504
FXUS63 KDMX 130437
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1137 PM CDT Sun May 12 2024

 ...Updated for the 06z Aviation Discussion...

.KEY MESSAGES...

- Scattered showers and thunderstorms this afternoon become
  more widespread overnight and on Monday.

- Additional storms chances later Wednesday into Thursday.

&&

.DISCUSSION...
Issued at 221 PM CDT Sun May 12 2024

It was a clear, quiet start to the day with clear skies and
pleasantly warm temperatures. This afternoon cloud cover has
increased as a system lifts into Iowa out of the central Plains. In
northern Iowa a band of cumulus has recently strengthened to storms
with some lightning detected while further to the southeast showers
out of Nebraska have edged into Iowa. These scattered showers and
thunderstorms will continue through the afternoon and into the
evening. And while instability exceeds 1000-1500 J/kg, shear is very
low which will prevent much organization or strengthening of storms.
Soundings remain pretty dry in the low levels so evaporative cooling
as rain falls could create some gusty winds with these storms, but
the overall severe threat remains low.

Showers and thunderstorms become more widespread overnight and will
continue across central and southern Iowa through much of the day on
Monday. As the upper level low completely cuts off it will slow
further, allowing showers to linger into southeast Iowa even into
Tuesday morning. Despite the slow storms motions, hydro problems are
not anticipated as precipitation remains light, generally 1-1.5",
and occurs over a prolonged period (vs similar amounts over a short
period). Cooler air filters in behind the system with highs in the
upper 60s to low 70s.

Tuesday into Wednesday will quiet again with drier conditions before
the next trough approaches. Recent runs have trends towards a less
phases approach with the northern/southern streams within the
trough. This is most pronounced in the 12z GFS where forcing is
separated enough the very little precipitation passes across Iowa.
The Euro has leaned this way but still retains a little more in the
way of QPF. Model continue to diverge later in the week and upcoming
weekend. While both the GFS/Euro indicate the potential for a
weekend system, timing an place are considerably different with
ramifications to both precipitation and temperatures.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1137 PM CDT Sun May 12 2024

Scattered showers/iso storms still on track this period. Little
overall change from previous forecast, with coverage of storm
most likely at ALO, DSM, and OTM. Cigs lower to MVFR/near IFR in
the south with periods of heavier showers aft 12z south. Over
the far north, some hint of approaching haze/FU due to forest
fires in Canada drifting into Iowa. May impact FOD and MCW. For
now have not included smoke in TAF, mainly due to uncertainty of
coverage. /rev

&&

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

&&

$$

DISCUSSION...Hagenhoff
AVIATION...REV