209
FXUS63 KABR 270515 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1215 AM CDT Fri Sep 27 2024

.KEY MESSAGES...

- Above normal temperatures will remain a constant for the next
  few days with the warmest readings expected this upcoming
  weekend. The combination of warm temps and windy conditions will
  pose some elevated fire danger concerns this weekend.

- A cold front will move through Monday ushering in a cooler air
  mass with temperatures returning closer to normal for this time
  of year.

&&

.UPDATE...
Issued at 1213 AM CDT Fri Sep 27 2024

Updated aviation discussion below.

UPDATE Issued at 810 PM CDT Thu Sep 26 2024

Winds have diminished this evening. This has lowered fire danger
across central South Dakota and allowed the Red Flag Warning to be
expired. No other updates are planned to the forecast.

&&

.SHORT TERM /THIS EVENING THROUGH FRIDAY NIGHT/...
Issued at 334 PM CDT Thu Sep 26 2024

A tight pressure gradient remains in place this afternoon across
parts of the forecast area as a sfc trough and associated cold front
make their way into the western and central portions of the Dakotas.
Southerly wind gusts this afternoon have topped out generally in a
35-45 mph range while lowest RH values have tanked into a 15-25
percent range mainly across our western and central zones. A Red
Flag Warning will continue for our Missouri Valley zones the
remainder of the afternoon into the early evening.

The aforementioned frontal boundary will continue tracking eastward
into central and northeast SD this evening and early overnight.
The gusty winds will gradually diminish from west to east late
this afternoon into this evening and switch around to a more
north-northeast direction once the front clears the area. An upper
level trough axis will shift across the Dakotas tonight with
little fanfare. A drier air mass gets advected in behind the
frontal boundary. Clear skies will persist as temps fall into the
upper 40s to mid 50s by daybreak Friday. Sfc high pressure will
build back into the region on Friday. A slightly cooler air mass
will briefly move in leading to a "cooler" day but still well
above normal. Daytime temperatures will still make it back into
the upper 70s to mid 80s for highs. Very quiet and continued dry
will be the main themes through the end of the period as upper
level ridging begins to build overhead allowing a warmer air mass
to return for the upcoming weekend.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 334 PM CDT Thu Sep 26 2024

Broad upper level ridge will remain in place through Sunday evening,
allowing warm dry air to advect in from the southwest CONUS. PWATs
will drop below three quarters of an inch which coupled with warm
temperatures (approaching the 99th percentile or greater at each of
the 500mb, 700mb, and 850mb levels) will create warm, dry conditions
across the forecast area. Surface temperature forecasts for Saturday
and Sunday reach the mid to upper 80s across eastern South Dakota,
approaching 15-20 degrees above normal for the end of September.
Daily high records over this area are in the low to mid 90s, and NBM
probabilities are pessimistic (<10%) about the James River valley
and east hitting 90 degrees on either day this weekend. The Missouri
River area is a different story however, with low 90s forecasted for
both Saturday and Sunday. Daily high temperature records are a
little bit lower here (low 90s as opposed to the mid 90s further
east) and so we may see some of those broken this weekend. NBM
probabilities give about a 30-40% chance for both the Mobridge and
Pierre areas to see these records broken, which may be boosted
further with clear sky conditions expected.

Wind will also play a factor this weekend, creating some fire
weather concerns. Southerly flow of 25 knots gusting to 35 knots
will line up with relative humidities below 20%. The main areas of
concern for fire weather are west of the Missouri River. Monday`s
setup poses concerns as well, with northwesterly flow reaching 25-30
knots and gusting up to 40. Relative humidities will be a bit
higher, up around 30-40%, but the strong flow may still be enough to
warrant concern.

The aforementioned shift in wind direction comes from a cold front
that is expected to move across the region Sunday night into Monday
morning. High temperatures will drop closer to normal behind the
front, reaching the low 70s Monday and through the rest of the week.
The vertical extent of the cold front will be limited due to the
location of the low pressure center in Canada. Therefore, the front
will have a difficult time clearing the warm air at the 500mb level,
limiting the buoyancy in the profile. Timing of frontal passage is
also not favorable for development. As such, no QPF is forecasted
with this system at this time, although there is a small possibility
for a light isolated shower or two in the lower levels along the
front.

Behind the frontal system, a zonal pattern aloft will emerge.
Temperatures remain close to normal and moisture content will be
similar to pre-frontal conditions. The next system looks to move in
and bring the next chances for rain at the end of next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1213 AM CDT Fri Sep 27 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected through the next 24 hours.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

UPDATE...SD
SHORT TERM...Vipond
LONG TERM...BC
AVIATION...SD