Jamestown, North Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

096
FXUS63 KBIS 111457
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
957 AM CDT Fri Apr 11 2025

.KEY MESSAGES...

- Critical fire weather conditions are expected today across
  western and much of central North Dakota. A Red Flag Warning
  remains in effect from late this morning through early
  evening.

- Temperatures will peak today, then will start to trend cooler
  on Saturday, turning colder Sunday and Monday. Widespread
  medium to high chances (50-80%) for rain expected Saturday
  night through Sunday night, ending on Monday. Some snow may
  mix in Sunday night through Monday morning.

- Temperatures trend warmer after Monday of next week, along
  with mainly dry weather conditions.

&&

.UPDATE...
Issued at 944 AM CDT Fri Apr 11 2025

Temperatures continue to warm across the state in the 50s. High
temperatures are forecast to reach the upper 60s to lower 80s in
the southwest. Relative humidity is already around 25 percent
this morning and is forecast to drop as low as 10 percent in the
southwest by this afternoon. Wind speeds are starting to hit 20
mph sustained across the northern half of the state. Winds are
expected to increase this afternoon across much of the state. No
updates are needed to at this time as the forecast remains on
track.

UPDATE
Issued at 627 AM CDT Fri Apr 11 2025

No changes. Dense fog continues to remain to our east, with far
eastern areas of the James River Valley perhaps at times seeing
visibility below a mile. Web cam imagery do not support
headlines. See below for further forecast discussion for the
forecast period.

&&

.DISCUSSION...
Issued at 420 AM CDT Fri Apr 11 2025

Currently, upper level ridge developing east into the Northern
Plains this morning, with surface high pressure to our southeast
and developing low pressure across the lee of the Northern
Rockies. Lack of wind and lingering boundary layer moisture over
eastern areas of the state contributing to areas of fog there
this morning, including eastern areas of the James River Valley.
Dense fog is currently mainly east of the James Valley, and
looking at web cams thus far visibility looks decent enough to
hold off on any fog headlines. Will continue to monitor.

Upper ridge axis pivots east over the Dakotas today, with the
aforementioned lee sfc trough developing into eastern MT this
morning, then across the far western Dakotas this afternoon.
Increasing southerly flow results, with sfc winds increasing
west to east as we lose the morning inversion. Peak gusts within
the boundary layer look roughly 25-30kts, so basically
unchanged from what models previously indicated. WAA will also
result, with highs well in the 70s west and central, and still
forecast around 80F in the southwest. As we mix, sfc dewpoints
are favored to drop into the low 20s and upper teens along and
west of Highway 83, with resultant min RH values as low as 10%
from southwest ND north/northeast into parts of the north
central. Some models (RAP and HRRR included) advertise upper
single digit RH values, which is very possible. All told, Red
Flag conditions are still expected late morning through early
this evening for western and much of central North Dakota. Main
change from the previous forecast was to lower RH values a tad,
and opted to add Bottineau county to the warning. See fire
weather discussion below for additional details.

Ridge flattens tonight as a potent S/WV slides east across
southern Canada, transitioning flow aloft to quasi-zonal.
Another embedded strong S/WV will approach the Northern Rockies
during the day Saturday, then closes off as it continues east-
southeast across the Dakotas Saturday night through Sunday
night. Lead embedded impulses will bring some light
precipitation to the west and parts of central ND tonight and
during the day Saturday, with the main forcing arriving Saturday
night into the day Sunday. This is when we expect widespread
rainfall chances, with the heavier amounts focused across
northern areas of west/central ND where upper level forcing
coincides with low/mid level frontogenesis near an inverted sfc
trough axis. Upwards to an inch of much needed moisture will be
possible there. Lighter QPF is depicted farther south, around a
quarter of an inch far southwest and south central, with
southern areas of the James Valley the lowest (a tenth of an
inch or less).

This initial upper low moves off to the east Sunday night,
followed by another embedded S/WV in northerly flow aloft during
the day Monday. Resultant weather will see precipitation chances
and coverage decreasing Sun night, with continued scattered
showers possible through the day Monday. In addition, colder
air pulled in behind the departing initial upper low, will
bring a chance of some snow mixing in with any lingering showers
Sunday night through Monday AM. At this time, not expecting any
impacts with this.

Along with colder temperatures and widespread precipitation,
winds will increase Sunday and continue through Monday as
gradient forcing increases. Wind headlines are possible.

Flow aloft is favored to be northwesterly after Monday, as an
upper level ridge attempts to rebuild over the western CONUS.
Overall, we are favored to see temperatures trend warmer after
Monday, with initially mainly dry weather conditions. Embedded
waves with the flow aloft may bring precipitation chances at
times next week, but for now the uncertainty is elevated with
NBM only generating slight chances for us mid to late next week.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 627 AM CDT Fri Apr 11 2025

VFR conditions are expected with occasional mid to high clouds
moving across the region. Winds will become southerly this
morning, before increasing and becoming gusty today. Winds
across western North Dakota will transition to more westerly
later in the afternoon.

&&

.FIRE WEATHER...
Issued at 420 AM CDT Fri Apr 11 2025

Critical fire weather conditions are expected today due to dry
and windy conditions. Minimum relative humidity is forecast to
drop as low as 10 percent in the southwest to around 14 to 20
percent from Renville/western Bottineau down to McIntosh
county. The strongest winds are forecast to by in the central
portion of the state with sustain winds from the south around 20
to 25 mph and gusts up to 35 mph. The southwest will see the
lowest minimum relative humidity, however their winds may
remain around 15 to 20 mph and will weaken after 21Z. Due to the
continued dry conditions, fires that can start may rapidly
spread and become difficult to suppress. Winds will decrease
this evening along with RH values recovering to over 30 percent
by midnight.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 9 PM CDT /8 PM MDT/ this evening for
NDZ001>004-009>012-017>022-031>036-040>047-050.

&&

$$

UPDATE...Johnson
DISCUSSION...NH
AVIATION...NH
FIRE WEATHER...NH