479
FXUS63 KABR 051127 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
627 AM CDT Sat Jul 5 2025

.KEY MESSAGES...

- There is a 40-80 percent chance for showers and thunderstorms
  late tonight into Sunday morning, mainly throughout the Missouri
  River valley region. There is a marginal risk (level 1 out of
  5) for severe thunderstorms late tonight capable of producing
  localized strong to severe thunderstorm wind gusts in excess of
  60 mph.

- There is a 20-30 percent chance for afternoon and evening
  thunderstorms on Monday, mainly across portions of central and
  northeast South Dakota and west central Minnesota. There is a
  marginal risk (level 1 out of 5) for severe thunderstorms
  capable of producing localized large hail and thunderstorm wind
  gusts.

- The weather pattern stays active next week with additional
  thunderstorm chances Thursday afternoon and evening.

- Seasonal temperatures are expected during the 7 day forecast,
  with the exception of Wednesday and Thursday, when high
  temperatures could bump back up into the mid to upper 90s
  throughout and west of the James River valley.

&&

.UPDATE...
Issued at 621 AM CDT Sat Jul 5 2025

See below for an aviation forecast discussion for the 12Z TAFs.

&&

.DISCUSSION...
Issued at 405 AM CDT Sat Jul 5 2025

At 3 AM CDT, skies are partly to mostly cloudy and a few lingering
showers are noted across the region. A cold front is passing through
the CWA, turning southerly winds around to the north. Water Vapor
satellite imagery would suggest that there is still some remnant mid-
level shortwave energy to move over the region over the next 6 to 12
hours. Temperatures are in the upper 60s to low 70s.

As long as there is still low level moisture around, and this cold
front over the CWA for forcing, a few showers/thunderstorms can`t be
ruled out as this shortwave energy moves across the region.
Mid/upper level have cooled a bit, so that will help to steepen
lapse rates once the sun comes up and starts the heating process.
Otherwise, high pressure building in today, and sticking around
through Sunday, should help to dry out the boundary layer and cool
things down, at least, 10 to 15 degrees off the pace of the past
couple of days. 925hpa thermal progs only top out in the upper teens
to mid 20s Celsius today and tomorrow.

What still needs some watching is how the models handle low level
moisture return (mainly across the central/northern high plains)
later tonight and on Sunday, as there is an upper level circulation
over the Pac-NW progged to induce convection over Wyoming/Montana
later today that could spread into western and maybe portions of
central South Dakota later tonight. SPC continues with its marginal
risk (level 1 out of 5) for severe thunderstorms throughout the
Missouri River valley of this CWA for late Saturday night. Still
plenty of deep layer shear (40-50kts) around later tonight, but
models have pushed the return of low level moisture a bit farther
west, suggesting storms could run out of instability real-estate as
they try to progress toward the central portion of South Dakota
overnight. Still, there is the mid/upper circulation, itself, to
contend with on Sunday, making the case for the need for some small
PoPs over the CWA during the day on Sunday.

Energy traversing the semi-zonal NOAM flow pattern aloft further
north on Monday is expected to drag a cold front down across the
Dakotas on Monday (timing is still being ironed out), where ample
deep layer shear and modest low level moisture is progged to co-
exist. This spells the potential for some scattered (possibly
severe?) thunderstorm activity during the day on Monday, lasting
into Monday evening, before leaving the CWA for Minnesota. SPC has
introduced a marginal risk (level 1 out of 5) for severe
thunderstorms over central and northeast South Dakota into west
central Minnesota for Monday afternoon into Monday night.

Then, after a couple of days break in precipitation chances
Tuesday/Wednesday, as the upper level ridge tries to build again
over the region, the next frontal passage could be working through
the region Thursday/Thursday night, where PoPs are in the forecast
to cover any thunderstorms that might form on this frontal boundary.

Wednesday into Thursday could become rather warm again, especially
west of the James River valley. High temperatures could be back into
the mid to possibly upper 90s throughout the Missouri River valley
both days. Otherwise, temperatures closer to climo for early July
are expected during the 7 day forecast period.

Surface boundary will still be tracking eastward across the eastern
CWA Friday evening, with good agreement amongst the GEPS/GEPS/ENS in
showing the position from southeast ND, southwest into the James
River valley and onward to south central SD at 06Z Saturday. By 18Z
Saturday it appears the boundary is far enough east into MN to let
PoPs reduce to 30-50% across the far east, much lower than the high
chances (70-90%) in the forecast for earlier Friday evening. PWATs
are still rather high Friday night into Saturday morning, generally
a tad either side of 1.75in shown by the Grand Ensemble. It`s not
until Saturday evening that these values lower down to around an
inch or less. There would appear to remain at least a marginal
threat for heavy rain and strong wind gusts and small hail between
00-06Z Saturday. MUCAPE values off the Grand Ensemble still
generally between 1000-1500 J/KG, although shear remains weak.

Cooler air follows in the post-frontal atmosphere for Saturday and
Sunday. 850mb temps in the +20s C on Friday gradually cool to
between +13C and +16C by 18Z Sunday. Highs cool down to the mid 70s
and low 80s on Sunday. Good agreement in warming conditions again by
mid-week, with highs likely getting back into the 80s and low 90s.

As for precipitation, the overall pattern seems to stay somewhat
active. We see a wave already impacting the region Saturday night
into Sunday, and will have 40-60% chances for showers and
thunderstorms along and west of the Missouri River Saturday night.
NBM PoPs also pinpoint a time frame Monday night with decent
potential (40-50% chances) for rainfall. Mid/upper level flow
pattern looks to set up over the Northern Plains, likely bringing
disturbances across the region. Of course, models having a tough
time with timing of these waves, so rainfall chances are somewhat
broadbrushed through the period.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 621 AM CDT Sat Jul 5 2025

Terminals KABR,KATY,KPIR,KMBG

There is a mix of VFR and less-than-VFR cigs over northeast South
Dakota into west central Minnesota this morning. Back over
central and north central South Dakota, VFR conditions conditions
persist. By 18Z today, all four terminals should be in prevailing
VFR conditions for the rest of the TAF valid period. Regional
radar shows a few pockets of rain working through north central
and northeast South Dakota, in the wake of a cold front that is
also moving through the region. Winds are in the process of
switching from southerly out ahead of the front to northwesterly
behind the front.

&&

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

$$

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