396
FXUS63 KDMX 091950
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
250 PM CDT Sun Mar 9 2025

.KEY MESSAGES...

- Red Flag Warning Monday parts of central and southern Iowa.
- A few record highs possible Monday.
- Significant storm system late in the week.

&&

.DISCUSSION...
Issued at 243 PM CDT Sun Mar 9 2025

The afternoon satellite imagery still showing a relatively narrow
corridor of snow cover from Denison to Guthrie center and
north/northwest through Kossuth and Winnebago counties at the IA/MN
border. Temperatures over the the snow cover is in the low to mid
50s while readings have risen into the 60s over the south. The snow
cover should continue to melt excessively this afternoon but with
overnight low temperatures falling back into the low 30s, the
melting will slow quickly and there likely will be some lingering
snow cover/wet ground to begin the day Monday. That will be
important for a couple reasons discussed below.

A strong push of thermal advection will arrive tonight into Monday
as the thermal ridge moves into Iowa ahead of a short wave trough
that will pass through Monday night. A very dry air mass will remain
over Iowa on Monday therefore good mixing will occur to around 900
mb and should get super adiabatic lapse rates near the surface. That
should be enough to push temperatures into the 70s at many locations
outside the lingering snow cover/wet ground areas mentioned
above where readings will remain it the 60s. The record highs on
Monday are relatively low in the upper 60s to mid 70s as they
are the lowest record highs by several degrees going forward in
March so do expect a few records. The wind will be gusty at
times with gusts over 30 mph possible. Also lowered the
afternoon dew points due to mixing potential of drier air aloft
.

A couple closed upper lows moving across the southern CONUS
through mid week will keep the Gulf moisture stream turned off
thus the dry air mass will remain in place through at least
Thursday. There will by a dry boundary passage Monday night
resulting in a cooler Tuesday. A transition back to zonal then
southwest flow will commence Wednesday and Thursday along with
the return of warmer weather.

The much talked about weather story remains the large storm system
expected to impact Iowa Friday into Friday night. Again, difficult
to get into too many details regarding this system but will the main
concerns with this system for Iowa would be potential for severe
weather and high winds. For the severe weather potential, a lot
will depend on timing of the system arrival and the amount of
moisture return that is able to occur. Recall, moisture this
week is basically shut down until just prior to this systems
arrival. The GFS and its ensemble members is the most robust
severe weather wise but not the earlier arrival (Friday
afternoon) may be too fast as upper level systems tend to slow
down, but also this system does not close off until it is east
of the Rocky Mountains so perhaps the earlier arrival is
possible.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1221 PM CDT Sun Mar 9 2025

VFR conditions will continue through Monday. Breezy west to
southwest wind will occur this afternoon before diminishing
overnight. The wind will be breezy from the southwest by late
Monday morning.

&&

.FIRE WEATHER...
Issued at 243 PM CDT Sun Mar 9 2025

Afternoon dew points should mix down below
guidance that will result in very low relative humidity values.
Those values along with breezy to gusty southwest winds with gusts
over 30 mph possible, will lead to near to above Red Flag Warning
criteria. The potential for fast fire growth exists. Therefore,
a Red Flag Warning has been issued mainly along and south of
Interstate 80 excluding Audubon and Guthrie counties due to
remaining snow cover. Do expect that snow to be gone by Monday
afternoon and fuels to being to dry, so it is possible further
expansion of the warning is needed.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon to 8 PM CDT Monday for IAZ059>062-
070>075-081>086-092>097.

&&

$$

DISCUSSION...Donavon
AVIATION...Donavon
FIRE WEATHER...Donavon