767
FXUS63 KTOP 051111
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
611 AM CDT Sun May 5 2024

.KEY MESSAGES...

- Confidence continues to increase in a line of severe thunderstorms
Monday afternoon into Monday night. Large hail, damaging winds, and
tornadoes will be possible.

- Gradual cooler and quieter trend for the second half of the
  week.

&&

.DISCUSSION...
Issued at 407 AM CDT Sun May 5 2024

Water vapor imagery this morning shows a weak convectively enhanced
shortwave over Oklahoma and Texas, with a much stronger upper low
moving onto the West Coast. The first system will mostly remain to
our south, keeping just a few showers over portions of east-central
Kansas today. No severe weather is expected, as lack of appreciable
instability will limit things to a few rumbles of thunder at most.
Increasing cloud cover will tend to keep highs in the 60s,
especially south of I-70.

Monday continues to be the main day of concern as the deep upper low
to our west approaches. Low pressure initially deepens Sunday night
over the High Plains before pushing a cold front east on Monday.
Convection looks to initially develop early to mid afternoon across
central Kansas as the front overtakes a dryline set up over the
area. 2000 J/kg of ML CAPE and 40-50 kts of effective shear should
result in initial supercells capable of very large hail and a few
tornadoes. However the stronger frontal forcing, along with
initially weaker/messier low-level shear, will tend to result in
upscale growth rather quickly. So by late afternoon and evening,
expecting more of a line of storms that will be marching
east/northeast across the area. The low-level shear does increase
over time, especially into the evening. This will increase the
tornado threat with any still semi-discrete supercells or any QLCS
segment that is oriented more N/S, better aligned to the 0-3 km
shear vector. The damaging wind risk will also increase with time
and eastern extent as convection grows upscale. Still some questions
with how far east/west storm initially form and how low-level shear
affects upscale growth. Storm-scale interactions will likely play
some role in the overall magnitude of the severe threat, and much of
this may not be known until the event begins to unfold. The threat
does look to subside after midnight as storms shift east of the area
and cooler/drier air gradually moves in from the west.

The pattern gradually turns cooler and quieter through the end of
the week as the large upper low slowly shifts east. One secondary
shortwave trough Tuesday night into Wednesday does offer a better
chance at a few more showers and thunderstorms. A majority (75%) of
ensemble guidance does still keep the unstable sector south of the
front to our south and east. Assuming this holds and there isn`t
a slight retreat in moisture towards the I-35 corridor, this
would keep the main severe weather threat just to our southeast.
Following this secondary shortwave, temperatures fall back to
near or slightly below average through the start of the weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 610 AM CDT Sun May 5 2024

Southeast winds below 10 kts will persist today and through tonight.
Ceilings stay VFR through most of the daytime today, but MVFR to
eventually IFR ceilings will increase from the south late this
evening and overnight. Some light mist/drizzle will be possible
towards the end of the period, though confidence in this is not very
high at the moment.

&&

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

&&

$$

DISCUSSION...Reese
AVIATION...Reese