440
FXUS63 KEAX 031129
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
629 AM CDT Wed Sep 3 2025

.KEY MESSAGES...

* Patchy shallow fog across the area this morning.

* A strong fast moving cold front will be the focus for
  thunderstorms later today.  Very large hail and damaging winds
  will be the primary severe weather threats.

* Cooler conditions through the remainder of the week, but northern
  flow may draw wildfire smoke back to the region.

&&

.DISCUSSION...
Issued at 329 AM CDT Wed Sep 3 2025

1017 mb high pressure across eastern Kansas this morning has lead to
mostly clear skies and light winds.  CAMs have come into better
agreement that we could see some patchy shallow fog this morning
mainly confined to low lying river valleys and across portions of
central Missouri from  Macon to Howard and Saline counties.  The
expectation is the fog will remain shallow and patchy enough that
there will not be a need for a headline.  Most dense fog should
abate within two hours of sunrise.

For today, the focus will be on a fast moving cold front. As of 08Z,
the front has worked into northern Iowa, but is expected to make
it`s way into northern Missouri by mid-day. Models hint there could
be an isolated non-severe shower or thunderstorm along the front,
but that would be conditional on adequate low level moisture.
Atmosphere ahead of the front is expected to rapidly destabilize
early this afternoon as low level flow  becomes southwesterly
drawing rich moisture across eastern Oklahoma northward.  Surface
dew points are expected to surge into the low -mid 60s F, leading to
ML CAPE values of 500 - 2000 J/kg by late afternoon supported by
moisture return and steep lapse rates below 800 mb. This will favor
the greatest destabilization across eastern Kansas into far western
Missouri. While this rapid destabilization occurs, wind shear
especially above 700 mb increases as low pressure north of the Great
Lakes deepens. This will lead to 0-6 km bulk shear values increasing
towards 30-40 knots- greatest across western portions of the
forecast area.  With all this being said, the outlook for severe
weather looks good focused on the region of greatest instability and
shear. While the atmosphere looks to be largely capped ahead of the
front, lingering moisture in the 925-700 mb layer behind the surface
front may support additional storm develop behind the surface front.
 These storms may be capable of even larger hail than storms near
the surface front as wind shear continues to strengthen through the
evening hours. Greatest severe threat appears to be concentrated in
the 4-9 PM time frame.  Thereafter, the cold front continues to
shift south with breezy north winds gradually decreasing through the
night.

The northerly winds are expected to draw wild fire smoke currently
across North Dakota southward into the region on Thursday. This
smoke may inhibit warming, keeping forecast highs a bit cooler than
what is currently shown in the current forecast.

A secondary cold front is expected to move through the region early
Friday morning.  Could see some elevated thunderstorms along and
behind the front, but limited amounts of low level moisture should
keep these storms at the non-severe level.

Cool Canadian high pressure is expected to build south across the
plains on Saturday keeping temperatures below normal. Large upper
level trough across the western US looks to break down strong ridge
across the western US this weekend. This upper trough looks to send
sporadic shortwaves in zonal flow next week leading to periodic
chances of showers and thunderstorms.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 627 AM CDT Wed Sep 3 2025

Shallow patchy fog should burn off towards 14Z. A strong cold
front will work through the region this afternoon, with
scattered thunderstorms developing along and behind the front.
Thunderstorms will mainly be concentrated in the 22Z
Wednesday-02Z Thursday time frame, mainly along and south of
I-70. A few of the storms could produce large hail. Behind the
front, wild fire smoke may lead to reduced visibilities Thursday
and beyond.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...None.
KS...None.

&&

$$

DISCUSSION...BT
AVIATION...BT