704
FXUS63 KFSD 300839
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
339 AM CDT Mon Jun 30 2025

.KEY MESSAGES...

- Showers and isolated thunderstorms continue to move east this
  morning. Otherwise, mostly dry today with some sprinkles for
  southwestern Minnesota. An isolated rumble or two of thunder
  cannot be ruled out.

- Chances for isolated to scattered (less than 40%) showers and
  storms return mid week. Confidence in the details is low, but
  periodic shower and storm chances continue for Independence
  Day and through the holiday weekend. Currently, highest
  chances (40-65%) are on Friday the 4th and Saturday. Keep an
  eye on the forecast if you have outdoor or travel plans.

- Temperatures generally near to above normal through the next
  week. Thursday through Saturday could see heat index values
  approach or exceed 100 degrees.

&&

.DISCUSSION...
Issued at 337 AM CDT Mon Jun 30 2025

CURRENTS-TODAY: Isolated showers and storms continue to move east
this morning along a weak wave ahead of the mid/upper trough axis.
Have seen some very localized fog in northwestern IA, leading to
isolated visibility below one mile. May see some additional
development here before daybreak closer to the main wave, but expect
coverage to remain isolated. Rain pushes east through mid/late
morning.

Mid and upper level trough axis continue to move east through the
day and into this evening. This trough and subtle vort max may
provide just enough forcing for some isolated rain chances this
afternoon and early evening across southwestern MN where instability
increases to around or less than 750 J/kg. However, limited pops and
precip mention to sprinkles due to the lack of moisture in the
soundings. If there is measurable precipitation, would expect a
couple hundredths or less. Can`t entirely rule out a rumble of
thunder, but confidence is too low to mention given instability
values.

Otherwise, near to slightly below average temperatures today with
highs in the upper 70s to mid 80s. Lows tonight fall into the upper
50s to near 60 as surface high pressure begins to build in.

TUESDAY-THURSDAY: Surface high pressure slides east through the
middle of the week, with ridging aloft building across the Rockies
into the southern Plains as well. We should stay mostly dry and
warmer than average through mid week with the ridge axis to the
west. That said, guidance shows a couple of poorly agreed upon ridge
riding waves Tuesday night into Thursday which could bring some
lower end (less than 40%) rain and storm chances to the area. Have
maintained the NBM pops for now given the low confidence in
timing/location. Southerly surface flow and increasing temperatures
aloft thanks to the aforementioned ridge allows temps to return to
above average by mid week - highs in the upper 80s to mid and upper
90s. Warmest temperatures Tuesday and Wednesday expected near/west
of the James River, with more widespread 90s expected Thursday as
the ridge axis moves east. Heat index values may approach or exceed
100 Wednesday and Thursday, so be aware if you have outdoor plans.
Lows generally in the 60s. Rainfall amounts during this time look to
be low, with chances of over 0.10" less than 40%.

JULY 4TH INTO THE WEEKEND: Model guidance begins to diverge into
Friday/Independence Day as the ridge axis moves east and a
wave/trough slides into the Rockies by the 4th and continues east
into the weekend. The GFS is the strongest and keeps the wave around
the northern/central Plains longest, while the Canadian keeps the
strongest portion of the wave near the International Border (the
ECMWF lies in between). By the early next week, the GFS already
brings in our next trough while the ECMWF/Canadian transition the
region to more zonal flow. Regardless of which model, this indicates
periods of showers and thunderstorms. Ensemble probabilities show
the highest chances for more than a tenth of an inch of rainfall
Friday into Saturday, with 50% or more probability. However, given
model spread, confidence is lower than average and maintained the
broad scattered chances from the NBM for the 4th into Saturday and
lower chances for Sunday into next week. Certainly keep an eye on
the forecast if you are planning to be outdoors late week into the
weekend.

Independence Day should see highs in the 80s and 90s once again,
with near to above average temps into early next week. Heat index
values on the 4th may again be near to above 100, so be prepared if
you have outdoor plans. Lows mostly in the 60s.


&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1133 PM CDT Sun Jun 29 2025

Showers and scattered storms move east across the region tonight
into early Monday morning. While it is difficult to pinpoint
exact timing/location of any thunderstorms, have included narrow
windows of more probable timing for KHON/KFSD/KSUX after
30/06Z.

Any showers/storms may produce erratic gusty winds, but overall
winds will remain fairly light until mixing increases midday
Monday, with gusts 20-25kt expected through Monday afternoon.
Gusts taper off after sunset Monday.

&&

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

&&

$$

DISCUSSION...SG
AVIATION...JH