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

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FXUS63 KEAX 261120

National Weather Service Kansas City/Pleasant Hill MO
620 AM CDT Wed Jun 26 2019

Issued at 353 AM CDT WED JUN 26 2019

Nocturnal convective development has been interesting to see evolve
overnight. There have been a few different surprises that have
developed that were not handled well by any guidance to include the
CAM guidance. In just about every case the guidance seemed to
underestimate the convective initiating power of the LLJ, no matter
how weak it may seem. The two main areas being monitored now for how
they will evolve are over southeast and central Nebraska. The area
of development over southeast Nebraska formed up quickly and
unexpectedly, but does coincide with the leading edge of the 850mb
LLJ which was able to tap into a marginal area of MUCAPE. Over the
last hour it has started to develop a cold pool and start a
southerly track following the Corfidi vectors (34020kts). This would
likely take any outflow and associated convection into eastern Kansas
just to the west of our CWA. The second developing MCS over central
Nebraska is slightly more concerning as it is about to run into the
gradient of the MUCAPE with 2000-2500 J/kg to work with and plenty
of effective bulk shear. If this feature follows the forward
propagating Corfidi vectors, which is has so far, it would track
south east then southerly as it approaches NW Missouri. This would
time out around 8-10 AM CDT. There is also a weak mid level
shortwave trough that could help maintain this MCS as it tracks
towards are area. Most CAM guidance has this feature quickly
dissipate as it enters NW Missouri, but our confidence with these
solutions is rather low seeing how they have done tonight. It is
likely this line will weaken some as it moves into the area with
strong winds and heavy rainfall possible. The severe potential will
not be zero though and it will depend on how balanced the cold pool
and shear continue to be as it approaches. This feature will likely
not make it much past HWY 36 as the first MCS in eastern KS tonight
has developed a pocket of stability that will lie around St. Joseph
at the estimated time of arrival. Once this feature dissipates the
drier pattern for western Missouri will start as a mid to upper
level ridge starts to build into the region. This warming in the mid
level should cap any potential development west of I-35, but may not
for central Missouri. Building MLCAPE and remnant boundary
interaction may allow a few storms to form up over central Missouri
in the afternoon, but lack of any shear will keep these storms sub-
severe and short-lived. The ridging and associated WAA advection
will allow highs to reach into the upper 80s with heat indices into
the mid 90s.

As this ridge builds into the region so will the potential for
higher temperatures going into the end of the work week and into the
weekend. Each day the highs will likely climb a degree or two with
the warmest day being Saturday with highs in the lower to mid 90s.
Fortunately for the area the dewpoints do not rise along with the
temperatures so heat indices will stay in the upper 90s with some
areas getting into the lower 100s this weekend. With this being the
first longer duration of heat the area has experienced it could
cause more heat related illnesses than these temperatures typically
would in late June. Heat related messaging and awareness will need
to be started so that people can start preparing for the heat will
be will experiencing in the coming week.


.Aviation...(For the 12Z TAFS through 12Z Thursday Morning)
Issued at 616 AM CDT WED JUN 26 2019

Overall VFR conditions are expected throughout the period with
light variable winds becoming more southerly by mid morning. The
only potential threat to aviation is a complex of storms over
southeast Nebraska currently. Guidance has been struggling with
how this will evolve and based on radar and satellite it does
appear it will keep moving to the southeast into NW Missouri. It
will weaken and start to dissipate as it gets closer to the area,
but how much and how fast is where the uncertainty comes into
play. To show the potential timing of this feature VCSH was added
with a broken mid cloud deck. I doubt lighting will still be
ongoing by the time it gets here, but there is a slight
possibilityso it will need to be monitored as it approaches the
area so the forecast can be adjusted accordingly.




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