653
FXUS63 KABR 232309 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
609 PM CDT Mon Jun 23 2025

.KEY MESSAGES...

- Cooler temperatures are expected to persist through the midweek.

- Showers and thunderstorms return Tuesday evening and continue
through Thursday. A marginal risk (level 1 of 5) for severe weather
is possible across south central South Dakota late Tuesday/early
Wednesday and for most of central/northeast South Dakota and west
central Minnesota on Wednesday and Wednesday night.

- Warming temperatures are expected the latter half of the week with
a brief period of dry weather before more precipitation chances return
late in the week and weekend.

&&

.UPDATE...
Issued at 608 PM CDT Mon Jun 23 2025

The forecast remains on track this evening. No major changes are
planned.

&&

.DISCUSSION...
Issued at 330 PM CDT Mon Jun 23 2025

The rest of the week will consist of cooler temperatures through the
midweek with temps back into the 80s/90s Friday and Saturday.
Otherwise, we will continue with an active weather pattern with the
potential for showers and thunderstorms into the weekend. As of 3pm,
skies were overall clear with a bit of smoke aloft over north
central SD with temps in the upper 60s to the mid 70s.

With this southwest flow and fires breaking out over California and
Utah, HRRR Integrated Smoke Model through Wednesday morning does
show ongoing plumes of smoke moving in southwest to northeast,
mainly over portions of north central and northeastern SD/western
MN. This smoke is forecasted to remain aloft. Otherwise, a
-PNA pattern setup is over the CONUS with an ongoing shortwave to
our north, where it will continue its track eastward across the
central Canadian provinces through Wednesday and its surface low.
Its cold front will drape horizontally across ND/MT Wednesday
through Wednesday evening. Within this flow aloft, several embedded
shortwaves (and shortwave energy pulses) will push northeast on the
downstream side of the trough/upstream side of ridge and over the
Northern Plains through the midweek as well. At the surface, high
pressure remains over the area through this evening. This high will
shift northeast tonight and is forecasted to be over northern MN by
12Z Tuesday. A low pressure system will develop and be over eastern
half of Colorado Tuesday morning, with a quasi-stationary frontal
boundary extending east/northeastward from this through KS/NE/IA.
Through the day Tuesday this surface low will shift a bit north with
more of a west to east oriented front tracking along the NE/KS
border by 00Z Wednesday. By Wednesday morning, this front lifts
northward, as a warm front, extending through central to eastern
NE/IA before stalling out once again. The low then shifts over this
front and over central NE by the evening. Its surface low finally
shifts northeastward, and its trailing cold front, by Thursday
morning where it will continue to track northeastward.

With this setup, overall moisture will increase as dewpoints are
forecasted to rise back in the the mid 50s to the lower 60s, highest
over south central SD By Tuesday afternoon. RAP 1000-500mb RH shows
an increase in humidity and surging northward over south central SD
Tuesday afternoon and evening and over the entire CWA by early
Wednesday morning. PWAT values by this time will range from 1.25 to
1.75", highest over southeastern SD. This is about 2 to 2.5 above
standard deviations per NAEFS. So being sandwiched between two
fronts and this increase in moisture, we will see the return of WAA
showers and thunderstorms as HREF indicates this precip moving in
from the south and west starting Tuesday late afternoon/evening,
over central SD, then spreading east and northeastward over the CWA
into early Wednesday. NBM pops show this well with pops of 40-90%
from 00-12Z Wednesday, highest over south central SD (closer to
front/low) with ongoing pops of 40-80% from 12Z Wed-00Z Thursday,
highest over the eastern CWA where this area is now closer to this
lifting warm front. Pops of 50-70% continue 00-12Z Thursday and
diminishing west to east through the day as this system tracks
further northeast.

With this slow moving frontal boundary and higher moisture/PWATs, EC
EFI ranges from 0.5 to 0.8 from south central through southeastern
SD with a shift of tails of zero for QPF. Highest EFI is over the
southeastern SD. Probability of 24 hr QPF> 0.50" 00Z Thursday is 50-
75% over the southern half of the CWA. As of now, the heavier rains
of 2-4" lies south and east of our CWA, closer to the stalled
frontal boundary. However, some of this rain could still be heavy at
times over south central through east central SD. WPC Excessive
Rainfall Outlook has a slight risk (level 2 out of 4) mainly along
and east of a line from Brookings to just south of Watertown 12Z
Wednesday-12Z Thursday. We will have to monitor if this slight risk
retreats westward (or any shift in the front/low) that would affect
overall rain amounts in our CWA. In addition to the heavy rain
threat, we will also need to watch for any training thunderstorms
that could cause for flooding concerns. There is also a risk for
some storms to be strong to severe Tuesday evening into Wednesday
morning as MUCAPE will be up to around 1000j/kg, bulk shear between
30-40kts, and an increasing LLJ, mainly over south central SD where
HRRR/HiResARW shows the storms forming and/or moving into this area.
This is is where the SPC marginal risk (level 1 out of 5) is
highlighted. Another round of severe storms is possible Wednesday
afternoon and evening as the atmosphere destabilizes with ongoing
lift and moisture from this boundary. So there is a marginal risk
over the entire CWA for Wednesday.

More of a quasi-zonal flow pattern sets up for the end of the week
and weekend (with ongoing embedded shortwaves moving within this
flow) with a surface system that is forecasted to push over the
Northern Plains Friday/Saturday bringing the possibility of more
showers and thunderstorms. Machine Learning indicates the
possibility of severe weather during this time, however, this is too
far out for any details. Looking ahead into early next week a high
moves in behind this and ridge aloft. The ridge will shift eastward
with the Northern Plains near or under the ridge Tuesday and
Wednesday.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 608 PM CDT Mon Jun 23 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected through Tuesday afternoon.

&&

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

$$

UPDATE...20
DISCUSSION...MMM
AVIATION...20