375
FXUS63 KDMX 121922
AFDDMX

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

.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 /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1234 PM CDT Sun May 12 2024

VFR conditions will continue into the afternoon. By late
afternoon scattered showers and thunderstorms will develop
across the area. The widely scattered nature of the storms makes
it difficult to pin down a precise timing of impacts to TAF
sites, if at all. Have targeted highest probability timing with
VCTS. Later overnight storms will weaken and congeal into a more
widespread area of showers from central into southern Iowa.
This will last through Monday with ceilings dropping near 1 kft.

&&

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

&&

$$

DISCUSSION...Hagenhoff
AVIATION...Hagenhoff