584
FXUS63 KFSD 101054
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
554 AM CDT Thu Oct 10 2024

.KEY MESSAGES...

- Dry and warm conditions expected through this afternoon.
  Marginally breezy winds with relative humidity falling to less
  than 30% will result in elevated fire danger.

- Thick wildfire smoke will continue to give our skies a milky
  appearance for the next few days.

- Temperatures cool Friday through the first half of next week.

- Monday morning will be our first fairly widespread risk of
  frost for some areas as overnight lows fall at or below
  freezing. The potential will be even higher for Monday
  night/Tuesday morning with widespread mid to upper 20s for
  lows.

&&

.DISCUSSION...
Issued at 254 AM CDT Thu Oct 10 2024

Today will be another warm one, with highs expected to climb into
the mid to upper 80s. There is still some possibility for highs
to top 90 in central South Dakota, but both ensemble and
deterministic guidance have backed off on the possibility of
90s in our area of responsibility. With record highs for October
10th in the low 90s, it is doubtfully we`ll break or tie any
records, but highs are still well over the average for this time
of year (mid 60s). Relative humidity this afternoon is expected
to fall to less than 30% for most of the region with pockets of
less than 25%. Winds this afternoon will be on the breezy side
with gusts up to 20 mph. As a result, fire danger for this
afternoon looks to be elevated, but remain sub-critical. Please
continue to use caution and report fires immediately. Lows
tonight will be warm, in the 50s.

Friday an upper trough over northern Canada will work to flatten our
ridge pattern from the past few days. At the same time a cold front
will move through the area a push of cold air behind it. High
temperatures will be dependent on timing of frontal passage.
Areas north of I-90 will see highs in the low 70s cooling as you
move north into the upper 60s. South of I-90 will see highs in
the low to upper 70s, with Woodbury and Ida county in
northwestern Iowa taking a run at 80. Winds behind the front
will be out of the north to northeasterly with gusts 20-25 mph.
The front should be completely through the area by early
afternoon, and the winds should begin to die down in the
evening. Lows will be in the 40s. No precipitation is expected
with this frontal passage.


Saturday a weak ridge and surface high pressure will briefly turn
winds southerly and temper our highs in the mid 60s to low 70s.
Saturday afternoon a deepening upper wave and surface low pressure
will drag a strong cold front across the region overnight. With the
tightening SPG ahead of the front, and the strong CAA behind, I feel
that the NBM is a bit low for winds and gusts. Have bolstered with a
blend of NBM/NMB90. Winds will turn northwesterly and increase to 15-
20 mph with gusts 25-30 by Sunday afternoon. Gusty winds will drop
off after sunset. Highs for Sunday will be seasonably cool, in the
50s and 60s. Lows for Sunday night have trended up the past couple
model runs. While we are still likely to see some frost it doesn`t
look to be as wide spread as previously forecasted, with areas north
of I-90 to be the most at risk for frost.

An upper ridge looks to build in for the first half of next week
with an associated high pressure at the surface. Winds for Monday
will be light and out of the north, bringing down more cold air.
Despite this, highs have trended slightly upward for Monday, but
will still only reach the 50s. Lows for Monday night have also
trended upward slightly, but will still fall to freezing or less for
most of the region. Areas along the Missouri River will have
slightly warmer lows that are just above freezing. Still, widespread
frost is expected by Tuesday morning. Tuesday afternoon winds will
swing around to the south as the surface high moves off to the east
and WAA will warm highs into the 50s and 60s. Strong WAA Wednesday
will begin another a warming trend through the second half of the
week. Wednesdays highs look to be in the 60s and 70s, and
warming into the 70s for Thursday.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 552 AM CDT Thu Oct 10 2024

VFR conditions for this period, with milky skies due to wildfire
smoke. The smoke should not impact flight operations. Winds are
currently light and variable, becoming southerly at 8-12 kts with
gusts 15-18 kts in the afternoon. Winds decrease after sunset.

A cold front is expected to enter KHON from the northwest around
11.06Z and move quickly southeast. Behind the front, winds become
north-northeasterly at 10-15 kts with gusts 20-23 kts. Breezy winds
continue through the end of the period. The front may be
approaching KFSD by the end of this period and should be
through by late morning. The front should be through KSUX mid
afternoon.

&&

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

&&

$$

DISCUSSION...AJP
AVIATION...AJP