FXUS63 KEAX 121856

National Weather Service Kansas City/Pleasant Hill MO
156 PM CDT Fri Aug 12 2022

Issued at 155 PM CDT FRI AUG 12 2022

Key Messages...

- Warm up into the weekend; highs back in the mid 90s F Saturday
  and Sunday with heat index values around 95 to 100 F.

- Rain chances begin early Monday, with best chances Monday night
  through Tuesday. Periods of moderate to heavy rainfall are
  expected, with widespread amounts between 1.0 and 1.5 inches
  across the area, with locally higher amounts more than possible.

Detailed Discussion...

The forecast hasn`t wavered much over the past few days looking
ahead into the weekend and beyond. Overall, the broad H500 ridge
remains in place, with a surface ridge quietly sliding southward,
trailing from the Mid-Mississippi Valley to the MO/KS border. On
it`s heels, a surface trough will develop over the northern to
central Plains; resulting in increased warm air advection overnight
and through Saturday. As discussed over the past few days, this will
aid in temperatures rising back into the mid 90s for many locations
tomorrow. The good news, dew points in the low 60s will keep max
heat index values around 100, below advisory criteria. Sunday is not
looking as hot as previously discussed, as the surface trough
weakens as it sinks toward Mid-Missouri, cutting off stout warm air
advection return flow. Highs will still be in the lower 90s, but max
heat index values will only touch the upper 90s.

Sunday night, the stout H500 ridge will begin to weaken, flattening
out as the eastern trough strengthens and a weak short wave begins
to advance eastward across the Badlands. This will increase
convergence ahead of the weakly associated surface trough over
NE/KS. With a Baroclinic zone taking hold along the lee side of the
ridge, modest forcing for ascent will be present across the region,
from MO to IA/NE. This will be the focus for showers and scattered
thunder through much of the day. Monday night into Tuesday, expect
precipitation chances to become more organized as the short wave
begins to propagate southeastward along the Missouri Valley into the
area through day break. The enhanced ascent ahead of the surface low
and increasing low level jet from the south and southwest will
provide a combo of moisture and focus for periods of moderate to
heavy rainfall across the region from early Tuesday through midday.
It`s a ways out there, but as a heads up, widespread amounts will
range from around an inch to one and a half inches, with locally
higher amounts more than possible given the slow moving nature of
the overall mesoscale pattern and available moisture.

With the exit of the short wave southeast through Wednesday,
precipitation chances will decrease through the day.


.Aviation...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1218 PM CDT FRI AUG 12 2022

VFR conditions are expected to prevail through the period. FEW to
SCT mid to high level ceilings may drift through area airfields
through the remainder of the day. Winds will generally remain
light and out of the southeast and south.





NWS EAX Office Area Forecast Discussion