Lily, South Dakota Weather Forecast Discussion

856
FXUS63 KABR 111914
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
214 PM CDT Thu Sep 11 2025
.KEY MESSAGES...
- There is a Marginal Risk (level 1 out of 5) of severe weather
  over portions of north central SD this evening and again on
  Friday. Additional strong to potentially severe storms will be
  possible this weekend.
- High temperatures will run 5 to 15 degrees above normal through
  next Wednesday.
&&
.DISCUSSION...
Issued at 213 PM CDT Thu Sep 11 2025
At 2 PM CDT, skies are mostly sunny. Temperatures are warming
through the 70s and 80s on south winds 15 to 25 mph with gusts up to
35 mph. Until a couple of hours ago, elevated showers and
thunderstorms were noted on regional radar mosaic developing/moving
over far western South Dakota (mostly west of this CWA).
There is a lee-of-the-Rockies/Black Hills surface trof/low out
across the far western Dakotas this afternoon, serving as a source
of low level forcing for potential convection for the next several
hours. There is also a 100kt upper level jet streak nosing its way
up into Wyoming (and eventually extending out toward the western
Dakotas later this evening/overnight), including some embedded
shortwave activity, which will serve as the needed synoptic-scale
atmospheric lift to aide convective initiation. Other parameters for
(supercellular) convection include more than 1500J/kg MLCAPE and
more than 30kts deep layer shear and steep mid-level lapse rates at
or above 8C/km. There is, however, a fairly strong (for September)
mid-level thermal capping inversion (+11C to +12.5C at 700hpa) in
place between 850-500hpa, which may delay or stymie convective
development through early this evening. There is another round of
low level jet southerly winds expected across the region later
tonight. Perhaps once the low level jet reforms, elevated convection
could become a thing that glances a portion of our north central
zones overnight. However, seems like the better zone for convection
is north and west of this CWA through 12Z Friday. At any rate, there
remains a marginal risk (level 1 of 5) for isolated strong to severe
thunderstorms capable of hail up to an inch and wind gusts up to 60
mph mainly over portions of north central South Dakota.
May see a similar convective potential unfold Friday afternoon/night
as the surface trof/low shifts a bit further east into the Missouri
River valley region of the CWA. Watching southwest CONUS in water
vapor today/tomorrow to see what, if any, additional shortwaves
emerge that could move over the region tomorrow/night. There is a
marginal risk (level 1 of 5) for isolated severe thunderstorms
Friday and Friday night mainly across north central South Dakota.
Additional surface troffing is progged over the CWA heading into
Saturday, when upper level steering flow goes almost meridional in
response to the upper level ridge in place finally shifting off to
the east of the CWA and the western CONUS upper low/trof moves
closer to the region. Meridional flow with more than ample low/mid-
level moisture in the column introduces some concern for the
potential of training south-to-north moving storms rolling into
Saturday evening/night, and perhaps again on Sunday/night. Something
else to put on the back burner and monitor.
For the rest of the 7-day, the incoming upper low/trof looks to
stick around through Sunday night, bringing additional precipitation
chances before getting kicked out/off to the north-northeast away
from this CWA on Monday due to another upper low quickly approaching
the region out of the Pac NW. Models are in fair agreement on
handling mid/upper level features through this timeframe.
Monday/night looks dry in between systems, but once this next system
arrives for Tuesday/Wednesday, precipitation (in the deterministic
GSM`s and the various ensemble families) chances start showing up
again in the forecast.
Finally, with the large, over-arching upper level ridge still in
place across northern Canada through the middle of next week,
southern Canada and the northern U.S. plains should remain shielded
from any "arctic cold air intrusions" through the end of the 7-day
period. Warm, above normal, temperatures should continue until
further notice.
&&
.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1214 PM CDT Thu Sep 11 2025
Terminals KABR,KATY,KPIR,KMBG
VFR conditions will be prevailing through the evening and into
Friday morning. During this time, the winds will be from the south-
southeast to the southeast through the night with gust of 25 to 30
kts weakening into the morning. There is also a marginal risk (level
1 of 5) for severe weather this evening and overnight mainly over
north central SD. While the potential for storms to develop
is limited, any storms that do form will have the potential for
damaging wind gusts of 60+ mph and a secondary threat for large
hail.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
DISCUSSION...10
AVIATION...12

NWS ABR Office Area Forecast Discussion