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000
FXUS63 KEAX 172340
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
640 PM CDT Wed Apr 17 2024

.KEY MESSAGES...

- Thunderstorms Possible Late Tonight Early Thursday

- A Few Storms Late Tonight / Early Thursday May Be Severe

- Cooler Temperatures Remainder of Week

&&

.DISCUSSION...
Issued at 405 PM CDT Wed Apr 17 2024

Broad troughing over the Northern Rockies has been promoting dCVA
across much of the High Plains and Central Plains this afternoon,
allowing a surface cyclone to deepen across the OK/TX Panhandle
Region. This system has started to shift northeastward, and has
allowed lower level winds to shift from the southwest. Last night`s
cold front and subsidence behind it helped keep skies mostly clear
across the region, allowing temperatures to jump back into the upper
70s and lower 80s across the area. There has been increasing ascent
along the 305K isentrope but with little moisture to work with thus
far no clouds or stratiform rain have been able to develop. As of
this afternoon, dewpoints across the region are still only in the
upper 40s. However, the low-level flow shift in response to the
surface cyclone developing should help to bring in an airmass from
Oklahoma and other portions of the southern Plains where dewpoints
have been in the mid 60s. Once this moisture reaches our area,
precipitation chances will start to increase. Current synoptic scale
deterministic guidance has the trough lifting back into Canada with
strongest vorticity heading back northward, but continues to show a
signal a for few vort maxes to eject southeastward across the
Central Plains into the Lower Missouri River Valley. This will be
enough to provide subtle H5 height falls and should help to increase
mid-level flow and overall deep layer shear. As the cyclone
continues along with this area of subtle H5 height falls, the low-
level jet remains progged to strengthen, with some guidance
suggesting a magnitude as high as 45-50kts. Convergence along this
and the trailing cold front late this evening will provide and
opportunity for convection initiation. Since this morning, the HRRR
has be depicting a few clusters of storms developing in eastern
Kansas after 04z then moving northeast into our forecast area
between 05-08z. The system then stalls out for a few hours, but then
another short-wave from the north sinks further south sending
another vort max, which will push the system and cold front back
toward the southeast. By this point there will likely be sufficient
moisture transport into the lower Missouri River Valley sending
dewpoints in to the mid 50s, with lower 60s in our far southern
counties. Convergence once again increases and is expected to result
in more convection initiation. CAMs the past few cycles have been
pointing toward a line of cells developing along this forcing,
pushing from northwest Missouri across a large portion of the state
through the morning and early afternoon. Model soundings across the
warm sector show a moderately strong temperature inversion above the
boundary layer which will limit surface based parcels. However,
lapse rates between 850mb-600mb will be just a tad under 8.0 C/km,
cloud layer shear around 63 kts and effective-bulk wind difference
around 40 kts. MUCAPE values are currently progged between 750-1000
J/kg. With the low-level jet present, the shear and instability
should be supportive of organized updrafts resulting in stronger
thunderstorm activity. A few severe storms could also be possible.
The main threat with storms through Thursday morning would be hail
at least 1" in diameter. Current thinking is that tornado threat
will be extremely limited given that the lowest portion of the
curved hodograph will not be realized with inflow bases above 1km
for these storms. Typically with elevated convection damaging wind
is not a primary concern, but there have been a few CAMs pointing to
potential of gravity wave structure that could help wind gusts punch
through a statically stable boundary layer. This could produce winds
to around 60 MPH especially with stronger momentum around the 700mb
layer. However there is some uncertainty with this, therefore will
consider hail the primary concern with stronger storms Thursday
morning. Overall confidence in precipitation along the front is
fairly high, with most ensemble suites well over 90 percent for at
least 0.10 inches of rain across most of the forecast area. GEFS
probabilities for at least 0.50 inches are 50 to 60 percent for a
corridor between Hwy. 36 to just south of Interstate 70.

Cold front is progged to push through the area after 20z tomorrow,
with moisture around the backside helping to keep stratiform cloud
cover in place. Most of the accumulating precipitation should be
ending, though a few lingering showers may still be possible,
especially if the front stalls longer earlier Thursday morning. Once
the front moves through, expecting a few days of cooler temperatures
generally in the lower to mid 60s across the area. The synoptic
pattern will generally be zonal with minimal areas of vorticity
advection which should limit most of the precipitation chances.
Perhaps if there is subtle wobble southward from the H5 closed-low
over Canada a light shower could be squeezed out over the weekend.
However amongst NBM members and other ensemble suites, probabilities
for measurable rain through the weekend remains below 20 percent for
our counties and under 10 percent for a threshold of 0.10 inches.
Mid-level ridging over the Central Plains will help promote
subsidence and anticyclone development across our area through most
of the weekend. For next week, ridging over the western CONUS is
progged to amplify which should start to promote southwesterly flow
back across the Central CONUS and helping to bump temperatures back
up across the area. Inner-quartile spreads amongst NBM members for
temperatures through next week are a bit larger, which would
indicate there is some uncertainty with how a few of the short-waves
across Canada behave. It may be possible if one of those that sink
further south, the ridge does not amplify as much and keeps our
temperatures cooler. This may even be able to provide rain chances
across our northern counties.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 637 PM CDT Wed Apr 17 2024

Currently VFR conditions at all terminals with light and
variable winds. Scattered showers and thunderstorms may impact
the terminals in the 5z to 9z window this evening/early
overnight. These storms could pose a hail threat. Another
round of storms is likely in the 10z to 14z time frame, with
showers lingering behind the storms for a few hours before
precipitation finally clears east of the terminals by early
afternoon. IFR/MVFR CIGs are likely for much of tomorrow morning
and afternoon. Northerly winds should increase behind the front
tomorrow afternoon with gusts up to 25 knots.

&&

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

&&

$$

DISCUSSION...Krull
AVIATION...BMW