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

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000
FXUS63 KEAX 260528
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1228 AM CDT FRI AUG 26 2016

.Update...
Issued at 700 PM CDT THU AUG 25 2016

Have lowered rain chances for tonight, especially the evening hours.
While there is a slow moving frontal boundary lying just south of the
MO River there is very little low-level convergence along it to force
convection. The narrow band of convection over Lafayette county is
likely to dissipate an hour or so after sunset as it appears to be
mainly supported by the diurnal heat cycle.

The better forcing is much further south along an "effective"
boundary extending from northern OK into central MO. Both the very
short range and operational models are having a devil of a time
resolving the overall evolution of convection overnight. Current
thinking is to monitor the northern OK activity to see if the NAM`s
increasing warm air advection on the 310K surface can lift this
activity northward or reform it northward. Overall confidence is low
and if by late evening this activity is not materializing we will
reevaluate the Flash Flood Watch.

&&

.Short Term...(This Evening through Saturday Night)
Issued at 255 PM CDT THU AUG 25 2016

Relatively quiet thus far early this afternoon across the forecast
area but this will change as the evening progresses. Stalled frontal
boundary is currently draped across Leavenworth County, KS through
NE MO and is expected to provide a focus for renewed convection
tonight. High effective shear values persist in the forecast area
with amounts as high as 60 kts. Instability has also been on the
increase with diurnal heating this afternoon, with the highest values
found across central Missouri, south of where the morning MCV tracked
through. Little to no cap appears to be in place for the southern
portions of the forecast area, where locations reside within the warm
sector. Add in copious amounts of atmospheric moisture and the setup
exists for not just strong storms to develop but for hydro concerns.
Earlier today, received a report of 0.55 inches falling within a 15
minute period so little doubt exists in the efficiency of any storms
that develop. Limiting factor on the severe threat is the meager to
marginal lapse rates across the area. Any stronger storm that does
develop will have the potential to not only contain heavy rainfall,
but gusty to perhaps damaging winds, although the wind threat appears
to be less this evening as compared to last night. Additionally,
flash flood guidance has lowered given the rain that has fallen
across much of the forecast area. With the boundary lingering in the
KC metro area, the lowered FF guidance, the high PWATs, and the
inherently prone issues the metro faces in a heavy rain event, felt
it prudent to issue a FF watch for the metro and counties south and
east.

As well-advertised by this point, the region remains locked in an
unsettled pattern into next week. Despite the aforementioned boundary
still forecast to wash out tomorrow, the forecast area will linger on
the periphery of an upper ridge centered near the Mid-Atlantic
states. Surface easterly flow tomorrow looks to transition into
southerly flow by the weekend with southwesterly flow aloft
persisting, pulling in a constant stream of moisture. Therefore,
precip chances are in the forecast well into the weekend, although a
complete washout isn`t expected. Even in the short-term, it`s
challenging to rely too much on direct model input given how widely
varied they are as they struggle to resolve some of the finer
mesoscale details, such as lingering boundaries. Not much to discuss
with respect to the temperatures as they`ll remain near normal for
this time of year into the upcoming weekend.

.Long Term...(Sunday through Thursday)
Issued at 255 PM CDT THU AUG 25 2016

The upper pattern will begin to flatten as the Northern Plains
trough exits the area late into the weekend. Split upper flow with a
southern jet max progged over central Iowa and northern Missouri
will still permit upper level support for continued showers and
thunderstorms into the early to mid work week. This will further be
supported by persistent southerly moist flow at the surface through
the end of the forecast period. By the mid week, a deepening trough
over the Pacific Northwest will build a broad upper ridge across the
central CONUS. This will begin a warming trend by the end of the
forecast period as warm and moist southerly surface flow remains
firmly in place.

&&

.Aviation...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1214 AM CDT FRI AUG 26 2016

Convection will gradually expand northward into terminals overnight
with low end VFR ceilings generally expected. Lull in thunderstorms
possible by mid-morning with another round during the mid/late
afternoon.

&&

.EAX Watches/Warnings/Advisories...
KS...Flash Flood Watch until 10 AM CDT this morning for KSZ057-060-
     103>105.

MO...Flash Flood Watch until 10 AM CDT this morning for MOZ028>030-
     037-038-043-044-053-054.

&&

$$

Update...MJ
Short Term...lg
Long Term...Welsh
Aviation...Blair


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