Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

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FXUS63 KEAX 200609
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
109 AM CDT Sun May 20 2018

.Update...
Issued at 750 PM CDT SAT MAY 19 2018

We will continue to watch eastern Kansas and northern Missouri for
severe storms through late this evening, but currently severe
weather is not looking favorable in areas from Kansas City east into
central Missouri. The storms in central Missouri that are still near
severe limits are a bowing line that is moving east along what looks
like the an east-west boundary left behind from storm activity
earlier in the day. Once that activity moves to the east of our area
(expected by 8 PM) the only storms to watch will be the ones trying
to redevelop along an elevated convergence line extending from east
central Kansas northeast through north central Missouri; roughly
along I-35. Both operational and CAM models hint at the
redevelopment this evening as a weak low level jet tries to develop
across west central Missouri in advance of the shortwave trough,
which is still spinning over central Nebraska. This expected burst
in the low level jet is not expected to last long, so neither is the
redeveloping storms. More widespread storm activity may develop
early Sunday morning as it grows from the activity in north central
Oklahoma, but the severe threat by the early morning hours of Sunday
will be very minimal.

&&

.Discussion...
Issued at 236 PM CDT SAT MAY 19 2018

The main concern for the late afternoon and evening hours
continues to be with the potential for strong to damaging winds
and large hail across the local area, particularly for areas over
eastern Kansas and and western Missouri.

The complex forecast is beginning to come into resolution as
depicted via visible satellite trends with multiple features in
play. Widespread convection from this morning has worked to
stabilize the environment in the near-term, though a gradual
clearing has been noted across eastern Kansas and more recently,
western Missouri. Synoptically speaking, a cold front is stretched
across central Kansas with a stationary boundary draped from north
central Kansas to northwestern Missouri. An inverted trough axis is
also noted along an axis extending from the Texas Panhandle into
west central Missouri. A weak mid-level shortwave is positioned
over southwestern Nebraska as of the early afternoon.

As the frontal boundary slowly pushes eastward driven by the
overhead shortwave trough, the downstream trough axis will
continue to pull northeastward into the local area. While these
features should remain displaced overall, the merging of these
features with time will result in the potential for organized
convection late this afternoon into the evening hours. Expanding
CU fields are noted ahead of the frontal boundary, while ongoing
convection is noted along the trough axis to the southwest. The
initial area to monitor will be across northeast KS and northwest
MO as storms form near the cold front further west and advect
into the area. While there remains some uncertainty on the amount
of destabilization with which to work, steep mid-level lapse
rates and adequate shear profiles may support the development of
storms capable of producing large hail, strong winds, and perhaps
an isolated tornado through the late afternoon and early evening.
The second, perhaps more certain feature conducive to severe
potential, is the inverted trough axis to the southwest. Strong
850 hPa flow will continue to expand into eastern KS and western
MO this afternoon and evening. If the cold front is able to merge
with this feature, there is greater potential for organized
storms to develop after 5 to 6 PM, beginning near eastern KS and
western MO, including the Kansas City Metro. With that said,
strong flow near 700 hPa may effectively cap the environment,
especially with consideration to the slower surface warming trend
due to lingering morning storms. Thus, it is a conditional setup
as to the amount of severity within this activity. Should
organized convection form, there is the potential for large hail
and strong winds, mainly east of I-35 and south of the Missouri
River. Activity should quickly weaken to sub-severe thresholds
later this evening as storms advance into central Missouri.
Localized heavy rainfall and isolated flash flooding is also
possible, as PWAT values approach 1.5 to 1.75 inches.

Additional rain showers and thunderstorms will then redevelop late
tonight into Sunday morning as an embedded disturbance advects
overhead the LLJ, though no severe weather is expected heading into
Sunday morning. Off and on rain chances will continue across the
area through the afternoon before tapering off late Sunday evening
as the PVA anomaly continues to advect downstream. There is some
potential for isolated strong to severe storms across the eastern
CWA during peak heating Sunday afternoon, though activity should
not be as organized as compared to this evening.

More seasonable temperatures are expected in the wake of the cold
frontal passage Monday before a ridging pattern brings a return of
above seasonable temperatures through much of next week. Off and on
air mass type storm chances will also be present, which may
temporarily limit some of the afternoon heating trends.

&&

.Aviation...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 1244 AM CDT SUN MAY 20 2018

Boundary residing from KEMP to KIXD and continuing northeastward
into northeast Missouri should slowly work south with time.
Northerly winds to the north of this boundary will usher in
IFR/MVFR cigs into northern Missouri later after 08-10Z. South of
the boundary scattered showers and thunderstorms continue to move
northeastward out of southeast Kansas, thus, KIXD and KMKC may
have some VCTS. Hi-res models develop another round of scattered
showers and storms into eastern Kansas and western Missouri
between 09-12Z. Some light, patchy fog may develop south of the
boundary but ongoing convection should prevent dense fog from
developing.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&

$$

Update...Cutter
Discussion...Welsh
Aviation...Pietrycha



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