515
FXUS63 KBIS 242003
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
303 PM CDT Fri May 24 2024

.KEY MESSAGES...

- Rain and snow showers central east, gradually tapering off
  from west to east this evening. Chance (30%) of showers and
  thunderstorms again in the southwest overnight.

- Winds gusting to 45 mph in portions of south central North
  Dakota including parts of the James River Valley. A Wind
  Advisory is in effect until this evening.

- Areas of frost over much of western and central North Dakota.

- Active weather pattern continues with rain chances over much
  of the area through Monday, then again Thursday to Saturday.

&&

.DISCUSSION... Issued at 305 PM CDT Fri May 24 2024

The stacked low pressure system continues to slowly move east
across the North Dakota Minnesota border. In our area,
temperatures have remained much cooler than first forecasted in
the central and north on the backside of the low. This is
allowing snow to mix with the rain falling. The Turtle Mountains
area has received around 6 inches of snow so far! A rain/snow
mix has been reported in the southern James River Valley and
into South Dakota as well. Our forecast challenge of the day
has been this, where will the rain snow mix be the rest of the
day? We have adjusted from the NBM to have a rain snow mix the
rest of of the day where precipitation is falling. This area is
between Bismarck and Jamestown, up to the Canadian Border and
east. The Wind Advisory is still in effect west of the river
until 23z, and east of the river until 01z. Although they will
most likely be cancelled early as the tight pressure gradient is
over the James River Valley right now and moving east.

In the cyclonic flow around the upper low, showers and maybe a
thunderstorm are possible across the west and southwest for a
few hours tonight, about a 30 percent chance. Lows overnight
across the area will dip into the mid-30s with light winds. A
Frost Advisory has been issued until 13z Saturday for this
reason. Localized lower elevations could drop near or below
freezing. The rest of Saturday will be drier, with highs still
slightly below average in the upper 60s and lower 70s. The
Turtle Mountains will be 50 degrees or cooler, especially with
the snow on the ground, so this could be over forecasted. Frost
is most likely again Saturday night in the northeast with
temperatures in the mid 30s again. The pattern aloft Saturday
has a brief weak ridge moving through before another upper low
and shortwave move in Sunday.

Sunday will still be below average temperatures with showers and
thunderstorms (non-severe) likely, moving west to east. The
highest chances move to the east by 00z as the next ridge
pushes into the west. The chances of rain look to continue all
night and into Monday afternoon. This ridge will continue until
Wednesday night when another big low digs south through the
Pacific Northwest. This puts us back into the active southwest
flow with plenty of diffluence aloft for thunderstorms through
Friday. Temperatures all week will remain just below average as
our cooler Spring continues into June.


&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 305 PM CDT Fri May 24 2024

Mainly MVFR now, going to VFR clouds this evening. Rain showers
in the central and east will continue push east. Snow could be
mixing in with the rain. Breezy northwest winds, calming
overnight and turning easterly. A few rain showers are possible
around KDIK this evening, with a chance of thunder.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 6 PM CDT /5 PM MDT/ this evening for
NDZ034-035-042-045.
Wind Advisory until 8 PM CDT this evening for NDZ036-037-
046>048-050-051.

&&

$$

DISCUSSION...Smith
AVIATION...Smith