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000
FXUS63 KOAX 091719
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1119 AM CST Sat Dec 9 2023

.KEY MESSAGES...
- There is a 40-70% chance for light snow this morning into
  early afternoon across portions of northeast Nebraska and
  west-central Iowa. Accumulation is expected to be around 1/2"
  or less, with some slick roads possible.

- If any snow/moisture remains on roads this evening,
  quickly falling temperatures will cause it to freeze and lead
  to lingering slick spots.

- Wind gusts of 30-45 mph today could lead to reduced visibility
  in falling snow. In addition, a Wind Advisory is in effect for
  portions of eastern Nebraska into west-central Iowa.

&&

.DISCUSSION...
Issued at 247 AM CST Sat Dec 9 2023

Early morning analysis showed an upper level trough setting up
over the central CONUS with a cutoff low spinning over western
MN. On the back side of the low, some weak shortwave energy was
pushing southeastward across the Dakotas and leading to some
light snow. In addition, a tightening pressure gradient was
leading to 30-40+ mph wind gusts across SD into northeast NE as
of 2 AM. The snow and wind were combining to bring visibility
down to near 1 mile or less in a few spots.

The snow will continue southeastward into portions of northeast
NE and west-central IA this morning. Latest HREF guidance
suggests a 70 to 90+ percent chance of accumulating
precipitation in much of northeast NE. While there will be some
dry air to contend with at first, a vast majority of model
soundings show a least a couple hours of saturation sufficient
for precip (snow) to occur. That said, the strongest forcing for
ascent looks to remain well to the northeast, near the
aforementioned cutoff low, so snow looks to taper off toward
early afternoon as the low continues to push eastward. As a
result, accumulations largely look to remain near or below 1/2
inch with latest guidance suggesting only spotty 10 percent
chances of locations seeing 1 inch. Still, should be enough to
lead to a few slick spots, and when combining the snow with
wind, travel may also be impacted by reduced visibility. In
addition, temperatures look to get up into the mid to upper 30s
this afternoon, which will melt at least some of the fallen
snow, but quickly plunging temperatures this evening may freeze
some of that moisture on roadways, leading to lingering slick
spots overnight (i.e. a flash freeze). It`ll really depend how
much snow/moisture remains on roadways this evening.

For Sunday, the main trough axis will push off to the east,
leaving us under northwest flow. Guidance is in decent agreement
of another weak shortwave sliding into the area Sunday
afternoon, and while CAMs do show some light reflectivity, model
soundings reveal much more dry air in place, so not expecting
anything more than increased cloud cover. Zonal upper level flow
then sets up for the first part of the week. Several pieces of
guidance still suggest some weak shortwave energy may move
through sometime Tuesday afternoon/night, potentially bringing
some light precip, but overall consensus keeps us dry at this
time. The next chance for precip looks to arrive toward Friday
as a cutoff low over the Desert Southwest looks to eject
eastward while a cold front surges in from the north. However,
there remains a lot of spread in guidance regarding track,
strength, and timing of these various features, so overall
precip forecast confidence remains low.

Otherwise, temperatures through the week look to largely to be
above average for this time of year. Most days will see highs in
the 40s and 50s, though Tuesday currently looks cooler, with
highs in the mid 30s to lower 40s. Overall, not too bad for
December.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1113 AM CST Sat Dec 9 2023

Light snow will continue to move through KOMA through the first
few hours of this TAF period. Otherwise, MVFR cigs will continue
to move east through the afternoon with all sites becoming VFR
by late afternoon. Gusty northwest winds up to 40kts will
begin to diminish after 00z, becoming less than 10kts into the
overnight.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Wind Advisory until 6 PM CST this evening for NEZ011-012-
     015>018-030>034-042>045-050>053-065.
IA...Wind Advisory until 6 PM CST this evening for IAZ043-055.

&&

$$

DISCUSSION...CA
AVIATION...Kern