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

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FXUS63 KEAX 301741

1241 PM CDT Tue Jun 30 2015

Issued at 402 AM CDT TUE JUN 30 2015

While one more day of nice dry weather is in store for eastern
Kansas and Missouri that will come to an end tonight as the
on-again-off-again rain chances develop and keep the threat of
storms persistent through the weekend as the amplified flow across
the Nation continues to leave the Central Plains under the influence
of a northwest flow.

In the most recent couple of days the flow has been rather quiet as we
find ourselves in between perturbations that would generate storms,
which has allowed temperatures to slowly warm. Today wont be much
different as mostly clear and sunny skies will help temperatures lift
well into the 80s and lower 90s. However, of interest for tonight is
a shortwave noted topping the ridge axis in Montana early this
morning. As this shortwave trough slides into the northwest flow
later today the focused nose of the nocturnal low level jet will
develop, and with a relatively open Gulf to our south, moisture
transport will likely beget storms across southeast Nebraska into
northwest Missouri and adjacent areas of eastern Kansas later

Storms tonight have a decent chance at bringing both torrential rain
and some severe weather. As the nocturnal jet gets going expect
isentropic lift to generate storms in eastern Nebraska and/or far
northwest Missouri late this evening, with the resulting storms
sliding southeast due to the prevailing flow. Low level jet looks to
be almost normal to the storm motion, which will allow the storms
to have unfettered access to moisture through much of the event; and
with precipitable water values climbing to around 2 inches by
Wednesday morning expect torrential, possibly flash flooding, rains.
Will let the day shift look at where to place a flash flood watch
based on the latest model runs, but expect that one will be needed
for much of the forecast area tonight. Otherwise, storms tonight
might be able to pack hail and wind conditions similar to the storms
that blew through Kansas City last Thursday night/Friday morning. As
the storms move into Missouri, 0-3KM shear values are expected to be
in the 25 to 35 knot range with 0-6KM jumping into the 40 to 50 knot
range at times, also normal to the expected storm motion. However,
given the wind field, thoughts are that the storms will be liner in
nature, with a tendency to develop into discreet bow echos if the
cold pool associated with the rain can strengthen and organize
enough. Large hail might also be an issue, but think that damaging
winds and torrential rain --especially if storms can train across
the same areas-- will be the primary threats.

Stepping back to look at the general evolution, thoughts are storms
will bubble up in Nebraska and Missouri late tonight and move
southeast eventually into central Missouri. Better access to the
nocturnal jet across central MO will likely result in the
development of a convective complex which will then slowly shift
east through the day Wednesday. This may leave linger showers and
thunderstorms, especially across central Missouri. Models then key on
the redevelopment of another convective complex Wednesday night as
the nocturnal jet gets going. However, focus of the low level jet
for Wednesday should be farther south --southern MO-- so the only
threat for our section of Kansas and Missouri will likely be from
scattered showers that might develop overnight, but even those
chances are looking low at this time as southern Missouri is where
the focus will be.

Temperatures will cool over the next couple of days thanks to some
northerly winds and cooling rains. This should keep afternoon highs
restricted to the 80s through the coming holiday weekend.

Otherwise, expect a chance of storms to persist through the weekend
as some form of the northwest flow stays in place. As various time
periods grow near, models might allow us to dry out certain periods;
but in general, this far out in time, timing and other model
disagreements make it difficult to define periods that will be dry,
so have kept a combination of chance and slight chance POPs going
through the weekend into next work week.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1214 PM CDT TUE JUN 30 2015

VFR conditions are expected to continue through this afternoon.
Smoke/cirrus deck will remain across the region with scattered to broken
10-12kft deck moving in from the north through the day. Scattered
thunderstorms will develop later this afternoon to early evening
ahead of an approaching cold front. A larger convective system will
move down across the region by early tomorrow morning. While models
disagree on the exact placement and timing of the complex, consensus
is that the main complex will stay east of the terminals. For now
have kept mention of VCTS at all terminals until models come into
better agreement on timing of the complex.




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