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000
FXUS63 KFSD 110908
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
408 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.

- 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 at times.
This combined with the mild temperatures will lead to some near
critical to 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 decreasing our highs a few degrees from
the previous day. However, as another ridge builds into the region
by Sunday; another shot of warm air advection will move across the
mid-level continuing our trend of temperatures towards 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%) could return
starting as early as Monday night as a potentially strong low
pressure system lifting 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 0.50" of an inch of QPF while the Euro
has high confidence (60%-80%) in the same parameters. Lastly, its
worth noting that medium to long range deterministic guidance has
started to shift the center of the surface low a bit further
eastwards towards central Iowa with this 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
watch 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 240 PM CDT Wed Apr 10 2024

Thursday will see a return of elevated fire weather. Northwest winds
will likely gust to 35 to 45 mph through the day, but for now many
locations lowest afternoon relative humidity will be borderline. The
best combination will be west of I-29 where RH values drop to about
20 to 30 percent, lowest in south central SD. Given such strong
winds, the 25 percent RH values are not quite as strict, and any
area with roughly 30 percent or less will be quite dangerous to burn
in. Luckily fuels are not completely cured as some green is
beginning to pop up and recent rains have left soils somewhat wet in
various locations. Regardless percent greens are still less than 30
percent, and in many locations 10 to 20 percent, so fuels will
likely be responsive if a fire gets going. Weak instability,
especially east of the James River, may allow for a few sprinkles or
light showers on Thursday afternoon, but any amounts would be
light.

&&

.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...08