374
FXUS63 KFSD 021132
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
632 AM CDT Wed Jul 2 2025

.KEY MESSAGES...

- Scattered showers and storms move southeast this morning.
  Additional isolated storms are possible this afternoon and
  evening, mainly east of I-29. A couple of strong to severe
  storms are possible with large hail up to the size of a
  quarter (1 inch) and damaging winds to 60 mph.

- Chances for showers and storms continue for Independence Day
  through the holiday weekend. Currently, highest chances
  (45-70%) are expected Friday afternoon/night and again
  Saturday afternoon. Severe weather risk remains low and
  locally heavy rain is possible. Keep an eye on the forecast if
  you have outdoor or travel plans.

- Temperatures generally near to above normal through the next
  week. Heat index values today in the 90s, climbing to around
  100 Thursday and Friday.

&&

.DISCUSSION...
Issued at 349 AM CDT Wed Jul 2 2025

CURRENTS-THURSDAY: Weak mid level waves move through the
northwesterly flow this today. The first of these waves moves
through this morning, with showers and thunderstorms moving
southeast - mainly along and east of the James River. These have
developed along the wave and the nose of the LLJ, with instability
peaking around 1000-1200 J/kg of MUCAPE. Although instability is on
the lower side, DCAPE values are near 1000 J/kg as well per SPC
Mesoanalysis, which would support wind gusts to 60 mph. Mid level
lapse rates around 7 deg C/km and effective shear around or
exceeding 35 knots supports hail to the size of quarters. Overall
though, severe weather risk looks to be isolated and through about
10 AM as storms move southeast.

Another weaker wave moves through this afternoon and evening,
bringing the return of isolated to scattered showers and
thunderstorms. With much of the same environment, could again see an
isolated stronger storm after 4 PM through 10 PM if storms are able
to develop with that weaker wave. Main risk is along/east of I-29,
although confidence is lower than average in placement due to vast
disagreement in the CAMs (and hence the lower pops). Storm chances
diminish through the overnight, and expect a dry Thursday with
mid/upper ridge axis sliding overhead.

Highs today in the 80s and 90s, warmest west of the James River. As
the aforementioned ridge slides to the east, temperatures continue
to warm into the middle and latter part of the week. More widespread
highs in the 90s are expected Thursday - which looks to be the
hottest day of the next week. Increasing humidity with south to
southeasterly surface flow pushes heat index values near to above
100 by Thursday. Lows in the mid 60s to mid 70s.

JULY 4TH-THE WEEKEND: Mid/upper ridge slides east for Independence
Day, with a trough ejecting out of the Rockies. At the surface, lee
side low pressure stretches into eastern ND and western ND by the
afternoon/evening hours. Still some disagreements in the details of
these features, but models are beginning to show more agreement.
This pattern brings additional shower and thunderstorm chances
beginning late Friday morning and continuing into the day Saturday.
Greatest chances are currently Friday afternoon/night and Saturday
afternoon/evening. Low pressure exits the region sometime Saturday,
which keeps those precip chances around.

By Sunday, another wave is progged to move through relatively flat
but mostly northeasterly flow. Confidence is low given the timing
and strength differences in the models, but periods of showers and
storms may return for the end of the holiday weekend. Most models to
keep us dry with the better forcing outside our area.

Severe weather risk remains isolated for the 4th and into the
weekend due to a lack of shear across the region and meager mid
level lapse rates. However, there is some concern for locally heavy
rainfall as PWAT values lie in the top 1% of climatological
guidance. Southerly flow aids in increasing moisture. Deep warm
cloud layer around 12kft supports efficient rainfall. Probabilities
of more than 0.25" Independence Day into Saturday have increased to
40-60% areawide. If you have travel or outdoor plans, keep an eye on
the forecast.

Outside of precipitation chances, heat continues to build. Warmest
day of the holiday weekend will be the 4th with highs in the upper
80s to mid 90s - leading to heat index values near 100. Highs in the
80s to lower 90s the rest of the weekend with lows in the 60s to
lower 70s.

EARLY-MID NEXT WEEK: Quasi-zonal flow with a couple of mid level
waves prevail early next week. A more defined wave looks to move
through a portion of the northern Plains by Tuesday. This should
bring the return of shower and storm chances, but confidence in the
details is low. Temperatures remain near normal.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 625 AM CDT Wed Jul 2 2025

Scattered showers and isolated thunderstorms continue to move
southeast this morning from the US Highway 14 corridor. There
are weakening as they head south, but have included a brief
mention for SHRA at KFSD. Another area of showers this morning
south of KSUX should stay south of that terminal. Another round
of isolated to scattered showers/storms may develop this
afternoon and this evening, mostly likely along/east of I-29.
Given isolated nature, left out of KFSD/KSUX for now. Convection
could produce MVFR/IFR conditions for a brief period.

Outside of convection, VFR conditions expected with winds
variable from southwest to east.

&&

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

&&

$$

DISCUSSION...SG
AVIATION...SG