Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 171932
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
232 PM CDT Sun Mar 17 2024

.KEY MESSAGES...

- Warming Tuesday then slightly cooler

- Late Week Northern Stream System

- Very active weather late in the weekend

&&

.DISCUSSION...
Issued at 232 PM CDT Sun Mar 17 2024

.Short Term /Tonight through Monday Night/...

Confidence Short Term:  High

Cold airmass with reinforcing shot of cold air has been moving over
Iowa today. A number of cold fronts have been associated with the
stronger upper level system over Quebec today. With the much colder
air, flurries have been moving into Iowa as well. Temperatures have
struggled to reach the mid to upper 20s north with lower to mid 30s
expected in the central to south this afternoon. Though much of the
cloud cover is diurnally driven, some lingering clouds are anticipated
through evening due to the frontal forcing moving through the region.
Once the front over central MN at 12z moves south of Iowa tonight,
skies should begin to see more broken cloud cover. Despite some
patchy clouds, the airmass will support relatively cold
overnight mins tonight. Lows will drop to the lower to mid teens
north while central to southern areas drop to the upper teens
to near 20. Monday will see a mixture of clouds and sun once
again, with mid to high level clouds continuing east. Western
areas will see more sun for the day. H850 temps will slowly warm
to single digits below zero by late day. Some increase in
clouds will again move over the north late day due to some
upstream warm air advection. Highs Monday will again be held
down, but recover a bit from today. Over the north, highs will
remain in the mid to upper 30s with southern sections reaching
the upper 30s to around 40. Winds will relax tonight with some
return northwest gusts Monday. Monday will be breezy once again
with northwest winds of 20 to 25 mph.


.Long Term /Tuesday through Sunday/...

Confidence: Medium

Active weather pattern being signaled by the medium range models;
especially for later in the period next weekend. With a rapid
return of warm air Monday night into early Tuesday, temperatures
will rise into the mid 50s to around 60. The latest runs show a
trough/front passing southeast of our area by 12z, with cold
air advection returning in the afternoon. This may keep highs
mainly in the 50s. With the stronger winds, lower RH and temps
in the upper 50s, there may be some increase for fire weather
concerns in the south. Following the passage of the Tuesday cold
front, a general slide toward colder weather is anticipated for
the remainder of the week. H850 temperatures slide back to 5 to
10 below aloft by Wednesday. This will push highs/lows back
down into Wednesday and Thursday. Highs will fall back to the
30s and 40s with lows in the 20s to 30s. We will be monitoring a
northern stream clipper like wave tracking east southeast from
the Rockies toward Colorado. With the stronger baroclinic zone
showing some overrunning precipitation from southern MN to
northern IA and east southeast; a band of snow is expected to
develop late Wednesday night into Thursday afternoon. At this
time the northern quarter appears to be most impacted by the
possibility of light snow accumulations with heavier amounts in
MN. The GEFs continues to support the more northerly solution as
does the EPS. This system is expected to exit on Friday with
another dose of more winter like air invading the Northern
Plains and Iowa by Friday into the weekend. As Arctic high
pressure builds southeast over Manitoba, the cold air will
settle into the region into Saturday. Confidence from late
Saturday into Sunday/Monday continues to be low. The one
constant is the available moisture expected to advance north
from the Gulf of Mexico. It looks like the Central Plains/Midwest
will be in a favorable fetch of moisture for 24 to 36 hours.
However, the expected evolution of the late weekend/early
following week storm remains in question. Though the ensemble
guidance still suggests that any heavier snow would fall farther
north into MN and/or far northern Iowa; the deterministic GFS
has continued to bring a nightmare snow scenario to the region;
somewhere from Missouri to southern MN the past several days.
Odds are continuing to lean against that here in our area,
though the GEFs 12z run shows a higher 50% chance of some
heavier snow making it into the north third compared to the 15%
yesterday. The EPS and deterministic Euro have been trending
slower, farther west and farther north with the system. Both
medium range models have been focusing 2 to 3+ inch precipitation
maxes somewhere near or over Iowa; welcomed news if it can soak
in, rather than running off too quickly. Better consensus on
the track and development of the late weekend storm should be
had in the next several days.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1228 PM CDT Sun Mar 17 2024

Stratus continues over the region with breezy winds. Mainly VFR
conditions with a few pockets of MVFR cigs. Flurries continue to
form through afternoon, though limited in coverage. Winds will
continue gusting to 30kts; especially north. Tonight the cigs
will thin somewhat with winds relaxing to near 12kts. Aft 12z
some return of mid level clouds, but main concern will be winds
mixing to 15 to 20kts prior to 18z. /rev

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...REV
DISCUSSION...REV
AVIATION...REV


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