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000
FXUS63 KDMX 151149
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
649 AM CDT Mon Apr 15 2024

 ...Updated for the 12z Aviation Discussion...

.KEY MESSAGES...

- Well above normal temperatures continue today with near-
  critical to critical fire weather conditions northwest where a
  Red Flag Warning was issued. Elevated fire weather elsewhere.

- Breezy to gusty winds expected this afternoon through Tuesday.
  30-40+ mph gusts may occur at times outside of storms.

- Multiple rounds of storms tonight through Tuesday with severe
  storms possible tonight and expected on Tuesday. Some severe
  storms could be significant Tuesday with all hazards possible.

- Rainfall amounts of 1-2+ inches tonight through Tuesday,
  locally higher amounts possible.

- Colder late week into weekend - frost/freeze potential for
  mainly the north half of the region.

&&

.DISCUSSION...
Issued at 400 AM CDT Mon Apr 15 2024

Today:

Early morning conditions feature mostly clear skies with
temperatures ranging from still in the low 60s to down in the upper
30s with light and variable winds. Today will be another warm day as
flow gradually shifts to be out of the southeast with winds
gradually increasing, especially west, later this morning into the
afternoon hours as the pressure gradient increases with the
approaching system. With dry conditions still in place, minimum
relative humidity values fall again to the 15-30% range by the
afternoon, the lowest values in the north to northwest. Areas
northwest will also be where wind gusts approach 30-35 mph by the
afternoon and a Red Flag Warning has been issued for the extreme
fire weather conditions expected. Outside of the Red Flag Warning,
fire weather conditions will still be elevated given the combination
of warm, dry, and increasingly breezy winds, especially north where
fuels remain more cured. Caution is certainly advised for anyone
with plans to burn. Temperatures today look to top out in the upper
70s to 80s.

Tonight through Tuesday:

The system bringing our multiple rounds of thunderstorms tonight
through Tuesday remains on track with early morning water vapor
imagery showing the system over the southwest U.S. approaching the
Four Corners Region. The upper low will cross through the central
Midwest today into tonight before lifting northeast and crossing
through the state Tuesday into Wednesday. There is pretty good
agreement amongst models that the developing surface low today
becomes stacked with the upper low on our doorstep early Tuesday
before crossing through the state as just mentioned into Wednesday.
Before this happens, moisture advection begins to increase gradually
later this afternoon into tonight with an open gulf. However, the
southeast flow will delay the onset and prevent us from immediately
tapping into the upper 50 to 60 dew points located less than half a
state away as of the 8Z April 15 surface analysis. That changes
tonight after 00Z, aided by the low level jet, when shower/storm
chances begin in the far southwest, gradually pushing northeast with
time through the overnight hours as the initial wave/push of
warm air advection moves in. For the bulk of the area, these
storm chances will be during the overnight hours. The best
potential for severe storms tonight will be in the west, where
the SPC Day 1 Slight Risk (Level 2 out of 5) is located. With
storms still looking elevated, large hail and locally heavy
rainfall remain the primary threats, but with winds in general
increasing this afternoon into Tuesday, some strong wind gusts
are possible given wind gusts may start to near 40+ mph outside
of the storms, especially central and north. Although a tornado
tonight cannot be completely ruled out, the overall tornado
threat in our area is low and any tornado that could form, if
one did, would be in southwest Iowa closer to the warm front,
with the better tornado threat west/southwest of the area where
surface-based convection is more likely to be realized.

With the warm, moist air remaining into Tuesday and Iowa located in
the warm sector of the system in proximity of both a warm front and
an approaching dry line Tuesday will bring an even larger threat for
severe weather. This warm front is expected to stall out over the
area during the overnight hours and will certainly be a focus for
new storm development as will the dry line as it approaches the area
into the afternoon. There are still a number of different ways
Tuesday could play out with mesoscale details that are still unknown
at this point playing a big role in convective evolution. Many 00Z
to 06Z CAMs have started kicking off new storms shortly after the
end of the initial Monday overnight wave with overall little break
in between. Ongoing convection/lingering clouds may delay the timing
of this second wave but models continue to point to numerous chances
for severe storms during the daytime to early evening Tuesday. All
hazards remain on the table with tornadoes, damaging wind gusts and
large hail all possible, and significant severe weather not out of
the question, as detailed in the SPC Day 2 Enhanced Risk (Level 3
out of 5). Details will continue to be monitored today, but winds of
60-70+ mph, large hail 2+ inch in diameter, and some tornadoes,
possibly strong, are all possible during the day Tuesday. Storms may
also occur in more than one wave with storms moving quickly (45-55+
mph) so the main take aways are to prepare now for severe weather,
have a plan to get warnings and seek shelter if needed, and don`t
let your guard down as storms may occur in more than one round
Tuesday!

Widespread rain amounts of 1-2" are expected with pockets of higher
2-3+" depending on how storms track. This may lead to some ponding
issues in localized areas, but overall these rain amounts are likely
welcome considering the ongoing drought.

Wednesday and Beyond:

As the system departs on Wednesday, flow will become out of the
northwest ushering in cooler air which will remain in place through
the rest of the week. Some rain showers and non-severe thunderstorms
will also continue on Wednesday before finally clearing out on
Wednesday night. Another system looks to move through on
Thursday with a dry forecast returning by the weekend. High
temperatures look to be in the 50s through the rest of the week
and weekend, but morning low temperatures drop to the 30s next
weekend introducing some frost/freeze concerns for any
susceptible plants.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 634 AM CDT Mon Apr 15 2024

VFR conditions ongoing and expected to continue through the
daytime hours today. Winds out of the southeast will increase
through the day becoming gusty tonight into Tuesday. Ceilings
will also gradually decrease tonight, mainly through the
overnight hours, as showers and storms move into and through the
area southwest to northeast. Have started with shower mentions
but storms, some strong to severe, are expected but confidence
in exact timing of impacts to the terminals is less certain, so
will continue to evaluate trends and add thunder mentions as
timing details are better known.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 11 AM this morning to 7 PM CDT this
evening for IAZ004-005-015-023-024-033-034-044-045.

&&

$$

DISCUSSION...KCM
AVIATION...KCM