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000
FXUS63 KFSD 171128
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
628 AM CDT Wed Apr 17 2024

.KEY MESSAGES...

- A few lingering light showers will dissipate by mid morning.
  Any additional accumulation will be light.

- Wednesday night into Thursday precipitation chances return,
  this time with the focus along and south of HWY 18. There is
  70-100% probability of 0.1 inches of accumulation, with
  pockets up to 0.5 inches possible for this area and south.

- Gusty northwest winds decrease after noon today. Winds will be
  periodically gusty through early next week.

- Cooler, in the 40s and 50s through Saturday. Then, we warm
  back into the 60s by mid week.

&&

.DISCUSSION...
Issued at 333 AM CDT Wed Apr 17 2024

TODAY: Water vapor imagery shows the strong low pressure that
brought showers and thunderstorms Tuesday spinning over the Tri-
State region this morning. The center of the surface low is located
over eastern Iowa and Minnesota. On the backside, scattered light
showers continue. These showers may produce another tenth or two of
rain, but overall we are not expecting much more out of them. The
showers should cease totally by mid morning. A tightening SPG due to
a mid-level ridge and a strong push of CAA will boost our
northwesterly surface winds this morning, as well as limit highs
into the 50s and 60s. Good mixing will tap into the 40-50 kt LLJ,
resulting in gusts of 30-40 mph. Winds taper off after noon as the
low continues to move off to the east. Clouds thin through the day
and will give us peaks at the sun this afternoon before the next
round of showers begins tonight.

TONIGHT: An upper short wave and associated surface cold front moves
through bringing more rain to area, with the focus of heavier rain
along and south of HWY 18. An 850-700 mb deformation zone sets up
just south of the South Dakota/Nebraska border in the late hours of
Wednesday night. Here, 850-700 mb frontogenesis will serve as the
focal point for shower formation. There is a small elevated mixed
layer providing very weak instability. So, the most likely scenario
is these remain garden variety rain showers with a few rumbles of
thunder possible. Ensembles indicate 70-100% probability the
aforementioned area will see at least a tenth of an inch, with a 30-
70% probability of at least a half inch. This matches well with WPC
QPF guidance. Chances for precipitation drop off quickly as you head
north of I-90.

THURSDAY-SATURDAY: Showers clear out by Thursday late morning.
Thursday afternoon through Saturday, surface high pressure will be
present with mostly zonal flow aloft. Winds will be primarily
northwesterly and periodically gusty. This pattern brings
several pushes of CAA with it, keeping our temperatures cooler
than average by about ten degrees, in the upper 40s to low 50s.
Overnight temperatures during this period will drop below
freezing, into the upper 20s. So, if you had spring fever and
already bought plants for your gardens, be sure to either bring
them inside or cover them so they won`t get frost nipped.

SUNDAY AND BEYOND: Sunday brings a change in wind directions as a
surface high pressure moves through to the southeast. Winds will
become southerly, bringing warmer air with it. Highs will begin to
climb back to normal for Sunday afternoon, in the upper 50s to low
60s. This warming trend will continue through the middle of next
week. Our next shot at precipitation will be Monday night as a low
pressure system over Saskatchewan drags a couple fronts through the
area. Model guidance agreement is low at this time, and so we
encourage you to check back for updates.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 626 AM CDT Wed Apr 17 2024

MVFR with IFR/LIFR over southwestern Minnesota this morning.
Expect ceilings to improve IFR by late morning/early afternoon
as clouds dissipate. Winds will be northwesterly sustained at
15-20 kts with gusts 25-30 kts. Winds will decrease gradually
after noon.

Rain chances again late this evening into Thursday. The heaviest
rain is expected to remain south of I-90, however there could be
sprinkles as far north as KHON and KBKX. The heaviest rain is
expected to be near or at KSUX by 18.05Z and continue through about
18.12Z. These showers are expected to remain light, however under
active rainfall visibility may be reduced down to around 4 miles.

&&

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

&&

$$

DISCUSSION...AJP
AVIATION...AJP