126
FXUS63 KBIS 181738
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1238 PM CDT Sat May 18 2024

.KEY MESSAGES...

- Windy and cooler today with highs mostly in the 60s. A Wind
  Advisory is in effect from mid morning through this afternoon
  for northern and central North Dakota.

- A chance of afternoon and evening thunderstorms Sunday far
  southwest and south central, some possibly strong to severe.

- Seasonable temperatures through the work week with morning
  lows in the upper 30s to mid 40s and daytime highs mainly in
  the 60s. Periodic chances for showers and thunderstorms
  continue through the work week.

&&

.UPDATE...
Issued at 1228 PM CDT Sat May 18 2024

Winds are increasing as expected with widespread observations of
gusts in the 40 to 50 mph range across portions of the west and
central. Thus, the Wind Advisory looks to be in good shape. It
will remain windy through the afternoon with plenty of fair
weather cumulus. A few showers will remain possible through the
early afternoon across Bottineau, Rolette, and northern Pierce
counties but amounts should be rather light. No major changes
were needed for this update. Just blended in the latest
observations to the going forecast.

UPDATE
Issued at 850 AM CDT Sat May 18 2024

No major changes were needed for this update. A few showers
continue to linger across the north as an upper low spins to the
north of the International Border.

UPDATE
Issued at 631 AM CDT Sat May 18 2024

Shortwave pushing through central ND is producing a narrow band
of shower activity along the Highway 83 corridor. This shower
activity will continue to track east, exiting the forecast area
later this morning. Otherwise windy conditions are expected
across the area today with advisory criteria winds mainly over
northern and central ND. Updated PoPs and sky cover based on
latest radar and satellite imagery. Updated text products will
be transmitted shortly.

&&

.DISCUSSION...
Issued at 221 AM CDT Sat May 18 2024

Currently, thunderstorms are exiting the southern James River
Valley. An area of rain showers continues to push from western
and into central ND ahead of a shortwave lobe pushing into
western ND. Surface low pressure is exiting eastern ND as high
pressure is pushing into the western Dakotas from the Northern
Rockies. This is producing a strong pressure gradient currently
over western ND. Winds are gusting into the 40 to 50 mph range
over southwest ND. The shower activity is likely adding to the
gusts and this brief bump in winds can be traced west to east
across southern ND this morning from the bufkit soundings. This
brief bump in winds is not expected to last long as it
propagates east through mid morning. Later this morning and this
afternoon, strong gradient winds will remain across northern
and central ND between the low that lifts northeast into Canada
and the surface high that slides southeast into South Dakota. We
have issued a wind advisory (in effect from mid morning,
through the afternoon) for northern and central ND, along and
north of the I-94 corridor. The gradient isn`t all that strong
but steep lapse rates and good afternoon mixing should result in
low end criteria wind advisory winds over a good portion of the
forecast area. Although the aforementioned brief bump in winds
tracks across the far south early, daytime wind potential will
be lowest across the far southern tier counties.

Winds diminish quickly tonight and we see low drop into the 40s,
with some upper 30s possible in the north and west as surface
high pressure propagates across the forecast area.

another shortwave rotating around the mean upper low situated
over southern Canada tracks across the Northern Rockies on
Sunday. Surface low pressure will develop in the lee of the
Northern and Central Rockies and exit into the plains during
the day. By Sunday afternoon, deterministic guidance is
depicting surface low pressure over South Dakota with a
southwest upper flow from the Central Rockies into the Northern
Plains. This will set the stage for a possible round of
thunderstorms Sunday afternoon and evening tracking through the
Dakotas. Based on the deterministic and ensemble location of the
surface low, there would be a risk of strong to severe storms
over south central into southeast North Dakota Sunday
afternoon/evening. SPC has placed portions of south central ND
(Sioux/Emmons east through Lamoure/Dickey counties) in a
marginal risk for severe storms, with a general risk of
thunderstorms over the far southwest and the remainder of south
central ND. Based on the location of the surface low, all
threats would be in play, including tornados. CSU_MLP has the
low tornado probs up to the SD/ND border in south central ND.
Bufkit sounding from Ashley shows a very warm, moist and
highly sheared environment, but potentially capped. With a
decent shortwave moving into the area, the potential will be
there for enough forcing to initiate convection. Will certainly
continue to monitor the south central for severe potential
tomorrow afternoon/evening.

Once this wave moves through Sunday/Sunday night, it looks like
we may have at least a brief break in the convection early next
week. The aforementioned upper low will linger over southern
Canada pretty much through the work week. The next wave coming
off the Pacific may take more of a southern track into the
Central Rockies before lifting back north and east as it tracks
through the central portion of the U.S. There is quite a bit of
uncertainty in whether this wave misses us, or clips southern
and eastern portions of the forecast area on Tuesday. Beyond
this, the barrage of upper lows lifting into the Northern Plains
continues through remainder of the forecast period.

Temperatures remain seasonable next week with morning low in
the upper 30s and 40s and daytime highs mostly in the 60s.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1228 PM CDT Sat May 18 2024

We will see widespread fair weather cumulus this afternoon but
should remain in VFR categories through the period. Some
isolated to scattered showers will develop across the south
central and James River Valley early Sunday morning before
lifting north. Due to the isolated to scattered nature and exact
location uncertainty, have not included mention in any site
specific forecast at this time. It will remain windy through
this afternoon with winds mainly out of the west northwest.
Sustained values may reach 30 mph with gusts to 45 mph.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 7 PM CDT /6 PM MDT/ this evening for
NDZ001>005-009>013-017>023-025-031>037.

&&

$$

UPDATE...ZH
DISCUSSION...TWH
AVIATION...ZH