360
FXUS63 KABR 170851
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
351 AM CDT Thu Jul 17 2025

.KEY MESSAGES...

- There is a 30-60% chance of showers and thunderstorms late tonight
  through Friday morning. No severe weather is anticipated.

- There is a Marginal Risk (1 out of 5) for severe storms Friday evening
  along a warm front that stretches from south central SD toward
  west central MN. There is a Marginal Risk on Saturday, mainly
  west river.

- A system moving across the Northern Plains will bring the return of
  showers and thunderstorms (30-45%) Sunday through early next
  week. Confidence is low on severe weather threat at this time.

&&

.SHORT TERM /TODAY THROUGH FRIDAY AFTERNOON/...
Issued at 351 AM CDT Thu Jul 17 2025

A dry and cool airmass remains in place through this afternoon with
highs in the upper 60s to upper 70s (warmest Pierre south). Sfc high
pressure shifts off to the east today into this evening. To the
west, a warm front will develop, stretching off a low in Wyoming. A
llj forms ahead of the front this evening. A few storms may fire
with the llj, but the addition of a shortwave trough and the impetus
from the frontal boundary make convection more likely by 9z. Showers
and thunderstorms will progress east through Friday morning,
remaining on the nose of the sfc boundary. By afternoon, the sfc low
moves into NE and the front tightens more across south central and
southeast SD.

Hi-res CAMs aren`t that impressed on Friday, possibly given the
extent of the first wave of showers and thunderstorms that prevents
instability from building in daytime heating. However, SPC has a
marginal risk out for Friday afternoon/evening for convection along
the front that stretches up into Grant county in the east and clips
counties south of Hwy 14 in central SD.

&&

.LONG TERM /FRIDAY EVENING THROUGH WEDNESDAY/...
Issued at 351 AM CDT Thu Jul 17 2025

Clusters are in decent agreement of zonal flow aloft starting out
Friday evening as a low amplitude ridge, positioned over the
northern Rockies, will shift eastward and over the Northern Plains
through the weekend. Behind this ridge, a -PNA pattern sets up over
the northwestern to western CONUS Saturday with a mid level low
forming over the western Canadian provinces. This low, becoming an
open wave, will track eastward over Canada through early next week.
Otherwise, an overall -PNA pattern continues through the end of next
week with the Northern Plains in zonal flow, within the crest of a
ridge (Clusters diverge on exact amplitude at this time) that
resides over a large subtropical high that will just sit over the
southern/southeastern US. This unsettled weather pattern continues
as several weak waves/pulses will push west to east within this flow
over the Northern Plains.

At the surface, the area of low pressure will continue to track
south of the CWA Friday evening/early Saturday as a high pressure
system moves in behind it from the north. As of now, lingering
showers and thunderstorms (NBM pops of 15-30%) are possible just
north of this low/front mainly over south central to east central SD
during this time. This high will keep the area dry for most of
Saturday with the exception of along and west of the Mo River where
pops of 15-25% are possible, closer to the next incoming low
(marginal risk of severe weather here). The high will track eastward
Saturday evening/Sunday with this low (and fronts) forecasted to
move across the Northern Plains through early next week (associated
with the shortwave across Canada) with a secondary lee low/front
forming and stalling out over the area through the midweek. This
will bring the return of shower and thunderstorm chances (30-45%)
during this time. With this being several days out timing of the low
and track may change. CSU Machine learning does highlight a broad 5-
15% chance of severe weather, with NSSL up to 30% chance, over the
Northern Plains with this system, however, confidence remains low on
exact setup. Ongoing low chances of precip (20-35%) continue through
the end of the week in this unsettled weather pattern setup.

Highs will still run about 5-10 degrees below average on Saturday
with highs ranging in the mid 70s to the lower 80s. Temps will
gradually warm back up into the 80s, with highs in the upper 80s to
around 90 along and west of the MO for Sunday. This warmer air will
spread eastward over the CWA early next week, as southern winds will
bring in heat and moisture ahead of the low, with highs overall in
the 80s/90s through the middle of next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1204 AM CDT Thu Jul 17 2025

Terminals KABR,KATY,KPIR,KMBG

The only thing that could interrupt good VFR conditions over the
next 24 hours, under surface high pressure influence, is early
morning radiational fog. Winds may stay up enough, though, to
keep fog from forming. The Glacial Lakes region (KATY) could
produce some fog off all the various lakes, though. Will watch and
see what happens. Very late in the period, convection potential
starts to increase over/near the KPIR/KMBG terminals.


&&

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

$$

SHORT TERM...20
LONG TERM...MMM
AVIATION...20