sd discuss
Office: FSD
FXUS63 KFSD 061050
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
550 AM CDT Sun Jul 6 2025
.KEY MESSAGES...
- Scattered showers and storms will be possible today, mainly
west of the James River Valley. The risk of severe storms is
low.
- Greater potential for scattered thunderstorms late Monday into
Monday night. Some of these storms could be severe, especially
west of US Highway 81 through the evening where a Level 2 of 5
risk for severe storms is in place. Hail up to golf ball size
and wind gusts to 70 mph are the primary threats.
- Additional storms are again possible later Thursday into
Friday. While details are uncertain, a few strong to severe
storms may develop, so continue to monitor your local forecast
for updates.
- Seasonal high temperatures in the upper 70s and 80s are expected
through Tuesday, with highs in the 90s briefly returning to some
areas west of I-29 midweek.
&&
.DISCUSSION...
Issued at 355 AM CDT Sun Jul 6 2025
TODAY-TONIGHT: First wave of storms which were robust as they
moved through western SD early in this overnight period have
weakened substantially and are not expected to bring much of an
impact to our far western counties. A trailing area of storms
which has redeveloped over the High Plains of western SD are
likewise projected to move east through the early-mid morning.
Expectation is for this activity to similarly weaken as it moves
across the Missouri River, but will hang onto lower end chance
pops in our far western counties to cover the potential. Another
seasonably cool day today with highs in the upper 70s to mid 80s,
but less humid as dew points briefly drop into the upper 50s to
mid 60s.
For tonight, will have to monitor track of a wave induced by late
day storms which are expected to develop over western Nebraska. If
the wave tracks far enough north, it could bring some nighttime
showers/storms to the Missouri River Valley/Highway 20 corridor
into Monday morning. Greater consensus leans toward keeping this
activity south of our area, but will carry some low (20-30%) pops
for now.
MONDAY-MONDAY NIGHT: Aforementioned low pops for our far southern
counties will linger into Monday afternoon, but focus primarily
shifts to a stronger wave and associated boundary dropping into
central-northeast South Dakota by mid-late afternoon. While exact
timing/location of initiation is uncertain, confidence is fairly
high that we will see scattered storms develop along the boundary
in the mid afternoon, with ample instability (>1500J/kg) and deep
layer shear (35-40kt) supporting initially discrete severe storms
capable of large hail and perhaps an isolated tornado. While the
location differs, CAMs are in generally good agreement that the
storms will rather quickly transition into bowing line segments
which will track southeast into the evening. Primary threat will
evolve into damaging wind gusts up to 70 mph, with embedded QLCS
tornadoes possible. Activity should weaken as it tracks farther
east, with primary threat window from around 4pm through midnight.
TUESDAY-THURSDAY: As the Monday trough moves east, a modest mid to
upper level ridge builds over the Rockies/High Plains. This will
allow warmer air to build back into at least our western counties
with highs pushing back into the lower 90s by Wednesday-Thursday.
Aside from a potential for storms lingering in northwest Iowa into
Tuesday, the midweek period looks primarily dry. However, this
may depend on subtle waves which drift through the weak flow
aloft, with some solutions bringing showers/storms back to the
area by Wednesday night-Thursday.
THURSDAY NIGHT-SATURDAY: A stronger wave breaks down the ridge
by late Thursday with a northern stream wave digging into the
northern Plains Thursday night-Friday. While the chance for
showers/storms should increase, potential for severe storms is
uncertain at this range, with ensembles indicating low (<30%)
probabilities for sufficient shear to support organized severe
storms. However, various machine learning/AI solutions highlight
probabilities for severe on Thursday-Thursday night in portions of
the northern Plains, as does the latest Day 5 outlook from SPC,
so this late week period will merit watching for those with
outdoor plans.
Temperatures behind this wave do cool more substantially, with
highs in the 70s to lower 80s more probable for the end of this
week.
&&
.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 550 AM CDT Sun Jul 6 2025
VFR conditions through the period. Very low chances for light
showers or a stray thunderstorm approaching the James River Valley
(KHON) today, and the Highway 20 corridor (KSUX) tonight. However,
confidence is too low to mention.
Light northerly winds today become variable to light easterly
tonight.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...JH
AVIATION...JH
Office: UNR
FXUS63 KUNR 061115
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
515 AM MDT Sun Jul 6 2025
.KEY MESSAGES...
- Isolated strong to severe thunderstorms are possible today,
mainly across portions of northeastern WY into southwestern and
south central SD.
- Additional strong to severe storms may occur Monday.
- Hotter temperatures and drier weather by Tuesday/Wednesday.
&&
.DISCUSSION...(Today Through Saturday)
Issued at 403 AM MDT Sun Jul 6 2025
Current radar imagery shows widespread convection is ongoing over
the CWA. Though the severe threat has greatly diminished, some of
the stronger updrafts have been capable of gusty winds and sub-
severe hail. Showers and storms will continue across western SD
through the morning hours before moving out from west to east
early this afternoon. Right now, it's looking like the outflow
from this morning's storms will push the more buoyant airmass to
the south. NAM and HRRR solutions do show some recovery in
southwestern SD, the Black Hills, and portions of northeastern WY
with SB CAPE climbing to above 1000 J/kg by the afternoon. This
could point at some severe potential in those areas later this
afternoon. However, confidence in this forecast remains low as
it's still unclear how the storms this morning will impact the
environment later this afternoon.
Turning our attention to Monday, another shortwave will cross the
region with low level southerly flow ahead of a sfc trof
advecting moist air into the region. MLCAPE values could
potentially climb above 2000 J/kg through Monday afternoon,
especially across south central SD. Increasing deep layer shear
through the afternoon and evening hours will support organized
convection and supercellular structures. Main concerns with these
storms will be large hail and damaging wind gusts, there is also a
low tornado risk. The major forecast challenge is the timing and
location of the sfc trof and thus the timing and location of the
storms.
Upper ridge builds into the western US by Tuesday/Wednesday,
bringing hotter temperatures and lower chances for precipitation,
though an isolated storm or two can't be ruled out.
&&
.AVIATION...(For the 12Z TAFS Through 12Z Monday Morning)
Issued At 459 AM MDT Sun Jul 6 2025
TSRA over western SD will continue through this morning before
gradually moving out from west to east. MVFR conditions, small
hail, and gusty winds are expected with these storms. MVFR CIGs
will develop over portions of northeastern WY, the Black Hills,
and southwestern SD this morning as storms move out.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...Wong
AVIATION...Wong
Office: ABR
FXUS63 KABR 060947
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
447 AM CDT Sun Jul 6 2025
.KEY MESSAGES...
- There is a 20-50 percent chance for afternoon and evening
thunderstorms on Monday, mainly across portions of central and
northeast South Dakota and west central Minnesota. There is a slight
risk (level 2 out of 5) for severe thunderstorms capable of
producing localized large hail and thunderstorm wind gusts.
- The weather pattern stays active next week with additional
thunderstorm chances by Thursday night into Friday.
- Seasonal temperatures are expected during the 7 day forecast, with
the exception of Wednesday and Thursday, when high temperatures
could bump back up into the low to mid 90s throughout and west of
the James River valley.
&&
.DISCUSSION...
Issued at 446 AM CDT Sun Jul 6 2025
As of 3AM, there are currently showers over areas west of the
Missouri River, with some storms over south central SD. This
precipitation is currently moving south while starting to dissipate.
The precipitation will move over areas just east of the Missouri
river, but it looks to stay west of the James River Valley this
morning. There is more precipitation and storms over western SD
moving towards central SD, though they look to be weakening as they
get closer. This will lead to scattered chances for mainly showers
over central and south central SD into and through the morning, with
a chance for a storm or two.
The upper-levels have semi-zonal flow over SD today into Monday,
with a weak high pressure developing at the surface moving in behind
the departing showers this morning. This high pressure, as well as a
lack of a lifting mechanism, will help to keep precipitation and
storms from developing Sunday afternoon into the overnight hours.
Additionally, the weak high pressure over the area will help to keep
winds light, with gusts mostly staying below 15 mph today.
An upper-level shortwave is forecast to move over SD Monday
afternoon, which helps to support a surface boundary moving into
north central SD during the afternoon and through the state into the
evening. Models currently show instability values of 1000 to 2000
J/kg over central and eastern SD on Monday, with some variation in
the location of the highest values. The models have adequate moisture
that moves into central and eastern SD from a tongue of moisture
currently over eastern MT/WY, however they vary where that moisture
moves over and when it start to interact with the boundary. With
models variation in a key component to storm development, it does
lower the confidence in storm timing, location, and strength. Even
with this lower confidence, the Storm Prediction Center has a slight
risk (level 2 of 5) for severe storms to develop over central and
eastern SD Monday afternoon into the evening. With bulk shear of 30-
40kts in the models, storms that do develop could be multicell or
become supercellular. Storm motion on model hodographs is showing a
movement to the east southeast around 20kts. This storm motion will
keep any storms that develop close to if not along the boundary as
the boundary pushes through central and eastern SD. This could lead
to training storms or storms that eventually take on a linear
structure, leading to a higher risk of strong winds.
An upper-level ridge looks to start moving towards SD by the mid-
week, bringing in weak high pressure to the area. This then starts
to advect warmer temperatures into central and eastern SD, which
will help to increase surface temperatures from the low to mid 80s
at the beginning of the week into the low to mid 90s Wednesday and
Thursday. While there is weak surface high pressure over central and
eastern SD, it doesn't fully rule out precipitation and storm
chances. It is possible for a few ridge runner shortwaves to move up
over the north central plains upper level ridge, which could lead to
one or more surface frontal passages. This could generate additional
late week showers and storms. As we get closer to the mid-week, the
lack of precipitation in the forecast could change, so an eye will
need to be kept on this time.
&&
.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1225 AM CDT Sun Jul 6 2025
Terminals KABR,KATY,KPIR,KMBG
VFR conditions are occurring and will continue to occur at KABR
and KATY. Rain showers are currently moving towards KMBG and will
likely stay around through into the early morning. KPIR currently
has storms and rain showers moving towards it that will stay
around into the morning. Occasional reductions in visibility are
possible with any storms that move over KPIR.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
DISCUSSION...12
AVIATION...12
