375
FXUS63 KEAX 181956
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
256 PM CDT Sat May 18 2024

.KEY MESSAGES...

- A few brief, isolated storms remain possible this evening.

- Active Pattern Sunday Night through Tuesday Night. Severe
  thunderstorms possible each day.

- High temperatures well into the 80s, around 10 degrees above
  normal, through Tuesday.

&&

.DISCUSSION...
Issued at 254 PM CDT Sat May 18 2024

19Z surface analysis reveals a modest surface trough stretched from
northern Iowa southwest through northwest Missouri into Kansas.
Behind the surface boundary, winds are gusting around 20 to 25 mph.
Visible satellite reveals some minor cu development in southwest
Iowa toward S. Joe and into northeast Kansas. The latest runs of the
HRRR have been less bullish with convective development along this
boundary as it advances toward the KC Metro and lower Missouri
Valley through the late afternoon and early evening. Forecast
soundings suggest a rather deep, 5 to 6kft, mixing layer and rather
weak wind profiles. Elevated instability will be sufficient, but
given the lack of supportive shear, organized updrafts are looking
difficult to come by. Regardless, will keep a low PoP mention going
through the evening, with the best window between 5 and 8 PM CDT. If
any one updraft can tap into the 1000 to 1500 J/Kg MLCAPE, an
isolated bout of severe hail or wind cannot be ruled out.

Positively tilted mid-level ridging will continue to strengthen
aloft across the region through Sunday morning. Overnight tonight, a
complex of thunderstorms is expected to develop with support from a
weak, open, H500 short wave trough traversing the larger flow
pattern along the northern Kansas and southern Nebraska. Through
sunrise, whatever remains of this activity will slide begin to slide
across northwestern Missouri and continue east through the day along
the MO/IA border. Most precipitation chances will exist along and
north of the US-36 corridor during the day. South of this activity,
modest return flow will persist ahead of a developing surface trough
over the western High Plains. Low to mid 60s surface dew points will
develop through the late afternoon. Convection is forecast to fire
in central Kansas by mid-afternoon near the triple point, with
convection growing upscale into a line or broken line of storms as
it moves into far eastern Kansas and western Missouri by late in the
evening. Some of this line may be strong to severe as it arrives
with damaging winds and hail and flash flooding the primary
concerns. Storms are expected to lower in intensity as they move
east through early Monday morning, with localized flooding a
lingering concern.

Monday, lingering showers and thunder may be ongoing across portions
of the area, likely ending through midday. At the same time, a long
wave trough will strengthen across the western CONUS, with another
surface trough developing over the western High Plains of CO/KS.
With better access to return flow and a more robust synoptic pattern
setting up to the west, recovery is expected in the wake of any
lingering precipitation in the morning. The good news for now is
that the better focus forcing looks to be in western Nebraska to
central Kansas, nearer the low center and focused along the warm
front, which the latest mid-range guidance has a bit farther north.
However, as the low level jet increases through the evening and the
region well within the warm sector, some organized convection is
expected and could result in some strong to severe updrafts.

Tuesday could be the more significant day for severe convection
across the region. It goes without saying, but any morning
precipitation would influence recovery, but with a more negative
tilt to the H500 shortwave trough ejecting across Nebraska in the
morning, strong WAA will persist, with ample recovery more than
likely ahead of the surface trough as it pushes east into the
afternoon. With steep mid-level lapse rates and surface dew points
nearing 70 F, MLCAPE between 1500 and 2500 is possible. However,
forecast soundings through the afternoon from the NAM suggest a
sizable capping inversion and given 700mb southwest flow, it`s
likely the inversion will hold off initiation until the arrival of
the surface front. Latest guidance has the line lighting up around
00Z from northwest Missouri southward toward the KC Metro. Timing of
the boundaries arrival will be key and a primary forecast focus as
step through the next two days. 0-6km shear orientation suggests
initial convection would be isolated, supercellular in nature, but
quickly developing into a line as the surface front surges south-
southeast through the evening. Damaging winds and hail and a tornado
or two cannot be ruled out with storms Tuesday evening/night.

Precipitation will clear out through Wednesday with surface ridging
briefly holding on before another trough arrives into Friday from
the west.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1203 PM CDT Sat May 18 2024

VFR conditions are forecast through much of the afternoon. A
frontal boundary will push into the region around 00Z. Widely
scattered thunderstorms are expected to develop along this
front and lasting for a few hours through sunset. Added a
window of VCTS to all sites to account for the possibility.
Prevailing TSRA will have to hold off until later as better
confidence in timing and coverage exists. Winds will shift to
the northwest, post frontal, and northeasterly through the early
morning hours. Toward the end of the period, winds will increase
and shift out of the southeast.

&&

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

&&

$$

DISCUSSION...Kurtz
AVIATION...Kurtz