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141
FXUS63 KEAX 231131
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
631 AM CDT Sun Jun 23 2024

.KEY MESSAGES...

- Hazardous Heat and Humidity This Week

- Heat Advisory Monday Afternoon

- Shower/Storm Chances Tuesday and Wednesday

&&

.DISCUSSION...
Issued at 318 AM CDT Sun Jun 23 2024

Today Through Tuesday Morning:

Short-wave trough and associated surface cyclone with trailing cold
front have passed through the forecast area during the early morning
hours of Sunday. A few light sprinkles are still ongoing in the
Howard and Cooper County area but will be ending as the front
continues to progress toward the southeast. This afternoon subtle H5
heights gradually rise in the AVA regime and promote weak subsidence
that should result in surface pressure rises. This will help break
apart lingering cloud cover by this afternoon and promote
anticyclone development at the surface across the area. Mid-level
ridge axis sets up over the High Plains but expecting a few short-
wave perturbations to navigate their way through the flow. This will
create surface pressure falls over the Front Range and High Plains,
and as the surface anticyclone over the lower Missouri River Valley
shifts eastward, should provide south to southwesterly low-level
flow. For Sunday afternoon, expecting temperatures in the lower to
mid 90s across the area as WAA begins to ramp back up accompanied by
strong insolation through the afternoon. The weak northerly winds
through the morning should prevent some heating through the day.
Monday though, WAA takes off along with stronger moisture transport
that will result in hazardous heat index values across two-thirds of
our forecast area. Surface temperatures are setting up to be in the
upper 90s across much of eastern Kansas into Central Missouri, with
strong signal in ensemble probabilities for upper 90s. This will
also bring in dewpoints in the lower 70s to much of the area, which
will yield heat index values between 104F and 107F. Therefore, have
issued a heat advisory for much of the area Monday afternoon. For
right now, have dry conditions in there as there will not be much in
the way of forcing but will need to monitor trends, as there could
be potential for the boundary layer to reach its convective
temperature and allow a few airmass showers/storms to develop. But
without any substantial mid to upper-level flow, should not last for
an overly long period of time. Heading into Monday night and
Tuesday, not much is expected in the way of temperature relief. H5
height rises continue through the overnight hours with strong WAA,
resulting in lows temperatures in the upper 70s to possibly lower
80s.

Tuesday Afternoon and Beyond:

Latest GFS model guidance indicates ridging over the southern CONUS
Tuesday morning. Upper-level troughing is observed simultaneously in
central Canada, with another system offshore the Pacific northwest
coast.

Additionally, warm air advection due to the southerly flow from the
Gulf of Mexico will keep highs in the lower 90s in the afternoon
hours on Tuesday. The upper-level low in Canada will increase
atmospheric instability and enhance precipitation chances throughout
the day on Tuesday.

Moving forward in time, GFS guidance places this upper-level high
pressure center in extreme northeastern New Mexico at 12Z Wednesday
morning. This ridge retrogrades back west on Wednesday as a
consequence of interacting with the short-wave trough centered in
central Canada as it continues to progress east, digging into Great
Lakes region in central/eastern CONUS. As the system begins to
impact upper-level conditions on the eastern seaboard, the frontal
passage will provide temporary relief with temperatures on Thursday
peaking in the mid 80s in our area.

Chances for showers and storms return Thursday afternoon and
continue into the weekend, as the trough previously located in the
pacific northwest traverses east across the mountainous west. After
frontal passage on Saturday morning, summertime ridging builds back
in over the southern/western United States, surface winds returning
afternoon highs to the upper 80s lower 90s on Saturday and Sunday
despite predominantly northerly surface and northwesterly H5
winds.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
-- Changed Discussion --
Issued at 632 AM CDT Sun Jun 23 2024

Mostly clear skies oversee VFR conditions through the period. Winds
are expected to be light and variable throughout the day on Sunday.
Predominantly northerly winds will initially be observed at the TAF
sites, followed by easterly and southerly winds shifts in the
afternoon and evening hours.
-- End Changed Discussion --

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Heat Advisory from noon to 8 PM CDT Monday for MOZ001>006-
     011>015-020>023-028>032-037>040-043>046-053-054.
KS...Heat Advisory from noon to 8 PM CDT Monday for KSZ025-057-060-
     102>105.

&&

$$

DISCUSSION...Hayes/Krull
AVIATION...Hayes