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

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FXUS63 KEAX 250418

National Weather Service Kansas City/Pleasant Hill MO
1118 PM CDT Mon Apr 24 2017

Issued at 356 PM CDT MON APR 24 2017

Strong pressure gradient at the surface setting up today, which have
caused winds to respond by strengthening out of the south. With the
better gradient across eastern Kansas and western Missouri, have
seen winds generally in the 15 to 25 mph range with gusts
approaching 30 to 40 mph in some areas. Warm temperatures and good
mixing have helped bring up those wind gusts through the day. Expect
these winds to gradually wind down around sunset with late day
decoupling as well as the pressure gradient loosening up.  As we go
into Tuesday the pattern temporarily changes as a mid/upper level
trough forms to our west and encroaches the area with SW flow aloft
Tuesday. This will bring a chance for some severe weather, mainly
south of Interstate 70 Tuesday evening and Tuesday night. At the
surface a ridge of high pressure will nose into the area Tuesday
afternoon and evening, which will be the trigger for strong storms.
With upper 50 to perhaps lower 60 dewpoints reaching the MO/IA
border there will be some instability to provide fuel for
thunderstorm formation, but the better instability will be located
south of I-70, back toward SE Kansas and NE Oklahoma. Expect storms
to form generally along Interstate 35, in areas south of I-70 around
00z, then move eastward into the area. Storm mode appears to be
mostly linear, especially as it approaches far eastern Kansas and
western Missouri, since deep shear vectors look to be rather
parallel to the cold front boundary. A few storms may start as
discrete storms, but will likely congeal into a linear system by 06z
and race across southern and central MO. While the concern for
tornadoes can`t be completely ruled out due to good backing of winds
ahead of the line, the linear mode of the storm system, as well as
rapidly increasing of stability with diurnal cooling will make the
tornado concern rather minimal. Expect the best chances for rain to
be along and south of I-70, however a few locations north of I-70
could see a few storms Tuesday night. Post frontal rain should
continue through the day on Wednesday, mainly across Western
Missouri, into Central Missouri as the amplified trough rolls
through the area. Expect the Wednesday activity to be mostly
stratiform rain, with perhaps a small chance of some thunder.

After a lull in the action on Thursday, Friday will usher in an
active weather pattern for the weekend. Southwest flow aloft sets up
over the forecast area for Friday as a large trough carves its way
into the jetstream over the intermountain west. This trough will
meander its way south and ultimately eject into the Central CONUS by
the end of the weekend, but in the meantime will keep off and on
precipitation going over the forecast area through the weekend.
While much of the details surrounding the exact timing and intensity
of individual batches of rain remain elusive at this point the focus
for heavy rain could be a surface boundary which looks to set up
somewhere near the I-44 corridor. As the SW flow aloft flows over
the moisture rich warm sector several rounds of heavy rain will
materialize. While areas north of that boundary, such as Northwest
and Central Missouri, will see several rounds of rain, the
expectation at this point is that the bulk of the rain will likely
be anchored to that boundary. The boundary could definitely set up
in a different location than models currently have, so will need to
refine the forecast at a later time. But in the meantime with the
general idea that the boundary will be south of the forecast area,
the thinking for now is that areas of northern Missouri could see
rather minor amounts of rain from this prolonged event, to perhaps
several inches of rain over a 48-60 hour period across areas of
central and Southern Missouri.

The trough will eject out of the area by Monday, bringing another
lull in the action for the first part of the week before the next
system moves in Tuesday night into Wednesday.


.Aviation...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 1117PM CDT MON APR 24 2017

VFR conditions will prevail for the majority of the TAF period
until a frontal boundary pushes through after 00Z. Scattered
showers are expected to form along the MO/KS border around 00Z
with thunderstorms expected to form up a few hours later as the
front starts to progress to the east. MVFR ceilings will accompany
the frontal boundary and thunderstorms after 03Z. The exact
location of the thunderstorm development still has some
uncertainty leading to VCTS being utilized to show this potential
timing for the time being.




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