233
FXUS63 KDMX 301927
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
227 PM CDT Thu May 30 2024

.KEY MESSAGES...

* Showers and thunder slide in from the west late this afternoon,
  tonight, and through Friday. Very low strong to severe threat.

* Additional/periodic shower/storm chances into next week, but model
  spread continues to make details hazy. Mid-week next week may be
  next opportunity for stronger storms.

* Warming temperatures by late weekend into next week. Highs
  into the mid 80s at times.

&&

.DISCUSSION...
Issued at 226 PM CDT Thu May 30 2024

Conditions early this afternoon remain largely pleasant across the
area with temperatures into the mid and upper 70s. It has been
notably breezier across western and central areas, gusting into the
mid to upper 20s mph at times out of the SE, with the tightening
surface pressure gradient. Cloud cover has been slow to move over
the area, with largely translucent high level cloud cover streaming
across at this time, but will gradually increase as showers/storms
continue to encroach from Nebraska. Many may be able to enjoy
another fairly pleasant evening before said precipitation chances
slide in.

Short-term guidance has continued to latch onto the general split
and fading of shower/storm activity as they enter and move across
the state. This is largely driven by the northern stream trough and
southern stream shortwaves being less in-phase and the core of their
forcing being centered north and south of the state respectively.
That also led to lingering and unusually high variance within
overnight (06z) CAM guidance through Friday. The 12z runs showed
more consistency, coming closer to extended run HRRR solutions, with
weakening convective activity entering western areas of the CWA
around/after 03z and struggling mightily to even reach I-35
overnight. By daytime tomorrow, the split forcing becomes more
apparent with southern and northern areas most likely to see
appreciable precipitation, including thunder as weak boundary slides
into northern/northwest Iowa. The risk for strong/severe remains
very low with sub-par shear profiles and thermodynamic profiles
tending to yield weak MUCAPE of only a couple/few hundred J/kg.
Initial storms this afternoon/evening may have a few stronger gusts
with dry profiles in place. Overall activity will continue to trend
downward Friday night and may be mid-day Saturday before exiting
eastern portions of the CWA.

Upper level flow pattern becomes more zonal across much of the CONUS
by the end of the weekend into next week, allowing multiple
shortwaves to potentially initiate periods of showers and non-severe
storms. With the subtle nature of the shortwaves, model depictions
continue to vary in strength, coverage, and timing. This continues
to result in broader PoPs than what will surely occur. The next
potential strong/severe threat window continues to look like mid-
week next week as a larger trough drops out of the PNW and southern
Canada. That would be the time frame to watch for more impactful
weather.

Temperatures remain slated to warm by late weekend into next week,
bringing highs back into the mid 80s, but confidence too is hampered
by the discrepancy shortwave handling.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1233 PM CDT Thu May 30 2024

Unusually high uncertainty remains with regards to precipitation
and thunder potential during this TAF period. Guidance remains
widely spread on evolution across the area, affecting all TAF
sites. With the broader trend of greater thunder chances
residing north and south of the area, have limited mentions of
VCTS to KFOD and entered VCSH at remaining sites. Prevailing
MVFR cloud cover will be most likely west during latter portions
of the period, but confidence not great enough to have
prevailing at KFOD or KDSM at this point.

&&

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

&&

$$

DISCUSSION...Curtis
AVIATION...Curtis