513
FXUS63 KDMX 151937
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
237 PM CDT Sun Sep 15 2024

.KEY MESSAGES...

- A few showers and isolated thunderstorms mainly south and east
  into early this evening.

- Mainly dry with above normal temperatures this week.

- Pattern change expect late this week and into next weekend.

&&

.DISCUSSION...
Issued at 236 PM CDT Sun Sep 15 2024

Another day and little change in the overall going forecast outside
of the typical delayed progress by the mid to late portion of the
week. Widespread cumulus development has occurred this afternoon as
temperatures in the low to mid 80s are near convective temperatures.
Proximity soundings show some weak capping is holding just above the
cumulus base level and is helping hold convective potential in
check. A fragment of energy from Francine remnants is lifting into
southeast Iowa this afternoon and evening, the overall kinematic
forcing is low but there is some convective bubbling going on over
that portion of the state. A few weak showers and thunderstorms will
remain possible across that area into  early this evening.

As mentioned, little has changed going forward. The pseudo Rex block
is undergoing a transition as a non-tropical low moves over the
Carolinas tonight and this low will eventually absorb the remnants
of Francine during the day Monday. This will lead to a further
deepening upper low that will move very slowly over the eastern
CONUS much of this week. Out west, another deepening upper low is
diving south over Oregon and northern California this afternoon.
That system will eventually eject northeast while another deep upper
low dives south along with west coast. Eventually the other system
will move east towards the end of the week. What does this all mean
for Iowa. For the most part, weak high pressure ridging will remain
intact across much of the area this week with above normal
temperatures and generally dry conditions. Will note that the
overall trends with this entire setup is a bit further west and
delayed meaning less precipitation chances mid-week.

The first system lifting northeast will bring some modest kinematic
forcing into far western Iowa but as noted, the shift a bit west
will diminish the areal coverage for precipitation chances into
central Iowa. This shift includes that Gulf moisture stream north
which is trending more into eastern Nebraska as opposed to western
Iowa. Much of central and eastern Iowa likely will remain dry
through the work week before the stronger system finally breaks the
pattern stalemate over Iowa. This should bring cooler Fall like
temperatures sometime next weekend and greater precipitation
chances.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1239 PM CDT Sun Sep 15 2024

Cumulus will continue to develop this afternoon with bases
around 4-5 kft expected. The cumulus will diminish overnight and
is likely to redevelop by late Monday morning. There remains a
non-zero chance for precipitation this afternoon and early
evening but potential remains low enough to no mention in the
forecast. South to southeast wind less than 12 kts is forecast.

&&

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

&&

$$

DISCUSSION...Donavon
AVIATION...Donavon