365
FXUS63 KBIS 180935
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
435 AM CDT Tue Jun 18 2024

.KEY MESSAGES...

- Widespread showers with isolated to scattered thunderstorms
  today.

- Below normal temperatures today and tonight, with frost
  possible tonight. Some temperatures below freezing can not be
  be ruled out in southwest North Dakota. Seasonably cool
  temperatures continue through Saturday.

- Mostly dry Wednesday, then chances for showers and
  thunderstorms return late Thursday through Saturday.

&&

.DISCUSSION...
Issued at 316 AM CDT Tue Jun 18 2024

Strong convection has exited the southern James River Valley and
the thunderstorm watch has been cancelled. A large area of
stratiform rain with some embedded thunder, extends west into
south central ND, west of the Missouri River, with some strong
northeast winds. This precipitation is expected to exit the area
this morning. However, with upper level low pressure situated
over eastern Montana shower activity will linger through the
day.

High pressure will build over the area tonight bringing clearing
skies. By 12 UTC Wednesday, surface high pressure is situated
over the western Dakotas. Currently the NBM is depicting low
temperatures in the mid 30s to upper across a good portion of
western North Dakota, most notably over southwest ND. MOS based
temperatures support this with mid 30s indicated at both
Dickinson and Hettinger. The NAEFS SA table indicates a high
probability of very dry air over the Mondak region Wednesday
morning. The ECMWF SA page indicates a high probability of cold
temperatures over all of western ND Wednesday morning. The NBM
is currently depicting a rather large area of patchy frost early
Wednesday morning over the southwest, with patchy frost also
extending into portions of the northwest and south central, west
of the River. Will let the day shift make the call, but would
expect a Frost Advisory, with the potential of some freezing
temperatures over or normally cool areas south and west of the
Missouri river and Lake Sakakawea.

Besides the cold temperatures Wednesday morning, this mid-week
period should be pretty quiet with, maybe a hit or miss shower,
but overall mostly dry conditions Wednesday morning through the
daytime Thursday.

Another upper level shortwave will track from the West Coast,
across the Rockies and into the Northern Plains region late in
the work week and into the weekend. This will bring increasing
chances for showers and thunderstorms late Thursday through
Saturday.


&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1231 AM CDT Tue Jun 18 2024

Ceilings will continue to drop tonight as showers and
thunderstorms track east across easter portions of the forecast
area. Widespread LIFR to MVFR stratus will be possible at times
pretty much through Tuesday morning. A few strong to severe
storms may also be possible over the James River Valley,
including KJMS. The strongest storms will have the potential to
produce golf ball size hail and winds to 60 mph. If one of the
stronger storms move overhead, brief IFR visibilities will be
possible along with gusty and erratic winds. The strongest
storms should move out of the area by around 3 AM or so.

&&

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

&&

$$

DISCUSSION...TWH
AVIATION...TWH