St. Joseph, Missouri 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

136
FXUS63 KEAX 202334
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
634 PM CDT Sat Jun 20 2026

.KEY MESSAGES...

- Dry weather will persist through the afternoon and then we
  turn our attention to storms moving in from the northwest this
  evening, mainly north of Kansas City.

- Severe storms (mainly strong winds) possible late tonight into
  early Sunday morning. Heavy rain with flood potential is
  forecast. A Flood Watch is in effect.

- Additional severe thunderstorm redevelopment is possible
  Sunday afternoon from Kansas City south and southeast.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 206 PM CDT Sat Jun 20 2026

This afternoon and evening...

Am closely watching ongoing severe thunderstorms across central
and southeastern Nebraska associated with upper level shortwave
trough that is tracking across the central plains. Latest 12Z
models show a wide variety of possible convective evolution
scenarios. The HRRR model runs consistently weaken and track
the Nebraska convection in a more easterly direction with the
mean upper flow keeping it north of the Kansas City metro area
this evening with showers and weakening thunderstorms mainly
north of St Joseph. In this scenario the Kansas City metro area
would remain dry until around or after midnight.

The 12Z RRFS and several REFS members better maintain the
Nebraska convection and dive this stronger convection more
towards the southeast until it eventually weakens. These
solutions could threaten the Kansas City metro area with
thunderstorms during the evening hours 8-midnight. However,
these are generally outliers and the most likely storm track
will be somewhere between the more northern HRRR runs and the
more southern RRFS/REFS.

Radar trends at 2:15 PM over Nebraska already indicate a
weakening trend with the strongest cells. The strong cells have
been moving southeast, but once they weaken they should start to
be more influenced by the mean upper flow and track more east.
The rain shield out ahead of the last strong storm near Hebron
will result in a less favorable storm environment and continued
overall weakening of this storm complex is expected. Therefore,
the remaining showers and decaying thunderstorms should track
more easterly and mainly impact areas north of Saint Joseph this
evening.

The thunderstorms that are most likely to impact the KC area and
points further south will not develop until 4-5 PM across far
northwestern Kansas and are not likely to arrive until after
midnight. Can not rule out a few isolated storms developing
just ahead of this late evening Kansas convection that could
impact KC prior to midnight, but just a small chance 20-30%. The
high chances (>80%) for the KC and areas to the south and east
will be after midnight and especially a few hours either side of
sunrise Sunday morning.

The northern thunderstorms (north of KC) this evening do not
have much instability to work with and should be elevated
greatly limiting the severe weather threat.

Late Night/Early Sunday Morning...
The overnight/early Sunday morning thunderstorms will likely be
in the form of a MCS/QLCS with the main threat by the time they
reach our area being heavy rain (localized flash flooding) and
strong to severe wind gusts. Can not rule out a weak QLCS
tornado within the line of stronger winds given backed low
level winds (strong shear) but that is a small chance given
fairly stable low level environment. Precipitable water values
remain impressive (90-99th percentile) with readings over 2
inches possible. Therefore, we have that flood watch out for the
possibility of flash flooding.

Sunday Afternoon...
Thunderstorms are expected to redevelop early Sunday afternoon
(1-2 PM) along the cold front around the KC area and then track
southeast through the remainder of the afternoon. We are under a
slight risk for severe thunderstorms with the main threats being
severe hail and winds. The surface winds veer Sunday afternoon
along the cold front becoming more southwesterly, which will
limit any tornado threat across our area. Heavy rain will
continue to be a primary concern especially if we see training
storms along and just ahead of the cold front.

&&

.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 206 PM CDT Sat Jun 20 2026

The big story will be the cooler temperatures across the area
behind the cold front with highs only in the 70s on Monday and
Tuesday. Even Wednesday through Friday should remain rather nice
with highs in the upper 70s to lower 80s until we start to warm
up next weekend. The pattern also turns drier with no rain to
maybe 20 percent chances through much of the week (Monday -
Thursday). The next storms system could arrive around
Friday/Saturday, but only 20-40 percent rain chances at this
point in time with a lot of uncertainty that far out. Most of
my time today has been focused on our more active short term
period through Sunday.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 633 PM CDT Sat Jun 20 2026

Quiet to start the forecast period with a sector of storms currently
over SE KS. Latest trends have been for a weakening trend and a
shift to the east as they progress. However, if they hold together
they would reach the terminals between 2-3Z. The main show still
looks to arrive after midnight with widespread heavy rain and
thunderstorms. An MCS is projected to develop over KS and could lead
to a swath of damaging winds impacting the terminals. Timing of when
storms and showers leave remains contested among the high res
guidance with the general consensus being in the late morning to
early afternoon hours. Depending on how things evolve through the
overnight hours, an additional round of strong to severe storms
could develop tomorrow afternoon. However, most guidance has this
firing off a boundary that would be south of the terminals.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Flood Watch through Sunday evening for MOZ001>008-011>017-
     020>025-028>033-037>040-043>046-053-054.
KS...Flood Watch through Sunday evening for KSZ025-057-060-102>105.

&&

$$

SHORT TERM...Wesely
LONG TERM...Wesely
AVIATION...Britt