244
FXUS63 KABR 211101
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
601 AM CDT Thu Aug 21 2025

.KEY MESSAGES...

- Expect heat index values of upper 90s to around 100 degrees this
afternoon, highest over portions of central SD.

- The passage of a low pressure system and cold front late this
afternoon through tonight will bring a 40 to 70 percent chance of
precipitation, with a marginal risk (level 1 out of 5) of severe
storms.

- Temperatures Saturday through Tuesday of next week will run about
10 to 15 degrees below normal, meaning highs is the 60s and 70s with
lows in the 40s and 50s.

&&

.DISCUSSION...
Issued at 329 AM CDT Thu Aug 21 2025

Another hot and humid day is expected over central SD, with
dewpoints only dropping into the 50s over portions of our south
central SD counties this afternoon. Still, with temperatures in the
upper 90s to 100 degrees in that area it was enough to bring heat
index values again into the 100 to 103 degree range for portions of
our southwestern counties this afternoon. As a result, a Heat
Advisory has been issued for this afternoon.

The 09Z surface map features low pressure from south central Canada
(Saskatchewan/Manitoba) through western ND and far western SD and
WY. We`ve had light shower activity most of the early morning hours
across and northwest of Corson County in north central SD. A few
lightning strikes were noted over the northwestern portion of the
state. Most CAMs are a little slower with the shower activity, and
the forecast has been adjusted for this.

There is a Marginal Risk of severe storms in the day 1 SPC outlook
for. While the main concern for strong to severe storms will be
around 4 PM-midnight tonight per SPC city charts, a few strong to
severe storms may still be possible through 3-5 AM Friday. We`ll be
watching the track of the surface low as it crosses south central SD
18Z/1 PM today and stays nearly steady until around 09Z/4 AM Friday.
Storms will still be able to fire north and northeast of the low
near the cold front, assisted by an increasing 20-30kt low level jet
(mainly over our southern counties). Confidence is low on specific
timing of the strongest storms. The surface low and associated cold
front should be southeast of the forecast area by 15Z Friday. A dry
Friday afternoon is currently forecast. However, this could change
as some CAMs still keep at least spotty light shower activity around
into the early evening hours.

Confidence is high on temperatures Friday being 5-10 degrees lower
than today. The NBM 25-75th percentiles are pretty consistent and
within around 5 degrees across the forecast area.

Northwesterly flow both aloft and at the surface will stay over
central and eastern SD though the weekend and the beginning of the
work week. This northwesterly flow will help to push cold air into
the state, cooling temperatures down about 10 to 15 degrees colder
than normal for this time of the year. The max temperatures during
the weekend are forecast to get down into mid 70s to mid 60s.
Additionally, the minimum temperatures look to drop down in the low
50s to mid 40s, so it will be a bit chilly overnight and into the
early morning. The chance for precipitation is relatively low as
well during the weekend and early work week.

Winds aloft look to pick up during the weekend because of the fairly
tight pressure gradient between the upper-level low to the northeast
and the upper-level high pressure to the southwest. The strong cold
air advection that is pushing the colder temperatures into our area
will also be pushing some of these stronger winds aloft down to the
surface. The strongest winds are forecast for Saturday and will be
around if not slightly more than 15mph with gusts up to 25 mph over
central and mostly northeastern SD.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 601 AM CDT Thu Aug 21 2025

Terminals KABR,KATY,KPIR,KMBG

Mainly VFR conditions are expected over the next 24 hours. The
main concern will be shifting winds as a cold front sinks
southeast across the area through the period. Showers over
northwestern SD and western ND will also be sinking southeast near
the cold front. However, timing them out and if/when thunderstorms
are more likely will be difficult. Rain showers were included at
least temporarily at all but PIR, with any mention of
thunderstorms left out at this point. The most likely location
will be ABR or ATY, but timing remains a concern between the early
evening or overnight hours.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory from 1 PM CDT /noon MDT/ this afternoon to 8 PM
     CDT /7 PM MDT/ this evening for SDZ033-035-045-048.

MN...None.
&&

$$

DISCUSSION...06/12
AVIATION...06