914
FXUS63 KDMX 261753
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1253 PM CDT Sun May 26 2024

 ...Updated for the 18z Aviation Discussion...

.KEY MESSAGES...

- Showers and storms to continue through the morning with a
  waning severe weather threat. A few thunderstorms possible
  southwest this afternoon.

- Additional rain chances Monday and Tuesday. Some Monday storms
  could be strong in the east.

- Midweek dry period with seasonal temperatures with rain
  returning Thursday night. On and off rain through next
  weekend.

&&

.DISCUSSION...
Issued at 225 AM CDT Sun May 26 2024

Convection progressively coated the state overnight, overrunning the
surface warm front found in Missouri. 00z upper air analysis placed
the nocturnal jet into central Iowa, bringing plenty of upgliding
moisture into the state with mostly elevated thunderstorms with
sparse hail reports. Expect instability to wane southward through
the night as the MCS in Kansas takes over and sinks southeast, which
will largely diminish severe weather chances for us.

Otherwise, showers and storms will form from the jet-influenced
theta-e advection, the passing shortwave, and the left exit region
of the upper level jet. Southern Iowa can expect amounts between a
half inch to an inch of rain with higher amounts with thunderstorms.
The HREF probability matched mean QPF has a max along the H850 warm
front between the Highway 20 and Highway 30 corridors where
localized amounts nearing 2 inches will be possible. Rain and cloud
cover will focus more south through the day Sunday under the
influence of the deformation axis and pressure trough, finally
exiting after sunset. Enough instability will remain for these to
become thunderstorms, but northwesterly winds will inhibit the
amount of moisture available. CAA will keep highs in northern Iowa
near 70 for the day. Southern Iowa will be in the mid 70s.

Additional rain will be possible along passing waves on Monday and
Tuesday. CAMs build in an instability axis along the cold front
on Monday, bringing thunderstorm chances mostly east. Effective
shear at 40kts could organize some of the storms and produce
hail and gusty winds. Tuesday`s rain will be focused north. A
tightening pressure gradient and dry boundary layer will make
for a breezy Monday with 30 mph gusts possible in the west.
Upper level ridging will build in by midweek and spare the state
from rain until Thursday night when upper level troughing
influences the weather pattern again through next weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1253 PM CDT Sun May 26 2024

Areas of MVFR/IFR ceilings will linger northeast through the
afternoon with VFR conditions elsewhere. Although guidance
depicts otherwise, pattern recognition with relatively light
winds and persistent low afternoon temp/dewpoint spreads
suggests there is some fog potential overnight where the
stratus has lingered this afternoon. A token MVFR mention has
been introduced at northern TAF sites, but lower conditions are
certainly possible and may be needed as confidence increases.

&&

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

&&

$$

DISCUSSION...Jimenez
AVIATION...Small