975
FXUS63 KABR 180104 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
804 PM CDT Thu Jul 17 2025

.KEY MESSAGES...

- There is a 30-60% chance of storms during overnight, after
  around 09Z over north central SD and eastern SD into west
  central MN from daybreak through late morning. There is a
  marginal risk (level 1 out of 5) of severe weather over portions
  of north central SD overnight into early Friday.

- There is a 40% chance of storms over far eastern SD into west
  central MN from mid afternoon Friday into the early evening
  hours. There is a marginal risk (level 1 out of 5) for severe
  storms.

- There is a marginal risk (level 1 out of 5) of severe storms
  Saturday afternoon and evening, mainly west of the Missouri
  River.

&&

.UPDATE...
Issued at 800 PM CDT Thu Jul 17 2025

No changes planned to the tonight period. Still two possible ways
of seeing convection enter the CWA late tonight/early Friday
morning. The first is from long-track supercells that are supposed
to develop out over Montana (happening now) and sweep
southeastward into the Dakotas. The second is with any low-level
jet-forced showers/storms over central/north central South Dakota
up into central North Dakota that would move off to the east or
southeast through the morning on Friday. But, again, this is all
expected to happen well after midnight tonight.

UPDATE Issued at 618 PM CDT Thu Jul 17 2025

See below for an aviation forecast discussion for the 00Z TAFs.

&&

.DISCUSSION...
Issued at 344 PM CDT Thu Jul 17 2025

Dry weather start us out, with fair weather cumulus clouds across
much of the forecast area. These clouds are continuing to slowly
erode from west to east in advance of a more stable layer of clouds
currently over central SD. Moisture will increase this evening and
overnight, with PW values rising to 1.25 to 1.5in by 12Z Friday,
with the highest values over portions of central SD. An area  of
general low pressure over northern NV through eastern ID and WY will
push a low over southwestern SD by 09Z Friday, with a trough
extending north-northeast through north central SD. This will be the
focus for potential showers and thunderstorms late tonight into
early Friday morning, along with a 30-35kt low level jet.  There is
around a 2-4 hour timeframe where the strongest storms could be
capable of producing quarter sized hail, or potentially winds to
60mph as they shift east to east-southeast around 25kts. Instability
diminishes through the morning, limiting the threat as the showers
and storms potentially shift into northeastern SD by 15Z Friday.

We`ll be watching for additional strong to potentially severe
thunderstorm development 20 Friday - 00Z Saturday over our far
eastern and southeastern counties. This will be with the surface low
moving to south central SD by 18Z Friday and the trough extending
north to near ABR, and over our southeastern counties by 21Z Friday.
Dewpoints will be nearing 70F with along a ribbon of 2k J/kg CAPE
values and near 50kt 0-6km shear. PW values also increase to near
1.75, with moderate to brief heavy rain expected with any storms
that develop. Confidence on thunderstorm development is lower in our
southwestern counties, but can`t be completely ruled out due to the
placement of the surface low. We`ll continue to linger 30-50%
chances for showers and thunderstorms over eastern SD/west central
MN through late afternoon. A few of these storms could become strong
to severe, before shifting into Minnesota Friday evening. The main
threat with the strongest storms will again be hail to the size of
quarters or winds to around 60 mph. We do have the added 2% tornado
threat as well with any initial storms.

The next surface ridge will build into the eastern Dakotas and MN
Saturday. On the back side of the ridge, we do have slight chance
(15-25%) chances of showers and thunderstorms. While a couple of
strong to severe storms will be possible Saturday afternoon and
evening, the main concern will be farther to our south/closer to the
main surface low/trough. Farther out, we`ll be monitoring the rising
temperatures for late this weekend into early next week. Highs are
forecast to be in the 90s over our southwestern SD counties Sunday
through Tuesday. If storms are able to develop Sunday afternoon over
central SD, shear isn`t high but CAPE values near 2k J/kg may help
sustain a few storms into the evening hours. Most of the
precipitation is expected to stay across ND Sunday into Monday.
There is a 40% chance of 0.5" of rain near the ND/SD border Sunday
into Monday, while only around 15% along our southern counties. A
summertime pattern will continue, with 20-40% chances of showers or
storms every 24 hours.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 618 PM CDT Thu Jul 17 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast through most of the TAF valid period
for most of the TAF sites. Early Friday morning, there is the
potential for storms to move through north central and
northeastern SD. There is a marginal risk for these storms to be
severe mainly over KMBG, with the chance for mainly large hail and
severe strength wind gusts to occur. Thunderstorm chances spread
over into northeast South Dakota and west central Minnesota from
about mid-day Friday through early Friday evening.

&&

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

$$

UPDATE...10
DISCUSSION...06
AVIATION...10