444
FXUS63 KBIS 301806
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
106 PM CDT Tue Apr 30 2024

.KEY MESSAGES...

- Widespread rain showers are expected to move across the state
  from west to east through the day. A rumble or two of thunder
  is possible.

- Windy across southwest North Dakota today, with critical fire
  weather conditions expected in the afternoon and early
  evening. A Red Flag Warning has been issued.

- Daily chances (low to medium) for rain (and maybe an isolated
  thunderstorm or two) through the rest of the week, with
  temperatures slightly below normal.

&&

.UPDATE...
Issued at 1240 PM CDT Tue Apr 30 2024

The Red Flag Warning was canceled for the southwest read the
fire weather discussion for more information. Showers continue
to push eastward across central North Dakota as a warm and cold
front push across the region. Thunderstorms are possible across
central North Dakota this afternoon as instability increases.
Windy conditions are forecast this afternoon across the west as
the low moves off to the east bringing in wrap around winds.
Strong cold air advection will mix stronger winds aloft to the
surface, but this will be a little to late to maximize the
wind gusts.

UPDATE
Issued at 1005 AM CDT Tue Apr 30 2024

Rain showers continue to push eastward this morning. This trend
will continue through the day, with some embedded thunderstorms
at times. Breezy and dry conditions are still forecast in the
southwest. There is some uncertainty to the extent of critical
fire weather conditions as many areas in the southwest have
received a tenth to a quarter of an inch of rain this morning.
For now will monitor the amount of drying and wind behind the
morning band of rain and maintain the current forecast.

UPDATE
Issued at 630 AM CDT Tue Apr 30 2024

We have seen some showers make their way into the far west and
these radar echoes should become more and more widespread over
the next few ours as the main upper level wave and cold front
front moves in. Patchy dense fog (down to a quarter mile at
times) has also become a bit more widespread this morning,
mainly across northern areas and down into the James River
Valley. We will go ahead and issue an SPS through 15z to account
for this threat. Otherwise, no major changes were needed for
this update.

&&

.DISCUSSION...
Issued at 425 AM CDT Tue Apr 30 2024

An upper level ridge axis will continue to move off to our east
early this morning while western and central North Dakota
settles into southwest flow aloft. A surface cold front is
currently located near the Montana/North Dakota border and this
boundary will cross this state from west to east this morning
and afternoon.

Widespread rain showers will accompany the cold frontal passage
with radar returns now currently approaching the Montana/North
Dakota border. Some of the CAMs have been aggressive in ramping
this activity up in the 12 to 14 UTC time frame and beyond,
even suggesting the potential for some embedded lightning
strikes. That being said, instability will be limited as the RAP
is only showing the potential for a couple hundred J/kg MUCAPE.
Still, an embedded rumble of thunder or two isn`t out of the
question and much of the forecast area has been highlighted in a
general thunderstorm outline by the Storm Prediction Center.

We will clear out rapidly late this morning and early afternoon
across the west behind the front, especially the southwest
where modest pressure rises and cold air advection will lead to
some gusty west northwest winds. These winds will team up with
the dry airmass behind the front to usher in some near critical
to critical fire weather conditions across the southwest and
portions of the south central. See the Fire Weather section
below for more details.

Most of the rain will move out to the northeast by late this
evening. The heaviest totals continue to look probable across
portions of the northwest and north central where the NBM is
suggesting a 40 to 60 percent chance of a half inch of rain or
more. The NBM suggests that almost all of western and central
North Dakota has a 50 to 90 percent chance of a quarter inch of
rain or more. The one exception will be across the far southwest
and south central where probabilities drop off quickly.

Most will see a break in rainfall on Wednesday but we could see
some lingering showers across the far north. The next wave then
rotates around the very slow moving upper low that will be
centered near the Montana/North Dakota/Saskatchewan border by
Wednesday night. We will then see our next round of low to
medium rain shower chances Wednesday night through at least
Friday, if not Saturday, as the upper low slowly moves across
the region. Thursday looks to be the wettest day of the
aforementioned period and the NBM suggests that much of the
central and southeast could see a medium chance for another
quarter inch of rain or more on Thursday. We will also start to
see a bit more instability towards the middle to end of the week
so some more isolated thunder will be possible as well.

Regarding temperatures, we will see highs close to normal for
this time of year on Wednesday, ranging from the upper 50s
northwest to the mid 60s southeast. However, in the Thursday
through Saturday time frame, we will be a bit cooler than normal
with highs mainly in upper 40s to around 60. The NBM then
suggests a return of highs in the mid 60s to lower 70s range by
Sunday and Monday. That being said, considerable ensemble spread
continues to be noted this far out.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1240 PM CDT Tue Apr 30 2024

A system continues to moves through the state resulting in rain
across the region. Rain showers will lead to temporary MVFR
conditions this afternoon. Thunderstorms are possible this
afternoon, but confidence is low on location and timing. Winds
are forecast to pick up across the west this afternoon as a
front moves through the region. Skies will begin to clear west
to east this evening as the system pushes eastward with winds
diminishing by sunset.

&&

.FIRE WEATHER...
Issued at 1247 PM CDT Tue Apr 30 2024

The Red Flag Warning for the southwest was canceled due to a
quarter inch of rain that fell this morning and cloudy conditions
increasing minimum relative humidity. Cloudy conditions will also
delay mixing delaying windy conditions. Windy conditions are still
anticipated across the southwest later this afternoon.
Thunderstorms are possible across the central half of the state
this afternoon leading to gusty erratic winds.

&&

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

&&

$$

UPDATE...Johnson
DISCUSSION...ZH
AVIATION...Johnson
FIRE WEATHER...Johnson