084
FXUS63 KDMX 141952
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
252 PM CDT Sun Jul 14 2024

.KEY MESSAGES...

- Enhanced Severe Storm Risk Monday with potential of
  significant damaging wind gusts over 70 mph
- Heat Advisory in place to this Evening and Monday South
- Cooler and Mainly Dry Tuesday through Sunday

&&

.DISCUSSION...
Issued at 252 PM CDT Sun Jul 14 2024

.Short Term /Tonight through Monday Night/...

Confidence Short Term: Low to Medium

Several competing factors in the short term forecast again this
period with regard to precip chances.  Heat remains the constant for
now, though debris clouds from leftover convection will modulate
highs a bit again today in some areas. Weak synoptic surface
features remain over the region. Aloft at H700, the leading edge of
the cap of 10C was over eastern Iowa at 12z. This did allow the two
MCS to increase in strength around sunrise as they reached the
eastern extent of the H700 cap. The approaching wave/MCS from South
Dakota has now entered the region of warmer air aloft and
correspondingly diminished over northern Iowa as anticipated. By
this afternoon, some increase in storm coverage is expected as the
H700 wave over the Northern Plains tracks east into Iowa this
evening and crosses the state overnight.  The synoptic models
(EC/GFS) are holding the H700 cap over Iowa through the overnight.
CAMS, particularly the HRRR and ARW cores are showing some weakness
in the cap again over eastern Iowa by 21-23z this afternoon. Though
no solution is heavily favored over the other, we will keep some
thunder chances this afternoon over the northeast along the US20 to
US30 corridors. Tonight the main areas of convection should hold
north of Iowa until late in the period when some storms may cross
into northern Iowa prior to sunrise as a stronger MCS moves through
southern Minnesota and Wisconsin. Lows tonight will fall to the
upper 60s to lower 70s in the north while the central to south will
remain in the mid 70s. Tomorrow lingering debris clouds north and
the sagging surface boundary will hold temperatures in the 80s north
while the south again will be in the 90s with heat indices in the
100s.  Tomorrow will be similar to today with regard to timing out
convection. We will still be battling the H700 cap for a portion of
the day into the afternoon hours. The main difference tomorrow is
the added surface moisture convergence along the boundary moving
through the region, plus increasing shear during the day and
afternoon. CAMS are now showing some earlier initiation with late
morning into early/mid afternoon firing of convection along the
sagging boundary into central Iowa. Upper level wind fields are
looking more favorable for a potential severe bowing system
with more significant damaging thunderstorm winds into the
afternoon hours. Still a fair amount of uncertainty with
initiation and placement, but a corridor between US20/I80 and
around or slightly east of I35 is more favored at this time. SPC
is upgrading SWODY2 to enhanced over central to eastern Iowa
with this potential in mind. Will need to monitor trends
overnight into early Monday morning with regard to outflow,
approaching upper level system and model convective trends.
After the main area of early afternoon convection exits the
region, we will still see trailing convection along the boundary in
the evening into overnight hours south as the front sags into
northern Missouri. With upper level return flow over the boundary,
more storms will be possible through Tuesday 12z in this area.
Lows Monday night will fall to the lower 60s north to the lower
70s in the south.

.Long Term /Tuesday through Sunday/...

Confidence: Medium to High

After tomorrow`s potential significant convection, we will get a
welcomed break from storms, heat and humidity through the end of the
period.  Still looking on track for highs to cool to the 70s to
lower 80s with lows in the 50s to lower 60s for much of next week.
There is some uncertainty late in the period with regard to return
moisture, but some showers may advance back into western section
around next Sunday.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1259 PM CDT Sun Jul 14 2024

MCV and lower MVFR cigs over northern areas this afternoon may
still spark some convection between 21 to 00z. Otherwise, next
up will be another MCS spreading southeast from the Dakotas into
southeast MN by 12z. This should impact MCW and possibly ALO
with scattered showers/storms prior to 14z. Tomorrow, though
uncertain, may see a strong convective bowing system somewhere
between I80 and US20 sometime late morning and maturing aft 18z.
Please monitor later forecasts/SPC updates for additional
information.  /rev

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM CDT this evening for IAZ004-015-023-
024-033>035-044>048-057>062-070>075-081>086-092>097.
Heat Advisory from 1 PM to 8 PM CDT Monday for IAZ057>062-
070>075-081>086-092>097.

&&

$$

DISCUSSION...REV
AVIATION...REV