163
FXUS63 KFSD 281058
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
458 AM CST Fri Feb 28 2025

.KEY MESSAGES...

- Strong 40 to 50 mph northwest winds today will promote near
  critical to critical fire weather conditions through the
  evening hours. A Red Flag Warning has been issued for parts of
  the area. ALL planned burning activities should be postponed.

- Turning cooler on Saturday, though above normal temperatures
  persist into next week.

- Measurable precipitation chances (50%-60%) will return by next
  Tuesday into Wednesday. While amounts remain uncertain, most
  of this will fall as rain with most ensemble guidance showing
  moderate probabilities (30%-40%) in a 0.10" inch or greater of
  QPF across the area.

&&

.DISCUSSION...
Issued at 350 AM CST Fri Feb 28 2025

An upper level shortwave and surface low currently over northern MN
will track to the southeast today, becoming situated over the
western Great Lakes region by this evening. These features will pull
a couple frontal boundaries through our area today - one passing
through by mid morning, then a more significant one which will sweep
through the region during the afternoon. With cold air
advection/steepening lapse rates behind the frontal boundaries,
mixing will tap into winds of 40 to 50 kts aloft, resulting in a
windy day with gusts of 40 to 50 mph. As a result, the current Wind
Advisory remains appropriate for the afternoon and early evening
hours. The above normal temperatures and strong winds will result in
an enhanced fire danger as outlined in the discussion below. Warmest
temperatures will reside through the MO river corridor with highs in
the mid to upper 50s. Somewhat cooler temperatures will be found back
to the north, as the stronger cold air advection with the afternoon
front will impact those areas first, and looking at highs in the mid
40s to lower 50s - with falling temperatures over east central SD
and southwestern MN in the later afternoon as the front drops
through the area. Some CAMS would indicate some possible brief light
rain over southwestern MN in the afternoon - this with some mid
level saturation in the presence of weak instability, and weak lift
provided by an upper level vort tail swinging through the region. In
any event, if anything occurs it would most likely be in the form of
sprinkles.

Surface high pressure begins to build southward into the region
tonight, and with the cold air advection and slowly dying winds it
will be a much cooler night than seen recently. Lows look to drop
into the teens to lower 20s across the area. The surface ridge
settles into the region on Saturday, and with our area being on the
backside of the 850 mb thermal trough, it will be a cooler days with
highs mainly in the 30s. Although the colder/drier air will result
in afternoon RH values around 25 percent east of Interstate 29,
light winds will mitigate the fire danger.

The cool down will be short lived however, as the surface high
shifts off to the east - bringing a returning southerly flow to our
area on Sunday and Monday. This will be most realized on Monday when
the 850 mb thermal ridge becomes oriented over our area. This
will push highs into the mid 50s to lower 60s on that day. In
addition, breezy conditions on Sunday may again result in some
fire weather concerns. An upper level low will drift through the
Central Plains on Sunday night, and this will bring a small
chance (20-30%) of light rain to northwest IA. Even so,
appreciable moisture looks bleak with latest ensembles
indicating only a 30-40% probability of that area receiving
0.01" of rain, with only a 10% probability of accumulating
0.05".

Although temperatures cool down a bit for the remainder of the next
week, readings will remain above seasonal averages through the
period. Highs will mainly be in the 40s (except a few 50s for
Tuesday) with lows in the 20s. A little better precipitation
chances will come for midweek as an upper level low over the
southern Rockies shifts into the Southern/Central Plains on
Tuesday into early Wednesday. Still seeing model differences in
the track of this system and its possible impact on our area,
though latest ensembles would indicate around a 40-50%
probability of our area receiving at least 0.05" - though
dropping to around 30-40% for 0.10". With the relatively mild
temperatures it looks like most of this precipitation would be
in the form of rain.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 455 AM CST Fri Feb 28 2025

VFR conditions expected through the TAF period. With strong
winds aloft, LLWS will occur at the TAF sites through 15Z.
Otherwise, increasing northwesterly winds through the morning,
gusting 30 to 40 kts in the afternoon and evening. Winds slowly
taper downward tonight.

&&

.FIRE WEATHER...
Issued at 350 AM CST Fri Feb 28 2025

Deep mixing behind a couple frontal boundaries will bring wind
gusts of 40 to 50 mph across the area during this afternoon and
evening. In addition, with temperatures into the 50s across much
of the area and drier air behind the frontal boundaries,
afternoon RH will drop to 30 to 35 percent through the western
James River Valley, the Missouri River Valley, and northwestern
Iowa. With deeper mixing, RH values could drop even lower than
this over that area. In spite of the fact that RH is expected to
be higher than 20-25 percent, with the aforementioned very
strong winds any fire starts could exhibit explosive growth. In
light of that, issued a Red Flag Warning for the above areas.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from 9 AM this morning to 6 PM CST this evening
     for SDZ038>040-050-052>071.
     Red Flag Warning from 10 AM this morning to 6 PM CST this
     evening for SDZ038-050-052-053-057>061-063>071.
MN...Wind Advisory from 9 AM this morning to 6 PM CST this evening
     for MNZ071-072-080-081-089-090-097-098.
IA...Wind Advisory from 9 AM this morning to 6 PM CST this evening
     for IAZ001>003-012>014-020>022-031-032.
     Red Flag Warning from 10 AM this morning to 6 PM CST this
     evening for IAZ001>003-012>014-020>022-031-032.
NE...Wind Advisory from 9 AM this morning to 6 PM CST this evening
     for NEZ013-014.
     Red Flag Warning from 10 AM this morning to 6 PM CST this
     evening for NEZ013-014.

&&

$$

DISCUSSION...JM
AVIATION...JM
FIRE WEATHER...JM