894
FXUS63 KABR 182016
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
316 PM CDT Fri Jul 18 2025

.KEY MESSAGES...

- There is a marginal to slight risk, levels 1 to 2 of 5, for severe
storms into early this evening primarily east of a line from Miller
to Sisseton. Hail of 1 inch in diameter and winds of 60 miles per
hour are the main threats. A tornado may also be possible with these
storms, mainly south and east of Watertown.

- There is a marginal risk, level 1 of 5, for severe storms Saturday
night west of the Missouri River. Hail of 1 inch in diameter and
winds of 60 miles per hour are the main threats.

- There is a marginal risk, level 1 out of 5, for severe weather
late Sunday afternoon into Sunday night. Hail of 1 inch in diameter
and winds of 60 miles per hour are the main threats.

- Heat index values will be in the upper 90s to near 100 degrees
Monday afternoon, across central SD primarily south of Pierre.

&&

.DISCUSSION...
Issued at 316 PM CDT Fri Jul 18 2025

The surface low we`ve been watching track across southern SD all day
has moved to south central SD (near and south of Jones/Lyman
Counties). A trough remains extended northeast from the low,
stretching to far northeastern SD and our west central MN counties.
This will be the area of concern for storm initiation 21-23Z this
afternoon and shifting east or southeast by mainly 09Z. The deck of
stratus cloud over much of central and northern SD late this morning
started to show signs of mixing, with more pockets of sunshine this
afternoon. As of 1930Z we`ve had showers increasing in coverage over
west central MN over the past hour. We`ll continue to monitor along
and east of the surface trough for quick thunderstorm development.
Currently, 0-6km bulk shear is 40-50kts over eastern SD/western MN
with mid level lapse rates of 6.5-7.5. DCAPE values are generally
around 800 J/kg or less. PW values are on the increase, expected to
top out between 1.5-2in from 21-00Z. ML CAPE is 1.5-2k j/kg, highest
over south central SD.

Dry weather will return by late evening as the surface high over
south central SD pushes across ND by 12Z Saturday extending a ridge
over eastern SD/western MN through the daytime hours. There is a 30
percent chance of light showers over central South Dakota for a
brief period after daybreak Saturday morning, with otherwise dry
weather in the afternoon. A 50 percent chance of showers and
thunderstorms will return to central South Dakota Saturday night,
where there is a marginal risk, or level 1 out of 5, of severe
weather. By 12Z Sunday the surface map will show low pressure
stretching from southern Saskatchewan through western SD and central
KS as the high slowly exits over northeastern MN and northern WI.
The system of lows will only slowly shift east into central SD
Monday night and finally to our east later Wednesday. Pin pointing
specific times for showers and thunderstorms will become
increasingly difficult. Ahead of the low, temperatures Monday will
rise into the 80s, with low to mid 90s over much of central SD. Heat
index values will be in the upper 90s to near 100 degrees Monday
afternoon, across central SD primarily south of Pierre, with
dewpoints in the upper 60s to low 70s. A longer period of more dry
air, or at least chances of precipitation at 25% or less will arrive
Thursday through Friday.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1232 PM CDT Fri Jul 18 2025

Terminals KABR,KATY,KPIR,KMBG

Mainly MVFR ceilings will be over the terminals for most of the
period, though KMBG will have a break with VRF ceilings this
afternoon and through the evening. IFR ceilings are possible over
KABR late tonight. KABR, KMBG, and KATY will see a quick shift in
wind direction this afternoon and into the evening as a surface
trough moves through. There is the potential for thunderstorms to
develop at KATY this afternoon into the evening, with a chance for
these storms to be severe. The main threats from these storms will
be winds of 60 mph and hail of 1 inch in diameter. MVFR fog is also
possible at KATY after 06z if moisture from the storms and rain
linger overnight.


&&

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

$$

DISCUSSION...06
AVIATION...12