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000
FXUS63 KFSD 110941
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
441 AM CDT Thu Apr 11 2024

.KEY MESSAGES...

- Most of the Fire Weather Watch has been converted to a Red
  Flag Warning for portions of southeastern SD, northwestern IA,
  and far northeastern NE. A Fire Weather Watch remains in
  effect for portions of eastern SD and northeastern IA.

- More light showers will develop starting late this morning
  mostly along the Hwy-14 corridor and east of I-29 with up to
  a few hundredths of accumulation possible.

- After a slightly cooler day today, warmer temperatures return
  over the weekend with highs expected to be in the 70s and
  potentially 80s by Saturday and Sunday. The continued warm and
  breezy condition could lead to some elevated fire weather
  concerns.

- Confidence continues to increase in more meaningful
  precipitation chances (40%-80%) return as early as Monday
  night as low pressure system lifts into the region.

&&

.DISCUSSION...
Issued at 406 AM CDT Thu Apr 11 2024

The Short Term (Today & Tonight):

Slightly cooler and windy conditions will be on tap for the day.
Taking a look satellite imagery, an area of light to moderate
showers has developed this morning along the Hwy-14 corridor near
Brookings as increasing lift at the base of the trough interacts
with about 200-300 J/kg of instability. Over the next several hours,
this developing activity will continue to gradually slide to the
southeast into parts of southwestern MN and potentially northwestern
IA if things can hold together. While this has resulted in some
slightly higher accumulations this morning, accumulative are still
expected to remain below a tenth of an inch for the day. Shifting
gears to the rest of the day, northwesterly surface winds along with
lingering cold air advection from yesterday`s cold front will help
slightly decreasing our temperatures for the day.

As a result, highs are expected to peak in the mid to upper 50s and
low 60s. With that being said, deeper mixing throughout the day will
help transport stronger winds and drier air to the surface
throughout the day with gusts between 35-45 mph expected. This
combined with the mild temperatures will lead to elevated to
locally critical fire weather conditions this afternoon. More
on this in the fire weather section. Looking aloft, another weak
trough is expected to dive southeastwards late this morning
bringing a few more sprinkles to light showers to areas along
the Hwy-14 corridor and east of I-29 this afternoon. However,
with PWAT values closer to the 10th percentile on the ESAT
Tables for the day mostly due to drier air aloft; accumulations
are expected to be mostly light with up a few hundredths
expected. Otherwise, conditions will gradually clear up late
this evening as a surface high moves across the northern and
central plains this overnight.

The Long Term (Friday-Wednesday):

Heading into the weekend, quieter and potentially warmer conditions
are ahead as the upper-level component of the ridge builds across
the region by Friday. Northwesterly surface winds will become more
southerly by Friday afternoon as mid-level warm air advection
continues to strengthen into Saturday. This along with 925 mb
temperatures increasing to the upper teens to low 20s by Saturday
afternoon will lead to highs going from the low to upper 60s on
Friday to the upper 70s to mid 80s by Saturday. Temperatures could
slightly cool down by Sunday as a dry cold front slides through the
area by Saturday afternoon. However, as another ridge builds
into the region by Sunday; another shot of warm air advection
will move across the mid-levels continuing our trend of
temperatures near the 90th percentile and higher of climatology
according to the ESAT Tables. Lastly with slightly breezier
conditions expected on Saturday and Sunday, some elevated fire
weather concerns will be possible on both days.

Looking ahead into the new week, a pattern shift is likely on the
horizon as more concrete rain chances (40%-80%) return starting
as early as Monday night as a potentially strong low pressure
system lifts out of the Desert southwest into the Plains. While
details regarding amounts and potential timing are still
uncertain at this time, both the GEPS & Euro have low to medium
confidence (30%-50%) in up to half an inch of QPF while the
Euro has higher confidence (60%-80%) for the same parameters.
Lastly, its worth noting that medium to long range deterministic
guidance has started to gradually shift the center of the
surface low a bit further eastwards towards central Iowa with
the latest run of guidance. While its too early to tell,
pattern recognition for previous events indicates that this
could mean our rainfall amounts could decrease over the next few
days. Either way, this will be something that we`ll have to keep
an eye on moving forward.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1044 PM CDT Wed Apr 10 2024

Isolated showers/sprinkles will slide southeast across the
region tonight, with chances lingering east of I-29 through
Thursday. A period of MVFR ceilings may accompany or follow the
showers later tonight into early Thursday, with MVFR conditions
currently expected to remain northeast of our TAF sites.

Northwest winds occasionally gusting to 20-25kt through early
Thursday will increase behind a cool front, with gusts 30-40kt
becoming more widespread by Thursday afternoon. The stronger
gusts will diminish with sunset Thursday evening.

&&

.FIRE WEATHER...
Issued at 435 AM CDT Thu Apr 11 2024

Continued mild, breezy, and dry conditions this afternoon will
lead to elevated to locally critical fire weather. Similar to
yesterday, deeper mixing along with a tightening SPG will lead
to increasing northwesterly winds with gusts between 35-45 mph
starting as early as the late morning. As more dry air gets
transported to the surface, dew point will gradually decrease
leading to RH values between 20-30 percent with a sharp gradient
occurring along a Huron-Sioux Falls-Ida Grove, IA line
westwards. With all this in mind, parts of the Fire Weather
Watch mainly across portions of southeastern SD, northwestern
IA, and far northeastern NE have been converted to a Red Flag
Warning since the stronger winds can overcome the slightly
higher RH values. However, with cloud cover expected to increase
across areas east of the previously mentioned line with the
potential precipitation chances this afternoon; decided to leave
part of the watch in place just in case further expansion is
needed.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Fire Weather Watch from noon CDT today through this evening
     for SDZ039-055-062-067.
     Red Flag Warning from noon today to 8 PM CDT this evening for
     SDZ038-050-052>054-057>061-063>066-068>071.
MN...None.
IA...Fire Weather Watch from noon CDT today through this evening
     for IAZ001-012.
     Red Flag Warning from noon today to 8 PM CDT this evening for
     IAZ020-031.
NE...Red Flag Warning from noon today to 8 PM CDT this evening for
     NEZ013-014.

&&

$$

DISCUSSION...Gumbs
AVIATION...JH
FIRE WEATHER...Gumbs