036
FXUS63 KTOP 202309
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
609 PM CDT Thu Jun 20 2024

.KEY MESSAGES...

- Isolated showers and storms possible across far
eastern/northeastern Kansas this afternoon (15-20%)

- Hot and muggy conditions continue over the next week with
Saturday, Monday and Tuesday seeing the highest heat indices.

- Rain and storm chances return Saturday afternoon and evening, some
becoming strong to severe.

&&

.DISCUSSION...
Issued at 248 PM CDT Thu Jun 20 2024

Happy Summer solstice! A hot and muggy solstice is underway across
northeastern Kansas as a large upper level ridge set up over the
southeastern US keeps a warm and moist air mass near the surface.
PBL mixing this afternoon has led to a widespread cu field,
especially south of a weak surface boundary that has slowly pushed
its way north towards the Topeka area. Enhanced convergence along the
boundary can be seen on visible satellite imagery as a few
thunderstorms have developed over northern MO where surface
convergence has helped to lift parcels to their LFC. Over the
remainder of the afternoon, isolated showers and a thunderstorm or
two will be possible (15-20%) across eastern KS, especially where cu
can congeal enough to tap into the elevated instability. ML lapse
rates will remain weak, promoting weaker updrafts, and with little
shear to work with, not expecting any severe storms this afternoon
or evening. High temperatures area-wide will top out in the low 90s
with temperatures falling back into the low 70s by sunrise Friday
morning. Cannot rule out some patchy fog development Friday morning,
mainly in low-lying areas, but not confident in any widespread
development.

Similar conditions can be expected over the afternoon Friday with
highs reaching the low 90s and a slight chance for an isolated
storm. Confidence in storm development Friday afternoon is a bit
lower than this afternoon as lift will be limited and diffuse. Most
areas will remain dry, but cannot rule out an isolated (10-15%) non-
severe shower/storm.

Come Saturday, the upper-level ridge retrogrades west towards Texas
as vorticity maximums associated with a deamplifying trough across
the western CONUS advect east of the Rockies. A deepening lee
cyclone Saturday afternoon will push its way across northern Kansas,
increasing chances for rain and storms for northeastern KS by the
afternoon and evening. A few storms that can develop along the
boundary Saturday afternoon and evening could become strong to
severe with the presence of 0-6 km shear ranging from 30-35 knots
and SBCAPE between 1200-2000 J/kg. Hazards with the strongest storms
would be hail up to the size of quarters and damaging winds to 60
mph. Ahead of the boundary, southwesterly low-level flow will help
to advect in hot 850mb temps leading to afternoon highs warming into
the mid to upper 90s. With dewpoints still hovering in the low 70s,
heat indices will approach advisory criteria.

The remainder of the weekend and into early next week will remain
fairly dry with oppressive heat building back into the area by
Monday and Tuesday with the continued retrogression of the mid-level
ridge. Upper 90s to low 100s will be expected across the area and
with the humidity still in the area, heat indices will approach 110-
115 degrees. The heat does not appear to last into Wednesday as mid-
level energy rounding the ridge axis pushes a surface boundary
across the area Tuesday evening, shifting winds to the northwest and
increasing precipitation chances across the area.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 609 PM CDT Thu Jun 20 2024

VFR conditions are expected. Isolated showers and perhaps a
thunderstorm are possible through 02Z then again after 18Z. A
more mixed boundary layer today and through the night should
keep diurnal BR formation in check.

&&

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

&&

$$

DISCUSSION...Griesemer
AVIATION...Poage