865
FXUS63 KFSD 081726
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1126 AM CST Fri Nov 8 2024

.KEY MESSAGES...

- Periods of rain spread northeast across the region late
  tonight into Saturday, exiting Sunday morning. Ensemble
  guidance continues to show high (70-90%) probability of 0.25"
  rainfall or greater for areas south of I-90 and into south
  central South Dakota. No snow is expected.

- Rain and clouds keep highs on Saturday in the 40s. Otherwise,
  anticipate high temperatures 5 to 10 (or more) degrees F above
  average today and most of next week.

&&

.DISCUSSION...
Issued at 328 AM CST Fri Nov 8 2024

CURRENTS THROUGH SUNDAY NIGHT: This morning, stratus is slowly
lifting north in northern NE, with high clouds into south central SD
ahead of our next system. Clouds have been struggling to get further
north than a Philip to Winner to O`Neill line thanks to dry air
aloft. Temperatures fall into the mid 20s to mid 30s this morning
for a near average start to the day.

Surface high pressure off to the northeast continues to move away
from the region as the aforementioned system (low pressure) moves in
from the southwest through at least the first half of the weekend.
Clouds increase through the day today as the low lifts north. With
clouds and weak WAA, expect highs in the 50s.

Slowed the progression of pops tonight into early Saturday morning,
as soundings and hi-res guidance show our area struggling to
saturate the mid and into the lower levels until near 09.06z
(midnight CST) in our far southwestern counties. Expect rain to
expand in coverage overnight as we saturate and as WAA increases
with the low pressure moving north. Ensemble guidance has been
consistent in showing a high (70%+) chance of more than 0.25" of
rainfall; however, the 08.00z runs have shifted the highest
probability more into south central SD than south of I-90 (slightly
further west than 07.12z runs). Probability of a quarter inch or
more decreases as you move into southwestern MN, only around a 40%
chance of exceedance through Sunday evening. Still anticipate most
of the precipitation to fall tonight into early Saturday, ahead of a
stout dry slot around 500 to 700 mb wrapping into the low. With the
loss of the mid level saturation, could end up with periods of
drizzle during the day Saturday and into Saturday night between
occasional showers. At this time, think winds will be too strong for
fog development, but can`t rule out some patchy fog Saturday night.

Clouds and rain keep our diurnal temperature range small. Lows
tonight fall into upper 30s to lower 40s - coldest in southwestern
MN and into the Hwy 14 corridor where clouds may be slower to
expand. Given temperatures should remain in the 40s when precip
starts, all rain is expected. Highs Saturday "warm" into the mid and
upper 40s with lows Saturday night in the upper 30s and lower 40s
once again.

As mentioned in the previous discussion, models are struggling with
the exit of rain chances as the stacked low pressure meanders
north/northeast Sunday. The GFS is the quickest of the models,
taking the center of the mid level low into eastern MN by 12z/6 AM
CST Sunday, with the other deterministic models lagging by 6 hours
or so. Thus, could see some lingering light rain in southwestern MN
after daybreak Sunday. Will keep an eye on trends, but kept things
dry for now. Skies clear Sunday with highs in the 50s.

NEXT WEEK: Models struggle with the details of the mid and upper
level flow pattern, especially timing, strength, and path of any
short waves and troughs through most of next week. Broadly, models
show ridging for the early and latter parts of the week, with a
trough digging in Wednesday to Thursday. Therefore, expect highs in
the 50s for much of the week, with cooler days in the middle. Lows
predominately in the 30s, although some cooler nights see
temperatures fall into the 20s. Based on the patten, could see
periods of light rain, but confidence in details due to model spread
is too low to stray from the NBM at this time.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1126 AM CST Fri Nov 8 2024

VFR conditions look to continue this afternoon and evening, as cloud
cover gradually builds overhead. Winds should remain light and
variable, with direction turning more east/southeasterly after
sunset. As alluded to in the previous discussion, expect showers to
develop along the MO River Valley between 09.00Z - 09.06Z. Will then
see coverage expand northeastward through the morning hours as an
upper level low edges closer to the region. As such, expect cigs and
vsbys to gradually lower, with MVFR levels likely across much of our
area Saturday morning. Otherwise, look for gusts to range between 15
to 25 MPH, with cigs approaching IFR levels by the end of the
period.

&&

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

&&

$$

DISCUSSION...SG
AVIATION...SST