486
FXUS63 KLSX 010339
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1039 PM CDT Tue Apr 30 2024

.KEY MESSAGES...

- Thunderstorms may remain strong or marginally severe as they
  enter northeast Missouri and west central Illinois late this
  evening. Wind gusts to 60 mph and perhaps hail up to the size of
  quarters will be the threat.

- A renewed threat of numerous showers and thunderstorms arrives Thursday
  afternoon, with a MARGINAL RISK of severe thunderstorms across
  the western portion of the CWA.


&&

.SHORT TERM...  (Through Late Wednesday Night)
Issued at 200 PM CDT Tue Apr 30 2024

An active spring weather pattern will continue for the foreseeable
future with a parade of shortwaves marching across the center of the
CONUS. In the near term (next few days) the highest threat of severe
thunderstorms remains to our west, but there are indications in the
longer range guidance that by early next week we may be in the thick
of it again.

The first shortwave we will focus on is currently moving across the
Plains and into the upper Midwest. An accompanying cold front will
continue to move southeast and provide the focus for thunderstorms
to develop across eastern Nebraska, western Iowa, northeast KS and
northwest MO this evening. Some of these thunderstorms will
become severe. As they move east/southeast and congeal into a line
along the front they will likely weaken as diurnal instability
wains. Nevertheless, we can`t rule out one or two of them
remaining strong/severe as they cross the CWA border into
northeast MO after 10 PM. The threats with any storm that remains
severe would be marginal hail and wind gusts to 60 mph.

The cold front will stall across the CWA on Wednesday and set the
stage for isolated to widely scattered thunderstorm chances during
the afternoon and evening. The consensus of model guidance has this
occurring across the Ozarks. Forecast values of instability and
shear do not support widespread severe thunderstorms, but a few
could be strong. High temperatures tomorrow will range from the
middle 70s north of the front to the upper 80s to the south of the
front. Chances of showers and thunderstorms increase Wednesday
night as the front starts to advance back north as a warm front.

CVKING

&&

.LONG TERM...  (Thursday through Next Tuesday)
Issued at 200 PM CDT Tue Apr 30 2024

The next shortwave and cold front will bring a renewed threat of
showers and thunderstorms to the region on Thursday/Thursday night.
While subtle timing difference are noted in the plethora of
guidance, the overall consensus is that a band of showers and
thunderstorms will develop and move west to east across the CWA
during the afternoon. SPC currently has the western portion of the
CWA outlooked in a Marginal Risk which matches well with the
instability and shear values forecast. Temperatures will range
from near 80 degrees in central MO, while the eastern CWA climbs
into the middle to upper 80s ahead of the front.

The probability of precipitation decreases on Friday as the cold
front moves east of the area followed by weak and temporary high
pressure settling across the lower Missouri and middle Mississippi
River Valleys. Some of the NBM membership has a slower departure
of the front and therefore POPs linger longer than I would
suspect. Friday`s high temperatures will be slightly cool with
middle to upper 70`s forecast.

The dry weather will not last long as a series of shortwaves in
southwest flow aloft will bring renewed chances of showers and
thunderstorms through the weekend and into next week. Temperatures
will remain seasonal with highs in the upper 70s/lower 80s and lows
in the 50s/60s.  Latest extended guidance from St. Louis University
CIPS and Colorado State University shows a pattern supportive of
severe thunderstorms in the CWA next week.

CVKING

&&

.AVIATION...  (For the 06z TAFs through 06z Wednesday Night)
Issued at 1034 PM CDT Tue Apr 30 2024

The earlier storms moving eastward across Missouri toward the
local terminals have mostly dissipated, and are expected to have
nearly completely dissipated by the start of the TAF period. KUIN
may see a glancing blow by some remnant showers, but confidence in
that occurring remains low at the moment. I also can`t rule out
rain at KCOU and/or KJEF near the start of the period, but
confidence in that occurring is even lower than at KUIN.
Otherwise, dry and VFR flight conditions are expected through a
majority of the TAF period. Showers and thunderstorms may threaten
the area near the end of the period, but details in timing and
location relative to terminals is unclear at this time.

Elmore

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

$$

WFO LSX