251
FXUS63 KBIS 141929
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
229 PM CDT Fri Jun 14 2024

.KEY MESSAGES...

- There is a Marginal Risk (level 1 out of 5) for severe
  thunderstorms this afternoon through tonight, specifically
  across the western portions of the state.

- There is a Slight Risk (level 2 out of 5) for severe
  thunderstorms late Saturday afternoon through Saturday night,
  covering most of western and central North Dakota.

- There is a Marginal Risk (level 1 out of 5) for severe
  thunderstorms Sunday across far southeastern portions of the
  state.

- High temperatures are forecast to peak in the 80s on Saturday
  (potentially reaching the 90s in the southwest), with a
  gradual cooling trend through the first few days of next week.

- Periodic showers and thunderstorms are expected next week,
  with the best chances Monday night with precipitation chances
  ranging from 60 to 80 percent across the state.

&&

.DISCUSSION...
Issued at 129 PM CDT Fri Jun 14 2024

The main forecast challenge is the potential for severe weather
this afternoon through this weekend.

Presently, a transitory ridge is passing through the central
Dakotas with a weak trailing shortwave analyzed over eastern
Montana towards western South Dakota. This shortwave and
associated WAA will help generate showers and thunderstorms this
afternoon possibly lingering into the overnight hours.
Instability will become moderate in the west with CAPE values
around 1000 to 2000 J/kg, especially in the southwest, as Gulf
moisture advects into the area. Shear is on the lower end at
around 30 to 40 kts, but it`s enough for a few severe
thunderstorms to develop. One of the biggest limitations to
potential severe weather is that capping is quite strong in the
west. While it is progged to deteriorate, there is some question
as to whether it will break in time or not. As a result, there
is a window for severe weather mainly in the west this afternoon
and early evening, but it`s also possible storms will stay sub-
severe. The primary threats are hail up to the size of ping pong
balls and 60 mph wind gusts.

A bigger severe weather threat is possible on Saturday. Unlike today
where Gulf moisture is primarily advecting into western ND, Gulf
moisture will be present over most of the state. This will result in
mixed layer dewpoints approaching 60 degrees, thus creating ample
instability over much of the area. In the late afternoon, wind
shear looks marginal (though enough) along and south of I94,
while areas further north of I94 and west of Highway 281 are
progged to have strong shear in excess of 50 kts of 0 to 6 km
bulk shear. Moderate instability and strong shear values migrate
eastward through Saturday night. The primary forcing mechanism
looks to be a moderate shortwave along with associated surface
cold frontal boundary, which looks to begin sliding through the
area in the late afternoon. This will result in severe weather
potential in the later afternoon, through the evening, and
potentially into the early overnight hours.

In regard to potential hazards for Saturday, shear vectors are
generally parallel or between parallel and perpendicular. Overall,
this favors a more clustered event that may become linear. However,
a few discrete supercells are possible earlier on. With any discrete
supercells, hail of two inches or greater is possible. There
remains a very conditional brief tornado threat window should
any discrete cells develop. Otherwise, in a more disorganized
cluster, threats include wind gusts up to 70 mph and hail up to
ping pong ball size. Any hail threat will diminish as storms
become more linear leaving a primary threat of wind gusts up to
70 mph. Isolated gusts up to 80 mph are not out of the question.

Beyond Saturday, breezy to windy conditions are possible in the
north and west, and especially the northwest itself, as the
pressure gradient tightens between low pressure to the north
and high pressure to the southwest. One point to this is that
with strong pressure rises and moderate CAA progged in
deterministic models at this time; winds may wind up being
stronger than presently forecast. Otherwise, expect periodic
showers and thunderstorms with severe weather not out of the
question Sunday in the far southeast CWA, and Monday in the
eastern CWA.

The highest confidence for widespread precipitation next week is
Monday through Tuesday afternoon, and especially Monday night,
as deep low pressure originating in Wyoming moves through the
central/northern Plains. As a result, the entire forecast area
is already forecast for a 60 to 80 percent chance of seeing
showers and thunderstorms. This low pressure will also bring a
return of cooler temperatures. Though exact values will be
ironed out in the future, the majority of the forecast area is
favored to see highs return to the 60s Monday through Wednesday.
A gradual warming trend is then favored for the latter half of
next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1258 PM CDT Fri Jun 14 2024

VFR ceilings and visibility are present to start the TAF period.
Shower and thunderstorm chances will begin entering western
North Dakota this afternoon and progress eastward through the
evening and overnight. A few severe thunderstorms are possible
this afternoon and early evening primarily in western North
Dakota. The primary threats are quarter size hail and erratic
winds up to 60 mph. MVFR ceilings are also possible in the
south central, including KJMS, late tonight through Saturday
morning.

&&

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

&&

$$

DISCUSSION...Telken
AVIATION...Telken