113
FXUS63 KFSD 211952
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
152 PM CST Fri Feb 21 2025

.KEY MESSAGES...

- A rapid rise in temperatures is expected through the weekend,
  but the degree of warmth remains at least partially dependent
  on snow melt and potential for resultant fog development.
  Highs in the 50s will be possible Sunday through Tuesday with
  some 60s in central SD.

- Watch for refreeze of melted snow causing scattered slick
  spots through at least early Sunday, as nighttime
  temperatures fall back below freezing.

- Predominately dry conditions will persist through early next
  week. Low to moderate (30%-40%) chances for light rain remain
  on track for Tuesday night through Wednesday, with low (<20%)
  probability of light snow north of I-90 corridor.

&&

.DISCUSSION...
Issued at 151 PM CST Fri Feb 21 2025

Stronger southwesterly flow will weaken this evening and become
fairly light overnight into Saturday morning. This should allow for
some relatively cold temperatures on Saturday morning in the single
digits above zero. While fog is unlikely, some patchy low land
radiational fog will be possible.

Westerly flow aloft will remain persistent Saturday into Sunday which
will allow for milder temperatures. Melting snow pack will of course
initially absorb some of this potential warming, but areas with
only an inch or so will see this snow melting fairly quickly.
Latest satellite images indicate very little snowcover over
Beadle county with light amounts over the counties just south.
Far southern SD into parts of northwest IA also appear to have
some lesser amounts of snow on the ground. Overall, most
locations have less than 3 inches, so that should go pretty
quickly Saturday through Monday.

As a note, went the a blend of the 50th and 75th percentile for
highs Sunday into Tuesday with very mild temperatures aloft and
solid westerly flow which many times leads to a bit deeper mixing
and warmer temperatures than expected. If snow melts more quickly,
can probably lean a little warmer.

Sunday will likely be a solid melting day with westerly flow
allowing for a very mild day. Highs should climb into the 50s near
and west of the James River, with mainly 40s to the east.

Stronger westerly flow aloft will sag into the area on Monday which
should bring the potential for strongest winds, especially if most
of the snowpack is gone and deeper mixing occurs. Both the GFS and
Nam show about 40 knots or more around 850 mb, which we could mix
to. Highs Monday should be in the 60s near and west of the James
River and 50s to the east. The fast moving wave that moves by to the
north will bring some mid level clouds, but the chance for
precipitation Monday into Monday night remains very low, roughly 10-
20 percent chance for a hundredth across mostly southwest MN.

Flow turns a bit more northwesterly Wednesday into Friday which
should result in a bit cooler temperatures, but likely still nicely
above normal. There is some general agreement on colder air working
into the area the next weekend as northerly flow aloft strengthens.
Nothing like what we just had, but would likely drop temperatures
below normal for a few days.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1144 AM CST Fri Feb 21 2025

VFR conditions are expected through the TAF period, with just some
passing high clouds from time to time tonight into Saturday morning.
Some model guidance indicates the potential for patchy fog after
06Z, but with limited snowmelt expected through the rest of today,
fog looks unlikely and thus will not be included in any of our TAF
sites.

Southwesterly wind gusts will slowly wane through the mid-
afternoon hours, though 20-25 kt gusts will continue for mainly
southwest Minnesota into adjacent parts of northwest Iowa down
to KSLB through about 06Z. Otherwise, winds turn mainly light
and variable into early Saturday morning except for those
aforementioned areas of MN and IA where winds look to stay
sustained out of the southwest around 8-10 kts.

&&

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

&&

$$

DISCUSSION...08
AVIATION...Samet