731
FXUS63 KABR 011701 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1201 PM CDT Fri Aug 1 2025

.KEY MESSAGES...

- Showers and thunderstorms expected west river this morning.
  Another round moves in this evening with a marginal to slight
  risk (level 1 to 2 out of 5) for severe weather, mainly west
  river. All hazards are possible.

- There is a 40 to 60 percent chance of showers and thunderstorms
  Saturday and Saturday night. No severe weather is expected at
  this time.

- Surface smoke from wildfires is expected to persist across much
  of the region through Saturday. Monitor the latest from the EPA
  and state agencies, as there may be impacts for those sensitive
  to smoke.

&&

.UPDATE...
Issued at 1157 AM CDT Fri Aug 1 2025

See below for an aviation forecast discussion for the 18Z TAFs.

UPDATE Issued at 834 AM CDT Fri Aug 1 2025

No changes planned to the today period forecast. Will continue to
monitor short-term/rapid-update model cycles for trends/details on
the potential for strong to severe thunderstorm development
in/west of the Missouri River valley by early this evening.

&&

.SHORT TERM /TODAY THROUGH SATURDAY AFTERNOON/...
Issued at 411 AM CDT Fri Aug 1 2025

A quasi-stationary line of showers and thunderstorms has developed
early this morning just west of the forecast area. This line is
expected to slowly advance this morning further into central SD
remaining west river until afternoon. Due to the slow motion, heavy
rain and associated flooding are possible. There is a slight risk (2
out of 4) for excessive rainfall. Then, this evening, models have an
upper low/MCV type feature moving across northern SD, producing
additional showers and thunderstorms through tonight. Some of the
initial storms in central SD may be strong to severe. There is a
marginal to slight (1-2 out of 5) risk for severe storms with all
threats possible when cells are discrete. Outflow boundaries and
earlier convection may confound some of the later day development.
MUCAPE and shear are limited across north central SD this evening,
but Stanley county south has 1000-1500 J/kg and 35 kts of shear
along with steep lapse rates.

Near sfc smoke will continue to affect the region into Saturday.
Visibilities are currently 5 to 7 miles around the area.
Precipitation also remains over the region on Saturday on southerly
sfc flow, with highest chances from the Missouri Valley to the James
Valley.

&&

.LONG TERM /SATURDAY EVENING THROUGH THURSDAY/...
Issued at 411 AM CDT Fri Aug 1 2025

The main theme in this period will be the continuation of a fairly
active storm track across the Northern Plains the latter half of the
weekend into early next week. Upper level ridging will remain
centered across the Desert southwest and northwest Mexico for the
duration of this forecast period. Multiple rounds of shortwave
energy are expected to track over the top of this ridge into the
Northern Plains and be the impetus for convective development nearly
each day by the start of this period on Saturday night through at
least Monday. Sfc high pressure located across the Great Lakes and
lee side troughing across the Northern High Plains into western SD
will continue to promote south to southeast low level flow and a
continuous feed of a warm and moisture rich air mass. This all
should culminate in nearly a daily 30-60 percent chance for showers
and thunderstorms Saturday night through Monday night. This appears
to be the best time frame in this period to see the most active
weather. Deterministic and ensemble guidance depicts portions of
central and south central SD as having the more favorable
environment in terms of instability and shear during this time frame.

GEFS/GEPS/EC ENS indicate upper level ridging might try and nose its
axis northeastward into the Dakotas by about Tuesday of next week
but it also indicates this feature will be fleeting as quasi-zonal
flow aloft takes shape and likely more shortwave energy resumes its
track across our region late in the period. Temperatures will
initially settle in a 5-10 degree below normal trend at the start of
this period but a gradual warming trend next week will bring these
values more in line with early August norms.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1157 AM CDT Fri Aug 1 2025

Terminals KABR,KATY,KPIR,KMBG

VFR cigs and MVFR vsby in smoke will continue into Saturday. Some
improvement is expected Saturday evening into Sunday morning.
Showers/thunderstorms are expected between late this afternoon and
late tonight at KMBG/KPIR (and possibly by 12Z Saturday at KABR).
Heavy rain is one of the primary threats, in which MVFR/IFR vsby
would be possible.

&&

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

$$

UPDATE...10
SHORT TERM...20
LONG TERM...Vipond
AVIATION...10