000
FXUS63 KEAX 250716
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
216 AM CDT Thu Apr 25 2024

.KEY MESSAGES...

- Showers and storms increasing in coverage through the day
Thursday. Potential for severe weather is low but could see 1-2" of
rain through early Friday morning.

- Potential for strong to severe storms Friday afternoon/ evening.
All hazards look possible.

- Strong to severe storms possible again Saturday afternoon/
evening. Widespread moderate to heavy rain likely with potential for
another 1-3" of rainfall.

- Additional storms possible Sunday. Best chance for strong to
severe storms looks east of the KC area.

&&

.DISCUSSION...
Issued at 208 AM CDT Thu Apr 25 2024

Thursday - Thursday night: Isentropic ascent is leading to scattered
showers and a few thunderstorms early this morning across
eastern KS. This ascent is best noted on the 300K to 305K
surfaces. While coverage will initially be scattered, as
stronger moisture develops later this morning over eastern KS
and western MO, coverage of precipitation is expected to
increase and then build eastward with the strongest ascent and
moisture transport. The threat of anything severe looks low
today as the amount of instability will be very limited given
nearly moist adiabatic lapse rates. Of course that indicates the
potential for the first of several rounds of heavy rainfall.
Overnight, as the shortwave moves close, moisture transport
intensifies with another round of strong isentropic ascent. For
the first 24-hours of this prolonged rainfall/thunderstorm
event, there is nearly a 70-80% chance for over an inch in the
24-hour period ending 12Z Friday. These probabilities drop
considerably for most areas when looking at 2"+ potential. But
there are swaths of 20-40% probabilities of exceeding 2" of
rainfall through the KC metro. More widespread and greater
percentages exist across southern MO/ southeastern KS.

Friday - Friday night: The potential for severe weather will
increase Friday for several reasons. First, mid and upper level
moisture moves away and that allows for mid-level lapse rates
to steepen. At the same time, lower-level moisture increases and
that combination will lead to much greater instability.
Secondly, A strong negatively tilted shortwave will move into
eastern KS/northwestern MO during the afternoon. The timing of
the upper wave may be too fast leading to convection developing
earlier and out of sync with the greatest instability. However,
at the surface, a mid-60 degree dew point airmass will be
present with the surface front potentially just west of the
forecast area. The warm and humid low-level airmass coupled with
the cooler air aloft will lead to moderate instability. SREF
MLCAPE probabilities suggest CAPE values will be between 1000
J/KG and 2000 J/kg. This will occur within a strongly sheared
environment with high probabilities of 40+ kts of effective
shear. Models also show the orientation of this shear nearly 90
degrees to the north-south oriented boundary. This will enhance
the potential for discrete convection and given the parameters,
supercells with potential for large hail, damaging winds, and
tornadoes will all be possible.

Friday also looks very windy. With a deep surface low over central
NE, a tight pressure gradient will develop over the area.
Additionally, very strong cyclonic flow will develop ahead of the
low-level closed low. NAEFS shows 850mb flow that is 3-4 standard
deviations above normal with a return interval greater than 1 day in
a decade. This is very anomalous and will likely need a wind
advisory for most, if not all, of the forecast area.

Saturday - Saturday night: The main longwave trough over the
Intermountain West will remain in that region and this will
allow the system to essentially reload. The Pacific front/
modified dryline the will help initiate Friday`s convection
will occlude with the cold front across northern MO while the
southern extent of the boundary retreats westward. This allows
southerly flow to persist, pumping moisture into the area. In
fact, we may see dew points in the upper 60s, which is actually
close to our normal highs. This rich moisture will lead to
greater instability and a very broad warm sector. MLCAPE values
will likely be 2000 to 3000 J/kg. SREF probabilities of MLCAPE
greater 2000 J/kg are greater than 90% and still show 20-30%
probabilities of exceeding 3000 J/kg. This will still occur
within a strongly sheared environment. Model forecast soundings
show CIN nearly completely eroding. If that does occur,
supercells would be likely within the large warm sector. What
looks more likely though is that storms initiate closer to the
boundary in central KS and possibly in northeastern KS/NW MO.
This activity then grows upscale and affects the forecast area
as a strong to severe MCS during the late evening and overnight
hours. Given the ample moisture available (PWAT values that are
2-3 standard deviations above normal) this convection will
likely produce copious amounts of rain. While the area needs
rainfall, a couple inches in a night is excessive and may lead
to flooding concerns across the area.

Sunday: The main upper trough should finally shift eastward Sunday,
helping to push a cold front through the area. This front may lead
to additional storms but it doesn`t look like much recovery will
occur from the Saturday night/ early Sunday activity. Forecast
instability is significantly less but still strong enough that given
the still strong shear, may lead to severe storms, mainly east of
the KC area.

Monday - Thursday: There will be a brief reprieve in the
thunderstorm potential Monday and Tuesday. However models show
another front front sagging southward into the area. This may result
additional thunderstorm activity as the front stalls over the
region.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1224 AM CDT Thu Apr 25 2024

Conditions will start VFR through tomorrow morning. But
scattered showers and an occasional thunderstorm over eastern KS
will spread eastward tomorrow morning with conditions trending
to IFR by late in the morning or early afternoon. Think coverage
of storms is fairly low initially relative the overall coverage
of showers, but as more instability builds later in the
forecast, with the morning activity moving away, potential for
storms becomes better. So have initially gone with a SHRA and
then trended to VCTS later in the forecast. Winds will be steady
from the south with gusts around 30kts likely tomorrow
afternoon.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...None.
KS...None.

&&

$$

DISCUSSION...
AVIATION...CDB