114
FXUS63 KBIS 290311
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1011 PM CDT Sun Apr 28 2024

.KEY MESSAGES...

- High chances (60 to 90 percent) for rain across south central
  North Dakota from around the Missouri River and east into the
  James River Valley late this afternoon through tonight, with
  medium chances (30 to 50 percent) elsewhere across central
  North Dakota. Dry across western North Dakota.

- Light rain may become mixed with, or briefly change over to
  light snow late tonight into early Monday morning central.
  Patchy fog is possible late tonight into early Monday morning
  west.

- An active weather pattern will be over the region through next
  week, with daily chances for precipitation and slightly below
  normal temperatures.

- Critical fire weather conditions will be possible across
  southwest and portions of far south central North Dakota
  Tuesday afternoon through early Tuesday evening due to strong
  westerly winds and low relative humidity.

&&

.UPDATE...
Issued at 1007 PM CDT Sun Apr 28 2024

For late night update main change was to increase cloud cover to
the west, and keep the clouds through the overnight into Monday
morning a little longer based on latest guidance and latest
trend keeping features a bit further to the west.

UPDATE
Issued at 631 PM CDT Sun Apr 28 2024

Rain showers continue to very gradually spread north and west
into the area. Main change for early evening update was to pull
higher chances a little further to the west as showers are
rotating in a little quicker than previously thought.

&&

.DISCUSSION...
Issued at 225 PM CDT Sun Apr 28 2024

A surface and upper level will lift from the central Plains this
afternoon, into the northern Great lakes region by Monday
afternoon. Current radar reflectivities can be seen over
southeast North Dakota and extending west in to far south
central North Dakota and then back down to the southwest to the
Black Hills and south into far southwest South Dakota.
Precipitation lifting northward through eastern South Dakota and
Minnesota will continue to wrap back west into central ND and
this deformation zone will remain over central ND tonight.
Heavier rain amounts up to around three quarters of an inch are
possible over portions of the southern James River Valley before
all is said and done Monday. While amounts will not be as
impressive back over the south central, respectable amounts of
a tenth of a third of an inch are possible from around Bismarck
and Linton, north and east to Harvey and Carrington. Late
tonight a rain snow mix or even a period of all snow can not be
ruled out with some very light accumulations possible on grassy
surfaces. With dewpoints remaining at or above freezing, impacts
are not expected. Precipitation tapers off over central ND on
Monday with highs ranging from the 60s in the west with much
more sunshine, to the lower 50s over the James River Valley
which sees clouds through much of the day. A period of patchy
morning fog is possible in the west as lower clouds don`t make
it out that far. Morning lows will also drop below freezing over
portions of the west.

An active weather pattern continues Tuesday through the end of
the forecast period as another upper level low tracks from the
west coast, across the Rockies and into the northern Plains
region before stalling and continuing to spin over the Northern
Plains into the Canadian Prairie Provinces.

The initial wave and attendant surface system tracks through
the forecast area on Tuesday with scattered showers expected
along the surface boundary. The main impact from this system
though will most likely be fire weather related with strong
winds and low humidities expected southwest (See Fire Weather
discussion below). Wind highlights may also be needed over the
southwest Tuesday afternoon. It looks like a little break in the
action is possible Wednesday before shower chances increase
again Thursday into Friday as another shortwave swings through
the forecast area, around the initial wave that stalls just to
our north. Some wrap around moisture will probably keep
lingering light precipitation chances across the north on
Saturday as the entire system lifts slowly north.

Temperatures will remain around normal through the forecast
period. Normal late April highs are around 60 and normal lows
are in the low to mid 30s. Daytime highs this week will vary
from the lower 50s to upper 60s. Lows will range from the upper
20s to lower 40s.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 631 PM CDT Sun Apr 28 2024

Widespread MVFR to IFR ceilings, with occasional LIFR further
east, are expected over southeast and south central North Dakota
including the KJMS and KBIS terminals through mid-day Monday
before gradually improving in the late afternoon from west to
east. Over north central into southwest North Dakota including
the KMOT and KDIK terminals, conditions start out VFR, but a
deterioration to MVFR ceilings are expected late this evening,
continuing into Monday morning before improving late morning
into mid-day. Most of northwest North Dakota is expected to
remain VFR through the forecast period.

&&

.FIRE WEATHER...
Issued at 225 PM CDT Sun Apr 28 2024

Critical fire weather conditions are possible Tuesday afternoon
through early Tuesday evening across southwest and portions of
south central North Dakota. Minimum relative humidity values are
expected to drop as low as 18 percent, with westerly winds around
30 mph and gusts to 50 mph.

North of the fire weather watch and bounded to the north and
east by Lake Sakakawea and the Missouri River near critical
fire weather conditions are possible Tuesday afternoon.

More uncertainties remain over the near critical area. Namely
the potential for a wetting rain Tuesday morning. Lower wind
speeds and higher humidities should also limit the rate of
spread of any fires that may ignite. The rates of spread are
forecast to be highest over the far southwest Tuesday afternoon
and the Duration of fire weather conditions has dropped a bit
as you approach the big Lake and the Missouri River. If forecast
winds/humidities would worsen, we would still have the time on
the overnight shift tonight to add additional counties.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Tuesday afternoon through Tuesday
evening for NDZ031>033-040>045.

&&

$$

UPDATE...JJS
DISCUSSION...TWH
AVIATION...JJS
FIRE WEATHER...TWH