157
FXUS63 KBIS 042115
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
415 PM CDT Tue Jun 4 2024

.KEY MESSAGES...

- Strong west to northwest winds are expected during the daytime
  hours across western and central North Dakota this afternoon
  through Thursday.

- The strongest winds are expected in southwest North Dakota
  Wednesday morning and afternoon with gusts up to 55 mph.

- Near to slightly below normal temperatures with mostly dry
  weather through this weekend.

&&

.DISCUSSION...
Issued at 409 PM CDT Tue Jun 4 2024

Nearly-stacked low pressure is analyzed over southeast Saskatchewan
this afternoon. This low is forecast to slide into Manitoba through
Wednesday as a strong upper jet/vort max digs underneath into North
Dakota. The main concern with this system for our area is strong
winds, mostly driven by the pressure gradient force. For the rest of
this afternoon, the strongest winds will be focused over northwest
North Dakota, particularly at higher terrain locations such as the
Williston Airport. Later tonight, the approaching upper jet streak
will induce a low level jet with northwest winds around 50 kts. This
LLJ is forecast to pass over southwest North Dakota Wednesday
morning. Multiple deterministic model soundings from Bowman to
Lemmon, SD show downward momentum transfer potential of 50-60
kts, with the the top of the mixed layer possibly building closer
to 700 mb. However, there are several limiting factors that
could keep the strongest winds just below warning criteria of 40
mph sustained and 58 mph gusts, including the lack of strong
surface pressure rises and low level cold air advection, as well
as the earlier time of day for the core of the strongest winds
aloft. HREF mean 10 m winds and gusts are also just below
warning criteria. Confidence is therefore not high enough for a
High Wind Warning, though a few gusts to 60 mph both spatially
and temporally seem plausible. Elsewhere across western and
central North Dakota, confidence is high in northwest winds
increasing to 30-35 mph on Wednesday, with gusts up to 45-50
mph. A Wind Advisory has been issued, with a 5 AM MDT start time
in the southwest, and 10 AM CDT start time elsewhere, ending
for all locations at 9 PM CDT Wednesday evening. Aside from the
wind, there are no other noteworthy items in the forecast for
Wednesday. A few morning showers are possible in the southwest,
and isolated afternoon showers could develop from the Turtle
Mountains to the Devils Lake Basin. Highs on Wednesday are
forecast to reach the lower to mid 70s.

The synoptic pattern will transition to northwest flow over the
Northern Plains on Thursday as a trough digs into the Great
Lakes region. Another day of strong northwest winds is likely
across northern and eastern North Dakota as high pressure
building upstream maintains a strong pressure gradient. The
northwest flow pattern is forecast to continue into the weekend,
which could include the passage of a stronger shortwave on
Saturday or Sunday. Such a feature would likely introduce
chances for rain into the forecast, but ensemble spread and
forecast time range supports maintaining a mostly dry forecast
from Thursday through the weekend. For early to mid next week,
there appears to be a variety of solutions in ensemble data sets
that eventually transition to mean ridging over the central
CONUS. This keeps forecast confidence low on rain and
thunderstorm chances, but all ensembles show a warming trend to
above normal by the second half of next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 118 PM CDT Tue Jun 4 2024

VFR conditions are expected through the forecast period. Light rain
will remain possible at KJMS until mid afternoon. Westerly winds
around 15-25 kts with gusts around 25-40 kts will continue through
the afternoon, strongest in northwest North Dakota. Wind speeds will
diminish to around 10-15 kts later this evening and tonight.
Stronger westerly winds are then expected for Wednesday, with
sustained speeds around 25-30 kts and gusts to 35-45 kts. The
strongest winds on Wednesday are expected in southwest North Dakota.
A period of low level wind shear concerns is expected at KMOT late
tonight.&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 8 PM CDT /7 PM MDT/ this evening for
NDZ001-002-009-010-017.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 8 PM CDT /7 PM MDT/ this evening for
NDZ001-002-009-010-017.
Wind Advisory from 10 AM CDT /9 AM MDT/ to 9 PM CDT /8 PM MDT/
Wednesday for NDZ001>005-009>013-017>023-025-034>037-042-
045>048-050-051.
Wind Advisory from 5 AM to 8 PM MDT Wednesday for NDZ031>033-
040-041-043-044.

&&

$$

DISCUSSION...Hollan
AVIATION...Hollan