St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

033
FXUS63 KEAX 091717
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1217 PM CDT Mon Mar 9 2026

...18z Aviation Update...

.KEY MESSAGES...

- Much above normal temperatures Monday - Tuesday. Record highs most
  at risk on Monday, but within reach on Tuesday as well.
  - Monday Record High Temperatures:
    MCI: 77 in 2021
    STJ: 76 in 2021

- Strong to severe storms possible Tuesday afternoon - overnight.
  - SPC Slight and Enhanced Risks over portions of the area.
  - WPC Slight Risk for Excessive Rainfall

&&

.UPDATE...
Issued at 248 AM CDT Mon Mar 9 2026

Local Thoughts on SPC SWODY2 Outlook:

The Enhanced Risk was pulled/expanded westward which covers more of
Central Missouri (our eastern CWA). 00z and 06z model runs
(especially the RAP) have deepened the surface low that will move
across the eastern Plains and lower Missouri River Valley supported
by the H5 closed-low ejecting out of the southern Plains and a short-
wave with stronger mid-level vort maxima moving across the Northern
Plains. This pushes the warm front northward into Iowa, though far
northwest Missouri likely misses out on this. Strong surface
pressure falls through Tuesday afternoon should increase
convergence, and strong jet streak and associated dCVA should
provide lift late afternoon into the evening. The 00z and 06z RAP
has been hinting at a few hours of H5 height rises through the
afternoon on Tuesday, which may provide enough subsidence to
substantially thin out cloud cover if not provide complete breaks
allowing for stronger insolation. Further, 850-700mb flow appears to
be more southwesterly ahead of the southwestern trough ejecting,
positioning a strong EML over the region by mid afternoon on
Tuesday, while flow near the surface will be more southerly allowing
plenty of moisture transport from the Gulf. As a result, projected
CAPE values have been increasing across the warm sector with this
system, but so has the strength of the cap given the more prominent
EML. This still leads to uncertainty if there will be robust updraft
initiation Tuesday afternoon. If there is enough lift to break
through the cap, a supercell storm mode will be supported by the
background kinematics presenting all hazards. Picking a few model
soundings, the strong EML and elongated mid and upper-level
hodographs standout the most for the mid and late afternoon hours.
This would suggest large hail potential, around 2" or larger, along
with damaging winds. The tornado threat during the afternoon is not
as clear. SRH values are higher given the amount of low-level shear
that is present ahead of this system and deepening cyclone, but for
most of our forecast area, surface winds remained more veered, and
low-level vorticity more crosswise than streamwise. From northeast
Missouri and into Central Illinois is where more backing and better
low-level vorticity could support a greater a tornado threat.
However, if the southern Plains H5 low opens up and starts to lift
earlier and shifts the surface cyclone track, enhanced area of
surface pressure falls or changes in the warm front position could
help to back winds and change the low-level shear environment.
Similar to the Friday-Saturday event, there is higher confidence in
convection once the primary cold front moves across later in the
evening, with better forcing and shear present. This would primarily
be a wind threat. Current 0-3km bulk shear orientation does not
favor mesovort generation at this time. As the cold front moves
through, attention may actually turn more to hydro/flooding. 850-
300mb mean flow is parallel to the cold front, favorable for
training storms. And as mentioned in the evening shift`s discussion,
PWAT values are very high already, which could lead to flooding
especially if we see any 1.00+ inch per hour rainfall rates.

&&

.DISCUSSION...
Issued at 1228 AM CDT Mon Mar 9 2026

A zonal polar jet is situated across the northern CONUS/ southern
Canada, with the sub-tropical jet moving along the base of a closed
upper-low off the northern Baja California Peninsula. This pattern
is allowing southwesterly low-level flow and warm advection into the
local area. Temperatures should be able to climb another 5-10
degrees on Monday with highs in the 70s expected across the area.

This flow regime will eventually begin to pull Gulf moisture
northward into the area late Monday and especially into Tuesday. The
closed upper-low will begin move eastward Tuesday and that will help
moisture surge northward in the area, resulting in dewpoints
climbing into the mid 60s ahead of a stalled front. Temperatures are
forecast to climb into the lower 80s, but this could be tempered
some by increasing low-level cloud cover. Regardless, ample
instability is likely to build during the day with MLCAPE values
near or exceeding 2500 J/kg. This will be held in check initially by
a strong EML. Increasing mid and upper-level flow will lead to a
favorable shear environment with 35-45 kts of 0-6km bulk shear
forecast. Strongly veered surface and low-level flow will limit
helicity values for this event, limiting the potential for
tornadoes. But with steep mid-level lapse rates and favorable shear,
supercells with large hail and damaging winds look possible before
storms congeal. Additionally, storms may be tied to the front with
storm motions along the front. This sets up the potential for
training storms and increases the potential for heavy rain and flash
flooding. With flow roughly parallel to the boundary, it progresses
southward very slowly. While this will be modified by any cold pool
that develops, it suggest that overall, a slow southerly progression
to convection will occur as the convection weakens into the
overnight. Precipitable water values will also be very high for this
time of year with NAEFS percentiles in the 99.5 range and 3 standard
deviations above normal. Given the setup, a flood watch may be
needed for this event as well.

That front finally pushes south of the area Wednesday morning with
cooler air spilling into the region. Highs Wednesday will likely be
25-30 degrees cooler than on Tuesday, which actually just drops us
back to normal levels for this time of year. The remainder of the
extended looks fairly quiet as the polar jet remains well north of
the region. The next chance for precipitation comes next weekend
when a trough moves through the Northern Plains and helps to push a
front southward into the area.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1214 PM CDT Mon Mar 9 2026

VFR conditions to prevail across the TAF sites through the
period. Winds will continue out of the SW throughout, with some
wiggles more southerly at times late overnight and into daytime
Tuesday. Occasional gusts today into the low 20s kts, easing
overnight, and then a bit stronger gust potential into the mid
20s kts Tuesday.

&&

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

&&

$$

UPDATE...Krull
DISCUSSION...CDB
AVIATION...Curtis