046
FXUS63 KDMX 042343
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
543 PM CST Wed Dec 4 2024

 ...Updated for the 00z Aviation Discussion...

.KEY MESSAGES...

- Wind Advisory in effect until Midnight tonight. Sporadic 55
  mph+ winds possible in the north before sunset (confidence
  around 20% for any given point).

- Cold Thursday morning with subzero wind chills near statewide.
  Highs only near 20 degrees.

- Above average temperatures expected this weekend with highs
  topping out in the 50s Sunday.

&&

.DISCUSSION...
Issued at 255 PM CST Wed Dec 4 2024

Windy conditions have panned out about as expected so far this
afternoon with some 50+ mph wind gusts reported in northern Iowa. A
pocket of clear skies behind the main boundary has helped these
faster winds reach the surface thanks to more efficient mixing.
Further east, clouds have made comparable gust magnitudes a little
more sporadic. The potential for higher winds still exists this
afternoon as rapid height rises take place across the north.
Pair this with CAA, steep low level lapse rates, and further
enhancement from a PV anomaly, but also the negative factor in
the loss of diurnal heating before 5pm. At that point, expect
winds to remain gusty, but slow down after sunset, peaking
around 35 mph after the Wind Advisory expires at Midnight. Have
decided to hang on to just the Advisory this afternoon given the
confidence that winds have generally hit their peak for the day
already with only sparse readings reaching Warning criteria.

The other story in the near term is the snow showers present across
the north and northeast for the remainder of the day. The snow is
primarily convectively-driven, evidenced by the HCR seen on
satellite. Most of this activity will dissipate upon losing surface
heating. Until then, expect localized bursts of snow that may reduce
visibility in the wind. Little to no accumulation is expected.

Temperatures will bottom out in the single digits for much of the
area tonight and winds will make it feel much colder. Wind chills
cross the north will be in the negative teens. Northwest winds will
keep highs in the 20s. Southerly winds will return once the surface
high shifts eastward, boosting highs into the 50s by Sunday. A
series of waves move into the central US, but the main moisture at
this point looks to be displaced south and east of the area. The
certain change will be the temperatures which will return to
December norms.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 544 PM CST Wed Dec 4 2024

Strong, gusty winds from the northwest will ever so gradually
decrease overnight and moreso through the day on Thursday. A few
gusts to near 50 knots remain possible in the next few hours
with MCW recently recording 49 knots. Narrow cloud bands vary
with VFR to MVFR ceilings and have generally favored VFR at all
but MCW, but could see brief periods of MVFR ceilings at ALO
(>50% chance) and at FOD (<20%) this evening. Otherwise, VFR
conditions are expected to prevail.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until midnight CST tonight for IAZ004>007-
015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097.

&&

$$

DISCUSSION...Jimenez
AVIATION...Ansorge