081
FXUS63 KFSD 280331
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1031 PM CDT Sat Apr 27 2024

.KEY MESSAGES...

- Periods of light to moderate showers return tonight and
  should continue into the day on Sunday. A few storms may
  become severe by Sunday Afternoon mostly across northwestern
  IA. However, the severe risk will be conditional.

- An additional half inch to inch of accumulation is expected
  through Sunday night with isolated pockets up to 1.25 inches.
  Localized ponding in low lying or poor drainage areas will be
  possible.
Showers will gradually overspread the area late tonight into
Sunday, with visibilities falling into the MVFR range. While
MVFR ceilings will be predominate early tonight, look for
lowering into the IFR/LIFR range later tonight into Sunday.
Winds will be northeasterly through the period, with gusts 20
to 25 kts late tonight through Sunday.
- An active weather pattern will continue through next week
  with periodic rain chances expected. However, precipitation
  chances and overall temperatures remain a bit uncertain.

&&

.DISCUSSION...
Issued at 401 PM CDT Sat Apr 27 2024

A mild and dreary day continues! Taking a look across the area, a
layer of stratus continues to blanket most of the area as a quick
mid-level ridge approaches the area from the southwest. Ahead of the
ridge, lingering cold air advection (CAA) along with consistent
cloud cover will keep temperatures fairly similar to yesterday with
highs expected to peak in the mid to upper 50s and low 60s for the
day with the warmest conditions expected across northwesterly IA. By
tonight, our attention shifts to the southern Rockies as another
Upper-Level Low (ULL) lifts northeastwards out of the Desert
Southwest bringing our next precipitation chances. Looking aloft,
mid-level warm air advection (WAA) will strengthen ahead of the
inverted trough axis late tonight bringing our first round of
showers mostly across northwestern, IA and the Missouri River
Valley. However, with the better instability expected to be to
the south and southeast of the area; most of the developing
activity will likely stay sub-severe. Nonetheless, periods of
moderate to heavy rainfall will be possible.

As the main surface low continue to slowly rotate towards our area
on Sunday, increasing isentropic lift and 700mb frontogenesis will
lead to the development of more scattered showers and potentially a
few thunderstorms. A few isolated storms could become severe by
Sunday afternoon mostly across northwestern IA as the stratus
potentially thins and the dry slot sets up. With decent instability
(800-1000 J/kg) and 35-45 kts of shear, can`t rule out the potential
for some quarter sized hail especially with mid-level lapse rates
approaching 7 degrees C/km. However, this threat will be
conditionally dependent on if the stratus can clear out and the
atmosphere can recover enough from tonight rain chances for things
to hold together. Nonetheless, as additional half inch to an inch of
accumulation is expected across the area though Monday with
localized ponding possible across poor drainage areas.

Heading into the new week, any lingering showers will continue to
lift northeastwards by Monday morning with the departing Upper Level
Low (ULL). Breezy westerly surface winds will then return with gusts
between 20-30 mph as a quick mid-level ridge moves over head. This
combined with increasing WAA and effective mixing should help our
overall temperatures slightly recover with highs expected to be in
the mid 50s to low 60s for the day. A more active pattern will
continue aloft starting Monday night as quasi-zonal flow brings
multiple waves through the region over the course of the week.
However, with timing and location differences among guidance decided
to leave the default POPs in for the extended period. Lastly, mostly
seasonal conditions will continue across the area into the weekend
as daily highs peak in mid to upper 50s to low 60s.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1030 PM CDT Sat Apr 27 2024

Showers will gradually overspread the area late tonight into
Sunday evening, with visibilities falling into the MVFR range.
While MVFR ceilings will be predominate earlier tonight, look
for lowering into the IFR/LIFR range later tonight into Sunday.
Winds will be northeasterly through the period, with gusts 20 to
25 kts late tonight through early Sunday evening, then tapering
downward late in the evening.


&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...Gumbs
AVIATION...JM