109
FXUS63 KABR 101732
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
1232 PM CDT Thu Jul 10 2025

.KEY MESSAGES...

- Marginal risk (level 1 out of 5) for severe storms mainly across
  central South Dakota this afternoon and across northeast South
  Dakota into west central Minnesota on Friday. Hail up to an
  inch in diameter and thunderstorm wind gusts up to 60 mph are
  possible within the risk area on both days.

- Heat and humidity persists today mainly west of the James River
  valley, with high temperatures expected in the low to mid 90s
  and heat indices in the mid to upper 90s.

- The potential exists for a noticeable cool-down during the
  middle of next week (temperatures 10 to perhaps 15 degrees
  below normal).

&&

.UPDATE...
Issued at 1221 PM CDT Thu Jul 10 2025

There has been a slight cut back on POPs and the SPC marginal risk
across the northern tier of South Dakota for this afternoon with
the associated shortwave sticking closer to the I90 corridor
today. Cant rule out an isolated storm north of this feature, and
matched POPs to that thinking, with CAMS showing a random storm
here and there today, so confidence is really low.

See below for update to the aviation discussion...

&&

.DISCUSSION...
Issued at 257 AM CDT Thu Jul 10 2025

At 2 AM CDT, one area of MCS stratiform rain continues to gradually
dissipate over the Prairie Coteau while a separate area of elevated
showers is approaching north central South Dakota from the west.
Temperatures have cooled into the 60s to low 70s. Winds are
generally light (less than 10 mph) and have a southerly component
for the most part.

Not much change in the flow pattern aloft, compared to 24 hours ago.
Upper level troffing will take a turn being over the region
Friday/Saturday (cooler than normal) before subtle upper level
ridging returns for Sunday/Monday (back to warmer than normal). But,
the pendulum swings back to upper level troffing over the region
next Tuesday/Wednesday. Again, no lack of low to mid-level thermal
advection, fropas and precipitation chances. The RRFS model is
suggesting the atmosphere will even throw in a bout with Canada
wildfire smoke, both aloft and near the surface Saturday and Sunday.

The lee-of-the-Rockies surface trof that brought CI to the region
Wednesday afternoon and the ensuing line-of-storms Wednesday evening
is still progged to be hanging out over about the same region of the
Dakotas by the end of peak-heating today. With similar instability
and steep mid-level lapse rates around to work with, but weaker deep
layer shear, it`s not entirely certain whether there will be much
more than isolated/widely scattered thunderstorm
development/coverage there across portions of northwest/north
central South Dakota up into North Dakota this afternoon. 700hpa
temperatures over the boundary are forecast to be a degree or two
cooler this afternoon, compared to 24 hours ago. SPC`s Day 1 outlook
has the western half of forecast zones in a marginal risk (level 1
out of 5) for severe weather. Perhaps pulse to multi-cell-type
thunderstorms could happen, capable of large hail and damaging
winds. If a storm can stay anchored on/in the vorticity attached to
the surface trof, perhaps a conditional isolated tornado threat
could exist somewhere in/near north central South Dakota late this
afternoon/early evening. Model guidance, in general (CAMs and GSMs)
has really backed off with precipitation coverage over this CWA
today/tonight, though. Models also appear to have slowed the strong
frontal passage timing a bit, bringing it through moreso during the
day on Friday, rather than late Thursday night into Friday morning.
It does still look as though the best precipitation chances will be
tied to that frontal passage, either storms developing on the
boundary across the eastern forecast zones (SPC`s Day 2 marginal
risk, level 1 out of 5, over the eastern forecast zones on Friday)
or behind the boundary.

Much cooler/dry high pressure dominated conditions for the rest of
Friday, behind the fropa, including some gusty north-northwest winds
up to 30-35 mph, with said cooler/dry conditions continuing into
Saturday. The low level WAA doesn`t waste any time, though, with
mid/upper level height rises expected Sunday into Monday.
Temperatures back up into the 90s across the western half of the CWA
is expected Sunday/Monday. That next strong frontal passage progged
for Monday night into Tuesday is currently forecast to generate the
next round of showers and storms over the CWA. The latest trends in
the ensembles is for 850hpa temperatures to be between 1.5 and 2
standard deviations below normal, which in mid-July looks like high
temperatures only topping out in the low to mid 70s.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1221 PM CDT Thu Jul 10 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions for all terminals. Cant rule out a storm or two,
however its too low confidence to nail down a timing/location for
inclusion in TAFS. Convection west of Pierre has the best chance
for impacting the KPIR terminal in the next few hours, however
that is weak and may not translate effectively that far west.


&&

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

$$

UPDATE...07
DISCUSSION...10
AVIATION...07