FXUS63 KFSD 111741

Area Forecast Discussion
National Weather Service Sioux Falls SD
1141 AM CST Mon Dec 11 2023


- After a brief cool down on Tuesday, conditions will remain
  warmer than normal through the weekend.

- Mostly dry conditions are expected through the weekend.


Issued at 350 AM CST Mon Dec 11 2023

Today & Tonight:

Mild and mostly quiet conditions ahead! Taking a look at satellite
imagery, low-level stratus and areas of dense fog continue across
the area this morning mostly along the Buffalo Ridge and portion of
I-90 in southwestern MN. With a several sites reporting visibilities
less than a mile over the last few hours, a dense fog advisory has
been issued for most of southwestern MN (besides Rock county)
through 9 am CST. While making your morning commutes this morning,
remember to: 1. Keep your lights on, 2. Be prepared for rapid
changes in visibility, and 3. Give yourself some extra time to make
it to your destinations safely. Nonetheless, expect the fog to
persist through the mid-morning before gradually dissipating.

Looking aloft, warm air advection will begin to spread across the
mid-levels this afternoon ahead of an incoming shortwave. This along
with decent mixing should allow for slightly warmer temperatures
this afternoon as highs peak in the upper 30s to mid 40s. Otherwise,
expect cloud coverage to increase in response to the wave from
northwest to southeast as a cold front swings through the area this
evening bringing a strong shot of cold air advection (CAA) to the
region. This will likely cause a sharp drop in our temperatures as
we head into the overnight hours as lows drop into the low to upper
teens for the night. Lastly, light and variable winds throughout the
day will become more northwesterly this evening behind tonight's
cold front as the SPG tightens. Wind gusts between 15-25 mph will be
possible overnight with the winds gradually taper down by daybreak
Tuesday morning.

The Extended Forecast (Tuesday-Sunday):

Heading into the extended period, colder air continues to funnel
into the region behind Monday's recently departed cold front as
surface ridging moves into the region by Tuesday. As mentioned in
previous discussions, 850:925 mb temperatures will plummet below
freezing for the day. This along with light northwesterly surface
flow and mostly clear conditions will lead to a temporary cool down
temperature-wise on Tuesday with highs only expected to reach the
upper 20s to mid 30s across the area. Otherwise, mid-level
ridging moves overhead bringing a quick dose of warm air
advection aloft. This along with southerly surface flow should
be enough to kick start our trip back to more mild conditions on
Wednesday as 925 mb temps return to above freezing thresholds
(+1.0 to +3.5 degrees C).

With all this in mind, temperatures should rebound nicely as high
slightly increase into the upper 30s to low 40s across the area on
Wednesday. It's worth noting that medium-range guidance has start to
show a pool of moisture moving into our areas along and west of I-29
Wednesday night into Thursday ahead of a weak shortwave that's
traveling up the more pronounced long-wave in the four corners
states. While most guidance keeps us precipitation-free for the
period, model derived soundings show a decent amount of lower
level saturation in sites along the Missouri River throughout
the day on Thursday. As a result, this could lead to a few sites
seeing some embedded drizzle in the stratus. Nonetheless, with
subtle differences in guidance and soundings, confidence remains
very low in precipitation occurring at this time.

As we head into the latter parts of the week, our attention pivots
to the Rockies as a series of shortwaves move through the region
over the next several days. However, even though the waves will
bring multiple surface fronts through the region; most long-range
guidance continues to shows limited precipitation chances through
the weekend. Nonetheless, there could be some smaller precipitation
chances (10%-20%) on Friday night into saturday morning as a
clipper wave brings some weak lift to the region ahead of the
surface cold front. While confidence is a bit low at this time,
a few isolate flurries will be possible in northwestern IA.
Otherwise, the main story continues to be the mild conditions
into the weekend. With 850:925 mb temps continue to mostly stay
above freezing into the weekend, expect the milder temperatures
to continue through at least Monday with daily highs varying
from the low to upper 40s (and possibly low 50s) from Friday
through Monday with the warmest condition expected on Saturday.


Issued at 1138 AM CST Mon Dec 11 2023

VFR conditions are expected through the period. Light southwest
winds will turn west this afternoon. A weak cold front will
bring increased mid level clouds and will shift winds to
northwesterly late this afternoon and this evening. Gusts up to
20 kts may occur behind the front.

Winds will weaken Tuesday morning as sfc high pressure builds in
from the northwest.