Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 151106
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
606 AM CDT Fri Mar 15 2024

.KEY MESSAGES...

- Cooler temperatures and breezy conditions are expected heading into
  the weekend, with highs at or below seasonal normals Sunday.

- Elevated to potentially critical fire weather conditions
  possible both today and Saturday. Sunday as well but a bit on
  the cold side.

- Maybe a bit of a shift in the pattern late next week which
  would bring increasing chances for precipitation. Too far out
  for details but something to watch.

&&

.DISCUSSION...
Issued at 334 AM CDT Fri Mar 15 2024

A fairly weak ridge of high pressure will slip southward through the
day as low pressure to the north brings an increase westerly
gradient to the area. The morning inversion is not excessively
strong, but should aid in slowing the diurnal mixing some this
morning. The increased surface pressure gradient also lags a bit
until mid to late afternoon and especially more into the evening, so
winds will not be overly strong like they sometimes can be with
deeper westerly flow and droughty conditions. A quick look through
model soundings shows that mixing down winds of 25 mph or greater
would take some overmixing as these winds are mainly above the
inversion, roughly 850mb or higher. So, with this in mind, afternoon
relative humidities do get fairly dry, but at this time most areas
will remain above 25 percent. Near the James Valley and west they
could dip closer to 20 percent, but for now the HRRR, RAP and SREF
min RH all keep the area just out of red flag conditions. Should get
close in a few spots.

The pressure gradient increase this evening before a shot of cooler
air settles south. This will keep overnight lows on the mild side
with most locations only falling into the mid to upper 30s. Cold
advection and strong low level winds will support a much windier day
Saturday with gusts of 35 to 40 mph likely. This will spur another
fire weather concern with critical conditions possible. Afternoon
humidities will likely fall to 25 to 35 percent.

Breezy conditions continue Saturday night with windy conditions
expected again on Sunday. Temperatures will be on the cold side with
highs in the 30s to lower 40s and wind chills in the teens at times.
While fire weather will be a potential concern again temperatures
are not as favorable.

Monday into Tuesday strong northerly flow aloft slowly shifts east
of the area which will allow warmer temperatures to build back in.
Highs Monday should be in the 40s in southwest MN to the mid 50s in
central SD. By Tuesday most locations will climb into the 50s.

Flat marginally agreed upon ridging builds into the area setting up
a fairly tight thermal gradient across the region. With this thermal
gradient in place any weak waves that move through could produce
precipitation. Too far out to really get a feel for placement and
type as the amount or lack of ridging will play a role in how cold
conditions are. For now daytime highs of roughly 45 to 55 will be
common both days.

Potential system of interest late next week as the northern stream
low pressure exits into eastern Canada and a relatively strong upper
level jet moves along the Canadian border which may put the area in
the right entrance region of the jet. This could tighten up and low
to mid level boundary and enhance lift nearby. Of concern more than
just lift is the thermal structure of the low levels is marginally
close to supporting snow, especially near and north of the area.
Overall, just trends to watch over the next several days.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 604 AM CDT Fri Mar 15 2024

MVFR ceilings will be possible through a good chunk of the
morning, gradually spreading across eastern SD into southwest
MN and parts of northwest IA. On the leading edge of this
stratus a brief 1-2 hour period of IFR conditions is likely. By
afternoon VFR conditions are expected. Westerly winds will
develop and increase with gusts of 20 to 25 mph likely this
afternoon, then overnight gusts could approach 30 to 35 mph at
times, with the strong winds continuing through the day Saturday
as well.

&&

.FIRE WEATHER...
Issued at 334 AM CDT Fri Mar 15 2024

Westerly winds will combine with mild temperatures, dry air and
dry fuels to create High to Very High fire danger across the
area today. These conditions will continue into Saturday with
stronger winds, but slightly cooler temperatures. Sunday
temperatures will dip below normal with highs from the upper
30s to lower 40s, but continued breezy. Temperatures warm back
to above normal Monday into mid week with a likely continuation
of High to Very High Fire Danger. There are some hints for
precipitation potential late next week so that will be
something to keep an eye on.

&&

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

&&

$$

DISCUSSION...08
AVIATION...08
FIRE WEATHER...08


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