Tornado in South Dakota, July 13, 2025

Area Forecast Discussion
National Weather Service Aberdeen SD
148 PM CDT Sun Jul 13 2025

.KEY MESSAGES...

- Near record heat over portions of south central SD will create
heat index values in the 100 to 104 degree range Monday afternoon.

- There is a Marginal Risk (level 1 out of 5) of severe weather for
the afternoon and evening hours Monday and Tuesday. Main threats
include hail up to the size of quarters and 60 mph wind gusts.

- Heavy rain is possible along and east of the James River into west
central MN Tuesday.

- There will be a noticeable cool-down on Wednesday and Thursday,
with highs potentially 10 to 15 degrees below normal.

&&

.DISCUSSION...
Issued at 148 PM CDT Sun Jul 13 2025

We're starting out with a surface through set up from northern MN
through eastern SD. Cumulus cloud development has increased along
the boundary, with the potential for a few showers or even a
thunderstorm by 22Z. The threat of shower or thunderstorms will be
short lived (up to 2 hours) across our far eastern counties before
exiting east by 00Z. Our mainly dry weather will continue.

We've been watching the next round of smoke shift from south central
Canada through eastern ND/western MN during the day today. Forecast
guidance continues to show most of this smoke staying to the north
and east, with lighter concentrations over our far northeastern SD
and west central MN counties from around 05-18Z Monday. Additional
smoke looks to sink south from ND Tuesday, with unknown
concentrations at this time as it depends on way to many fire and
weather variables between now and then.

Higher temperatures and dewpoints in the upper 50s to upper 60s
(lowest over central SD) will combine with very warm air to create
heat index values in the 90s to near 105F. The highest heat index
values will be 100-105 over our southwestern counties Monday
afternoon. We'll continue to monitor the latest trends with the
potential for heat headlines for 3-5 of our southwestern most
counties. The current forecast for PIR of 100F is only 4 degrees
from the record high from 2006.

The next surface through over eastern WY/western SD 18-21Z Monday
will extend from southwestern SD through far southeastern ND by 06Z
Tuesday. While some CAMs do show the potential for thunderstorm
development just prior to 00Z Tuesday, most show the thunderstorms
over central SD 00-03Z Tuesday. The main question will be if
additional additional development will extend to northeastern
SD/west central MN during the overnight hours with help from the low
level jet that will be around 40kts. While the SPC marginal risk
(level 1 out of 5) would be over mainly central SD Monday evening,
it would be over much of the forecast area Tuesday. Given the
southwest to northeast oriented trough across SD at 12Z Tuesday,
sinking to southeastern SD by mid 21Z and much of the instability
exiting, the main focus for any stronger storms should be through
the 18-21Z time period. Another concern for Tuesday into Tuesday
will be heavy rain from slow moving/training showers and storms. PW
values Tuesday afternoon into Tuesday night east of the MO River
range from 1.5 to over 2.25in. The NBM is showing a 35-65%
probability of 1" or more rain from Brown/Spink Counties east, with
the highest values between Sisseton and Milbank. Still, there is
some uncertainly/lower confidence on timing of the surface trough
and other specifics, so stay up to date on the latest for this
evolving forecast. This is leading to a wider range in high
temperatures, with the 25-75th percentiles being anywhere from 75 to
near 90F at ABR. Expect potential changes in the ongoing forecast
for Tuesday.

Cooler air will sink in with the surface high Wednesday and
Thursday, with higher confidence in the forecast temperatures. Highs
will be in the 60s to near 70F Wednesday and mainly in the 70s
Thursday. Friday will be a transition day, as temperatures rise back
into the upper 70s to mid 80.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1240 PM CDT Sun Jul 13 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will continue over the next 24 hours. The main
change will be winds shifting out of the south late this evening
and overnight, still around 12kts or less.

&&

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

DISCUSSION...06
AVIATION...06

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