557
FXUS63 KBIS 041820
AFDBIS

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

.KEY MESSAGES...

- Strong west to northwest winds today through Thursday. Gusts
  up to 55 mph are possible in southwest North Dakota on
  Wednesday.

- Seasonable temperatures expected through the week with
  slightly warmer temperatures possible late in the week.

&&

.UPDATE...
Issued at 118 PM CDT Tue Jun 4 2024

Shower activity from east of Highway 83 in south central North
Dakota through the James River Valley has been much slower to push
east than expected. Observed trends now suggest rain may not fully
exit the forecast area until closer to 4 PM. The wind forecast so
far today has been somewhat challenging. Despite the tightening
pressure gradient and increase in diurnal heating, winds have shown
a slight weakening trend in the northwest, likely owing to the
increased cloud cover. However, several locations remain near
advisory criteria, and observations are still higher than the NBM
deterministic output. We will maintain the Wind Advisory in the
northwest for the afternoon.

UPDATE
Issued at 1020 AM CDT Tue Jun 4 2024

Numerous reporting sites across Divide, Williams, and McKenzie
Counties are reporting sustained winds in the 30 to 40 mph range
and gusts in the 40 to 50 mph range. We have issued a Wind
Advisory for those 3 counties as well as Burke and Mountrail
until 8 PM CDT. Advisory criteria winds and gusts could also be
reached more sporadically across the rest of western North
Dakota throughout the day.

UPDATE
Issued at 943 AM CDT Tue Jun 4 2024

Showers continue to propagate eastward along a line from Wells to
Emmons and Sioux Counties. No lightning has been observed for the
past several hours, and SPC mesoanalysis shows MUCAPE limited to the
southern James River Valley. We have removed the mention of thunder
form the forecast for the rest of the morning and kept only a slight
chance in southern James River Valley for the early afternoon as the
showers depart our forecast area.

Surface low pressure currently north of Saskatoon is forecast to
drive a strong pressure gradient into northwest North Dakota later
today, with recent guidance showing mean BL winds increasing to
around 40 kts. The Williston Airport is already reporting sustained
winds up to 34 mph. If these observed and modeled trends continue, a
Wind Advisory may be needed for the northwest this afternoon.

UPDATE
Issued at 630 AM CDT Tue Jun 4 2024

Showers continue in most of the CWA. The cold front is nearing
the Missouri River, turning winds to the west. There are
showers overrunning the front back to the Dickinson area. Winds
will start to increase west to east as a surface ridge and high
pressure squeeze winds between that and the low pressure in the
eastern Dakotas. The showers will push east and out by this
afternoon.

&&

.DISCUSSION...
Issued at 330 AM CDT Tue Jun 4 2024

Currently the upper level low and shortwave is located over
northeast Montana into North Dakota. At the surface a cold front
is moving east through North Dakota with showers and
thunderstorms ahead of it. A surface low is located in north
central South Dakota. The thunderstorms are east of the low in
the warm sector (James River Valley), while the light showers
are along the cold front to the west. These will continue moving
east this morning. With the upper low spinning in Canada and
the cold front, temperatures will be much cooler in the upper
60s and lower 70s today. There is a chance of rain in the north
central with a small wave from the upper low this afternoon.
Wednesday air at the surface will be squeezed between a high in
Montana and a low north of Minnesota. With this northwest
surface flow, cooler air and a pressure rise bubble move
through. Winds could gust as high as 50mph in the southwest. We
opted not to issue a High Wind Watch yet because of lower
confidence right now. However we will for sure need a headline,
whether its a high wind warning for a few hours in the
afternoon or a wind advisory all day. Flow aloft Wednesday goes
zonal while a large ridge moves overhead through the weekend.
This will give us a break from all these shower and
thunderstorms. Highs will stay around average (mid 70s) through
this time. Monday a small disturbance could move through
bringing with it a chance of showers and thunderstorms through
Tuesday morning. Then another ridge could move in 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.

&&

$$

UPDATE...Hollan
DISCUSSION...Smith
AVIATION...Hollan