485
FXUS63 KEAX 091728
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1228 PM CDT Sun Mar 9 2025

.KEY MESSAGES...

- Warm and Dry Next Few Days

- Hot, Dry, Windy Conditions Lead to Fire Weather Concerns Monday

- Strong System End of Week; Heavy Rain and Thunderstorms Possible

&&

.DISCUSSION...
Issued at 429 AM CDT Sun Mar 9 2025

Positively tilted mid to upper-level trough has pushed eastward into
the southern Plains with amplified mid-level ridge over the
Intermountain West. Weak AVA has continued downstream from the ridge
as all the stronger kinematics with the trough system are near the
Gulf. In this weak AVA regime, the surface anticyclone has spread
across much of the Central Plains into the lower Missouri River
Valley, providing mostly clear skies across the region. This
afternoon, H5 height rises will pick up in pace as the ridge axis
attempts to progress eastward. This pattern is providing downslope
off the Rockies, with adiabatic compressional heating increasing
temperatures in the 925mb-850mb layer. With the ridge axis trying to
shift eastward, flow within this layer has been westerly, which has
been providing a WAA regime across Plains to the middle Mississippi
River Valley. Clear skies should allow for some boundary layer
mixing this afternoon, providing temperatures in the lower to mid
60s across most of the forecast area. NBM inner-quartile spread is
fairly narrow with only about a 3F separation between the 25th-75th
percentile values for most locations in our forecast area. Winds
will generally be light through most of today, a few gusts to around
15 MPH possible. Monday afternoon, strong PV anomaly promoting
troughing just off the coast of California will provide an
additional kick to progress the ridge axis eastward across the
Plains toward the Ohio River Valley, with stronger dAVA pushing
southeastward, resulting in the surface cyclone pushing toward the
southern Plains and Gulf regions. This eventually results in
stronger southwesterly flow in the lower portions of the
troposphere, enhancing the WAA regime. Because of the position of
the surface anticyclone, any Gulf moisture transport is cut-off,
therefore dewpoints will not see any substantial rise through
Monday. Clear skies will allow for plenty of insolation, and
increasing flow is expected to create more turbulence and mixing,
setting the stage for a deeply mixed boundary layer by Monday
afternoon. In this strong WAA regime with robust mixing expected,
have trended Monday afternoon high temperatures toward the NBM 75th
percentile, which for our western areas bumps highs into the mid and
upper 70s. Mixing is also expected to lower dewpoints into the mid
30s by the afternoon, yielding relative humidity values in the lower
to mid 20s for a few hours, and an extended period of RH values
around 30 percent. In addition, winds toward the top of the mixed
layer are progged around 25-30 kts, which should easily for a large
portion of our forecast area provide gusts above 25 MPH. Given these
conditions, on-top of dry soil conditions, have issued a Fire
Weather Watch for the majority of our area. Only our southeast
counties have been excluded at this time, as the winds may not be as
gusty as they will be elsewhere. Tuesday, a vorticity maxima ejects
from a deeper trough approaching the coast of the southwestern
CONUS, and de-amplifies the previous mid-level ridge pattern to a
brisk zonal flow. A secondary ridge axis over the Northern Rockies
forces and anticyclone across the Northern Plains, but may be enough
to push a cooler airmass southward. As a result, temperatures in the
northern portions of the forecast area may cool into the lower 60s,
while south of Interstate 70 temperatures still reach the upper 60s
and perhaps lower 70s. With recent model trends, have noticed
amongst various ensemble suites that inner-quartile spread for
Tuesday high temperatures have seen an increase in spread,
especially for areas between Interstate 70 and Hwy. 36. This is
likely due to differences in how far any kind of weak thermal
boundary drifts southward. While there may some weak convergence,
there will be very little moisture transport preceding this weak
disturbance, therefore no precipitation is expected as this passes
through on Tuesday. Wednesday, weak disturbance passes by, modest
ridge axis moves through again providing WAA that is expected to
bump temperatures back into the upper 60s and lower 70s across most
of the area.

Late Wednesday Night, stronger short-wave trough and H5 vort maxima
races across the southern Plains as strong PV anomaly over the
Pacific results in typical early Spring time progressive flow across
the CONUS. Recent trends in model guidance both deterministic and
ensemble suites have been pushing stronger kinematic forcing
southward away from our area. In previous runs, there had been about
a 15 to 30 percent chance for measurable precipitation in our
southeastern counties Wednesday Night into Thursday morning. Now,
those probabilities have dropped below 15 percent, with better
forcing progged over the Ozarks Region and southward toward the Gulf
Coast. Therefore, will maintain a dry forecast, though we should
start to see modest increases in dewpoint temperatures through
Thursday. WAA ahead of this system is expected to bump afternoon
highs back in the mid 70s across much of the area, with lower 70s
closer to the Iowa state line.

Friday into Saturday next weekend, we are still seeing a strong
signal for robust mid-latitude cyclone system to move across the
CONUS. NAEFS continues to show favorable probabilities for near
record low H5 heights with the system, as well near record low MSLP
values relative to early and mid March values. Elevated shift of
tails values indicate increasing confidence in potential for H5
height and MSLP extremes to reached or nearly reached. The exact
track of the surface features remains uncertain, as the system
closes up and eventually experiences a drastic slow down. The WPC
cluster analysis depicts this, as the means of a few ensemble
systems vary substantially. Overall, this affects where the warm
sector develops, where the best moisture transport occurs, and when
favorable kinematics line up with robust thermodynamics. At this
point, would expect a favorable severe thunderstorm environment
ahead of this system, but unsure if that is going be concentrated
along the Gulf Coast, or if might move northward to the lower
Missouri River Valley or even portions of the upper Midwest.
Meanwhile, on the northwest side of this system, colder air will
likely provide winter weather conditions. For right now, there are
not many members that bring this colder air and deformation zone
area into our forecast area, perhaps far northwest Missouri gets
clipped with some kind of wintry precipitation. The higher winter
precipitation probabilities are confined northward of the Interstate
80 corridor. Regardless of severe thunderstorms or just general
thunderstorms, still anticipating a high QPF event from this system
with the strong push of theta-e that should occur. Some model
solutions produce high end CAPE relative to early Spring normals,
while others have very little CAPE, along with a strong EML placing
a large cap on the CBL. The only change to the forecast from NBM for
the system was to increase to thunderstorm chances along with rain
showers. Given how dynamic this system is expected to be, it`s hard
to imagine not realizing any kind of instability for at least a few
hours as this moves through, therefore this introduces thunderstorm
chances to the forecast Friday into Saturday.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1226 PM CDT Sun Mar 9 2025

VFR conditions expected for the duration of the TAF period. Winds
will come from the west-southwest and be fairly light with mostly
clear skies.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Fire Weather Watch from Monday afternoon through Monday
     evening for MOZ001>008-011>017-020>024-028>031-037-038-
     043.
KS...Fire Weather Watch from Monday afternoon through Monday
     evening for KSZ025-057-060-102>105.

&&

$$

DISCUSSION...Krull
AVIATION...Collier