National Weather Service Raw Text Product

481 
FXUS63 KFSD 121122
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
622 AM CDT Thu Jun 12 2025

.KEY MESSAGES...

- Showers and thunderstorms continue throughout today with the
  potential for strong to severe storms 2 to 10 pm. Strongest 
  storms may produce large hail up to 1.25" in diameter and 
  strong winds between 60-70 mph. 

- Isolated to scattered pockets of locally heavy rainfall remain
  possible through tonight. Most of the area will see less than
  0.5" of additional rainfall through tonight, although areas 
  near US Highway 14 may see totals of 1" or more.

- Unsettled weather pattern brings continued periodic shower and
  storm chances into next week, although details remain  
  uncertain. Monitor for strong storm and heavy rain potential.

&&

.DISCUSSION...
Issued at 331 AM CDT Thu Jun 12 2025

TODAY-TONIGHT: Showers and isolated storms along and north of I-90 
continue sliding east-northeast this morning. Looking a mesoanalysis 
data, this activity generally seems tied to the 925mb moisture and 
850mb frontogenesis. Further west, showers and storms across western 
SD are more tied to the mid level wave and associated PVA as this 
wave lifts northeast out of WY into western ND. Severe weather is 
not expected this morning with less than 500 J/kg of MUCAPE and bulk 
shear values around or less than 25 knots. Shower and storm chances 
continue today and tonight as the mid level wave and surface low 
work east - more specifics below. Breezy today with gusts to 30 mph. 
Highs in the 70s to 80s, coolest north of I-90. Patchy wildfire 
smoke may continue to mix down to the surface, especially across 
southwestern MN through this evening - reducing visibility and air 
quality at times. Lows tonight fall into the upper 50s to mid 60s.

Can't rule out some locally heavy rain through the day and into 
tonight; however, with the shift of the front to the north, heaviest 
rainfall looks to be focused near and north of the US Hwy 14 
corridor later today into tonight. Deeper warm cloud layer as well 
as more parallel flow to the boundary have shifted north too, 
following the front and mid level wave. Guidance does show some 
drier air working into the area later today (mostly in the 700:500 
mb range) which may limit rainfall totals. Generally expect an 
additional half of an inch or less through tonight decreasing as 
you head south.

Severe threat has also shifted to the north with the 850mb front, 
leading to a narrow corridor where instability and shear align 
between US Hwy 14 and I-90 this afternoon and evening. Additional 
strong to severe storms are possible if convection gets going 
near/along the surface cold front later today near the James River 
Valley. Timing of severe risk remains between 2 pm and 10 pm, 
although the window for any one location will be much more narrow (a 
couple of hours). Given instability at or less than 1500 J/kg, shear 
30-40 knots, and mid level lapse rates around 6.5 deg C/km support 
hail to half dollar size (1.25") and wind gusts to 70 mph.

FRIDAY-SATURDAY: Cut off/orphaned mid/lower level low pressure spins 
across MO Friday into Friday night, with another mid level short 
wave trekking through the Plains Saturday in the developing ridge. 
This keeps some lower end and periodic shower/storm chances in the 
forecast, but not expecting a wash out. Temperatures in the mid 70s 
to upper 80s for highs, with some areas near US Hwy 20 reaching 90 
Saturday. Lows in the upper 50s and 60s.

SUNDAY-MONDAY: GFS guidance keeps the orphaned mid level low pressure 
over MO into the early part of next week with ridging continuing to 
build and slide east. At least one ridge riding wave moves across 
the north central Plains into Monday night. Surface low may move 
through on Sunday. This pattern continues to bring periodic shower 
and storm chance to the region, although details remain murky. 
Guidance, including machine learning tools, indicate that there may 
be risks for strong to severe storms during this time, so continue 
to monitor the forecast. Locally heavy rainfall may also be 
possible. Temperatures near to above average into early next week.

TUESDAY ONWARD: Quite a bit of variance in model guidance as we 
reach Tuesday and beyond. While all guidance breaks down the 
mid/upper level ridge with a trough developing over the western US, 
all vary on the depth and motion of this feature into mid week. The 
12.00z GFS is the quickest and strongest with moving this trough 
east. Flat ridging and westerly flow return after this trough. This 
pattern keeps periodic shower and storm chances in place. Again, 
machine learning and other guidance continues to show at least low 
end risk (less than 15%) for strong to severe storms with locally 
heavy rainfall, so continue to monitor the forecast if you have 
outdoor or travel plans. Temperatures in the upper 70s to mid 80s 
for highs and upper 50s to mid 60s for lows.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 613 AM CDT Thu Jun 12 2025

Showers and isolated thunderstorms continue this morning, mostly
along and north of I-90 and into northwestern IA. Additional
showers and thunderstorms expected today and tonight, near and
west of the James River and north of I-90. MVFR conditions
expected with showers and storms, and could see some additional
patchy stratus north of I-90 through the period. Isolated 
showers and storms could be strong to severe and produce locally
heavy rainfall.

VFR conditions expected otherwise. Patchy smoke could lead to
reduced visibility through the evening in southwestern MN. Winds
will be mostly easterly through the day with gusts to 25 knots.
Gusts taper off and winds shift to southerly then northwesterly
toward the end of the forecast period from west to east.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...SG
AVIATION...SG