901
FXUS63 KEAX 280533
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1233 AM CDT Sun Apr 28 2024

.KEY MESSAGES...

- Thunderstorms with heavy rain will affect the area overnight.
  Flooding/flash flooding will be the main hazards.

- Heaviest rainfall looks to be south of I-70

- Additional thunderstorms are possible this afternoon. Coverage
  looks more scattered in nature. Threat of severe weather also
  looks lower.

&&

.MESOSCALE...
Issued at 1224 AM CDT Sun Apr 28 2024

A strong low-level jet has developed and has led to a northward
shift of the strongest thunderstorms. This should shift the axis
of the heaviest rainfall across the southern sections of the
forecast area, generally south of the I-70 corridor. The threat
of severe weather looks low through the remainder of the night
as we`ve expended much of the potential instability. But the
low-level jet is transporting abundant moisture northward so
it`s possible we`ll see another 1-3 inches of rainfall in the
heaviest axis in the southern forecast area. As a result,
flooding and flash flooding will be the main concerns going
through the overnight hours and into the morning hours.

&&

.DISCUSSION...
Issued at 243 AM CDT Sat Apr 27 2024

Today - Tonight: Satellite and radar imagery early this morning show
what is likely an outflow boundary draped from northeastern MO
southwestward over the KC area and then into eastern KS. It`s
possible this could be the cold front but there isn`t much of a
temperature/dew point difference across it. Regardless, models
have not initiated this boundary well and are too far north with
it. The boundary will stall close to where it is as of ~08Z.
The RAP 305K surface shows this reasonably well. There will be
enough forcing along this boundary that showers and storms
should increase in coverage across northern MO through the
morning hours. During the morning hours, when potential
instability is weakest, the threat of severe weather looks to be
low. Going into the afternoon and evening hours, as a very warm
and humid airmass builds south of the boundary, CAPE values
will increase substantially. Models vary on this as well but
HREF probabilities show a greater than 90% chance for 2000+ J/kg
of SBCAPE. There`s even a 20% chance for SBCAPE to be greater
than 3000 J/kg over eastern KS and western MO. Additionally, as
upper-level flow increases, deep-layer shear will increase so
we`ll be staring down the barrel of a potentially 3000+ J/kg
airmass with 40-50 kts of shear. If a storm can get going in the
open warm sector, it will very likely become severe with all
hazards possible. This still seems unlikely this far east and is
much more likely further west, closer to the dryline. The
region will also be in a favorable location of an
anticyclonically curved upper jet with strong diffluence noted
over the forecast area on streamline plots. In the lower-levels,
a strong low-level jet will increase in the evening with
intense moisture transport nosing right into eastern KS and
western MO. This all points to an increase in coverage/
intensity of convection this evening with rounds of very heavy
rainfall and flooding/ flash flooding likely into the overnight
hours.

Sunday - Sunday Night: Saturday night`s convection will bleed into
Sunday as the low-level jet shifts eastward through the day and the
diffluent upper flow persists. With convection ongoing at the start
of this period, and then continuing through the day, we`ll struggle
to rebuild the instability. CAPE values look to be at least half of
what we saw Saturday and likely even less, potentially less than
1000 J/kg. While deep-layer shear will remain impressive, the weaker
instability will limit the potential for severe weather.

Monday - Monday Night: This period looks to be dry as the main
trough that brought multiple rounds of severe weather to the region
exits to the east and a drier airmass moves into the area.

Mid to Late Next Week: Low-level flow returns to a southerly
trajectory Monday night into Tuesday. That will advect moisture back
into the area just in time for the next front to interact with
it Tuesday. The warmer and more humid airmass will lead to
moderate instability with potentially 2000+ J/kg of MLCAPE
Tuesday afternoon. With 30-40 kts of deep-layer shear, can`t
rule out additional chances for strong to severe storms.
Unsettled weather will likely continue through the end of the
week as the area remains in a humid airmass with multiple
shortwave troughs moving through the flow. This will be resolved
better (and this forecaster will have more time to look at it)
in the coming days.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1215 AM CDT Sun Apr 28 2024

Showers and storms will continue to impact the terminals across
eastern KS and western MO through the overnight hours. Radar
shows coverage has increased over eastern KS and will move
eastward over the next several hours. Showers and storms should
start to decrease in coverage after sunrise as the focus of low-
level jet shifts eastward. But additional scattered showers and
storms may develop tomorrow afternoon as the main front starts
to push through the area. It`s looking like storms should move
east of the terminals after 00Z.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Flood Watch through this afternoon for MOZ006>008-015>017-
     020>025-028>033-037>040-043>046-053-054.
KS...Flood Watch through this afternoon for KSZ025-057-060-102>105.

&&

$$

MESOSCALE...CDB
DISCUSSION...
AVIATION...CDB