370
FXUS63 KABR 082319
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
619 PM CDT Sat Jun 8 2024

.KEY MESSAGES...

- There is a 50 to 80% chance of showers and thunderstorms Monday
  afternoon through Tuesday morning. Some storms along and west
  of the Missouri River may become strong to severe Monday
  afternoon and evening.

- Above normal temperatures will return Wednesday-Friday of next
  week, with highs mainly in the 80s. There is a possibility of
  areas reaching 90 degrees on Wednesday (50-80% chance), mainly
  over central SD.

&&

.UPDATE...
Issued at 617 PM CDT Sat Jun 8 2024

No changes to the forecast this evening. Update to aviation
discussion below...

&&

.SHORT TERM /THIS EVENING THROUGH SUNDAY NIGHT/...
Issued at 319 PM CDT Sat Jun 8 2024

Overall, looking at pretty quiet conditions through the short term
period. The light showers/sprinkles over the southwest CWA from
earlier today have finally been reduced quite a bit in areal
coverage under this expansive mid-level deck down that way. Surface
high pressure stays in place through Sunday, making way for mostly
dry conditions and fairly light winds. Will have to watch western SD
on Sunday as a few CAMs indicate shower/thunderstorm potential
across the High Plains, with perhaps some of this spilling as far
east as the far southwest CWA. Have dry conditions going now, but
something to watch. Otherwise, looking at mild temperatures for
Sunday, with highs in the 70s to near 80 degrees.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 319 PM CDT Sat Jun 8 2024

Clusters agree pretty well with a shortwave moving in over the
Northern Plains Monday through Tuesday along with a 850mb/sfc low
skirting across southern Canada and northern ND/MN. GEFS seems to be
the quickest with the progression of this system. The high will
shift east early Monday and return flow ahead of this system will
help dewpoints rise into the 50s, with areas across central SD
rising into the mid to upper 50s to lower 60s Monday afternoon and
evening. Temps in this area will rise into the upper 70s to lower to
mid 80s as well. Probability of CAPE>1000 j/kg is 10-20% west of our
CWA, per EC ENS, and GEFS around 10-20% around and west of the Mo
River during peak heating hours. East of here instability drops off
significantly. Bulk shear will be out of the west between 20-30kts.
Ensemble means shows precip moving in and pushing west to east
across the CWA (again GFS being the quickest) and continuing through
Tuesday morning/afternoon (model depending) before ending west to
east, as the low tracks east.

Latest NBM matches well with the ensembles showing pops of 20-60%
around and west of MO River through Monday afternoon, increasing to
60-80% over the entire CWA between 00Z-12Z Tuesday with lingering 20-
30% pops through Tuesday morning east of the James River. With only
this marginal instability over central SD, the SPC has put a
marginal risk (1/5) for strong to severe storms Monday afternoon and
evening mainly over Rapid`s WFO with western portions of Corson and
Dewey in this coverage. I would not be surprised if they expanded it
further east around the Mo River area if the atmosphere is more like
what the GEFS was showing. Even after sunset, a LLJ will keep the
forcing for general tstorms through the night into early Tuesday as
the system tracks east.

A quick ridge aloft and high moves in behind the system for the rest
of Tuesday bringing dry weather and temps ranging in the mid 70s to
the lower 80s. Our attention then turns to Wednesday with overall
zonal flow aloft with a possible shortwave from 700-surface pushing
west to east with stronger winds aloft. Models agree on this but
still some variability between the ensembles on intensity and
timing. Return flow on PVA side of trough (over the eastern Dakotas
Wednesday afternoon/evening) will raise dewpoints in the upper 50s
to low 60s as temps will be quite warm in the 80s to the lower 90s
potentially. This will help prime the atmosphere as daytime heating
occurs. Prob of CAPE>1000 j/kg differs quite a bit between the EC
Ens/GEFS with EC ranging from 20% to pockets of 50% where GEFS is
much more bullish with probs 40-80% east of the Mo River and prob
over 2000 j/kg between 20-50%. GFS also has 40-55kt shear forecasted
as well and mid level lapse rates 6-7C. So all of this put together
and if everything lines up through the atmosphere, this could bring
a risk for stronger storms. However, it is still a bit early to nail
down the specifics as we are seeing a difference instability wise
and exact setup between models as mentioned. SPC and machine
learning severe guidance does indicate a Day 5 15% severe risk for
areas east of the Mo River, which does not happen too often around
here so it will be something to watch. Right now NBM pops are a
general 25-40% Wednesday afternoon and evening.

Beyond this, the pattern remains active with several chances of
moisture for the end of the week into the weekend as temps remain
above average through Friday.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 617 PM CDT Sat Jun 8 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions for all terminals.

&&

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

$$

UPDATE...Connelly
SHORT TERM...TMT
LONG TERM...MMM
AVIATION...Connelly