556
FXUS63 KEAX 171041
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
541 AM CDT Fri May 17 2024

.KEY MESSAGES...

- Warm Temperatures This Weekend

- Light Precipitation Chances Possible Saturday & Sunday

- Pattern Becomes Active Monday through Mid-Week

&&

.DISCUSSION...
Issued at 257 AM CDT Fri May 17 2024

Notable jet streak along the Gulf Coast with another in the Pacific
Northwest has resulted in a split-flow regime keeping the bulk of
our forecast area removed from any substantial forcing. Some of the
upper-level moisture from the system close to the Gulf has been
transported into the area which has been providing cloud cover
during the overnight hours. H5 trough axis along the Gulf Coast will
continue to move eastward while short-wave trough over the Northern
Rockies is set to lift into Canada. This will result in H5 height
rises across the bulk of our forecast area this afternoon with
increasing AVA, resulting in subsidence that will aid in clearing
skies out and result in the beginning stages of surface anticyclone
development. Weak convergence is possible in our far southern and
southeastern counties this afternoon on the periphery of the
moisture axis, but most CAM guidance keeps the shower activity
closer to the Interstate 44 corridor. Synoptic scale ensemble suites
hold between a 10 to 20 percent chance for any measurable
precipitation from Bates County [MO] to Cooper County [MO], and
under 10 percent for a QPF threshold of 0.10 inches. Most CAMs
remain dry. Temperatures this afternoon will generally be in the
lower 80s as the flow, although weak, will be southwesterly. Inner-
quartile spread amongst NBM members and other ensemble suites is
narrow, between 80 and 82 for most points in our forecast area.
Weak pressure gradient will keep winds light for most of the
afternoon.

Saturday, system lifting into Canada drags a cold front across the
northern Plains and into portions of the Missouri River Valley.
However, a short-wave perturbation near the Four Corners Region
helps to amplify H5 height rises across the Lower Missouri Valley
that will eventually stall cold front progress and place it over the
Upper Midwest region, allowing stronger surface anticyclone across
Central Plains into the lower Missouri River Valley. This will keep
conditions dry for most of Saturday afternoon. Southwesterly flow
should increase in magnitude Saturday afternoon providing WAA and
increased boundary layer mixing resulting in another warm day across
the area. Temperatures in the mid to upper 80s expected for most
points in our area, with inner-quartile spread amongst various
ensemble only demonstrating about 3 degrees of spread, with values
between 84 and 87. The H5 ridge axis will cross through our CWA by
mid-evening on Saturday. Strong PV anomaly over the Pacific
Northwest will continue to provide general troughing over the
northwestern CONUS that results in a short-wave trough and
compact vort max ejecting across the Central CONUS late Saturday
into early Sunday. This will result in subtle height falls
throughout otherwise southwesterly mid-level flow that could
result in a few light showers in the northwestern third of our
CWA Saturday evening. GEFS and other ensemble suite
probabilities for measurable precipitation (at least 0.01
inches) continue to trend upward through Sunday evening, though
probabilities for exceeding 0.10 inches Sunday evening are below
10 percent. Rainfall for Sunday evening may also depend on how
far south the cold front from the northern system is able to
travel before stalling out somewhere in Iowa.

Monday, first short-wave trough and compact vort max moves across
the area and will increase precipitation chances across at least the
northwest two-thirds of the CWA and may even bring activity across
the entire area. Ensemble probabilities for at least 0.10 inches of
rain jump above 90 percent Monday and into portions of Tuesday. The
strong PV anomaly maintains persistent troughing over the Pacific
Northwest keeping mid-level southwesterly flow through much of next
week, with multiple short-wave troughs progged to eject across the
Central Plains into the lower Missouri River Valley. Expecting a few
of these short-waves to promote strong dCVA and notable surface
cyclogenesis that will bring multiple rounds of precipitation, with
probabilities well above 90 percent for measurable rainfall
multiple times through the middle of the next work week. With strong
WAA and theta-e advection, potential for strong to severe storms
will be present, along with a stronger shear associated with
stronger mid-level kinematic forcing. At this time, there is still
too much uncertainty to pinpoint any particular wave that could
bring activity, and therefore will not dive deeply into the
mesoscale environment. Ensemble probabilities for MLCAPE above 1000
J/kg remain very high into next week. The main question will be if
the main troughing over the Intermountain West lifts before the
better forcing reaches our area, leaving more robust weather over
the Central Plains, or if it will extend far enough east. WPC
Cluster Analysis indicates medium-high confidence in overall
troughing that will provide the mid-level southwesterly flow through
next week, but does vary in the intensity of the trough which
usually impacts how far it will dig and propagate before lifting. As
for QPF, there are some ensemble members hinting at the potential
some events to exceed 2" of rainfall, which with higher PWATS next
week could be achieved if the forcing is enough to create robust
thunderstorm activity. If we do not realize severe convection with
respect to wind and hail next week, we could still see hydro related
issues from efficient rainfall production.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 535 AM CDT Fri May 17 2024

Aside from some fog at KSTJ early this morning (which should
dissipate rapidly after 13z), should see VFR conditions at the
TAF sites for the next 24 hours. Skies will be mostly clear,
with light winds (under 10 kt) featuring a predominant southerly
direction.

&&

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

&&

$$

DISCUSSION...Krull
AVIATION...CMS