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

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FXUS63 KEAX 300506

1206 AM CDT Sat Aug 30 2014

Issued at 401 PM CDT FRI AUG 29 2014

Out of the gate this afternoon...first round of convection continuing
to track east-northeast as initial shot of vorticity and pressure
advection associated with inbound upper wave slides east across the
region. Upstream behind this afternoon/s activity...skies have
cleared and weak destabilization has occurred with latest SPC
mesoanalysis suggesting anywhere between 1000-1500 J/Kg of MLCAPE
exists across eastern KS and western MO. Heading into the late
afternoon...main concern is for redeveloping convection as next piece
of shortwave energy and associated vorticity slides over the area. As
this occurs...long-lived frontal boundary which has been in place
across the central Plains in recent days should slowly slide across
the region which should also help with possible redevelopment. Fcst
models have been playing this card quite well with latest HRRR high-
res data supporting renewed convection across eastern KS this afternoon.
For now...have advertised chc pops pretty much across the western
2/3rds of the fcst area...before gradually spreading them east during
the early overnight period. In terms of severe threats...latest
mesoanalysis shows fairly weak shear aloft. This along with a DCAPE
min/trough across our region should largely prevent widespread
severe. That said though...a few strong downbursts cannot be ruled
out if convection actually does develop.

Main front to slide through the forecast area tonight as discussed
above. This should result in a gradual decrease in storm coverage
from west to east during the early morning hrs if storms do in fact
develop. Overnight lows tonight will largely reside in the middle to
upper 60s.

By all accounts...upcoming holiday weekend shaping up to be least early on that is as region will reside in a post
frontal airmass both Saturday and Sunday. Despite the fropa to no cooling seeing in the 850-mb temp field thus
expect high temps in the mid to upper 80s on Saturday...and
potentially into the lower to middle 90s on Sunday as warm air
advection increases ahead of next incoming wave/front.

Much more interesting weather by Sunday night/early Monday as well
advertised longwave trough continues to dig along the Front Range. As
this occurs...cyclogenesis expected across the northern Plains with
strengthening future then expected to quickly exit into the upper
Miss Vly/western Great Lakes region by early Monday. The end result
for our area will be a slowly progressing cold front which will begin
sliding south during this period...with increasing chances for rain
from Sunday night through the Tuesday time frame. Main issue seen
from this vantage point is that this feature will likely stall
somewhere across central Missouri as it begins to interact with stout
sfc ridging in place across the lwr Miss Vly and southern Plains. A
severe wx concern initially Sunday night may quickly morph into a
hydro concern as continued moisture advection resulting from a
strengthening low-level jet of 2-3 standard deviations above normal
ascends the stalled feature and cloud layer winds remain parallel to
the front. Will have to maintain vigilance with this feature as many
locations across our northwestern zones have received heavy rainfall
in recent days. If severe wx were to develop Sunday night...bulk
shear vectors orientation parallel to the incoming front will likely
support multicell type storm morphologies...with high winds winds
posing the biggest threat before concerns change over to possible
heavy rain. That said...better frontal convergence for forced ascent
will likely remain north of our fcst area which could ultimately
limit the severe threat for our region. In any event...both flooding
and possible severe pose a risk as seen this afternoon and will
maintain mention in the HWO product for now.

Beyond this...returning southerly flow will finally lift the front
north across the region with dry weather returning in its wake by
midweek. With zonal flow expected to dominate across the lower
48...temps through the conclusion of the period should remain near or
slightly above normal.


.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1206 AM CDT SAT AUG 30 2014

Thunderstorms continue to percolate around the Kansas City terminals
late tonight, but this activity is not expected to last much longer.
By the time the TAF is valid expectations are that the thunderstorms
activity will have moved to the east or dissipated. Therefore, only
issue in the TAF is the potential for MVFR to IFR fog as skies clear
in the wake of the storms. Winds this morning will be light and
variable which will likely result in at least some haze. Have kept IFR
conditions in for the KSTJ terminal. Otherwise, Light winds will
remain rather variable through the day Saturday, with speeds under `10
knots expected through the day.




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