Jamestown, North Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

537
FXUS63 KBIS 202032
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
332 PM CDT Sun Jul 20 2025

.KEY MESSAGES...

- Isolated to scattered thunderstorms are possible today and
  tonight. Expected hazards include hail up to 2 inches in
  diameter, damaging winds up to 60 mph, a tornado or two (far
  southwest and far south central), and locally heavy rainfall.

- Isolated severe thunderstorms are possible Monday afternoon
  through Monday night and again Tuesday afternoon through
  Tuesday night. Main hazards will be large hail, damaging
  winds, and locally heavy rainfall.

- Daily chances for showers and thunderstorms continue through
  the upcoming work week.

- High temperatures will generally be in the mid 70s to lower
  80s through midweek, before warming up into the mid 80s to
  lower 90s later in the week.

&&

.DISCUSSION...
Issued at 320 PM CDT Sun Jul 20 2025

Currently, an unsettled atmosphere remains over the region,
with a strong westerly flow aloft. Lead embedded waves
originating from a Pacific Northwest upper low are approaching
the region, with an agitating CU field developing over parts of
southeast MT and western ND as of 20Z this afternoon, along
with a few towers. A few radar returns are now showing up in
this area, along with some cloud to ground lightning. CAMs
generally initiate convection right about now in this general
area, then take any activity eastward across western and into
central ND over the next few hours. Additional development is
possible as well in southwestern North Dakota, but latest model
data suggests this is a lower probability. Nonetheless, decent
bulk shear and 100mb/MUCAPE is present across all of eastern MT
and western/central ND, and will keep expected hazards as is.
Best tornado potential will be far southwest and far
south central where better low level shear is expected just
north of a sfc low.

Another period of strong to severe convection for our area is
possible through tonight, with storms originating in Montana
eventually developing eastward across the Northern Plains.
Lingering elevated instability and a series of mid level waves
should maintain some of the storms moving out of MT later on.
CAMs try to portray a broken line pushing east this evening and
through the overnight.

On Monday we continue to warm as a mid level ridge attempts to
build north into our region. Looks to be mainly dry during the
day Monday after any lingering morning showers/storms, with a
decent capping inversion advertised despite plenty of CAPE
aloft, and lack of any kicker for convection. We will see better
chances for showers and thunderstorms Monday night as ridging
transitions to southwesterly flow and models try to bring a low
level jet across the central/eastern Dakotas.

Active flow showing no signs of abating through the middle of
the week, with a quasi-stationary southwest flow aloft as broad
troughing remains over the northwest/north central CONUS. This
will continue to bring daily and/or nightly chances for showers
and thunderstorms along with near to slightly below normal
temperatures. We start to transition out of this pattern towards
the end of the week to more zonal, which would support warmer
temperatures, yet continued chances for showers and
thunderstorms.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1248 PM CDT Sun Jul 20 2025

A mix of VFR and MVFR ceilings across western and central North
Dakota early this afternoon, with the MVFR areas under low level
diurnal CU. There is a chance for showers and thunderstorms
through most of the 18Z TAF period at most terminals. A few
rounds of showers/storms are possible (with perhaps the
exception of KXWA and KMOT) that will push eastward across the
state through early Monday morning. This could bring low VFR to
MVFR conditions at times. Will maintain PROB30 groups to
account for the more favorable time periods for these chances.
In addition, low stratus clouds and perhaps areas of fog will be
possible tonight into Monday morning, but for now opted to
leave fog out of the TAFs, but did maintain lower ceilings.

&&

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

&&

$$

DISCUSSION...NH
AVIATION...NH