Area Forecast Discussion
Issued by NWS Des Moines, IA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

000
FXUS63 KDMX 120455
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1155 PM CDT Mon Mar 11 2024

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

.KEY MESSAGES...

- Very high fire weather today through the remainder of the
  afternoon.

- A few strong elevated storms with hail potential possible
  Tuesday night.

- Additional strong storms possible Wednesday night and again
  Thursday afternoon and evening.

&&

.DISCUSSION...
Issued at 309 PM CDT Mon Mar 11 2024

Another mostly sunny, breezy and warm day across Iowa today with
temperatures warming into the 70s. It is also another elevated fire
danger day with the dry fuels along with relative humidity values
dropping into the upper teens and 20s along with the breezy
conditions. Satellite has been detecting several fires over the
state including Ringgold, Marion and Emmet counties. The primary
feature of interest today is the short wave currently over Utah and
Idaho, which will be over southern Iowa and Missouri by late in the
day Tuesday. The initial impact of the short wave will be increasing
high level cloudiness. There is already cirrus developing on the lee
side of the Colorado and Wyoming Rockies as moisture lifts over the
mountain range. The main forecast challenge with the cirrus for
Tuesday is the impact on temperatures pending how opaque the clouds
are and the subsequent efficiency at filtering sunshine. Still highs
should be in the 60s to low 70s. The low level jet will increase
ahead of the short wave Tuesday evening with speed convergence and
forcing focused into south central and southeast Iowa. This will
bring convective instability to those portions of the state with
MUCAPES over 1000 J/kg possible and mid-level lapse rates
approaching 8 C/km leading to good potential for updraft
acceleration. This all leads to the potential for a few strong
storms capable of producing large hail.

Another robust upper level short wave will begin to dive south from
British Columbia and into Idaho Tuesday night before dropping further
south into the far southwest CONUS Wednesday night. This will lead
to southwesterly flow to develop over Iowa as this occurs and also
will lead to surface cyclogenesis over southwest Kansas. A warm
front extending from the low pressure will race north during the day
Wednesday and is projected to be near the Iowa/Missouri border by
late afternoon. Similar to Tuesday night by on a larger scale, The
low level jet will increase again overnight with waves of theta-e
advection lifting into Iowa. Mid-level lapse rates will still be
good at 7 to 7.5 C/km along with MUCAPE potential in the 500-1000
J/kg range. Therefore again the potential will be there again for a
few strong storms capable of large hail. That activity could
linger into Thursday morning over northern Iowa.

The surface low is expected to be moving somewhere over central to
south central Iowa by mid Thursday afternoon with the warm front
extending to the east. The current setup suggests that stratus is
likely ahead of the warm front but less certain about stratus
lingering in the warm sector. There will be an elevated mixed layer
that could hold the stratus below in the warm sector. Still there
should be some surfaced based storm development by mid to late
afternoon in vicinity of the warm front with mid-level cooling from
the approaching short wave. Should any storms develop, deep layer
shear profiles would suggest the potential for organized storms and
possibly a few supercells. Hodographs and low level winds suggest
the primary threat would be large hail but will continue to evaluate
the situation over the next few days. Note, current forecast high
temperatures for Thursday are only in the mid 60s south of the
warm front. Should sunshine occur, readings should exceed these
values.

A deformation band of precipitation is expected from parts of
southern Minnesota and into northern Iowa late Thursday afternoon
and into Thursday night. At this time, profiles appear to remain
warm enough for mostly rain but again will continue to monitor the
potential for wintry precipitation. Cooler but still above normal
temperatures follow for Friday and Saturday. A stronger cold front
arrives Saturday night and into Sunday and there is a good chance
this will drop temperatures below normal for several days from
Sunday and into early next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1155 PM CDT Mon Mar 11 2024

VFR conditions remain widespread for the duration of the
forecast with steady south to southwest surface winds overnight.
A surface front passes through Iowa on Tuesday with a variable
wind field across the state. Visibilities remain unrestricted
for the entire forecast.

&&

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

&&

$$

DISCUSSION...Donavon
AVIATION...Cogil


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.