887
FXUS63 KBIS 011749
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1249 PM CDT Tue Oct 1 2024

.KEY MESSAGES...

- Critical fire weather conditions across the western half of
  the state this afternoon.

- Except for Thursday, above average temperatures are favored
  for the next several days, with highs mainly in the mid 60s to
  upper 70s.

- Near to sub-freezing overnight low temperatures are forecast
  across northern and western North Dakota both Wednesday and
  Thursday nights.

- Very little to no measurable precipitation is expected this
  week.

&&

.UPDATE...
Issued at 1249 PM CDT Tue Oct 1 2024

Over the past few hours winds have increased, temperatures have
risen rapidly, and minimum relative humidity values have
dropped significantly for much of the area. This is in line with
the forecast and therefore, no major updates at this time.

UPDATE Issued at 946 AM CDT Tue Oct 1 2024

Temperatures have risen to 40 degrees or greater for most of
the forecast area and will continue to rapidly rise this
morning. Therefore, both the Frost Advisory and Freeze Warning
have been allowed to expire at the top of this hour. Otherwise,
the forecast remains on track with critical fire weather
conditions expected for the western half of the state this
afternoon and early evening, with near-critical fire weather
conditions expected for most of the eastern half of the state.

UPDATE
Issued at 639 AM CDT Tue Oct 1 2024

The forecast for today remains on track. A few areas in far
western North Dakota have seen temperatures fall into the upper
20s early this morning, with widespread lower to mid 30s across
the western two thirds of the state.

&&

.DISCUSSION...
Issued at 329 AM CDT Tue Oct 1 2024

A southeastward progressing surface high pressure was centered over
the Black Hills early this morning under northwest flow aloft. The
influence of the surface high has allowed early morning temperatures
to fall into the 30s across western and parts of central North
Dakota. The ongoing Freeze Warning and Frost Advisory remain on
track.

The surface high will continue sliding southeast into the lower
Missouri River Valley today as northwest flow aloft turns
anticyclonic. This will allow for an increase in cirrus clouds but
also for warmer air to return to the region. Given the very dry
conditions as of late, and southwest surface flow also being
favorable for exceeding temperature guidance, we relied on the NBM
75th percentile for highs today, which brings mid 60s to the Turtle
Mountains and James River Valley increasing to the mid and upper 70s
in the southwest. The tightening pressure gradient behind the
departing high will increase southwest winds to around 20 to 25 mph
this afternoon, with gusts as high as 35 mph. Additionally, surface
dewpoints are forecast to decrease into the upper teens to mid 20s
this afternoon, causing relative humidity to fall into the 10 to 15
percent range across the western half of the state. The combination
of low RH and winds has prompted the issuance of another Red Flag
Warning for this afternoon along and west of Highway 83.

Warm air advection is forecast to persist through Tuesday night,
keeping overnight lows in the mid 40s to lower 50s. A west-to-east
oriented cold front will then begin sagging down from Canada on
Wednesday, with the low-level cooling not reaching the South Dakota
border until Wednesday evening. This will bring slightly cooler high
temperatures to northern parts of the state (lower to mid 60s) while
southern areas remain warmer (lower to mid 70s). Breezy conditions
are once again expected on Wednesday, this time from the northwest
around 20 mph with gusts to around 30 mph. The warmer temperatures
farther south combined with the wind could result in near-critical
fire weather conditions across far southern North Dakota on
Wednesday.

A large upper cyclone over central Canada will force cooler air into
the region Wednesday night through Thursday. Both Wednesday and
Thursday nights could feature low temperatures near to below
freezing on a widespread basis, especially across the west and north
central, and with higher odds for colder temperatures on Thursday
night. Thursday looks to be the coolest day of the extended period,
but only slightly below normal with highs forecast in the mid 50s to
mid 60s.

Ensemble guidance is converging on transient ridging over the
Northern Plains on Friday followed by a quick moving shortwave
Friday night into Saturday. Forecast implications from this setup
include warmer temperatures Friday and Friday night and stronger
northwest winds with fire weather concerns on Saturday. The passage
of a strong cold front prior to diurnal heating on Saturday would
theoretically lower high temperatures, but the NBM high temperature
spread is quite large for Saturday, likely owing to amplitude and
timing uncertainty of the wave. Precipitation prospects continue to
appear to be very low to nonexistent not only with this shortwave,
but over the whole forecast period. Behind the shortwave on
Saturday, ensembles once again favor broad ridging over the western
and central CONUS heading into next week, with higher odds of above
normal temperatures over the Monday to Tuesday time period when some
areas could approach 80 degrees.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1249 PM CDT Tue Oct 1 2024

VFR ceilings and visibility are expected through the period.
Breezy to gusty southwesterly winds are expected through the
afternoon before becoming light while remaining out of the
southwest tonight. Winds will shift to the northwest and become
breezy again Wednesday morning. LLWS is possible this evening in
the James River Valley, and in the southwest and south central
tonight into Wednesday morning. This later LLWS will primary
impact KDIK, however, may extend into KXWA and KBIS as well.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 7 PM CDT /6 PM MDT/ this evening for
NDZ001>003-009>011-017>021-031>035-040>046.

&&

$$

UPDATE...Telken
DISCUSSION...Hollan
AVIATION...Telken