708
FXUS63 KTOP 250850
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
350 AM CDT Sat May 25 2024

.KEY MESSAGES...

- The potential for a higher-end severe weather event remains this
  evening into early Sunday. Damaging wind gusts, large hail,
  and a few tornadoes are all possible.

- Thunderstorms chances continue through Sunday before drier and
  quieter conditions are expected Memorial Day through at least
  Tuesday.

&&

.DISCUSSION...
Issued at 350 AM CDT Sat May 25 2024

All is quiet across the region this morning with surface high
pressure positioned over the central Plains. A shortwave is
progressing east towards the Four Corners and will be the instigator
of this evening`s severe weather event. As this wave approaches the
Plains through the day, winds become south-southeasterly and a
surface low deepens across eastern Colorado and western Kansas.
Models continue to vary on the degree of low-level moisture return
during the afternoon and evening as a warm front lifts north.
Consensus shows dewpoints in the low to upper 60s across northeast
Kansas by later this evening (7-9pm) with some low 70 dewpoints
across southern Kansas. CAMs are generally in agreement with
convective initiation occurring in the 6-8pm timeframe across
western and central Kansas as the wave ejects across the area
and sufficient moisture makes it into the region. Supercells are
likely initially given the robust shear/instability parameter
space and have a high probability of producing large to giant
hail and damaging wind gusts. The uncertainty surrounding the
quality of low-level moisture leads to some questions around the
tornado potential especially with northern extent, but low-
level hodographs elongating and veering with time during the
evening and overnight certainly support tornadoes, perhaps even
strong tornadoes, if quality moisture is in place. Storm
evolution beyond into the late evening and early morning hours
Sunday remains somewhat uncertain, but increased ascent from the
passing wave is expected to transition convection to a linear
mode. CAMs show a wide range in potential locations of this line
of storms, but the most favorable location should be along the
nose of the low-level jet which is progged to be somewhere
between the Kansas/Oklahoma state line and Interstate 70.
Damaging winds of 60-80mph become more of a concern once an MCS
develops with a continued tornado threat given the degree of
low-level shear. There is a signal for storm motions to become
parallel to the boundary as the LLJ continues to pump moisture
into the region which would increase the potential for flooding.
HREF LPMM precipitation shows the potential for 2-4 inches of
rain in a couple hour period if storms can train/back build.

Even with the severe event ~18 hours out, uncertainty remains in key
aspects of the event including location of strongest storms and
timing. Some of these (on the synoptic and mesoscale) will
become clearer through the day today, but others (storm scale
interactions) will not be known until storms develop. The bottom
line is that the environment will be favorable for severe
weather this evening and tonight, including the potential for
significant severe weather, so stay weather aware and have
multiple ways to receive warnings especially at night.

The surface low continues its east-southeast progression on Sunday
as another trough ejects across the Plains. Steep mid-level lapse
rates on the backside of the low lead to MUCAPE of 1000-1500 J/kg
with effective shear of 20-30kts. This could lead to the development
of strong to severe storms Sunday afternoon capable of producing
large hail, but this will be dependent on how convection Sunday
morning evolves. Dry conditions are favored for Monday and Tuesday
as northwest flow sets up across the Central Plains. A couple of
passing perturbations lead to chances for showers and storms
Wednesday through Friday, but variability is high this far out.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1231 AM CDT Sat May 25 2024

Light easterly winds tonight increase from the SSE through the
day with gusts of 20-25kts this afternoon-evening. Storms are
expected to develop across central Kansas and move towards
terminals late in the period. Confidence in timing and coverage
is low, so mentioned VCTS with this issuance; refinement will
be needed with subsequent forecasts.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Flanagan
AVIATION...Flanagan