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000
FXUS63 KDMX 201927
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
227 PM CDT Sat Apr 20 2024

.KEY MESSAGES...

- Pleasant through tomorrow - two more frosty freeze nights with
  frost the main issue tomorrow night and only northeast, if at
  all.
- Weak system arrives Monday; mainly frontal passage with light
  rain chances 60 to 70 percent after midnight.
- Larger wave and more impactful weather late week by
  Thursday/and into the weekend

&&

.DISCUSSION...
Issued at 224 PM CDT Sat Apr 20 2024

.Short Term /Tonight through Sunday Night/...

Confidence Short Term:  High

Decent push of cool, Canadian air moving through the region tonight
and across the northeast Sunday evening.  We have struggled to break
the cloud deck today which will cap the highs in the lower to mid
40s north and in the mid to upper 40s south. With the cellular
clouds expected to break up in the evening hours, we will likely
drop even more overnight to early Sunday morning. Freezing
conditions are again expected over the region with overnight mins in
the mid to upper 20s north/Nish Valley to the upper 20s to lower 30s
elsewhere. There may be a skiff of clouds passing over the region
tonight, clouds that are currently located along the MN Canadian
border at this time. Otherwise, we will begin to turn the corner
tomorrow as the High Plains ridge of high pressure slides east into
Iowa. Highs tomorrow will reach the upper 50s to lower 60s across
the region. Tomorrow night a combination of more westerly flow and
increasing cloud cover ahead of an approaching clipper system will
keep most of the area above freezing and only a portion of the
east/northeast where some frost is expected, but no freeze. Tomorrow
night mins dip to the lower 30s there with mid to upper 30s
elsewhere.

.Long Term /Monday through Saturday/...

Confidence: Medium to High

Monday will see a surge of milder air prior to the arrival of the
cool front/showers in the afternoon/evening/overnight hours. This
will help lift highs to the upper 60s/lower 70s with brisk southwest
winds during the day; bufr soundings suggest a few areas may see
winds approaching 40 to 45 mph at times during the mid to late
afternoon. We continue to carry some thunder late afternoon/evening
in the central to southeast, but soundings and much of the model
guidance is not leaning in that direction. Will evaluate again in
the next package or two. Monday night the front will pass southeast
of the region with a weaker push of cool air entering the picture.
There will be little to worry about through Wednesday night as high
pressure builds east and sets up shop over the Great Lakes.  Your
typical model differences arise by then, with the faster GFS already
bringing precipitation into the area by Wendesday night while the
Euro holds off at least until Thursday. Will likely need to trim
that back a bit in the coming days. Meanwhile, temperatures will be
pleasant Tuesday/Wednesday with H850 temperatures rising to the
lower single digits, bringing lower to mid 60s back to the area for
both days. A few areas far northeast may remain around 60 on
Wednesday.  As we move ahead to the end of the forecast from
Thursday through Saturday, a more pronounced and significant, well
advertised system, will begin to impact the region. By Thursday some
return moisture with limited instability will arrive as a lee side
trough strengthens H850 flow and moisture return. Showers and a few
thunderstorms will be possible during the day Thursday. Highs will
hold in the 60s due to the rain chances and cloud cover, as
southeast winds increase and become gusty in the afternoon hours.
Several pieces of H500 energy will help to amplify the already in
place, lower atmospheric features with a deepening Plains surface
low tracking east by Friday afternoon. There remains significant
differences between the EC/GFS. Each respective model has some
support from its ensemble mean, but the Euro is ejecting the lead
wave faster while the GEFs mean is a bit slower. Both models are
attempting to keep the region in southwest flow through the weekend
with a potential of multiple rounds of rain and stronger
storms/severe weather. Though differences remain regarding the exact
amount of warming and modulation of moisture/dry punch locations, it
appears that a period of warmer and wet weather is anticipated for
late in the week and into the weekend. Highs in the 60s/70s to even
near 80 will be favored with possible stronger storm time frames
of Friday evening/night and again around Sunday. More details
on timing, coverage and storm mode will be apparent over the
next 4 to 5 days.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1214 PM CDT Sat Apr 20 2024

Generally solid VFR OVC continues with a few breaks over the
northeast and far western areas of Iowa this afternoon. By late
afternoon, deck should become more cellular with a few more
breaks. Northwest winds gusting to near 30kts with mixing but
mainly northeast at KALO/MCW with lesser gusts through 00z
elsewhere. Aft 00z, back to CLR/VFR with light winds and less
mixing Sunday through 18z. /rev

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from midnight tonight to 8 AM CDT Sunday for
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097.

&&

$$

DISCUSSION...REV
AVIATION...REV