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000
FXUS63 KDMX 130436
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1136 PM CDT Fri Apr 12 2024

 ...Updated for the 06z Aviation Discussion...

.KEY MESSAGES...

- Warming into this weekend with breezy south winds on Saturday
  leading to near critical fire weather conditions in the
  north.

- Thunderstorm chances return Monday afternoon through Tuesday.
  Some strong to severe storms possible, but details to continue
  to be refined.

- Much cooler arrives with the departure of the system midweek.

&&

.DISCUSSION...
Issued at 253 PM CDT Fri Apr 12 2024

Plenty of sunshine this afternoon as a drier airmass has moved into
the state today.  Northwest winds have remained robust for much of
the day but begin to quickly subside this evening as surface ridging
approaches.  The overnight remains quiet with the ridging passing
overhead providing clear skies and light winds.  Strong warm
advection begins late tonight into Saturday with a rapidly
tightening pressure gradient as pressures fall across the Plains.
Winds from the south to southwest quickly increase into the
afternoon with temperatures recovering nicely as thermal ridging in
the Plains approaches the Missouri River Valley.  Highs topping out
in the upper 70s to lower 80s are expected, nearly 20 degrees above
normal but still below record highs for mid April.  Fire weather
concerns also increase by afternoon and is covered in the discussion
below.

A shortwave passes through the Midwest on Saturday night with an
associated cold front moving through Iowa overnight.  With little
available moisture, the passage will occur with no fanfare other
than winds becoming northwest and some cooler air dropping into
northern Iowa.  Plenty of sunshine is expected on Sunday with the
warm conditions persisting despite some cooling in the north.

The main concerns in this forecast outside of the fire weather
problem on Saturday come into focus for early next week. A large
western trof propagates east through the intermountain west on
Monday emerging into the central United States on Tuesday.  Moisture
begins surging northward on Monday arriving into the state by later
in the day.  Convection is expected in the vicinity of the warm
front by late in the day across central Iowa.  At this time, the
convection is likely to be elevated with the main concern coming
from large hail along with some localized heavy rainfall.  The flow
of warm moist air remains into Tuesday as the upper system
approaches western Iowa by afternoon.  Still a bit uncertain as to
the amount of instability that will be present by Tuesday afternoon
as plenty of convection appears to be ongoing through much of the
day.  This may limit the overall instability and is somewhat of wild
card.  In addition, the surface low is beginning to slowly fill
during the day which may begin to weaken overall wind fields.  There
is still plenty of time to determine the convective outlook for this
day as uncertainty remains somewhat high.  Otherwise, this may
provide some decent rainfall over much of the forecast area and
continue to help alleviate drought conditions. Cooler air arrives
later in the forecast on the backside of this system to end the work
week.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1136 PM CDT Fri Apr 12 2024

Confidence remains high in VFR conditions through the period at
all terminals. Winds are beginning to change around and will be
from a southerly direction by sunrise and increase late this
morning into this afternoon with gusts between 20 and 30 knots.
Low level wind shear may develop late in the period Saturday
evening and thus may need to introduce LLWS to OTM/DSM in
future updates.

&&

.FIRE WEATHER...
Issued at 253 PM CDT Fri Apr 12 2024

Winds strengthening into Saturday with strong south to
southwest flow by afternoon as pressure gradient tightens.
Dewpoints should begin rising through the morning but as mixing
deepens into the afternoon, it is likely that a limit on the
increase will be reached if not some lowering into the peak
heating of the afternoon. This is expected to drop relative
humidity values into the mid to upper 20s across the north and
northwest. Fuels remain mostly cured across northern Iowa and
the combination of the fuels and weather conditions will produce
near critical fire weather during the afternoon across the
north. Therefore, have issued a Fire Weather Watch for possible
Red Flag conditions in northern Iowa into Saturday afternoon.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Saturday afternoon through Saturday
evening for IAZ004>007-015>017-023-024.

&&

$$

DISCUSSION...Cogil
AVIATION...Ansorge
FIRE WEATHER...Cogil