890
FXUS63 KEAX 191001
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
501 AM CDT Thu Sep 19 2024

.KEY MESSAGES...

- Showers and storms this morning. Strong to severe storms are
  unlikely with this early activity.

- Another round of storms is likely late this afternoon to evening.
  Strong to severe storms are possible with this activity.

- Widespread and much needed rainfall is likely this weekend with
  multiple rounds of showers and storms likely.

&&

.DISCUSSION...
Issued at 227 AM CDT Thu Sep 19 2024

Strong moisture transport and ascent along the 310K surface will
lead to scattered showers and storms developing over central/eastern
KS early this morning. This activity will spread east into far
eastern KS and western MO in the predawn hours through mid to late
morning. The threat of severe storms with this morning activity
looks low with MUCAPE between several hundred J/kg and about 1000
J/kg. Effective shear also looks marginal given the elevated nature
to the activity.

As the day progresses, morning convection will wane and strong
heating will lead to temperatures soaring into the low to mid 90s,
especially in our southern and southwestern zones where less cloud
cover is expected from the morning convection. This strong heating,
coupled with anomalously high moisture, will result in a very
unstable air mass by the afternoon/ evening hours. SBCAPE values
will almost certainly (>95%) exceed 1000 J/kg and likely (>70%) be
in excess of 2000 J/kg this afternoon. With mid and upper-level flow
increasing from the northwest through the day, deep-layer shear will
very likely (>80%) exceed 30kts. There is still decent curvature in
the low-level hodographs and a lengthy upper-level tail due to the
increasing northwest flow. Given the magnitude of the shear and the
curved hodographs, supercell structures look possible. This would
support the potential for large hail. But the limiting factor for
that appears to be relatively poor 700-500mb lapse rates. Lower-
level lapse rates are much steeper though and that would support
damaging winds. Also can`t rule out a tornado given the possibility
for some supercells and the low-level helicity noted by the curved
hodographs.

Friday looks like a relative lull in the active weather that will
uptick again late Friday night into Saturday. The front the helps
trigger the activity Thursday afternoon/ evening, should settle
south of the area Friday, with drier air through most of the
day. However, the front will lift northward Friday night in
response to a mid-level shortwave moving across KS. This will
lead to a strong low-level jet with convection most likely
developing in central KS and spreading east early Saturday
morning. Another round of storms looks likely Saturday night
into Sunday as a stronger shortwave beings to move into the
Plains. Similar to the night before, a strong low-level jet
develops and interacts with the boundary in the area, leading
another round of storms. Precipitable water values across
northern MO/ northeastern KS are forecast to be 2-3 standard
deviations above normal and are in the 97.5 percentile for the
NAEFS climate forecast system reanalysis. Given the anomalous
moisture with the system, heavy rainfall is likely. Across
northern MO, generally north of the Missouri River, forecast
rain amounts for the weekend, from 00Z Saturday through 12Z
Monday, are in excess of 3", with 1-2" amounts south of the
river. Given the extremely dry conditions and the resulting
developing drought, headwater guidance will likely not be
exceeded. Flash flood guidance is generally 2.5-5" for the 1hr
to 6hr time frame. Given this, the threat of flash and river
flooding looks low.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 458 AM CDT Thu Sep 19 2024

A line of storms has filled in over eastern KS and is slowly
tracking to the east. It`s not certain that these storms will
survive far enough east to impact the terminals. But they`re
close enough that have added several hours of storms this
morning to all sites. Essentially 12Z-15Z based on timing the
leading storms ahead of the line and the back edge of the line
of storms for the ending time. There will likely be brief
visibility and ceiling restrictions if these storms how together
into the terminals. Another round of storms is possible this
evening. For now, the VCTS group looks reasonable at 00Z.

&&

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

&&

$$

DISCUSSION...CDB
AVIATION...CDB