676
FXUS63 KABR 191348 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
848 AM CDT Wed Aug 19 2026

.KEY MESSAGES...

- A Marginal Risk (level 1 out of 5) for severe weather has been
  issued for areas just south and east of the Watertown area
  Thursday afternoon. Large hail to 1 inch in diameter and
  damaging winds of 60 mph will be the main threats.

- After a dry couple days Friday and Saturday, an active northwest
  flow aloft pattern will persist through the end of the week into
  early next week. Periodic chances for showers and thunderstorms
  will continue across the region.

&&

.UPDATE...
Issued at 845 AM CDT Wed Aug 19 2026

Complex of showers and thunderstorms is exiting the CWA to the
southeast. Had earlier made further adjustments to PoPs to
account for radar trends. Marginal Risk has been removed from
the entire CWA for today, so threat for severe storms has
diminished across the region today/tonight. Also made
adjustments to sky cover to better align with satellite trends.

&&

.DISCUSSION...
Issued at 207 AM CDT Wed Aug 19 2026

As of 2 AM CDT...scattered showers and thunderstorms continue to
track southeast through portions of the forecast area...mainly
across parts of central and south central SD. There will be an
isolated strong wind threat through the early morning hours for
parts of south central SD and possibly as far east as the James
Valley. This activity is in response to a well defined shortwave
trough on water vapor moving east-southeast across western and
central SD. This feature is progged to continue tracking southeast
into sections of eastern and southeastern SD the remainder of this
morning into the early afternoon. Precip chances will follow with it
as parts of our southern/southwestern zones will continue to hold
onto showers and storms through about mid morning. Drier conditions
should settle into the area for the afternoon hours. Although, some
spotty afternoon cells could be possible as a sfc warm front lifts
back to the north and east across the CWA. Instability and shear
values during peak heating today don`t look too impressive with
MLCAPE values of 1000-1500 J/kg across central parts of SD and 0-6
km bulk shear values of 25-30 kts. SPC has maintained a Marginal
Risk (level 1 of 5) for severe weather from south central sections
of SD northeast into portions of the James and Big Sioux Valleys.
Main threats will be large hail to 1 inch and damaging winds of 60
mph.

Tonight, with a sfc high centered east of our region, a sfc low and
associated trough will track eastward into the central and eastern
Dakotas. MUCAPE values are progged to be 500-1000 J/kg and 40-50 kts
of deep layer shear are progged to be present early Thursday morning
across northeast SD into west central MN. Expect another round of
scattered showers and storms in these areas after midnight through
at least the daybreak hour and possibly lingering longer into mid
morning. During peak heating Thursday afternoon, MLCAPE values will
build to about 1000-1500 J/kg and deep shear looks to top out around
35-40 kts across eastern SD and western MN. We could potentially see
some re-develoment of storms during the afternoon hours across our
far eastern zones, although by then the better chances could be just
off to our east and south. SPC`s Marginal Risk (level 1 of 5) for
severe weather clips portions of Hamlin and Deuel Counties Thursday
afternoon. Thursday night into Friday will feature a cold front
swinging south and east across the forecast area. Sfc high pressure
will move southeast across the eastern Dakotas and western MN on
Friday as the western CONUS upper ridge starts to amplify. This will
lead to increasing heights across the Northern Plains and should
bring a bit a short reprieve from the the nearly daily or nightly
passages of upper shortwave troughs.

With that said, some guidance is hinting at yet another upper trough
passage Friday night into early Saturday somewhere across the
eastern Dakotas or northern MN. Models are at odds on where this
feature could potentially track. Confidence remains low and we`ll
keep the forecast dry for now. Upper ridging is progged to crest
over the area this weekend. Dry conditions are expected Saturday
into early Sunday. By late in the weekend, another upper trough
working out the Pac NW will crash over the top of the ridge leading
to our next round of showers and storms the latter half of the
weekend. Knocking down the upper ridge looks to be temporary as
500mb heights bounce back early next week. Temperatures at or above
normal will return to the region Monday through Wednesday. On and
off again chances for showers and storms are expected to continue as
an active northwest flow aloft pattern remains entrenched across the
region.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 607 AM CDT Wed Aug 19 2026

Terminals KABR,KATY,KPIR,KMBG

Scattered showers and weak thunderstorms are currently tracking
south/southeast across portions of central and northeastern SD
near KABR and KATY terminals. These storms will be over/near the
terminals for the next several hours. No severe weather is
anticipated, however, stronger storms could produce wind gusts
of 25kts or so and pea size hail. Otherwise, dry conditions
before isolated to scattered chances of showers and
thunderstorms move back over portions of north central and
northeastern SD late this afternoon/tonight into the overnight
hours, mainly near KABR and KMBG. Otherwise, VFR cigs forecast
through the end of the TAF period.

&&

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

&&

$$

UPDATE...TMT
DISCUSSION...Vipond
AVIATION...MMM