525
FXUS63 KBIS 250601
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
101 AM CDT Sat May 25 2024

.KEY MESSAGES...

- Chance (30%) of showers tonight west and south central.

- Freezing temperatures overnight for portions of the north
  central.

- 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.

&&

.UPDATE...
Issued at 1257 AM CDT Sat May 25 2024

A couple areas of light rain showers continue over the far
northwest and along the southern border. These will continue to
move east before diminishing. Over the Turtle Mountains region,
a few flakes continue to fall at Rolla, but this should come to
an end in the next hour.

UPDATE
Issued at 938 PM CDT Fri May 24 2024

Winds have diminished in the James River Valley, the wind
advisory has been allowed to expire.

Snow continues over the Turtle Mountains of Rolette county and
is expected to linger into the early overnight hours.

Showers have moved into west central, southwest and south
central ND. As of yet, any lightning in eastern Montana has
fizzled before reaching North Dakota. With temperatures
continuing to fall this evening think most of the activity will
remain showers, although an isolated clap of thunder can`t be
ruled out through late this evening. We have updated pops to
keep the snow over the Turtle Mountains into the early overnight
hours. We also expanded pops in western ND, eastward through the
south central to the James River valley.

Latest NBM Minimum temperature guidance expanded the area of
freezing or below freezing temperatures in the north central.
Therefore, we upgraded the Frost Advisory to a Freeze Warning
for Rolette, Pierce, Bottineau, McHenry and Renville counties.
We kept the timing the same as the Frost Advisory.

Short term guidance has backed off on the fog late tonight over
the northwest/west central. For now will keep fog out of the
forecast. Updated text products will be transmitted shortly.

UPDATE
Issued at 627 PM CDT Fri May 24 2024

The wind advisory has been cancelled over the south central but
remains in effect for the James River Valley. As of 6 PM winds
were still gusting to 43 mph at Jamestown. Expect these winds to
diminish a bit later this evening. Clouds were diminishing over
western ND with some sunshine, but showers were over eastern
Montana, and have already pushed into the southwest. Expect
showers to move into the northwest in the next hour or so. There
has been some lightening associated with this activity but
there has been a decrease in lightning in the past 1-2 hours.
Expect mainly scattered shower activity but a few rumbles of
thunder can`t be ruled out this evening as this activity moves
into western ND.

In eastern portions of central ND, precipitation has ended over
all but the far eastern portions of the CWA. Also, snow
continues in and around the Turtle Mountains, but is expected to
taper off this evening.

&&

.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 /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1257 AM CDT Sat May 25 2024

Isolated rain showers over northwest and southern North Dakota
will taper off overnight. MVFR to IFR cloud cover over parts of
north central North Dakota will gradually diminish overnight
into Saturday morning. Otherwise, VFR conditions will prevail.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Frost Advisory until 8 AM CDT /7 AM MDT/ this morning for
NDZ001-002-009>011-018>023-025-033>037-041-042-044>048-050-051.
Freeze Warning until 8 AM CDT this morning for NDZ003>005-012-
013.

&&

$$

UPDATE...JJS
DISCUSSION...TWH
AVIATION...JJS