Area Forecast Discussion
Issued by NWS Des Moines, IA

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000
FXUS63 KDMX 272320
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
620 PM CDT Wed Mar 27 2024

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

.KEY MESSAGES...

- Warm Friday, but otherwise generally seasonal temperatures through the period

- Brief chances for showers and a few storms late Friday, with
  more appreciable precipitation possible this weekend or early
  next week

.DISCUSSION...
Issued at 259 PM CDT Wed Mar 27 2024

Our weather pattern will remain somewhat active through the
period with two windows of precipitation potential, the second
of which appears to be the most noteworthy. A relatively deep
long wave trough remains in place through the central CONUS this
afternoon with our lingering weather influences still
associated with broad cyclonic flow south of the Great Lakes
closed low. Although the forecast will remain dry, warm
advection will increase aloft through the MO Valley as the
upper trough departs spreading some mid cloudiness into the
state tonight and early Thursday. The associated short wave
ridging will reach the region early Friday with stronger warm
advection finally returning to Iowa later in the day. This will
boost temps well into the 60s central and south, and likely be
the warmest day through at least early next week.

A brief window of precipitation may develop later in the day and
evening however, mainly east. The persistent warm advection
coupled with minor short waves riding the fast quasi-zonal
Pacific flow will eventually provide sufficient lift and column
moistening for some showers and possibly a few storms through
the evening. A brief strong storm, most likely elevated with
hail, cannot be ruled out with 1000+ J/kg MUCAPEs per both the
NAM and GFS soundings with ~40kts of effective shear and
elongated hodographs.

The start of the weekend looks dry, but southwest flow aloft and
a maturing western CONUS trough will bring another prolonged
period of varied precipitation chances from Sunday through
Monday night. Confidence in details is low, such as surface
frontal placement and wave timing, however the general
progression appears to be weaker forcing setting the stage for
enhanced precip and convection with the last stronger
warm/theta-e advection surge ahead of the H85/H7 low around
Sunday night or Monday. The probability of measurable
precipitation is likely/60+% both Sunday night and Monday.

The majority of deterministic and ensemble solutions suggest
Iowa will just remain in the cool sector with the front no
farther north than far northern MO. However some elevated strong
to severe storms would be possible with models suggesting some
instability into southeast IA and stronger mid level flow aloft.
00Z GEFS based SLU/CIPS analogs and CSU AI/ML output both
increase severe probabilities somewhat into southeast sections,
most likely around Sunday night. Other AI/ML solutions also
suggest a slower, more aggressive warm sector into those same
areas and more surface based potential into Monday not being
ruled out. The magnitude of precipitation with this system
should be much less than last weekend, with NBM QMD 72hr
probabilities for 0.5" of precip ending Tue morning only 50+%
over the southeast half of the state. Northwest flow aloft
behind this system should return into the middle of next week
with a return to dry weather and more seasonally warm
temperatures.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 618 PM CDT Wed Mar 27 2024

VFR conditions prevail through the TAF period. Model guidance
develops scattered to broken status clouds and perhaps a few
sprinkles late tonight, mainly between 06z-10z. A chance still
exists that the cloud deck could drop into MVFR at times,
perhaps impacting KFOD and KALO. This scenario has been left out
of the latest TAF due to the low probability of occurrence, but
will be updated as needed.

&&

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

&&

$$

DISCUSSION...Small
AVIATION...Martin


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