915
FXUS63 KDMX 031141
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
641 AM CDT Thu Apr 3 2025

 ...Updated for the 12z Aviation Discussion...

.KEY MESSAGES...

- Brief break today into early Friday
 - Southern stream system brings more rain chances later
   Friday/Saturday
 - Return of pleasant and drier weather Sun through Tuesday
 - Milder by Wednesday with small chances for rain

&&

.DISCUSSION...
Issued at 307 AM CDT Thu Apr 3 2025

.Short Term /Today through Friday/...

Confidence: High

Few issues with the short term period.  This mornings exiting system
will keep some cloud cover over the north today as yet another
windshift/cool front drops into northern Iowa yet overnight.  Clouds
along and behind the colder air will keep highs there a bit chillier
than the remainder of the region. We still anticipate a southern
stream low to track up through the lower to mid Mississippi River
Valley Friday afternoon through early morning Saturday. Clouds from
that system will spread north later this afternoon from Missouri and
end up reaching our border early this evening. Overnight tonight the
area will become overcast, but remaining dry until stronger thetae
advection and lift begin to produce a shield of light rain due to
isentropic processes. Today at least, a dirty high will keep some of
us in a bit of sunshine and overall, despite some morning breezes,
the day will turn out fairly nice in the south. Highs this afternoon
will range from the upper 40s to near 50 north while central to
southern areas will see highs in the mid 50s. Tonight will be chilly
with overnight mins in the lower 30s in the far north while central
to southeast areas will drop to the mid to upper 30s. Friday will be
cloudy with highs similar to today. There will be a gradual increase
in light rain chances (20 to 30%) south in the morning, increasing
to 50 to 70% south in the afternoon south of I80 and 10 to 40% north
of Highway 20. With the clouds and rain shower potential, highs will
remain stalled in the lower 50s north to the mid 50s in the central
to south.

.Long Term /Friday Night through Wednesday/...

Confidence: High

The system to the south of Iowa will track northeast out of
Louisiana and pass northeast through the lower Ohio Valley by late
Saturday afternoon. Meanwhile, there is a trailing cool front from a
Canadian low near Hudson Bay that will track southeast out of the
Dakotas/Minnesota Friday night into Iowa. This will help to enhance
some of the precipitation over our area and also sweep the system
away by Saturday morning.  Overall, we will get mainly light
precipitation from these two processes and also get to enjoy a
rather cool, but pleasant Saturday and Sunday. Rainfall amounts from
the upcoming event will be much lighter than yesterdays. Though
there are differences between the EC/EPS and GFS/GEFs suites, the
lower of the two ensemble averages (EC) suggests less than a tenth
to 0.20 inches in the south for the 2 day period while the GEFs has
a farther north drift of the system with less than a tenth north to
up to a half inch in the far southeast. With the general northerly
bias in the GFS suite, the EC is preferred. Our modeled
precipitation forecast generally mirrors the lighter EC solution
with a slighter higher total of 0.30 in the southeast. A bubble of
cooler air will drop across the area Saturday, keeping highs in the
40s to lower 50s. It will be a bit breezy with north winds of 15 to
25 mph at times. Temperatures will moderate into Sunday, just ahead
of another stronger Canadian cold front. The system should remain
dry with only passing clouds Sunday night into Monday morning.
Colder Canadian high pressure will settle into the region Sunday
night into Monday. After highs in the lower to mid 50s Sunday, lows
Monday morning will be quite cool; reaching the lower 20s northwest
to the upper 20s/30 south. Monday will be breezy and chilly, with
afternoon readings in the lower 40s northeast to the upper 40s
south. Mins Monday night reach the lowest of the period with lower
to mid 20s regionwide. Though it will be one of the colder mornings
in quite some time, we will remain well above record lows set back
in 1997 and 1972 across central Iowa when the area experienced
single digits to teens/20. Tuesday into Wednesday we finally see the
pattern stretch back toward a more zonal flow at H500. Consequently,
heights/H850 temperatures will continue to recover as adiabatically
forced downslope air is brought east from the foothills of the High
Plains. After some 50s Tuesday, we will see highs in the lower to
mid 60s Wednesday with only small chances for precipitation Tuesday
night into Wednesday.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 640 AM CDT Thu Apr 3 2025

MVFR cigs will hang on over the north/central today with mainly
high clouds in the far south. NW winds will gust to the 20 to
24kt range through 18z; aft 18z slowly diminish with some
improvement in cigs by 20z. /rev

&&

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

&&

$$

DISCUSSION...REV
AVIATION...REV