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000
FXUS63 KDMX 110937
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
437 AM CDT Thu Apr 11 2024

.KEY MESSAGES...

- Showers and some thunderstorms expected today, especially in
  the north and east. Rainfall amounts generally under 0.10"
  possible.

- Fire weather concerns remain for today and tomorrow, but are
  limited by lower curing today and moisture content tomorrow.

- Very warm weather this weekend through Monday.

-Thunderstorm chances Monday afternoon into the overnight hours.
 Severe weather initially looks possible in southwest Iowa (15%
 risk).

&&

.DISCUSSION...
Issued at 434 AM CDT Thu Apr 11 2024

A boundary located in southeast Iowa continued to fight against dry
air overnight, producing light showers. Meanwhile, GOES water vapor
imagery illustrates a series of PV anomalies dropping down from the
Dakotas. The first of the two will bring rain to northern Iowa this
morning and later expand in eastern Iowa through the afternoon as it
phases with the upper level trough east of the state. As mentioned
in previous discussions, moisture associated with the main upper
level trough will have minimal, if any, contribution to rain today,
leaving us with the meager moisture content of the PV anomalies. A
noticeable change in this issuance is a higher presence of CAPE in
soundings in the afternoon hours. Have introduced thunderstorm
chances to reflect this possibility. Consequently, a more convective
nature to the showers has been reflected in the slightly higher QPF
amounts this afternoon. Storms that hold together could produced
localized rainfall amounts up to a tenth of an inch of rain.

The other component of today will be the winds. Not much change
compared to the previous forecast issuance. CAA and a tightening
pressure gradient will increase the winds through the afternoon
hours. Gusts will focus in the north and east overnight as the jet
aloft increases with the pressure gradient. Stronger CAA in this
region will preserve some mixing after sunset. Combine with
this layer subsidence and sporadic 35mph gusts are possible at
times, especially before midnight.

In regards to fire weather concerns, Thursday and Friday both
feature low RH values and elevated winds. A surge of dry air will
invade just behind the PV anomaly`s cloud deck and drop RH values
into the low 20s in the southwest. Curing in this region of the
state is starting to decrease as grass greens up, meaning the area
will be less vulnerable. Have elected to forego issuance any fire
weather headlines for today, but extreme caution while burning
should be taken due to the winds. Fire weather potential for Friday
will continue to be evaluated. Higher winds will be located
generally where rain will fall today and may inhibit fire weather
conditions.

Well advertised warm weather is still on track for this weekend and
will also linger into the start of next week. H850 temperatures
nearing 16C will advect over the southwest half of the state and
will push into the 80s. Southerly flow enhances on Monday as a
trough deepens over the Plains with temperatures reaching the mid
80s. Now to talk about the round of storms we could see next week.
The ensemble guidance mean negatively tilts this trough and
intensifies it as it arrives in the region. Ensemble guidance paints
a 50% prob of CAPE exceeding 1000J Monday afternoon across western
Iowa with a mean deep layer shear of 30kts. That`s enough of the
basic ingredients for severe weather, hence the slight risk in the
southwest. Timing and location discrepancies remain and will be
better refined in the coming days.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1146 PM CDT Wed Apr 10 2024

A boundary is moving across Iowa and will bring a switch to
northwest winds for all sites early. The wind will become gusty
late tonight into early Thursday then increase through mid day.
Some gusts in excess of 35 kt are possible. Cigs will lower into
Thursday also with a period of MVFR cigs possible though
confidence in duration is low. A few showers or even isolated
thunderstorms could occur Thursday. Conditions are expected to
start and improve late in the period.

&&

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

&&

$$

DISCUSSION...Jimenez
AVIATION...Donavon