659
FXUS63 KABR 041526 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1026 AM CDT Wed Jun 4 2025

.KEY MESSAGES...

- A 20 to 40% chance for showers, and a possible thunderstorm,
  across central SD today with better chances (40-75% most areas)
  Thursday and Friday. Severe storms are not expected through
  Friday at this time.

- A cold front will bring a 30 to 50% chance of thunderstorms
  Saturday afternoon/evening, with a limited risk (2-5%) for
  severe storms. This risk may increase as models evolve towards
  Saturday.

&&

.UPDATE...
Issued at 1022 AM CDT Wed Jun 4 2025

Main thing to watch today is the area of showers across southwest
SD and if any of this activity (or additional development this
afternoon) affects portions of central/south central SD. PoPs are
fairly limited over the western CWA today, so will be monitoring
for any possible expansion of precipitation chances. Otherwise, no
major changes expected as temperatures rise into the upper 60s to
mid 70s for most locations, with west to southwest breezes.

&&

.DISCUSSION...
Issued at 253 AM CDT Wed Jun 4 2025

As of 230am skies were mainly clear with some scattered mid to high
clouds moving in over the western CWA. Temps range from the lower
40s (James River Valley) to the mid 50s (warmest at Sisseton) with
calm to light winds.

A weak embedded shortwave will continue to move in from the west
today, and over the Northern Plains, tracking eastward through this
evening in this overall baggy longwave troughing pattern. At the
surface, a broad area of high pressure will continue over the area,
shifting a bit eastward tonight into Thursday. With this wave,
CAMs/HREF does indicate the possibility of spotty precip skirting
over south central SD towards the midday/afternoon to start out
where there is better lift and 1000-500mb moisture (70-80%).
Additional spotty precip looks to pop up north of here, mainly along
the ND/SD border along and west of the Missouri River through this
evening. Coverage does vary a bit of this northward extent and
intensity between the CAMs, so therefore, confidence is low on the
exact outcome due to this weak lift. So stuck with NBM for guidance.
Pops may need to be adjusted closer to time or broad brushed due to
the spotty nature. As of now pops run from 20-40% highest over our
far southwestern and far northwestern CWA. Instability will be
limited with CAPE at or under 500 j/kg with little to no shear. So
just general thunderstorms expected if we do get storms with the
main threat being lightning. Another shortwave will move over the
region Thursday and Friday (with several embedded pulses) with an
inverted trough setting up over central and eastern SD, north of a
stationary front sprawled across the central CONUS Friday. This
setup will bring a better chance of more widespread coverage of
precip as dewpoints rise into the 50s, more low/mid level moisture,
and PWATS up to an inch (highest over south central SD). Pops are
forecasted to range from 40-75% Thursday over the CWA and 40-60%
Friday, diminishing through Friday evening. Again instability will
be weak so just general thunderstorms possible both Thursday and
Friday afternoon and evening. It is tough to determine QPF due to
the convective nature but prob of QPF>0.50" from 12Z Thursday-12Z
Friday is 50-75% over the southern half of the CWA.

We then look ahead to the weekend as a stronger shortwave, and its
surface low, will move northwest to southeast over Canada with
GEFS/ENS/GEPS coming together better with the open wave over
~Saskatchewan/Manitoba by 00Z Sunday and strengthening into a closed
low over Manitoba/Ontario by 12Z Sunday. During this time, a cold
front will move through the region with precipitation firing up
Saturday afternoon/evening, ahead and along the front, with pops of
30-50% mainly east of the Mo River and highest over the eastern CWA
through Sunday morning. Timing of the departure of the precip over
the eastern CWA varies, with GEFS being the slowest. Dewpoints will
run in the mid to upper 50s Saturday afternoon and evening with CAPE
up to around 1000 j/kg and shear between 30-35kts out of the
northwest. Probability of CAPE>500j/kg, CIN>-25, and shear>30kts is
about is about 20%, mainly west of the James River. CIPS/CSU machine
learning have backed off on this severe threat with NSSL still
showing a 2-5 percent chance, mainly over central SD. This is still
several days out so we will continue to monitor this threat in the
upcoming days.

Behind this wave for early to middle parts of next week, Clusters
agree on the ridge that has been hanging out over the Pacific, will
move in over the western CONUS Sunday, and flatten out a bit Monday
as a shortwave will move over the crest and dampening it. This looks
to become more of a -PNA pattern by the middle to end of next week.
Highs will generally run around average to as low as 10 degrees
below average ranging in the upper 60s and 70s through Friday. Ahead
of the cold front, temps warm into the upper 70s to the lower 80s
and cooling down into the 70s behind the fropa Sunday. Temps look to
gradually warm back into the lower to mid 80s by Wednesday of next
week.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 616 AM CDT Wed Jun 4 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected to continue, with afternoon cumulus
clouds and a 20% chance of showers or less. The highest chance is
at PIR and MBG this afternoon.


&&

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

$$

UPDATE...TMT
DISCUSSION...MMM
AVIATION...06