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

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FXUS63 KEAX 091735
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
1235 PM CDT Wed Aug 9 2017

.Discussion...
Issued at 351 AM CDT WED AUG 9 2017

Scattered showers have developed across central Kansas as of early
Wednesday morning in response to weak isentropic ascent underneath a
subtle mid-level shortwave. This feature is ejecting south of a
deeper upper low over the Northern Plains as it pushes eastward.
Locally, the effects of the 850 hPa high will erode through
Wednesday morning as steady return flow advects northward, and the
pattern resets for a multi-day period of off and on storm chances
beginning this afternoon.

Precipitation chances today look to be held to the west at least
through the morning and perhaps even early afternoon. By Wednesday
afternoon, the moisture axis will finally push eastward along
with the subtle mid-level wave. This will bring the first round of
isolated to scattered storm chances across eastern Kansas and
western Missouri by the early to mid afternoon. A lingering dry
air mass and overall weak forcing may delay the onset of
precipitation, and at the very least minimize widespread
development until later this evening. By that time, the slowly
advecting moisture axis will further advance across the local area
and better forcing for ascent will arrive courtesy of a SW-NE LLJ
extending from the Texas Panhandle to northwestern Missouri. Deep
convection should be maintained by weak instability throughout
the event this evening and tonight. This activity will slowly
taper off Thursday afternoon with only a brief break in storm
chances before the next round arrives early Friday. By late
Thursday night/early Friday morning, two forcing mechanisms will
serve as the focus for the second round of storm chances. To the
north, a trailing cold front will sweep through northern Missouri,
south of a stacked low entering the Great Lakes Region. Storms
may fire ahead of the frontal boundary along and north of the
Highway 36 corridor heading into Friday morning, though the better
forcing for convection will reside near a secondary feature
further south. A modest mid-level wave will clip southeastern
Kansas overhead increased low level moisture compared to that
further north. This will present storm chances for southern to
central Missouri Friday morning, with the bulk of activity
affecting central Missouri and points south. Severe potential
looks to remain upstream of the local area, however may need to be
monitored as each event unfolds with consideration to timing.

Storm chances will then resume by the weekend, though the overall
pattern will remain fairly disorganized. Nearly zonal flow aloft
will advect ample eastern Pacific moisture atop southerly return
flow during this period. Any mid-level disturbances within this
pattern may provide sufficient ascent to force isolated to
scattered convection. Resulting cloud cover, in conjunction with
the southward extent of the upper-level jet, will keep temperature
trends below seasonal values through at least the next seven
days.

&&

.Aviation...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1235 PM CDT WED AUG 9 2017

Areas of showers across central/eastern KS will continue to shift
slowly to the east over the next few hours, reaching the terminals
by around 21-22z if they hold together and maintain current speed.
Ahead of this, congested cumulus will continue to build and spark
a few isolated showers or stray thunderstorm, and this mounting
instability could help showers out west intensity a bit as they
head east. As a result, have gone prevailing VCSH to show the
general lack of thunder activity, but tempo`ed TS to cover any
future intensification.

Winds will remain out of the SSW to SSE at speeds less than 10
kts, and will become light and variable tonight. Another round of
storms will develop across central NE/KS tonight and head east by
Thursday morning, potentially impacting terminals after sunrise.


&&

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

$$

Discussion...Welsh
Aviation...Laflin



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