572
FXUS63 KBIS 252355
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
655 PM CDT Sat May 25 2024

.KEY MESSAGES...

- Patchy fog is possible across portions of western and central
  North Dakota overnight, mainly in the Lake Sakakawea area and
  south.

- Breezy west to northwest winds are expected Sunday and
  Monday.

- Shower and thunderstorm chances (50 to 70 percent) return
  late tonight and continue through Monday morning.

- Expect a brief dry period Tuesday into early Wednesday, with
  an active weather pattern returning for the rest of the week
  after.

&&

.UPDATE...
Issued at 655 PM CDT Sat May 25 2024

Mostly quiet across the area this evening, with relatively light
winds and widespread fair weather cumulus that will diminish
through the evening with the loss of daytime heating.

Radar returns continue across the ND/SD border in Bowman and
Adams Counties, as well as to the north in Billings and Stark
Counties as of 2330 UTC. We did add in mention of isolated
showers and thunderstorms across the southwest and into the
south central through the evening, but overall not expecting
much with this activity. Additional precipitation is upstream in
central Montana with an approaching shortwave.

Only other forecast feature we will continue to look at tonight
will be frost potential in the Turtle Mountains area. Webcams
and satellite imagery show the majority of snow since yesterday
has melted off, with a few localized areas still broadly snow-
covered.


&&

.DISCUSSION...
Issued at 143 PM CDT Sat May 25 2024

Currently the stacked low from the past few days is sitting
north of Minnesota. We have low diurnal cumulus forming in the
cyclonic flow across the area. Aloft, flow is mostly zonal south
of the low, with a slight ridge in eastern Montana and a
shortwave west of that.

Tonight will be warmer than last night with lows in the 40s. We
lowered temperatures where the snow fell by blending in the NBM
50th with the NBM. Up there any non snow covered areas could get
frost. With lower confidence in the frost and warmer
temperatures we choose not to do a frost advisory. The only
areas that have a chance of frost are most likely snow covered
anyways. There might be patchy fog around Glen Ullin and
Bismarck, and north like this morning.

We will remain dry until later tonight when the shortwave opens
up over the west. Timing looks to be sometime between 06z and
10z depending on what CAM you look at unfortunately. These will
most likely just be rain showers until some daytime heating
kicks in for some energy. Then our chances for thunder goes up
to 45 percent after 1pm central time. The showers will move off
to eastern North Dakota with the low pressure Monday morning.
The chances will slowly go down after 7pm central time Sunday.
Rain totals look to be around 0.25 to 0.40 mainly east of the
river. Of course there could be higher amounts in thunderstorms,
otherwise it looks like a quick moving system. Winds will get
slightly breezy in the western counties from the west. A
pressure rise bubble mainly in Montana will be present with a
slightly tight pressure gradient.

Monday, Memorial Day, will be drier than Sunday but still a
30 percent chance of showers east of the river. This is from
some potential wrap around moisture and cyclonic flow aloft. The
south this time will have the tighter pressure gradient from
the low, so expect breezy winds through the evening.

After Monday a tall ridge with warmer 850mb temperatures moves
in. We will be dry with temperatures warming to the 70s west of
the river Tuesday where the thermal ridge is set up. Wednesday
will be the warmest day with the warm thermal ridge and breezy
south winds. Highs will be near 80 in the west and lower 70s
east.

Our active southwest flow returns Wednesday night when a big
trough digs through the Pacific Northwest. Chance of showers and
thunderstorms will be in the forecast late Wednesday evening
through Friday. Temperatures look to stay in the 70s.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 655 PM CDT Sat May 25 2024

Overall VFR conditions are expected through the 00Z TAF period.
Diurnal cu will diminish through this evening, with isolated
showers and thunderstorms across the southwest. Precipitation
chances increase from west to east late tonight through the day
Monday, with showers and thunderstorms becoming likely. Ceilings
are expected to stay low VFR around 4 to 6k feet, but MVFR
conditions are possible in any thunderstorms or heavier showers.
Winds will shift to westerly and increase in western ND towards
the end of the TAF period.

&&

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

&&

$$

UPDATE...Jones
DISCUSSION...Smith
AVIATION...Jones