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

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FXUS63 KEAX 221114
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
614 AM CDT Sat Jul 22 2017

.Update...
Issued at 534 AM CDT SAT JUL 22 2017

Have sent an update to the forecast to account for the southward
moving outflow boundary and the convection developing as it slides
southward. This should mainly stay across northern MO and
especially the northeastern portion of the forecast area. Further
south, forecast soundings show warmer air aloft which should
inhibit convection going until better forcing arrives. Given poor
model handling of the outflow boundary though, additional updates
will likely be needed through the morning.

&&

.Discussion...
Issued at 321 AM CDT SAT JUL 22 2017

A cold front will push into the area this afternoon, which will have
several effects on the weather, in the near term, as well as in the
coming days.

For today, with the cold front moving into northern MO by the
afternoon, there will likely be some compressional warming
along/ahead of it. This warming looks focused from east central KS
through west central MO. This may be KCI`s best chance at reaching
100 degrees. Something that hasn`t happened since 9/8/2013, or 1413
days, including today. This compressional warming ahead of the front
is noted by the nose of warm air aloft nosing into the area and the
increased thickness values as a result. Overall, temperatures along
and ahead of the front look to be 1 to 2 degrees warmer than
yesterday. So many areas will likely be flirting with the century
mark. Factoring in the mid 70 degree dewpoints and heat indices will
once again climb to around the 110 degree mark for most areas.

The other effect of the front this afternoon and especially this
evening/overnight will be the potential for thunderstorms. During
the day, forecast sounding suggest we remain capped. This is
supported by the lack of QPF during the afternoon hours. The
chances for precipitation should really increase late in the
evening though as an upper level shortwave trough moves into the
area from the west. This should provide the needed forcing to
overcome the capping. Forecast soundings when the upper wave is
moving through show a healthy 3000+ J/kg of CAPE. Shear though is
weak so storm organization potential seems low. Thus, think we`d
likely see pulsey updrafts with marginally severe hail possible
and some gusty winds. Extremely high precipitable water values and
slow storm motions would also support locally heavy rain and even
a flash flood threat. Fortunately, the cold front progresses
through the area, pushing convection south as it does. So it
doesn`t look like we`ll see in our area tonight what is occurring
in northeastern IA currently with training cells in a slow moving
MCS.

While it will be cooler on Sunday, it`s still likely to be above
normal and still humid with heat indices around 100. The real shot
of cooler and drier air comes with a secondary front that should
move south into the area Sunday night. This will set the stage for
more comfortable weather Monday and Tuesday. Highs will be closer
to normal with cooler dewpoints resulting in heat indices "only"
in the middle 90s. By the middle to later portions of the work
week, highs return to the middle to upper 90s. But this may be
short-lived as the upper ridge really builds over the Rockies
leaving our area in a classic northwest flow regime. This would
give us a better potential for thunderstorm activity moving into
the area. This looks especially true Friday night with a frontal
boundary potentially draped across the area.

&&

.Aviation...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 614 AM CDT SAT JUL 22 2017

A cold front will move into the area by this afternoon. Scattered
thunderstorms are possible along the front late this afternoon
through the evening hours. If a terminal sees a storm, then
temporary visibility and ceiling restrictions are likely. But for
now, there is enough uncertainty to keep mention only to VCTS and
VFR conditions. Winds will shift to the north by this evening in
the wake of the front.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Excessive Heat Warning until 8 PM CDT this evening for KSZ025-
     057-060-102>105.

MO...Excessive Heat Warning until 8 PM CDT this evening for
     MOZ001>008-011>017-020>025-028>033-037>040-043>046-053-054.

&&

$$

Update...CDB
Discussion...CDB
Aviation...CDB


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