000
FXUS63 KFSD 222311
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
611 PM CDT Mon Apr 22 2024

.KEY MESSAGES...

- A few sprinkles to light showers will continue to move
  through area east of I-29 this afternoon and evening.
  Accumulation are expected to be kept to a minimal.

- A few more isolated sprinkles will be possible Tuesday
  afternoon mostly along portions of southwestern MN.

- Rain chances return to the forecast late Thursday afternoon
  and continue throughout the weekend, with a lull in activity
  possible Friday night into Saturday. A few storms could become
  strong to severe.

&&

.DISCUSSION...
Issued at 241 PM CDT Mon Apr 22 2024

Tonight: Another warm and breezy day continues! Taking a look
across the area, partly to mostly cloudy skies continue as a
combination of high cirrus and altostratus push across the area
ahead of a mid- level trough. Current radar imagery shows a few
sprinkles to light showers developing within the altostratus.
However, dry air in the sub-cloud layer has prevented most of
the developing precipitation from reaching the surface. As warm
air advection (WAA) continues to strengthen east of I-29 along
with the LLJ, coverage of developing showers will likely
increase especially across the Buffalo Ridge leading to the
potential for some light accumulations. Nonetheless, most of
this activity should be out of our area by this evening giving
way to clearer skies.

Shifting gears here, our breezy southerly to southwesterly winds
have begun to shift to the northwest behind the cold front and
should continue to gradually decrease this evening. With only a few
sites (mainly KSLB & KSPW) across northwestern IA continuing to have
advisory level sustained winds and gusts, have decided to trim our
original advisory to reflect the sites with the strongest winds. The
wind advisory will continue through 4 PM CDT. Looking at soundings,
deep mixing will continue to bring drier air down to the surface
this afternoon behind the surface front. As a result, ended up
mixing in some RAP guidance into the forecast this afternoon to help
lower our dew points closer to observed values. While this has
resulted in critical RH values (15-25 percent) across most of the
area, greener fuels and moist top soil will keep our fire weather
concerns at marginal at best for a while. Lastly, temperatures will
continue to be above normal as highs approach the upper 60s to low
70s this afternoon with overnight lows only decreasing into the low
to mid 40s.

Tuesday: Looking into Tuesday, cloud cover will begin to build
mostly north of I-90 as another mid-level wave swings across the
area during the morning hours. Increased PVA ahead of the
trough along with an increasing LLJ may lead to a few sprinkles
to isolated showers developing mostly across portion of
southwestern MN. Similar to this afternoon, limited saturation
in the subcloud layer will likely lead to limited accumulations.
However, the dreary condition will likely persist into the
early afternoon hours before gradual clearing occurs from west
to east. Shifting gears to the winds, northwesterly winds will
again increase throughout the day with gusts between 25- 35 mph
possible. Otherwise, lingering cold air advection (CAA) aloft
and northwesterly surface winds will keep temperature more mild
than the previous day with highs only expected to peak in the
upper 50s to low 60s for the day. As conditions clear by the
late evening, the colder air aloft will be allowed to reach the
surface dropping our temperatures back into the low to mid 30s
for the night. While these temperatures could warrant a
frost/freeze headline Tuesday night, three back-to-back days of
freezing temperatures this week likely took out any developing
vegetation. As a result, the headline might not be necessary.

WEDNESDAY: Quiet conditions are expected to prevail as sfc high
builds across the area. Despite the increase in cloud cover during
the afternoon, will see highs rise into the low to mid 60s with the
aid of southerly flow. Gusts then look to gradually increase during
the evening and overnight period, especially along and east of I-29,
with values ranging between 25 to 35 MPH.

THURSDAY: Upper level low over the southwestern CONUS ejects
northeastward Thursday, causing showers and storms to return to the
forecast by Thursday evening. Should see largely dry conditions
persist through the afternoon as upper level ridging holds tight
overhead. Similar to Wednesday night, expect breezy southerly winds
to continue, with gusts between 25 to 35 MPH possible for much of
the day. As a result, expect highs to rise into the upper 60s to
lower 70s. Sfc warm front surges toward the region Thursday evening,
allowing WAA showers to blossom across our area. While some
development may be possible along the MO River Valley near sunset,
think the better chances (>60%) will arrive after midnight.

FRIDAY THROUGH SUNDAY: Widespread showers and storms are expected
heading into the Friday as the aforementioned upper level low nudges
closer to the region. As alluded to in the previous discussion, may
even see a few storms become strong to severe Friday evening if all
the ingredients come together. While the better dynamics currently
look to occur across the central Plains, SPC`s latest D5 Outlook
does maintain a 15% risk of severe weather across portions of NW
Iowa and NE Nebraska. Certainly something to keep an eye on in the
coming days. In regard to temperatures, currently have highs in the
upper 60s to lower 70s, though these values may be a touch too high
if FROPA across quicker than anticipated. Otherwise, look for
showers and storms to continue heading into the weekend. Depending
on how the upper level low tracks, may see a lull in activity late
Friday night through Saturday morning, with wrap around showers
still likely by Saturday afternoon. Model consistency begins to wane
by Sunday as yet another wave near the Rockies ejects toward the
region. Given that the track of this feature could still shift quite
a bit over the next few days, will not speculate on the details just
yet. For now, expect rain chances to continue heading into the new
week with highs generally in the 50s to 60s and lows in the 40s.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 611 PM CDT Mon Apr 22 2024

VFR throughout the period. Winds will continue decreasing into the
evening hours, becoming more westerly overnight. Areas south of I-90
may see some variable winds for a couple hours overnight, though
retaining a westerly component. Breezy northwest winds ramp up after
sunrise, sustained in the 20 to 25 knot range, with gusts 25 to 35
knots. Winds slowly decrease during the afternoon hours.

&&

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

&&

$$

DISCUSSION...SST/Gumbs
AVIATION...APT