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

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FXUS63 KEAX 041721

1221 PM CDT Sat Jul 4 2015

Issued at 356 AM CDT SAT JUL 4 2015

A broad area of surface high pressure has oozed into the area, with
its center roughly over far NW Missouri. This area of high pressure
has resulted in very little surface flow across the area, which when
coupled with clear skies and gradually cooling temperatures has
resulted in some hazy or even some patchy foggy conditions. This
surface ridge, in combination with the mid level ridging, which is
anticipated to form over the area should keep the area dry for
Independence Day festivities. No real lifting mechanisms along with
a pretty stout cap with lousy mid level lapse rates lend pretty high
confidence that the area will remain dry through the day on
Saturday. Perhaps the area to watch for any thunderstorm activity
would be more toward southern Missouri, where the southern edge of
the surface ridge will be located and some low level convergence
will take place. Latest NAM and GFS hint at a chance for some
showers, likely in the vicinity of the I-44 corridor, however that
would at least put the far southern zones in the EAX CWA at risk for
an isolated showers. Otherwise, dry for the area.

For Sunday, as the surface ridge shifts eastward, warm air advects
back into the forecast area. Rain chances will increase a bit for
Sunday, but not because there is any obvious trigger for
thunderstorm activity, rather because the atmosphere looks less
capped off with diurnal heating than Saturday, and some minor
isentropic lift will be present. But as just mentioned no areas of obvious
low level convergence and mid level flow dropping to near NIL
indicates that any storm activity will likely be left up to a
meso/microscale trigger. Temperatures for Sunday could be a bit
warmer, with the warmer/moister air moves in. Expect temperatures to
reach the upper 80s, or perhaps tickle the lower 90s. Dewpoints in
the upper 60s to lower 70s could contribute to some pretty warm and
muggy conditions, with heat indices in the lower to middle 90s.

The next obvious rain maker will come on Monday, as a broad trough
will clip the area, but also send a cold front through the very warm
and juicy atmosphere. Little change to the timing of the rain is
included in the forecast, so we are still anticipating the cold
front to enter the far NW corner of MO Monday afternoon, then diving
southward into KC Metro Monday evening and perhaps being out of the
area by Monday night. Severe weather, while unlikely at this point,
will be possible, as instability will likely be rather high. Deep
layer shear is still a bit desired, and this will likely be the main
limiting factor for severe weather, aside from the likely linear
storm mode. That being said, with the coverage of storms along the
front it`s possible that an organized cold pool will form and lead
to isolated bowing segments, causing some isolated to scattered
gusty winds. Otherwise, the other main severe hazards, namely hail
and tornadoes looks to be rather minimal. The main hazard with the
Monday cold frontal system will be flooding. While the area will
have seen a few days of dry weather leading up to this event it will
still not take much rain to exacerbate already swollen streams and
saturated soils. So, with low tolerance for heavy rain, the high
expected PWAT of around 2 to 2.25 inches will lead to efficient rain
making storms, which will likely result in some flooding across the
area. The scope and location of the worse flooding will depend on
storm tracks. Will continue to monitor the forecast for potential
flooding headlines, but at this point it looks likely that some
areas will see at least an inch or two of rain, with some areas
possibly seeing several inches of rain out of this system.

The middle to end of next week still looks a bit murky regarding
rain chances, as models don`t have a great handle on how far south
the boundary will reach before stalling and lifting back to the
north. The GFS still maintains that the boundary will lift north
fast enough to not give much break in the heavy rain through the
week. However the ECMWF still indicates a more progressive front,
stalling well south of the area, shunting the better rain south of
the forecast area, then lifting the boundary north by the late part
of the week. At any rate it looks like the best chance for rain
beyond the Monday system might be toward the end of next week, where
both GFS/EC have more agreement in rain occurring. The meantime
between Monday and Friday still needs some refinement to have any
confidence in either dry or wet scenario occurring.


.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1216 PM CDT SAT JUL 4 2015

VFR conditions will continue through the forecast period as high
pressure continues to move through the region. Will monitor the
potential for fog, which could slightly reduce visibilities early
Sunday morning. Otherwise, winds will veer while increasing after




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