613
FXUS63 KABR 151726 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1226 PM CDT Sun Sep 15 2024

.KEY MESSAGES...

- Highs/Lows 15 to 25 degrees above normal through the first half of
  next week.

- Next round of showers and storms tonight into early Monday (20
  to 40% chance for moisture). Not expecting any severe weather
  with this round.

- Multiple chances for precipitation will persist through most of
  next week. Highest chances will arrive Tuesday night and
  continue through midday Wednesday with a 50-80% chance for
  showers and storms.

&&

.UPDATE...
Issued at 1223 PM CDT Sun Sep 15 2024

See updated aviation discussion below.

UPDATE Issued at 1008 AM CDT Sun Sep 15 2024

Current forecast is on track, therefore no changes made at this
time.

&&

.SHORT TERM /TODAY THROUGH MONDAY AFTERNOON/...
Issued at 423 AM CDT Sun Sep 15 2024

Storms continue to linger in northeast SD, with a few CAMS
suggesting that convection will continue on through the morning
hours with this weak southwest flow shortwave moving on into the
western lakes region by about 12Z. As the upper trough over the
western CONUS deepens, we see increasing heights aloft and ridging,
so anticipate dry conditions despite continued mid level warm
advection. 700mb temperatures increase to +9 to +10C today (was
about +6C from the previous 12Z/00Z soundings), topping a standard
deviation above climo. This warm air aloft translates to
temperatures some 15 to 20 degrees above normal for today. While
probabilities for exceeding 90 degrees is only about 20 percent
across the northern tier of the state, it increases south of highway
212, peaking between 60-80 percent along and south of a line that
runs from Pierre to Redfield (but that doesn`t include the higher
terrain of the Sisseton hills). Recent rain, and southerly low level
flow will also result in increasing humidity. Some things holding us
back are that this fetch isn`t purely connected to the gulf, and
with corn ET diminished as we are into mid September, so the
probability of a dewpoint in the low 70s is negligible. Still NBM runs
in the mid/upper 60s east river, with a gradient to the west
initially, though even that washes out by Monday.

Our next southwest flow shortwave lifts into western South Dakota
tonight, tracking into central North Dakota. This will limit the
extent/coverage of convection to mainly western and central South
Dakota. The layout of 850mb temperatures Monday suggests nearly as
warm as compared to Sunday, with lower probabilities for reaching 90
over towards the Redfield area in comparison to Sunday.

&&

.LONG TERM /MONDAY EVENING THROUGH SATURDAY/...
Issued at 423 AM CDT Sun Sep 15 2024

An active upper flow pattern will be the theme that carries through
the majority of this period. A persistent and stubborn upper level
low will remain more or less planted across the eastern CONUS this
next week allowing for upper troughing across the western CONUS to
take up residence. This will promote southwesterly flow aloft across
our region the Northern Plains during most of this period. Periodic
shortwave energy will rotate out of the upper troughs and into our
region leading to frequent chances for precipitation through mid to
late week.

An ongoing round of showers and thunderstorm will be possible Monday
night into early Tuesday, associated with one such upper wave. PoPs
remain fairly limited to 20-30% across our eastern forecast area
with minimal QPF expected. Guidance progs show the daytime hours on
Tuesday will be mainly dry, warm and windy. Temperatures are likely
to top out in the 80s to low 90s. Highest probabilities of reaching
or exceeding 90 degrees are confined to zones along and west of the
Missouri River, especially for locales south and west of the Pierre
area. Deepening sfc low pressure across the Northern High Plains
will tighten the gradient locally and lead to gusty southerly winds
by Tuesday afternoon. Highest probabilities of seeing wind gusts
reach or exceed 40 mph are along and east of the Missouri Valley and
portions of the Glacial Lakes. The next slug of moisture will be on
our doorstep Tuesday night. Another incoming wave will aid in
allowing more showers and thunderstorms to develop. This wave still
appear to be the one that has more substance behind it. Likely PoPs
continue to be advertised with 50-80% chances across the forecast
area Tuesday night through midday Wednesday. This system could drop
some more widespread rainfall across the area. Highest
probabilities(50-80%) of seeing at least a quarter of an inch or
more in a 24-hr period ending 7PM Wednesday are bounded by an area
west of US Hwy 281 and south of US Hwy 12.

The remainder of the period will continue to feature more of the
same...on and off again chances for showers and thunderstorms.
Difficult to time out the next succession of upper waves to roll
through the region. We`ll continue to advertise an increase in PoPs
of about 30-50% from the latter half of Thursday through Saturday.
Temperatures will cool back just a bit for the end of the work week
but still above normal readings can be expected to continue. We
might finally get back closer to normal by late in the period when a
cold front finally sweeps through the region cooler temperatures
back closer to normal.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1223 PM CDT Sun Sep 15 2024

Terminals KABR,KATY,KPIR,KMBG

For the most part, VFR conditions will prevail across the area
through the TAF period. The exception will be with some shower and
thunderstorm activity that is expected across parts of central
South Dakota late tonight int early Monday morning. Periods of
MVFR vsbys will be possible with any thunderstorms.

&&

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

$$

UPDATE...Parkin
SHORT TERM...Connelly
LONG TERM...Vipond
AVIATION...Parkin