285
FXUS63 KABR 151922
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
222 PM CDT Tue Jul 15 2025

.KEY MESSAGES...

- A slight risk (level 2 out of 5) for severe thunderstorms this
  afternoon and evening south of a line from Watertown to Huron to
  Vivian, SD. A marginal risk (level 1 out of 5) for severe
  weather is in place elsewhere. The primary threats will be
  damaging winds, large hail, and heavy rain.

- Near-surface smoke moving through North Dakota will spread down
  into South Dakota by early this evening, potentially reducing
  visibility down to 2 to 4 miles.

- Heavy rain is possible through late this evening.

- Markedly cooler midweek temperatures with highs potentially 15
  to 20 degrees below normal Wednesday and 10 to 15 degrees below
  normal Thursday.

&&

.DISCUSSION...
Issued at 216 PM CDT Tue Jul 15 2025

At 2 PM CDT, skies are partly to mostly cloudy and scattered
showers/thunderstorms are ongoing across the forecast area. A slowly
southward moving cold front has just about cleared the CWA. Behind
the boundary temperatures have cooled into the mid 60s to low 70s,
while out ahead of the front temperatures have warmed into the
80s/low 90s. With most of the CWA behind the front, winds are
predominantly north around 15 to 25 mph with gusts up to 35 mph.

Enough shortwave energy (lift) combined with the forcing on this
cold frontal boundary and a strong zone of upper diffluence within
the right entrance region of a 120+knot upper level jet streak over
southern Canada is aiding in the continuance of showers and
thunderstorms over South Dakota. These showers and storms will move
off to the east, into Minnesota tonight, leaving things dry over the
CWA for appx 12 hours as dry and anomalously cold surface high
pressure begins building down across the northern plains. This
process of high pressure building into the region will continue
throughout the day Wednesday and into Wednesday night. Meanwhile,
additional showers/embedded thunder perhaps are expected on
Wednesday, mainly across central South Dakota as the next upper low
circulation over northwest MT moves over the region. At this point,
Wednesday night looks like a dry forecast period. Dry, but quite
cold. Low level thermal progs and ensemble-powerd standardized
850hpa temperature anomalies indicate high temperatures on Wednesday
will only be in the mid to upper 60s (normal highs are in the low to
upper 80s) and low temperatures will drop into the 40s across much
of the region (normal lows range from 60 to 65 degrees).

Also, there is a swath of near-surface smoke up over North Dakota
heading this direction. The HRRR model is progging this smoke to
advect down into west central MN, northeast South Dakota late this
afternoon into early this evening, and eventually over toward
central South Dakota late this evening/overnight. Smoke has been
added to the forecast for this afternoon through tonight. Any
extensions in time for smoke inclusion will have to be taken up by
the mid-shift.

For Thursday and beyond, the ensemble clusters analysis features a
"soft" ridge aloft over the region. The deterministic models depict
a couple of instances where this ridge is interrupted by an
occasional equally soft upper level trof moving west-east across
NOAM and dampening the ridge. The clusters qpf analysis depicts at
least a tenth of an inch over some part (if not all) of the CWA in
the Days 3 through 8 timeframe. An active/wet seven day forecast?
Will be watching for some nocturnal showers/storms to possibly
develop late Thursday night into Friday morning when a low level jet
is progged to form over the region underneath adequate mid-level
WAA.

The region is still feeling the effects of this cooler than normal
airmass on Thursday, with daytime highs expected generally in the
70s. Beyond that, the nearly zonal flow pattern aloft purports
temperatures getting back to something closer to normal, with next
Monday potentially being the warmest day of the period.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1238 PM CDT Tue Jul 15 2025

Terminals KABR,KATY,KPIR,KMBG

Outside of thunderstorms, prevailing VFR conditions at KABR, KATY
and KPIR will be deteriorating to MVFR/IFR (joining KMBG)
conditions in low stratus over the next 6 to 12 hours behind a
cold front slinking southward toward Nebraska and southeast South
Dakota. Showers and thunderstorms continue across the region this
afternoon and are expected to last into this evening before moving
south and east out of this region. An additional round of showers
is expected to work into central South Dakota Wednesday morning.

&&

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

$$

DISCUSSION...10
AVIATION...10