-- Discussion containing changed information from previous version are highlighted. --
285
FXUS63 KEAX 240429
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1129 PM CDT Mon Sep 23 2024

.KEY MESSAGES...

- Light Rain Shifts Eastward Through The Evening

- Light Rain Possible Tuesday Afternoon into Late Evening

- Active Weather Possible Friday Through The Weekend

&&

.DISCUSSION...
Issued at 216 PM CDT Mon Sep 23 2024

Mid-level tough axis is still working its way across our forecast
area, but the bulk of the robust kinematics associated with it have
shifted well east of the area. Surface anticyclone has managed to
move in underneath it, and the cold front has completely moved out
of Missouri and Kansas toward the southeast. Weak mid-level lift
will help maintain the stratus cloud cover and light precipitation
activity through the remainder of the afternoon. Based on radar
trends, this will primarily be east of Interstate 35. The cloud
cover will keep temperatures much cooler this afternoon, generally
in the mid 60s. This trough axis will move east of the Mississippi
River Valley between 08-10z Tuesday morning, and surface anticyclone
should be centered around the eastern Plains. There is a PV anomaly
sitting over the Canadian Prairie Provinces that is expected to drop
another lobe of vorticity into the Central CONUS through Tuesday
morning, while mid-level ridging amplifies over the western third of
the CONUS. This vort max will ultimately provide a closed-low system
that deterministic guidance has been depicting for the last few
days, hanging around the area for most of the weak. Although the
kinematics do not appear overly robust, there is potential for an
axis of weak convergence to setup somewhere along the Missouri River
Valley and eastern Plains late Tuesday afternoon and into the
evening that could generate light shower activity. There has been an
increase in measurable rainfall probabilities from various ensemble
suites late Tuesday into early Wednesday, generally 20 to 30 percent
chances for measurable rainfall, though for a threshold exceeding
0.10 inches those probabilities drop to below 10 percent. Amongst
both CAMs and coarser model guidance, most solutions only produce a
few hundredths of an inch of QPF. Weak instability may develop if
the clouds thin out enough, the HRRR does try to produce activity
that is more convective in nature, but the instability may never get
there, so for right now would expect mostly general rain shower
activity if anything materializes at all.

For the remainder of the week, the mid-level closed-low system will
keep the cooler airmass in place. Most ensemble suites have
converged better on keeping it centered nearly directly overhead of
Missouri, leading to high temperatures mainly in the mid 70s. Most
points in our forecast area have an inner-quartile range between 72
and 76 degrees, with far northeast portions of the area maybe only
seeing the upper 60s through the week. In general, morning low
temperatures will be in the mid 50s. Then aside from the Tuesday-
Wednesday light activity, there is not currently any other robust
signal for measurable rainfall, though will point out that as long
as cloud cover lingers isolated sprinkles cannot be ruled out
through Wednesday and Thursday.

Attention then turns to Friday and the remainder of next weekend.
The mid-level closed-low system should still be parked overhead,
while ridging continues to amplify over the western third of the
CONUS. There is a tropical wave moving through the Caribbean that is
likely to become a named tropical system at some point, which
appears to have a decent probability of coming ashore. However, this
system has not yet fully developed, and at this point still cannot
put any high amounts of trust into medium-range deterministic
solutions. The GFS still tries to depict a mid-level Fujiwhara
effect with the 500mb closed-low and the tropical cyclone sometime
Friday into Saturday. Most atmospheric variables and parameters in
the ensemble output shows you the wide spread in any potential track
as well as intensity of tropical cyclone activity. Inner-quartile
temperature spread for most points in eastern Kansas to Central
Missouri is over 10 degrees, ranging from the the mid 60s to nearly
lower 80s. QPF spread is also large heading into the weekend,
between just a few tenths to nearly 2.5 inches for inner-quartile
spread. And looking at a postage stamp view of 6-hour QPF from
individual members, you can see drastic changes in overall track of
any kind cyclone. With that being said, confidence in any specifics
is very low for the weekend forecast. Probabilities are high for
some kind of measurable rainfall, but with respect to any flooding
concerns and extremes it cannot be determined at this time. In
addition, if we see a tropical airmass move into the area, that
could bring enough instability to generate stronger thunderstorms,
but a more easterly solution could keep our area much more stable
thermodynamically as the stronger kinematics would approach the
area.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
-- Changed Discussion --
Issued at 1129 PM CDT Mon Sep 23 2024

Confidence is increasing that fog will affect the terminals
tonight. Satellite imagery shows low clouds eroding from the
north northwest and several observations in this area are
already reporting fog. Additionally HREF probability of
visibility less than 1 mile has increased to 70%+ for the area
that`s clearing out. Given this, have added fog IFR to VLIFR fog
to all sites. Fog begins to lift after sunrise with winds
increasing from the west. There may also be isolated to
scattered showers late tomorrow morning into the afternoon.
Have added a VCSH group to show this potential. It`s also
possible some afternoon storms develop. With so much impacting
the first 6 to 12 hours of the forecast, will leave this out for
now, given it`s still relatively low probability.
-- End Changed Discussion --

&&

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

&&

$$

DISCUSSION...Krull
AVIATION...CDB