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

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000
FXUS63 KEAX 161704
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
1204 PM CDT Wed Aug 16 2017

.Mesoscale Discussion...
Issued at 1204 PM CDT WED AUG 16 2017

Trends continue to be monitored for renewed convection this
afternoon as long awaited surface cold front starts working
through the area. Latest GOES-16 imagery showing plenty of
clearing in the wake of this morning decaying MCS activity, and
increasing instability is expected this afternoon as a result.
Latest BUFKIT fcst soundings suggest anywhere between 2-3000 J/kg
of MLCAPE this afternoon, with increasing deep-layered shear also
expected as upstream trough axis begins moving further east
across the Central Plains. Furthermore, 7.34 GOES-16 water vapor
channel showing a stream of warmer brightness temps advecting
northeast towards our area, which appears to be indicative of
steepening lapse rates resulting from an elevated mixed-layer
plume (note 12z Amarillo, TX sounding). In any event, look for
convection to develop along the cold front around 21z, with
discrete cells initially leading to an isolated tornado threat
before activity congeals into a forward propagating MCS. After
this occurs, main threat will transition to a damaging wind threat
as the line continues moving through west-central and central
Missouri.

&&

.Discussion...
Issued at 353 AM CDT WED AUG 16 2017

The main concerns in the short term will be for the chance for
severe weather this evening into tonight. Also, heavy rain this
evening may allow for localized flash flooding to occur.

Early this morning a large complex of showers and thunderstorms is
moving across central and eastern Nebraska and northwestern Kansas.
These storms are developing north of a east-west surface boundary
that runs from northern Missouri into south central Nebraska and
back to northwestern Kansas where the low level jet is focused. A
cold front extends from a surface low in northwestern Kansas into
western Kansas where additional storms have developed. This cold
front will be the main player in the potential for severe weather
this evening. However, this morning, scattered warm air advection
showers and thunderstorms out ahead of the system will bring
precipitation to the area this morning into this afternoon. Although
there will be significant cloud cover this morning, models still
suggest that as the front approaches the forecast area this evening
moderate instability of around 2000J/Kg will be available, and 0-6KM
shear will be around 40kts. These parameters would be sufficient for
storms capable of damaging winds and large hail. These storms will
also be capable of very heavy rainfall with PWAT values between 2"-
2.5". Storms are not expected to train but they will be slow movers
which may lead to localized flash flooding. These storms are expect
to progress across the CWA tonight as the cold front will exit the
area by tomorrow morning.

Temperatures will be near normal again today with highs in the mid
to upper 80s however with dewpoints in the low to mid 70s, heat
index values will reach into the low to mid 90s. Behind the cold
front on Thursday, temperatures will be a couple degrees cooler
however, without any cold air advection behind the front, highs will
still reach the low to mid 80s. Tranquil conditions will continue
Thursday night into Friday as high pressure resides over the area.
However, Friday afternoon high pressure will shift east and we get a
return to southerly flow allowing to warm a couple degrees into the
mid 80s.

The next chance for precipitation will come Friday night as a upper
level trough digs from the northern Plains into the Midwest. This
will force another cold front through the area and bring the chance
for storms...potentially severe...to the area. The remainder of the
weekend then looks to remain dry with a warming trend as a upper
level ridge build over the southeastern and south central CONUS by
Sunday. Expect highs in the mid 80s Saturday and in the mid to upper
80s by Sunday.

&&

.Aviation...(For the 12Z TAFS through 12Z Thursday Morning)
Issued at 628 AM CDT WED AUG 16 2017

A round of showers and thunderstorms are movg thru the terminals
this morning and will affect the TAF sites thru 13Z. Another line
of storms is movg eastward thru central KS this morning. These
storms are expected to wkn as they approach the TAF sites late
this morning however, they may hold together long enough to affect
the terminals. Have opted for a VC for now around 16Z to account
for storms holding together. The main round of storms is expected
this evening btn 00Z-04Z as a line of storms along a cold front
are expected to mov thru the TAF site. This line of storms may
pack strong winds and heavy rain. Behind the front, MVFR cigs are
progged to mov into the terminals btn 06Z-08Z.


&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&

$$

Mesoscale...32
Discussion...73
Aviation...73


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