380
FXUS63 KEAX 302333
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
633 PM CDT Thu May 30 2024

.KEY MESSAGES...

- Rain Showers Tonight; Isolated Thunderstorms Possible

- Rain Continues Friday and Saturday; Minor Flooding Possible

- Above Normal Temperatures By End of Next Week

&&

.DISCUSSION...
Issued at 313 PM CDT Thu May 30 2024

H5 ridge axis has been moving across the forecast area this
afternoon which provided a warm and dry start to the day. However
the first short-wave in a series of multiple waves over the next
couple of days has been producing shower and isolated thunderstorm
activity throughout Kansas and Oklahoma this morning and afternoon.
H5 height falls should start in our western counties in the next few
hours, developing new showers in eastern Kansas. An MCV over central
Oklahoma has stalled moisture transport into the lower Missouri
River Valley, which has slowed the eastward progress of the rainfall
this afternoon and has also slightly lowered QPF totals. However, a
longer period of insolation allowed for slightly better
destabilization of the boundary layer. Therefore, probabilities for
a few isolated thunderstorms are greater within widespread shower
activity later this evening. Our western forecast area is touched
the by the SWODY1 Marginal Risk given that a few CAM solutions
eventually erode most of the CINH after 00z this evening. However,
upper-level flow even with the passing vort max is not overly
strong, thus limiting deep layer shear and the ability for
convection to organize if it develops. Most favorable timing for
heaviest precipitation will between 01-03z west of Interstate 35
then expanding eastward into Central Missouri overnight.
Thunderstorm chances should drop off overnight as most of the
instability should diminish by then. However continued weak H5
height falls with increasing moisture transport should help to
promote more rain activity across the area.

Friday, first short-wave stalls near the Mississippi River Valley
while another vort max  breaks away from the main PV anomaly over
the Pacific Northwest. This second short-wave is currently progged
to be deeper and by Friday afternoon becomes a mid-level closed-low
system. Prior to becoming a closed low, stronger dCVA should promote
surface pressure falls across the Plains facilitating cyclogenesis
across the region. This will enhance lower-level meridional flow
across the lower Missouri River Valley and provide isentropic ascent
that will continue to support rain shower potential through most of
the afternoon on Friday. With persistent cloud cover starting the
day off, boundary layer destabilization will be hard to come by, and
CAPE values remain rather low (HREF mean under 500 J/kg). Therefore
a convective mode will not be dominant, though perhaps a few pockets
of instability could promote some isolated thunderstorm activity.
With weak mid-level flow and weak deep layer shear, any isolated
thunderstorms are not expected to present any kind of severe threat.
The main hazard concern will be attributed to flooding with
persistent rainfall. Synoptic scale ensemble probabilities currently
depict 40-50 percent chances for at least 1.00 inch of QPF for the
western two-thirds of our forecast area. This encompasses a 24 hour
accumulation total from Thursday evening (00z Friday) to Friday
evening (00z Saturday). Probability matched mean values from the 12z
HREF are in this same general vicinity, with a few pockets of 1.5 to
1.75 inches. Would think if an isolated thunderstorm is able to
develop that these higher end values depicted in the PMM HREF output
could be reached. But again, with the lack of destabilization would
will be difficult to achieve. At the current moment, hourly rainfall
rates from the HREF do not exceed more than 0.75 inches, which will
help to mitigate much of the flash flood threat across the area as
this distributes heavier rainfall over a longer period of time. Will
need to watch some urban areas and spots that more prone to flooding
if an isolated convective storm moves over. By the end of the day
Friday, standing water in some locations may become possible, as
well as rises on local creeks and streams. The WPC excessive
rainfall outlooks currently highlight this potential. Rainfall
activity may linger into the early morning hours of Saturday as the
system is progged to become vertically stacked. Continued rising
motion may promote some new development of shower activity. By
Saturday afternoon, most of the forcing should move into the Ohio
River Valley and give way to mid-level height rises across the
region, and bring a break from the precipitation later into the day
on Saturday.

Another short-wave trough and vort max moves through on Sunday with
ensemble probabilities in the ballpark of 50-60 percent chance for at
least 0.10 inches of QPF. The wet pattern continues through
Wednesday of next week, with probabilities for 0.10 inches over any
24 hour period above 60 percent for most of the forecast period with
several locations above 80 percent. Inner-quartile spreads of 10-12
degrees amongst NBM members highlights the likelihood of multiple
periods of precipitation and how that may affect afternoon peak
heating on any given day. At this time, there is no strong signal
for any severe weather, but will need to monitor as if there is any
period of destabilization the flow could support more organized
activity. Toward the end of the week, medium to long range
deterministic model guidance depicts a strong riding pattern across
the western two-thirds of the United States that will allow
temperatures to steadily climb upward, leading to above normal
temperatures. Most of this signal though is just outside of our 7
day forecast.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 632 PM CDT Thu May 30 2024

VFR cigs/vis are expected to prevail however showers and storms to
the west are expected to move over the terminals by 01Z.
Intermittent showers and storms are expected to last around 05Z and
then just transition to showers. Winds are expected to come
from the southeast and stay around 10 knots. There may be a
chance for some localized MVFR ceilings with showers, however
they were left out due to conditions not expected to be
widespread. Showers are expected to move out by tomorrow morning
with conditions remaining low VFR.

&&

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

&&

$$

DISCUSSION...Krull
AVIATION...Collier