104
FXUS63 KABR 092026
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
326 PM CDT Sun Jun 9 2024

.KEY MESSAGES...

- There is a 60 to 90% 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. Main threats are winds gusting around 60
  mph, with hail up to quarter size.

- There is a 20-40% chance of showers and thunderstorms Wednesday
  into Wednesday night, mainly along and east of the James River
  Valley. Some storms may become strong to severe.

- Above normal temperatures will return Wednesday-Friday of next
  week, with highs mainly in the 80s. However, areas in north
  central to south central SD could reach 90 degrees (50-80%
  chance)

- There is a 40% chance of above average precipitation for the end
  of the week into next weekend for the much of the forecast
  area.

&&

.SHORT TERM /THIS EVENING THROUGH MONDAY NIGHT/...
Issued at 326 PM CDT Sun Jun 9 2024

Did end up adding slight chance (20%) PoPs across the southwest CWA
for the remainder of the afternoon to account for the shrinking area
of light rain moving southeast across western SD. Otherwise, surface
high pressure over the area this evening will shift east overnight
and allow for southeast return flow winds to develop. These winds
will become windy/gusty across central SD by late morning and
persist through the afternoon as the pressure gradient tightens
ahead of an approaching cold front. Initially tonight out ahead of
the front, low-level jet winds strengthen across western/central SD,
and could lead to a few elevated showers come morning over north
central SD according to a couple CAM solutions. Included 20% chances
for showers over north central SD early Monday morning.

Bigger threat for storms comes later in the day as low-level
moisture beings surging northward into western/central SD out ahead
of the cold front. Dewpoints in the 50s to around 60 degrees look to
set up, with moderate instability (1000-2000 J/KG HREF mean CAPE)
developing during the afternoon. Joint probability of CAPE >500, CIN
>-25, and 0-6km bulk shear >30 knots generally show greater than 70%
across western SD. Values drop off quite a bit closer to the
Missouri River. Latest SPC Day 2 outlook keeps Slight Risk across
UNR CWA, with Marginal across central SD. Timing for any potential
strong/severe storms (based on HREF Paintball >40 dbz product) would
suggest around 21Z to 22Z for action to move into north central SD,
with activity eventually spilling into the Pierre region around 00Z.

Cold front will continue moving eastward Monday night, with good
chances (60-90%) for precipitation across much of the CWA. Although,
instability really begins to decrease by sunset and thereafter as we
head east of the Missouri River and into the James River valley.
HREF mean MUCAPE shows generally around 500 J/KG or less during the
Monday nighttime hours.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 326 PM CDT Sun Jun 9 2024

An unsettled weather pattern will bring several rounds of showers
and thunderstorms chances across the forecast area most of next week
into the weekend. Starting off Tuesday, Clusters are in agreement
with a shortwave continuing its track east across the Northern
Plains and its associated surface low to our north, over
ND/MN/Canadian border. At 12Z, ensembles agree on the cold front
positioned over the eastern part of the state with much of the CWA
behind it in northwest flow. By 18Z this front is forecasted to be
be out of the CWA and into MN. Ensembles show lingering 15-25%
across extreme eastern SD into western MN during this time ahead and
along the front. NBM shows this with 10-15% pops from Sisseton to
Watertown and eastward. Precip should move out shortly after with
the rest of Tuesday into Tuesday night looking dry as a ridge will
be over the Northern Rockies/western Northern Plains along with a
surface high.

Our attention then turns to Wednesday with the possibility of strong
to severe storms. Starting at the top of the atmosphere, 250mb winds
will be quite strong over the Northern Plains by Wednesday afternoon
with zonal flow to slight northwest flow, around 70-80kts,
increasing to 80-90kts by the evening, per Clusters. This will aid
in stronger upper level divergence for any convection. At 500mb,
this ridge will flatten out (or be very low in amplitude) overhead
with zonal to slight northwest flow, with winds between 30-50kts by
the evening. 850mb to surface will consist of a trough/low over the
area. Return flow at surface over the CWA will help temps warm well
into the 80s to the lower 90s and dewpoints in the upper 50s to
around 60, priming the atmosphere and making it juicy during peak
daytime heating. Prob of CAPE>1000 j/kg still varies as GEFS is more
bullish with 50-80% chance, highest over eastern SD/western MN,
where EC is more broad with 40-60% from northeastern SD into south
central SD by the evening. Prob of 2000 j/kg is 20-60% over eastern
SD/ western MN with GEFS where EC is only 10-30%. Both do agree
shear will be between 30-40kts out of the west. So all depends if
everything can come together at the right time and if convection
gets going, it will not take much for upscale growth. NBM has pops
of 20-40% Wednesday afternoon and evening, east of the Mo River.
This threat is why SPC has a Day 4 (15%) risk of strong to severe
storms over eastern SD into west central MN for Wednesday afternoon
and evening.

For Thursday, a slight ridging pattern is forecasted to be over the
western CONUS putting the CWA in northwest flow with a second area
of low pressure forming over the Central and Northern Plains. NBM
has 20-30% pops early Thursday morning then diminishing west to east.
The ridge should move in overhead by Friday but there is still
timing and intensity differences between the Clusters. A broad area
of low pressure over the Rockies could bring slight chances of
moisture (15-30%) for areas around and west of Mo River. By the
weekend this ridge pushes east and trough moves in over the western
CWA (and a formation of a low). This gives the possibility of
additional moisture for the weekend. CPC continues with a 45-50%
chance of temps above average for the end of the week into next
weekend and 40% chance of above average precip.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1225 PM CDT Sun Jun 9 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast through the TAF period.


&&

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

$$

SHORT TERM...TMT
LONG TERM...MMM
AVIATION...TMT