417
FXUS63 KEAX 130828
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
Issued by National Weather Service Springfield MO
328 AM CDT Tue Aug 13 2024

.KEY MESSAGES...

- A cluster of storms will move into western Missouri this
  morning. Gusty winds, lightning, and moderate to locally heavy
  rainfall are the primary hazards.

- A narrow swath of storms to develop across northwest Missouri
  tonight into Wednesday morning. Uncertainty remains on exact
  positioning, and there is a Slight risk (2 of 4) for
  excessive rainfall with this activity.

- A chance for severe weather Wednesday afternoon/evening.
  Strong to damaging winds seem to be the primary hazard at this
  time.

&&

.DISCUSSION...
Issued at 133 AM CDT Tue Aug 13 2024

Current Conditions and Synoptic Overview:
Regional observations and nighttime microphysics imagery show
low stratus clouds overspreading the region early this morning.
With persistent low-level moisture, further reductions to
ceilings will continue through sunrise. The latest HREF
probabilities of visibilities less than 1 mile are across
southern Iowa and northern Missouri, prompting a Dense Fog
Advisory until 7 AM for locations north of the Kansas City
metro. Water vapor imagery depicts broad upper-level ridging
across the Plains. A shortwave impulse has aided in convective
development earlier in the evening across the High Plains, which
will continue to gradually shift east through Kansas and into
Missouri this morning. This activity should gradually weaken as
instability wanes, though with 0-3 km bulk shear of 20-30 kt and
0-3 km theta-e differences around 20-25 degrees, gusty winds
will remain possible. Corfidi and forward- propagating vectors
suggest the remnants of this cluster begin to turn more
southeasterly as they cross into Missouri, which may keep the
strongest activity south of the Kansas City metro.

Heavy Rain and Severe Thunderstorm Potential Tuesday Night into
Wednesday Morning:
The aforementioned upper-level ridge will continue to shift east
through the Plains today. At the surface, a warm front will lift
north into central Kansas. CAMs develop a corridor of 2000-2500
J/kg MUCAPE across northwest MO by Tuesday night, which could
aid in the development of a few strong to marginal severe
updrafts capable of producing gusty winds and hail northeast of
the boundary. Of greater concern, however, may be the heavy rain
potential. Recent runs of the CAMs have been fairly consistent
in orienting these storms in a northwest to southeast swath from
southeast Nebraska down through Missouri Tuesday night into
Wednesday morning. Moisture will certainly not be lacking, with
forecast PWATs of 2.0-2.2" and 850 mb dew points of 15-18
degrees being anomalously high relative to climatology. Thus,
these storms will be efficient rainfall makers. The latest HREF
LPMM shows a fairly narrow swath of rainfall totals of 2-4
inches. It should be noted that a fair amount of uncertainty
exists in QPF location, though, as hi- res guidance has
disagreed in specific placement and has wobbled from run- to-
run. Rainfall totals will likely vary significant across
relatively short distances, and some locations may see little
rainfall. This uncertainty has precluded any Flood Watch
issuance with this forecast package, though one may be needed in
a future update if confidence in location grows. Three-hour
flash-flood guidance ranges from 2 inches northeast of the
Kansas City metro, to 3-3.5 inches elsewhere, therefore,
locations that have received heavy rainfall in the recent days
may be better primed for flooding. The Weather Prediction Center
has maintained a Slight risk of Excessive Rainfall.

Heat and Storms Wednesday:
As the aforementioned warm front continues to lift north, warm,
humid air will expand into the region. High temperatures in the
low to mid 90s and dew points in the mid 70s would support a
corridor of heat index values in the 100-105+ degree range,
generally south of I-70 and along I-49. By late afternoon, a
weak surface low should help initiate convection over eastern
Nebraska and northeast Kansas. Ample instability and sufficient
shear may support the potential for the development of more
robust and sustained updrafts. However, this potential is
conditional on diurnal recovery from the morning activity. The
Storm Prediction center has outlined portions of far northwest
Missouri and northeast Kansas in a Slight risk, with a Marginal
risk elsewhere.

Additional chances for showers and thunderstorms will exist
through the end of the week with shortwave impulses transiting
the northern Plains and Midwest. NBM interquartile ranges also
generally decrease through the period, with forecast highs in
the 80s each day.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1226 AM CDT Tue Aug 13 2024

Observations have shown clouds gradually lowering to MVFR to
near-IFR at the beginning of the TAF period. Ceilings are
expected to deteriorate to MVFR and IFR through the first
several hours of the forecast period. Areas of fog/low stratus
have also developed across portions of southern Iowa and and
eastern Missouri.

A complex of showers and thunderstorms will approach the TAF
sites after 12Z and is expected to weaken as it does so.
Therefore, confidence was too low to include any mention of
lightning in the current TAFs, but future amendments are
possible.

Light east-northeasterly winds around 5-7 kt will shift more
southeasterly after 18Z.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Dense Fog Advisory until 7 AM CDT this morning for MOZ001>008-
     011>017-020>025-032-033-040.
KS...Dense Fog Advisory until 7 AM CDT this morning for KSZ025-102.

&&

$$

DISCUSSION...WFO Springfield
AVIATION...WFO Springfield