Jamestwn, North Dakota Weather Forecast Discussion

803
FXUS63 KBIS 200548
AFDBIS
Area Forecast Discussion
National Weather Service Bismarck ND
1248 AM CDT Sat Sep 20 2025
.KEY MESSAGES...
- Areas of fog tonight into Saturday morning. Patchy dense fog
  possible.
- Temperatures warm back into the 70s and low 80s through the
  weekend, then remain in the 70s next week.
&&
.UPDATE...
Issued at 1248 AM CDT Sat Sep 20 2025
Patchy fog has developed over parts of the forecast area,
especially in northwestern ND. Based on the latest model runs,
areal coverage of fog is likely to expand tonight and may become
dense in some locations. Will continue to monitor should any fog
headlines be needed tonight and into Saturday morning.
UPDATE
Issued at 920 PM CDT Fri Sep 19 2025
Some patchy fog is beginning to form across the region. Added
fog to the grids to match current trends from the CAMs. Rain
continues to diminish across the James River Valley. No other
updates are needed at this time as the forecast remains on
track.
UPDATE
Issued at 631 PM CDT Fri Sep 19 2025
Rain bands continue across the James River Valley slowly
progressing eastward. Low stratus continues to progress slowly
eastward and will likely linger across the much of the state
tonight into tomorrow morning. No updates are needed at this
time as the forecast remains on track.
&&
.DISCUSSION...
Issued at 250 PM CDT Fri Sep 19 2025
Currently the upper level low sits on the South Dakota and
Nebraska border. A weaker upper level low sits just north of
North Dakota in southern Canada. Very weak flow over the
Northern Plains is a result of sitting between two low pressure
systems. To the west a flat ridge is through Montana, pushing
the southern low east. The southern low is stacked, so at the
surface the low is in southeast South Dakota. Rain bands
wrapping around the low continue from this morning. As the low
pressure slowly slides east, so will the rain this evening. The
NBM is holding onto the chance of rain in the James River Valley
and east until tonight. Scattered rain showers could then
continue from Valley City east through Saturday when the low
pressure reaches Wisconsin.
With the ridge building in from the west, this weekend will be
dry weather. Over the last week, areas of the south central
have received over 8 inches of rain, so it might be good to get
a break from rainfall. Temperatures will warm back into the 70s
and low 80s (far west) through Sunday with a thermal ridge.
Currently the ridge is on the western edge of North Dakota and
already eroding clouds across the west with the sinking air.
Early Monday another low pressure dives in from Canada, leading
to a quickshot of southwest flow. The NBM is still carrying a
slight chance of showers Monday, but is trending down from a few
days ago. As that low dives into the southeast CONUS, a Pacific
trough with a low could move on shore. This could lead to a
Omega blocking pattern across the Northern and Central Plains
mid next week. Above average temperatures are forecast through
the end of October both by the CPC and long range models.
&&
.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1248 AM CDT Sat Sep 20 2025
MVFR/IFR ceilings are present across at least the eastern two
thirds of the state. These will gradually improve from west to
east through the day Saturday, with all terminals except KJMS
likely to become VFR by the afternoon. Patchy fog has developed
across parts of the area, especially in the northwest. However,
no model run at this time confidently socks in any terminals.
Therefore, used VCFG to illustrate when a terminal is most
likely to be impacted, and will amend when/if needed. Any fog
should dissipate by late Saturday morning.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Telken
DISCUSSION...Smith
AVIATION...Telken

NWS BIS Office Area Forecast Discussion