729
FXUS63 KEAX 171952
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
252 PM CDT Sun Aug 17 2025

.KEY MESSAGES...

- Hot and humid conditions possible through Monday with triple
  digit heat indices. High uncertainty exists for Monday due to
  thunderstorm potential.

- Ongoing, isolated thunderstorms continue this afternoon for
  the southeastern fringes of our area (mainly east of a line
  from Howard to Henry counties). No severe weather expected.

- Multiple chances for thunderstorms starting early Monday
  morning and Tuesday.

- Seasonal temperatures return for the second half of this week
  with highs in the 80s.

&&

.DISCUSSION...
Issued at 251 PM CDT Sun Aug 17 2025

For today, broad mid to upper level ridging continues its dominant
streak over the area. This, combined with strong southerly winds has
resulted in hot and humid conditions over the area. High
temperatures today will range in the low to mid 90s with dew points
near the low 70s. This will yield heat index values around 100-105
degrees F. Areas near and north of St. Joseph are less likely to
reach heat advisory thresholds as deeper mixing this afternoon has
resulted in dew points mostly in the lower 70s keeping the northern
half of our CWA below heat advisory criteria. A Heat Advisory is in
effect until 7 PM today for areas south of a line from Leavenworth
(KS) to Macon counties.

A surface low extending from ND into western KS has strengthened the
pressure gradient over our area with higher pressure over the
eastern U.S. This has resulted in occasional gusts through the day
up to 10-15 mph mainly for eastern KS to central MO. Additionally,
as these slightly stronger winds collide with the slower winds
farther east, this low-level convergence will continue to be the
lifting mechanism for a few isolated thunderstorms this afternoon
into the evening primarily for the southeastern portions of our area
(east of a line from Randolph to Henry counties). As of 18Z, storms
have already begun to develop in Pettis and Cooper counties. No
severe weather is anticipated. Even though there is abundant
instability (3,500-4,500 J/kg of SBCAPE), very low shear (below 10
kts) will keep storms from being able to efficiently organize
resulting in fairly short-lived convection. Any cloud coverage from
these storms or surrounding cu fields will likely only provide
minimal relief from the heat.

Early Monday morning, our area enters the warm sector of the surface
low as it continues to slowly track to the northeast. WAA combined
with a 25-35 kt H850 low-level jet increasing moisture transport
will be enough for storms to develop over southern MN extending into
central KS. This line is then anticipated to track to the east
approaching northwest MO. Here is where the forecast becomes more
challenging as hi-res models diverge on solutions. The 12Z HRRR
tracks the storms almost to the KC Metro by late Monday morning. The
12Z NAMNST completely dissipates the storms in IA and keeps our area
dry. The most likely scenario appears to be storms entering
northwest MO and decaying north of the KC Metro (which the HREF
suggests). These storms will present low-end chances for severe
weather mainly for the MO/IA state line with the primary threat
being isolated strong to damaging winds (DCAPE values exceeding
1,000 J/kg). Guidance also suggests additional isolated thunderstorm
chances Monday afternoon into the evening for southeastern portions
of our area (near Howard, Pettis, and Henry counties). Again, this
will be determined on how storms develop through the morning.

Multiple rounds of possible storms on Monday adds complexity to the
temperature forecast. Broad mid to upper level ridging will still
remain over the area resulting in highs ranging in the low to mid
90s. Dew points will still be in the 70s yield heat indices around
100-105 degrees F. However, with the potential convection, increased
cloud cover could impede the effects of daytime heat causing them to
fall short of heat advisory criteria. For now, confidence is not
high enough to issue any heat headlines. Additional uncertainties
exist for Monday with respect to precipitation, as H700 vort maxima
and outflows from convection could result in multiple rounds of
showers and storms across the area through the day and late evening.
Thunderstorm chances continue into Tuesday as broad mid to upper
level ridging retreats to the west and and a H500 shortwave on the
northeastern periphery moves through the area. At the surface, the
low finally drags its northeast to southwest oriented cold front
through the area. For now, severe weather is not expected, but PWATs
ranging around 2 and tall, skinny CAPE profiles suggest the
potential for a few heavy downpours with these storms. The WPC has
issued a marginal risk (at least 5% chance) for excessive rainfall
for the whole area. However, storms look to be progressive enough to
stave off increased flooding concerns.

A surface high ushers in a much more seasonal air mass on the back
side of the surface cold front. Highs for the second half of this
week will range mostly in the 80s. Broad-scale subsidence with the
descending surface high and a stout mid to upper level ridge over
the western U.S. extending into the Plains seems to keep us dry
going into the weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1234 PM CDT Sun Aug 17 2025

VFR conditions anticipated for most of the TAF period. Winds
remain mostly out of the south with occasional gusts to 10-12
kts through today with daytime heating. Winds will weaken late
this evening and increase again tomorrow morning. There is a
chance for isolated to scattered thunderstorms towards the end
of the TAF period mainly for KSTJ. Therefore, added a PROB30
group for KSTJ. Left mention of thunderstorms out of other TAFs
for now due to low confidence in how far south storms will track.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Heat Advisory until 7 PM CDT this evening for MOZ025-028>033-
     037>040-043>046-053-054.
KS...Heat Advisory until 7 PM CDT this evening for KSZ057-060-
     103>105.

&&

$$

DISCUSSION...Collier
AVIATION...Collier