318
FXUS63 KDMX 282335
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
635 PM CDT Tue May 28 2024

 ...Updated for the 00z Aviation Discussion...

.KEY MESSAGES...

- Outstanding day on Wednesday with light winds and no
  precipitation.

- Confidence in widespread precipitation late Thursday through
  Friday night is declining and there is a slower trend.

&&

.DISCUSSION...
Issued at 249 PM CDT Tue May 28 2024

Another short wave is dropping southeast into northeast Iowa this
afternoon. Scattered showers and a few weak thunderstorms have
develop into southeast Minnesota and parts of northeast Iowa this
afternoon in response the system. Another area of precipitation was
just exiting far southern Iowa. No severe weather is
anticipated and this afternoon though some gusty winds and
perhaps very small hail could occur. The activity will shift out
of the area by late this afternoon as the system moves out of
the area and surface high pressure moves in from the west. The
area of high pressure will settle over the state tonight and
then move slowly east on Wednesday. Wednesday will be a nice day
with mostly sunny to partly cloudy skies with some cumulus
development. Light winds are also expected with mixed layer
winds generally 8 kts or less and only weak pressure gradient at
best. High temperatures will be in the low to mid 70s.

The area of high pressure will move little Wednesday night through
Thursday morning. The high will help keep the Gulf moisture blocked
to the south and southwest during this period. The upper ridge will
begin to advance east on Thursday as a strong system moves east
through Montana and the Dakotas and in turn will aid pushing the
high eastward. This will allow the Gulf moisture to return north
into the Nebraska and the central Dakotas by Thursday morning.
The area of high pressure should keep much of the forecast area
dry through the afternoon Thursday. Still maintaining some
chances west of Interstate 35 for the afternoon but expect later
trends that will hold off precipitation chances until Thursday
night to prevail. Weak mid-level lapse rates over Iowa and the
moisture transport and instability along the Missouri River and
westward all point to these later trends. Thursday night,
another high pressure moves east from Wyoming and Montana and
will congeal into high pressure ridging to the larger high to
the east. This will again shield move moisture transport to the
south. Therefore, confidence in precipitation from late Thursday
through Friday night is not the highest and some of the latest
deterministics are jumping on this drier trend for this period.
For Saturday night into early next week, the upper flow becomes
more zonal with a few short wave moving through later Sunday
into Monday but again confidence on widespread activity is still
not there let alone confidence in severe potential.
Temperatures will warm through the period with a return to
widespread 80s Saturday into early next week.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 635 PM CDT Tue May 28 2024

A few showers are near ALO at the start of the period, but look
not to impact the site remaining just east of the terminal so
have favored VCSH for the first two hours. Thereafter, a period
of dry weather is forecast with VFR conditions prevailing. FEW
to SCT cumulus development with bases above FL035 is expected
by late morning and early afternoon over eastern into central
Iowa before dissipating around sunset.

&&

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

&&

$$

DISCUSSION...Donavon
AVIATION...Ansorge