Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 131958
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
258 PM CDT Wed Mar 13 2024

.KEY MESSAGES...

- Showers and storms (some strong to severe mainly southern Iowa)
tonight through Thursday morning

- Lingering showers and storms are expected through Thursday
afternoon, some which could be strong at times

- Cooler Friday through the weekend, especially Sunday into Monday

- Potential fire weather concerns return by the weekend

&&

.DISCUSSION...
Issued at 257 PM CDT Wed Mar 13 2024

Satellite imagery this afternoon shows scattered mid to upper level
clouds pushing across Iowa, with warm air advection keeping
temperatures on the warm side in the mid 60s to low 70s. At the
surface, winds are primarily light out of the southeast ahead of a
developing low pressure system currently over western
Kansas/Oklahoma. Into the evening hours, increasing moisture return
and theta-e advection with a northerly advancing warm front is
expected to bring developing showers and storms this evening in
Missouri lifting north into Iowa after 7-8pm tonight. Model guidance
generally depicts storms along the front mainly south of I-80
through early Thursday morning which will be aided by the
strengthening low level jet. A rather favorable environment for some
strong to severe storms continues to be depicted across the southern
portions of the state as CAPE values up to 1000-1500 J/kg and steep
lapse rates around 8 C/km are expected, paired with stronger shear
in the 40-50 knot range. Therefore, hail remains the main threat
with any storms, which look to be elevated, that are able to
maintain themselves through the overnight hours, with other hazards
including heavy downpours at times and gusty winds. Rainfall totals
overnight into Thursday morning across the south generally look to
fall in the half inch to inch range.

The southward trend in tracking of the low pressure system continues
over the latest model runs, which continues to decrease the overall
severe weather threat beyond Thursday morning over Iowa as the warm
sector is expected to remain south of Iowa into Missouri and
Illinois. However, lingering showers and storms are expected to
remain through much of the morning across southern into central Iowa
as system starts to pull away from the region, though non-severe
storms are expected. A deformation zone also sets up further across
north-central into central Iowa as forcing remains overhead, which
will keep chances (60-80%) for showers and storms in the region
through at least Thursday afternoon, though looking non-severe.
Rainfall totals have trended downward across the north with this
band of precipitation, with totals generally up to a half inch
possible.

While the longwave trough over the western CONUS becomes more or
less cut off from the main flow pattern, high pressure over the
Dakotas drops southeast across the Central Plains, which will bring
dry and quiet, though cooler weather as northeast flow becomes
rather widespread across the state. Highs are expected to reach
through the 50. Into the weekend, a trough and strengthening low
pressure per model guidance looks to remain further northeast
as it pivots across the Upper Midwest. Despite winds shifting
further northwest and becoming quite breezy, temperatures are
expected to warm nicely into the 50s north and in the low 60s
further south. Breezy winds with RH`s dropping into the 30s by
the afternoon look to bring an increasing concern for at least
elevated fire weather conditions. Will continue to closely
monitor this over the coming days. Breezy and drier conditions
remain into Sunday, though will be much cooler as colder air
from the aforementioned trough drops into the region. Highs are
expected to be several degrees cooler in the 40s. Into much of
early next week, a wide ridge over the western CONUS pushing
eastward looks to allow for quiet weather, with gradual warming
back into the 50s and even 60s into midweek.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1247 PM CDT Wed Mar 13 2024

VFR conditions are expected to remain through at least the late
afternoon, with clouds increasing ahead of an approaching warm
front. After 00z, showers and thunderstorms are expected to lift
north across the state, which is expected to result in lowering
ceilings through much of Thursday, as well as periods of reduced
visibilities with any heavier downpours that could occur. The
strongest storms are expected until around 12z Thursday, though
lingering showers and weaker storms may continue, especially
over the northern terminals into the afternoon. Winds will
generally remain on the lighter side, before becoming breezy
across northern into portions of central Iowa late in the TAF
period.

&&

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

&&

$$

DISCUSSION...Bury
AVIATION...Bury


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