310
FXUS63 KABR 182359 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
659 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.

&&

.UPDATE...
Issued at 645 PM CDT Fri Jul 18 2025

See below for an aviation forecast discussion for the 00Z TAFs.

&&

.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 /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 645 PM CDT Fri Jul 18 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will be over the KPIR/KMBG terminals through the
period, while KABR/KATY will be bouncing between VFR and MVFR/IFR
(ceilings) mainly between now and 18Z Saturday. A thunderstorm or
two may move over/near KATY again this 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. Fog is
also possible at KATY after 06z, owing to moisture from any storms
that move over that area this evening.

&&

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

$$

UPDATE...10
DISCUSSION...06
AVIATION...10