s for highs and the low to mid-40s for lows.  There are
some low end chances (20-30%) for showers and thunderstorms
Saturday, with a better chance on Sunday (30-50%).  The best chances
for precipitation will be on Sunday, particularly for the southern
half of the state.

Memorial Day, a closed low remains in Canada, bringing the
possibility for some more wrap around moisture moving into the
region.  Although chances remain fairly low (20-30%) for showers and
storms, this may put a bit of a damper on outdoor holiday or travel
plans.

An upper ridge moves over the Dakotas heading into mid-week.  Dry
conditions are expected along with a return of temperatures to the
70s.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 104 AM CDT Thu May 23 2024

There are multiple aviation hazards this forecast period as a strong
low pressure develops southwest of North Dakota. Scattered showers
will be possible at all terminals tonight into Thursday morning, but
more so across the north. Rain will then become widespread Thursday
afternoon and evening, with thunderstorms across the south. Some
storms could be severe with large hail and damaging winds as high as
55-60 kts. Significant visibility restrictions can be expected with
any thunderstorm, and prevailing MVFR visibility is otherwise
possible with showers. Ceilings are forecast to lower to MVFR and
eventually IFR levels from north to south late tonight through
Thursday afternoon. Northeast winds will increase to 15-20 kts on
Thursday, with gusts to 25-30 kts.

&&

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

&&

$$

UPDATE...Hollan
DISCUSSION...Wekesser
AVIATION...Hollan