700
FXUS63 KDMX 121734
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1234 PM CDT Sun May 12 2024

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

.KEY MESSAGES...

* Unsettled weather returns later today into Monday - showers/non-
  severe storms

* Cooler after today - highs fall back into upper 60s to mid 70s
  through much of next week

* Additional shower/thunder chances return Wed/Thur - severe
  chances remain low

&&

.DISCUSSION...
Issued at 332 AM CDT Sun May 12 2024

While the auroras were no where near as strong last night as they
were Friday night, skies did generally cooperate for those that did
stick it out for another glimpse.

As of early this morning, the next weather maker for the area could
be clearly seen on various satellite products, churning its way
across the eastern Rockies, about to come out onto the Colorado
Front Range. Ahead of this system, the nighttime microphysics
product, showed mid-upper level cloud cover building across much of
western into central Kansas and southern into central Nebraska. For
much of today, the most notable changes in conditions will be
southerly winds, increasing cloud cover, and temperatures a couple-
few degrees warmer than Saturday. Dew points will increase some, but
will not make a marked impact on "feel" outside. While the overall
boundary layer will remain quite dry, the increased moisture will
allow for scattered showers/thunder to develop by the mid-late
afternoon. CAM soundings depict deep mixing once again with inverted
V soundings and cloud bases around 5-6kft. Main concern, if any,
with showers/storms will be potential for some gusty winds as
precipitation falls into/through that substantially dry boundary
layer. Additional activity across northern Iowa into South Dakota
and Minnesota will be driven by the cool front sagging in from the
north. Activity overnight and into Monday will be tied more directly
with the approaching upper low, but is likely to struggle to produce
much substantial precipitation with little to no MUCAPE to work with
and at least initially dry air to work through. Expect southern
areas to see the most precipitation from Sunday PM through Monday
with the most persistent lift and moisture to work with, while
northern areas of Iowa may be dry by midnight tonight. Biggest
question marks through central Iowa and how far north precipitation
can linger after this afternoon/evening.

Briefly quiet Tuesday into Wednesday before next series of
shortwaves glide through the southern and northern streams. Story
generally remains the same as previous discussions, with synoptic
guidance and ensembles in broad agreement on increasing chances
Wednesday afternoon through Thursday. One notable change is the
weaker northern stream wave and by virtue precipitation chances.
Southern stream wave remains fairly robust and precipitation amounts
could mirror what is expected later today through Monday. Strong to
severe chances remain quite low with sub-par CAPE and wind fields
depicted.

After Thursday, Euro and GFS continue to diverge in their handling
of the late week into next weekend pattern with GFS lingering
precipitation chances into Friday before drying out and the Euro dry
Friday but brings a northern stream shortwave trough and
precipitation chances further south to start the weekend. As a
result, NBM PoPs/precipitation chances appear never ending from
Wednesday onward. Inevitably, there will be windows of dry
conditions, just unable to to pinpoint at this time.

Temperatures after today will be a handful of degrees cooler across
the state thanks to aforementioned precipitation opportunities,
cloud cover, and periods of cooler northerly/northwesterly winds.
Expect highs predominantly in the upper 60s to mid 70s and lows in
the 40s to 50s.

&&

.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...Curtis
AVIATION...Hagenhoff